High-efficiency catalytic light olefin catalytic cracking aid and preparation method thereof

Abstract

The application discloses a high-efficiency catalytic light olefin catalytic cracking aid and a preparation method thereof. The aid is composed of acid-treated ZSM-5 molecular sieves with a silicon-aluminum ratio of 20-40 and mesoporous SiO2, the molecular sieves are in situ embedded in the mesoporous SiO2 framework and pore surface in the form of nanoparticles, and there is no agglomeration. The preparation method comprises SiO2 sol preparation, molecular sieve ultrasonic dispersion, mixed gel, hydrothermal reaction and calcination. The aid forms a "micropore-mesopore" multi-level structure, solves the problems of agglomeration, pore blockage and component separation of traditional physical mixed materials, and improves the catalytic efficiency and stability. In application, the conversion rate of n-heptane is more than 80%, the total yield of light olefins is more than 40%, the stability is good after 10 hours of continuous reaction at 550 DEG C, the process is simple and controllable, and is suitable for industrialization.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical catalysts, and particularly relates to a high-efficiency catalytic light olefin catalytic cracking additive and a preparation method thereof. Background Art

[0002] Light olefins (ethylene, propylene, and butene), as a key platform chemical, play an indispensable role in modern industrial systems. They are core raw materials for the production of cosmetics, lubricants, synthetic rubber, detergents, and various polymers (such as polyethylene and polypropylene). Their market demand is growing with the continued expansion of downstream industries, and they hold crucial strategic significance in the global chemical industry chain.

[0003] Currently, the industrial production of light olefins still relies primarily on the naphtha fluid catalytic cracking (FCC) process, which has developed into a relatively mature technical system after long-term development. However, the catalysts used in the traditional FCC process have exposed many problems that need to be solved in the actual reaction process: on the one hand, the pore structure within the catalyst often has a mass transfer and diffusion bottleneck, which limits the migration efficiency of reactants and products within the catalyst, affecting the reaction rate; on the other hand, the lack of selectivity for the target product light olefins leads to an increase in by-products and reduces the utilization efficiency of the raw materials; in addition, the catalyst is prone to poor stability during long-term operation due to problems such as carbon deposition and loss of active components, requiring frequent regeneration or replacement. This not only increases production costs but also restricts the continuity and efficiency of the production process, making it difficult to meet the current chemical industry's demand for efficient and low-cost production of light olefins.

[0004] Among the many catalytic materials, zeolite catalysts, with their unique microporous structure and abundant acid active sites, have demonstrated excellent performance in catalytic cracking reactions and are widely used as catalyst additives to improve reaction efficiency. Among them, ZSM-5 zeolite, due to its medium pore size (approximately 0.5-0.6 nm), can effectively promote the unimolecular cracking mechanism in catalytic cracking reactions and significantly inhibit the occurrence of multimolecular side reactions, thereby helping to improve the selectivity of light olefins. It has attracted much attention in related research and applications. However, it cannot be ignored that the inherent microporous structure of zeolite materials (pore size is usually less than 2 nm) still has obvious diffusion limitations for relatively large reactant molecules (such as heavy hydrocarbons), making it difficult for such reactants to reach the active sites smoothly, thereby affecting the overall efficiency of the catalytic reaction.

[0005] To improve the mass transfer performance of catalysts, mesoporous silica has become a research hotspot due to its large specific surface area (typically reaching hundreds of square meters per gram) and regular mesoporous structure (pore diameters ranging from 2 to 50 nm). Its open pore structure provides a smoother path for the diffusion of reactants and products, theoretically effectively alleviating the problem of limited mass transfer.

[0006] However, the traditional mesoporous silica-zeolite composite catalyst prepared by physical mixing has exposed a series of defects in practical applications: the mesoporous silica and zeolite are only bonded by physical forces, the interfacial interaction is weak, and component separation is likely to occur during the reaction, resulting in the destruction of the overall structure of the catalyst and a significant decrease in stability; at the same time, if the dispersion process is not properly controlled during the composite process, the zeolite molecular sieve is prone to agglomeration, causing a large number of active sites to be wrapped and unable to participate in the reaction, reducing the utilization rate of the active sites; in addition, the agglomerated molecular sieve particles may also block the pores of the mesoporous silica, which in turn weakens its originally excellent mass transfer performance, making it difficult to achieve a synergistic improvement in catalytic activity and mass transfer efficiency. Summary of the Invention

[0007] The present invention aims to overcome the shortcomings of the prior art and provide a highly efficient light olefin catalytic cracking additive and its preparation method. By regulating the surface properties of the molecular sieve, the state of the mesoporous sol, and the composite process, the problems of agglomeration, pore blockage, and weak interface bonding are solved.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A method for preparing a high-efficiency catalytic light olefin catalytic cracking additive comprises the following steps:

[0010] S1. Mix tetraethyl orthosilicate, a template, anhydrous ethanol, dilute nitric acid, and deionized water, and stir at 50-60°C for 2-3 hours to obtain a SiO2 sol;

[0011] S2, mixing the ZSM-5 molecular sieve and the dispersion liquid at a mass ratio of 1:20-30, and ultrasonically dispersing for 20-30 minutes to obtain a modified molecular sieve dispersion;

[0012] S3. Slowly add 20 mL of the modified molecular sieve dispersion in step S2 to 40-60 mL of the mesoporous SiO2 sol obtained in step S1. After the addition is completed, stir at 40-60°C for 1 hour to obtain a mixed sol. Then adjust the stirring speed to 1000-1500 r / min and add 5-6 mL of ammonia water to gel.

[0013] S4. Crush 10 g of gel, add 20 mL of deionized water, transfer to a hydrothermal reactor, conduct hydrothermal reaction at 140-160° C. for 12-24 hours, cool and centrifuge, wash to neutrality, dry and calcine at 500-600° C. for 4-6 hours to remove the template to obtain a catalytic cracking aid.

[0014] Ultrasonic treatment can effectively break up the agglomeration of molecular sieves and make small-sized molecular sieve particles evenly dispersed. The ZSM-5 molecular sieve is mixed with the dispersion liquid at a mass ratio of 1:20~30, which not only ensures the dispersion effect but also avoids secondary agglomeration caused by excessive concentration.

[0015] When modified molecular sieves are added to a mesoporous SiO2 sol, their large size makes them easily settle at the bottom, resulting in uneven distribution. By increasing the stirring speed and adding ammonia to the sol to gel, the modified molecular sieve particles are more evenly embedded in the mesoporous silica precursor network. Furthermore, the volume ratio of the modified molecular sieve dispersion to tetraethyl orthosilicate is 1:2-3, which ensures sufficient active sites while preventing excessive clogging of the mesopores by the molecular sieve.

[0016] The hydrothermal reaction causes the mesoporous structure to grow further in an orderly manner and form a stable interface with the molecular sieve.

[0017] The invention is further preferred as a method for preparing a highly efficient catalytic light olefin catalytic cracking aid.

[0018] Preferably, the added amounts of tetraethyl orthosilicate, template, anhydrous ethanol, dilute nitric acid, and deionized water in step S1 are: 15 mL, 1-2 g, 30 mL, 2 mL (concentration 1 mol / L), and 5-10 mL, respectively.

[0019] Preferably, in step S1, the template agent is polyethylene glycol 600 (PEG-600);

[0020] Preferably, in step S2, the silicon-aluminum ratio of the ZSM-5 molecular sieve is 20-40;

[0021] Preferably, in step S2, the dispersant solution is an anhydrous ethanol solution of silane coupling agent KH560 with a mass fraction of 0.8-1.2%.

[0022] According to the above preparation method, a highly efficient catalytic light olefin catalytic cracking aid is obtained.

[0023] The present invention also provides an application of a high-efficiency catalytic light olefin catalytic cracking additive in the production of light olefins.

[0024] The beneficial effects of the present invention compared to the prior art are:

[0025] (1) We innovatively propose a composite structure in which molecular sieve nanoparticles are in situ embedded in the mesoporous SiO2 framework and pore surface, breaking through the structural limitations of traditional physical hybrid materials. This design not only retains the microporous active sites of the ZSM-5 molecular sieve (ensuring catalytic selectivity), but also leverages the open pores of the mesoporous SiO2 to address the mass transfer and diffusion bottleneck. In practical applications, the n-heptane conversion rate can reach over 80%, and the total light olefin yield reaches over 40%, achieving a significant improvement in catalytic efficiency.

[0026] (2) By combining ultrasonic dispersion with in-situ sol-gel method, supplemented by silane coupling agent modification and hydrothermal reaction, a strong interfacial bonding between molecular sieve and mesoporous SiO2 is achieved, effectively avoiding problems such as agglomeration, pore blockage and component separation. This process enables the molecular sieve to be evenly dispersed in the form of nanoparticles with a complete mesoporous structure. At the same time, a stable chemically bonded interface is formed through hydrothermal reaction, which significantly enhances the stability of the catalyst. After continuous reaction at 550°C for 10 hours, the instantaneous conversion rate still remains above 80% of the initial value, reducing the regeneration frequency and production cost.

[0027] (3) By combining the high catalytic selectivity of ZSM-5 molecular sieve with the high mass transfer efficiency of mesoporous SiO2, and by regulating key parameters such as the silicon-aluminum ratio, dispersion ratio, and stirring speed, the synergistic improvement of light olefin yield, feedstock conversion rate, and catalyst stability can be achieved, thus solving the difficult problem of "activity-selectivity-stability" that is difficult to balance in traditional catalysts. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Transmission electron microscopy (TEM) images of the catalyst promoter prepared in Example 1: (a) is a low-magnification TEM image, and (b) is a high-resolution TEM image;

[0029] Figure 2 1 is a microscope photo and energy spectrum analysis picture of the catalyst promoter prepared in Example 1;

[0030] Figure 3 These are microscope photos and energy spectrum analysis images of the catalyst promoter prepared in Comparative Example 1;

[0031] Figure 4 is the N2 adsorption-desorption isotherm of the catalyst promoters prepared in Example 1 and Comparative Example 1;

[0032] Figure 5 is a transmission electron microscope photograph of the catalyst promoter prepared in Comparative Example 3;

[0033] Figure 6 is a bar graph of n-heptane conversion and total light olefin yield after the application of the catalytic promoter in Examples 1 to 3 and Comparative Examples 1 to 3;

[0034] Figure 73 is a curve showing the change of instantaneous conversion rate over time after the application of the catalyst promoter in Examples 1 to 3 and Comparative Examples 1 to 3. DETAILED DESCRIPTION

[0035] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, the following detailed description of the specific embodiments of the present invention is given in conjunction with the following embodiments. The following is merely an example and illustration of the concept of the present invention. Those skilled in the art may make various modifications, additions, or substitute similar methods for the specific embodiments described, and as long as they do not deviate from the concept of the invention, they shall fall within the scope of protection of the present invention.

[0036] The above preparation method of the present invention is described below through specific examples and comparative examples.

[0037] Example 1

[0038] A method for preparing a high-efficiency catalytic light olefin catalytic cracking additive comprises the following steps:

[0039] S1. Mix 15 mL of tetraethyl orthosilicate, 1 g of PEG-600, 30 mL of anhydrous ethanol, 2 mL of dilute nitric acid (concentration 1 mol / L), and 5 mL of deionized water, and stir at 50 °C for 2 h to obtain SiO2 sol;

[0040] S2, mixing the ZSM-5 molecular sieve and the dispersion liquid at a mass ratio of 1:20, and ultrasonically dispersing for 20 minutes to obtain a modified molecular sieve dispersion liquid; wherein the dispersant solution is a silane coupling agent KH560 anhydrous ethanol solution with a mass fraction of 0.8%;

[0041] S3. Slowly add 20 mL of the modified molecular sieve dispersion in step S2 to 40 mL of the mesoporous SiO2 sol obtained in step S1. After the addition is completed, stir at 40°C for 1 hour to obtain a mixed sol. Then adjust the stirring speed to 1000 r / min and add 5 mL of ammonia water to make it gel.

[0042] S4. Crush 10 g of gel, add 20 mL of deionized water, transfer to a hydrothermal reactor, conduct hydrothermal reaction at 140° C. for 12 h, cool and centrifuge, wash to neutrality, dry and calcine at 500° C. for 4 h to remove the template, and obtain a catalytic cracking aid.

[0043] Example 2

[0044] A method for preparing a high-efficiency catalytic light olefin catalytic cracking additive comprises the following steps:

[0045] S1. Mix 15 mL of tetraethyl orthosilicate, 1.5 g of PEG-600, 30 mL of anhydrous ethanol, 2 mL of dilute nitric acid (concentration 1 mol / L), and 7 mL of deionized water, and stir at 55 °C for 2.5 h to obtain SiO2 sol;

[0046] S2, mixing the ZSM-5 molecular sieve and the dispersion liquid at a mass ratio of 1:25, and ultrasonically dispersing for 25 minutes to obtain a modified molecular sieve dispersion liquid; wherein the dispersant solution is a 1.0% by mass silane coupling agent KH560 anhydrous ethanol solution;

[0047] S3. Slowly add 20 mL of the modified molecular sieve dispersion obtained in step S2 to 50 mL of the mesoporous SiO2 sol obtained in step S1. After the addition is completed, stir at 50°C for 1 hour to obtain a mixed sol. Then adjust the stirring speed to 1200 r / min and add 5.5 mL of ammonia water to make it gel.

[0048] S4. Crush 10 g of gel, add 20 mL of deionized water, transfer to a hydrothermal reactor, conduct hydrothermal reaction at 150° C. for 16 h, cool and centrifuge, wash to neutrality, dry and calcine at 550° C. for 5 h to remove the template, and obtain a catalytic cracking aid.

[0049] Example 3

[0050] A method for preparing a high-efficiency catalytic light olefin catalytic cracking additive comprises the following steps:

[0051] S1. Mix 15 mL of tetraethyl orthosilicate, 2.0 g of PEG-600, 30 mL of anhydrous ethanol, 2 mL of dilute nitric acid (concentration 1 mol / L), and 10 mL of deionized water, and stir at 60 °C for 3.0 h to obtain SiO2 sol;

[0052] S2, mixing the ZSM-5 molecular sieve and the dispersion liquid at a mass ratio of 1:30, and ultrasonically dispersing for 25 minutes to obtain a modified molecular sieve dispersion liquid; wherein the dispersant solution is a silane coupling agent KH560 anhydrous ethanol solution with a mass fraction of 1.2%;

[0053] S3. Slowly add 20 mL of the modified molecular sieve dispersion in step S2 to 60 mL of the mesoporous SiO2 sol obtained in step S1. After the addition is completed, stir at 60°C for 1 hour to obtain a mixed sol. Then adjust the stirring speed to 1500 r / min and add 6.0 mL of ammonia water to make it gel.

[0054] S4. Crush 10 g of gel, add 20 mL of deionized water, transfer to a hydrothermal reactor, conduct hydrothermal reaction at 160° C. for 24 h, cool, centrifuge, wash to neutrality, dry, and calcine at 600° C. for 6 h to remove the template, thereby obtaining a catalytic cracking aid.

[0055] Comparative Example 1

[0056] S1. Mix 15 mL of tetraethyl orthosilicate, 1 g of PEG-600, 30 mL of anhydrous ethanol, 2 mL of dilute nitric acid (concentration 1 mol / L), and 5 mL of deionized water, and stir at 50°C for 2 h to obtain SiO2 sol. Then take 60 mL of SiO2 sol and dry it.

[0057] S2. Mix the ZSM-5 molecular sieve and the dispersion at a mass ratio of 1:20, and ultrasonically disperse for 20 minutes to obtain a modified molecular sieve dispersion; wherein the dispersant solution is a silane coupling agent KH560 anhydrous ethanol solution with a mass fraction of 0.8%, and then take 20 mL of the modified molecular sieve dispersion and dry it.

[0058] S3. The dried products from step S1 and step S2 are mixed and ground, and then calcined at 500° C. for 4 hours to remove the template, thereby obtaining a catalytic cracking aid.

[0059] Comparative Example 2

[0060] The difference between this comparative example and Example 1 lies in step S3.

[0061] Step S3 of this comparative example is: slowly add 20 mL of the modified molecular sieve dispersion in step S2 to 100 mL of the mesoporous SiO2 sol obtained in step S1. After the addition is completed, stir at 40°C for 1 hour to obtain a mixed sol, then adjust the stirring speed to 1000 r / min, and add 5 mL of ammonia water to make it gel.

[0062] Comparative Example 3

[0063] The difference between this comparative example and Example 1 lies in step S3.

[0064] Step S3 of this comparative example is: slowly add 20 mL of the modified molecular sieve dispersion in step S2 to 20 mL of the mesoporous SiO2 sol obtained in step S1. After the addition is completed, stir at 40°C for 1 hour to obtain a mixed sol, then adjust the stirring speed to 1000 r / min, and add 5 mL of ammonia water to make it gel.

[0065] Comparative Example 4

[0066] The difference between this comparative example and Example 1 is step S4.

[0067] Step S4 of this comparative example is: crushing 10 g of gel, drying it, and then calcining it at 500° C. for 4 h to remove the template, thereby obtaining a catalytic cracking aid.

[0068] Figure 1These are transmission electron micrographs (TEM) of the catalyst promoter prepared in Example 1: (a) is a low-resolution TEM image, and (b) is a high-resolution TEM image.

[0069] From the transmission electron microscope, it can be seen that the molecular sieve is evenly dispersed in the mesoporous silica matrix, and from the high-resolution image, it can be seen that the composite material has obvious pores.

[0070] This shows that through ultrasonic dispersion and in-situ composite methods, the molecular sieve is uniformly dispersed in the mesoporous silica matrix, agglomeration and mesopore clogging are avoided, and the utilization rate of active sites is improved.

[0071] Figure 2 The following are microscope photos and energy spectrum analysis images of the catalyst promoter prepared in Example 1. The energy spectrum analysis image shows the distribution of elements, which further demonstrates that the synthesized molecular sieve is dispersed in the silica matrix without obvious agglomeration.

[0072] Figure 3 The following are microscope photos and energy spectrum analysis pictures of the catalyst promoter prepared in Example 1. Figure 2 As can be seen, Si and O elements are significantly more abundant on the right side, indicating that the right side is mainly distributed in mesoporous SiO2. The simple mixing method of mesoporous SiO2 and molecular sieves is unevenly distributed. This directly results in low active site utilization and hindered mass transfer, resulting in significantly lower conversion rate and yield compared to the example.

[0073] Figure 4 The N adsorption-desorption isotherms for the catalyst promoters prepared in Example 1 and Comparative Example 1 are shown. The higher adsorption capacity in the isotherm for Example 1 indicates a larger specific surface area. This is due to the uniform dispersion of the molecular sieve and the intact mesoporous structure, resulting in no pore blockage. In contrast, the mesoporous structure in Comparative Example 1 was disrupted due to uneven mixing and agglomeration. A larger specific surface area means more active sites and more accessible mass transfer channels, consistent with the design goal of the present invention: "micropore-mesopore synergy to enhance mass transfer efficiency."

[0074] Figure 5 This is a transmission electron microscope photograph of the catalytic promoter prepared in Example 3. It can be seen that there is obvious separation between the molecular sieve and the mesoporous SiO2. This is because the excessive content of the molecular sieve causes agglomeration after high-temperature treatment, resulting in separation.

[0075] Application test of catalyst additives:

[0076] To verify the actual effect of the catalytic cracking aid of the present invention, a catalytic cracking performance test was conducted in a fixed-bed microreactor using heptane as a model compound (simulating a heavy hydrocarbon feedstock), as follows:

[0077] Experimental materials and methods

[0078] Raw material: n-heptane.

[0079] Catalyst system:

[0080] Composite system 1: main catalyst + 10% of the auxiliary agent prepared in Example 1;

[0081] Composite system 2: main catalyst + 10% of the auxiliary agent prepared in Example 2;

[0082] Composite system 3: main catalyst + 10% of the auxiliary agent prepared in Example 3;

[0083] Comparative system 1: main catalyst + 10% of the auxiliary agent prepared in Comparative Example 1;

[0084] Comparative system 2: main catalyst + 10% of the auxiliary agent prepared in Comparative Example 2;

[0085] Comparative system 3: main catalyst + 10% of the auxiliary agent prepared in Comparative Example 3;

[0086] Comparative system 4: main catalyst + 10% of the auxiliary agent prepared in Comparative Example 4.

[0087] Reaction conditions: reaction temperature 550°C, catalyst-oil ratio 5, residence time 3s, nitrogen atmosphere (flow rate 50mL / min).

[0088] Analytical method: The products were detected by gas chromatography (GC-2014, Shimadzu) using a flame ionization detector (FID) with n-pentane as the internal standard. The yields of light olefins (ethylene, propylene, butene) and the conversion of heptane were calculated.

[0089] Figure 6The following is a bar graph showing the n-heptane conversion and total light olefin yield after the application of the catalytic promoter in Examples 1-3 and Comparative Examples 1-3. A comparison of the Examples and Comparative Examples clearly demonstrates that the Examples significantly outperform the Comparative Examples, a finding directly related to the beneficial effects of the present invention: the innovative composite structure of molecular sieve nanoparticles embedded in situ within the mesoporous SiO2 framework and pore surfaces retains the microporous active sites of the ZSM-5 molecular sieve to ensure catalytic selectivity while also leveraging the open pores of the mesoporous SiO2 to address mass transfer and diffusion bottlenecks. This results in an n-heptane conversion exceeding 80% and a total light olefin yield exceeding 40%, significantly improving catalytic efficiency. In contrast, in Comparative Example 1 (physical mixing method), since a stable composite structure was not formed, the molecular sieve and mesoporous SiO2 were only combined by physical action, resulting in uneven distribution, easy agglomeration, low utilization of active sites, and significantly reduced conversion rate and yield; in Comparative Example 2 (excess mesoporous SiO2), due to insufficient active sites, the catalytic effect could not be fully exerted, and the yield was low; in Comparative Example 3 (excess molecular sieve), the pores were blocked by agglomeration, mass transfer was hindered, and the conversion rate was greatly reduced, further confirming the key role of the structural design of the present invention in improving the catalytic efficiency.

[0090] Figure 7 The following is a graph showing the instantaneous conversion rate over time after the application of the catalytic promoters in Examples 1-3 and Comparative Examples 1-3. The curves demonstrate significantly superior stability in the Examples compared to the Comparative Examples, thanks to the process innovations of the present invention: through ultrasonic dispersion combined with an in-situ sol-gel method, supplemented by silane coupling agent modification and hydrothermal reaction, a strong interfacial bond between the molecular sieve and the mesoporous SiO2 is achieved, effectively avoiding problems such as agglomeration, pore blockage, and component separation. The chemically bonded, stable interface formed by the hydrothermal reaction enables the instantaneous conversion rate of the Example promoter to remain above 80% of its initial value after 10 hours of continuous reaction at 550°C, reducing regeneration frequency and production costs. In contrast, in Comparative Example 1 (physical mixing), weak interfacial bonding leads to component separation during the reaction, resulting in rapid activity decay. Comparative Example 3 (excess molecular sieve) suffers from severe localized carbon deposition due to agglomeration, resulting in reduced stability. Comparative Example 4 (no hydrothermal reaction) lacks a stable interface, resulting in easily degraded structure and significantly reduced stability. At the same time, this also reflects that the present invention combines the high catalytic selectivity of ZSM-5 molecular sieve with the high mass transfer efficiency of mesoporous SiO2. By regulating key parameters such as the silicon-aluminum ratio, dispersion ratio, and stirring speed, it achieves a synergistic improvement in light olefin yield, raw material conversion rate, and catalyst stability, solving the difficult problem of "activity-selectivity-stability" that traditional catalysts are difficult to balance.

[0091] In summary, Figure 1-7The test results verified the beneficial effects of the present invention from multiple dimensions such as structure, specific surface area, and reaction performance: through structural design and process innovation, the prepared catalytic cracking additive effectively solved the problems of agglomeration, pore blockage, and weak interface bonding of traditional materials, and achieved a synergistic improvement in catalytic efficiency, stability, and selectivity, providing a reliable technical solution for the efficient production of light olefins.

Claims

1. A method for preparing a high-efficiency catalytic light olefin catalytic cracking aid, characterized in that: The following steps are involved: S1. Mix tetraethyl orthosilicate, a template, anhydrous ethanol, dilute nitric acid, and deionized water, and stir at 50-60°C for 2-3 hours to obtain a SiO2 sol; S2, mixing the ZSM-5 molecular sieve and the dispersion liquid at a mass ratio of 1:20-30, and ultrasonically dispersing for 20-30 minutes to obtain a modified molecular sieve dispersion; S3. Slowly add 20 mL of the modified molecular sieve dispersion in step S2 to 40-60 mL of the mesoporous SiO2 sol obtained in step S1. After the addition is completed, stir at 40-60°C for 1 hour to obtain a mixed sol. Then adjust the stirring speed to 1000-1500 r / min and add 5-6 mL of ammonia water to gel. S4. Crush 10 g of the gel, add 20 mL of deionized water, transfer to a hydrothermal reactor, conduct a hydrothermal reaction at 140-160° C. for 12-24 h, cool, centrifuge, wash to neutrality, dry, and calcine at 500-600° C. for 4-6 h to remove the template to obtain a catalytic cracking aid; In step S2, the dispersion is a mixed solution of silane coupling agent KH560 and anhydrous ethanol with a mass fraction of 0.8-1.2%.

2. The method for preparing a high-efficiency catalytic light olefin catalytic cracking aid according to claim 1, characterized in that: The amounts of tetraethyl orthosilicate, template, anhydrous ethanol, 1 mol / L dilute nitric acid, and deionized water added in step S1 are: 15 mL, 1-2 g, 30 mL, 2 mL, and 5-10 mL, respectively.

3. The method for preparing a high-efficiency catalytic light olefin catalytic cracking aid according to claim 1, characterized in that: In step S1, the template agent is polyethylene glycol 600.

4. The method for preparing a high-efficiency catalytic light olefin catalytic cracking aid according to claim 1, characterized in that: In step S2, the silicon-aluminum ratio of the ZSM-5 molecular sieve is 20-40.

5. A high-efficiency catalytic light olefin catalytic cracking aid prepared by the preparation method according to any one of claims 1 to 4.

6. Use of the high-efficiency catalytic light olefin catalytic cracking aid according to claim 5 in the production of light olefins.

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