Composite multi-level pore ZSM-5 and ZSM-11 eutectic molecular sieve, modified catalytic material and preparation method and application thereof

Abstract

The application belongs to the field of gasoline processing, and particularly relates to a composite multi-stage pore ZSM-5 and ZSM-11 eutectic molecular sieve, a modified catalytic material and a preparation method and application thereof. The preparation of the eutectic molecular sieve comprises the following steps: preparing ZSM-5 molecular sieve and ZSM-11 molecular sieve precursors by using a dynamic crystallization method, ensuring that the size of the hydrolysis and condensation products of metal (non-metal) salt is small enough to enter the zeolite pore, obtaining uniform dispersion and eliminating the metal (non-metal) oxide agglomeration; finally, the ZSM-11 and ZSM-5 molecular sieve eutectic is prepared by using a ball milling crystallization method, the impact force and shear force of the ball are used to make the ZSM-11 molecular sieve nanocrystal more easily enter the mesopore channel inside the ZSM-5 molecular sieve, and the surface of the mesoporous molecular sieve is easy to form new growth points due to the high-speed impact of the ball, thereby avoiding the independent growth of the ZSM-11 and ZSM-5 molecular sieve.

Description

Technical Field

[0001] This invention belongs to the field of gasoline processing, specifically relating to a composite multi-level porous ZSM-5 and ZSM-11 eutectic molecular sieve, a modified catalytic material, its preparation method, and its application. Background Technology

[0002] Currently, the desulfurization and olefin reduction processing of catalytic cracking gasoline mainly relies on hydrodesulfurization technology. However, the olefin content is reduced by hydrogenation to alkane, resulting in a decrease in the octane number of gasoline products. Many researchers have begun to explore technical solutions for non-hydrogenated olefin reduction reforming of FCC gasoline, and the production route of using catalytic cracking light gasoline fraction as feedstock for catalytic reforming to reduce olefins and increase propylene production has gained good development opportunities.

[0003] The catalysts used in the catalytic reforming of light gasoline to reduce olefins and increase propylene production are mainly zeolite molecular sieve catalysts. Zeolite molecular sieves have advantages such as ordered pore structure, large specific surface area, and adjustable number of acid centers and acid strength. ZSM-11 and ZSM-5 molecular sieves are both two-dimensional pore systems of Pentasil zeolite. ZSM-5 molecular sieve is composed of elliptical ten-membered ring straight channels (0.54nm × 0.56nm) and sinusoidal channels (0.51nm × 0.54nm); ZSM-11 molecular sieve is formed by the intersection of elliptical ten-membered ring two-dimensional straight channels (0.51nm × 0.55nm). ZSM-11 molecular sieve has a similar composition, pore size, and acid properties to ZSM-5 molecular sieve. Both have similar pore sizes and excellent catalytic performance, and are widely used in very important industrial chemical processes such as alkylation, cracking, aromatization, and disproportionation.

[0004] However, ZSM-5 molecular sieves possess complex Zig-Zag channels, which restrict the diffusion of reactant and product molecules within these elongated channels, making them prone to side reactions. The problem of long diffusion paths can be addressed by reducing the crystallite size of the molecular sieve or introducing mesopores into the crystal. However, regardless of how short the micropores can be, the fact that the synthesized material retains the framework structure of ZSM-5 cannot change the fact that its channels are bent (Zig-Zag) along the a-axis. This problem can be solved by "straightening the channels." Replacing ZSM-5 with ZSM-11 can solve the problem of channel straightening. Synthesizing ZSM-5 / 11 eutectic molecular sieves, which combine the structural characteristics of both ZSM-11 and ZSM-5, and introducing mesopores into the eutectic, has become an important approach to improving its mass transfer performance.

[0005] Patent document CN1600757A discloses a method for catalytic cracking of C4-C6 olefins to produce propylene / ethylene. This method involves contacting the olefin feedstock with a modified ZSM-5 / ZSM-11 zeolite catalyst with a silica-to-alumina ratio greater than 30 to produce a light olefin effluent. The method also discloses using an ammonium-ion-exchanged ZSM-5 / ZSM-11 co-crystallized molecular sieve as the main component of the C4 olefin cracking catalyst, and using K, Mg, La, and Ce ions to modulate the performance of the molecular sieve catalyst. This patent prepares a common co-crystallized molecular sieve with narrow pore sizes. During the olefin cracking and upgrading reaction, larger reactant and product molecules have difficulty diffusing within the narrow pores, which not only affects the contact between reactants and active sites but also easily leads to side reactions.

[0006] The zeolite molecular sieves used in the above catalysts all belong to the category of microporous molecular sieves. Although microporous molecular sieves have an ordered and stable structure, their pore size is relatively narrow. In the process of olefin cracking and reforming reaction, it is difficult for larger reactant molecules and product molecules to diffuse between narrow pores. This not only affects the contact between reactants and active centers, but also easily leads to the occurrence of side reactions. Therefore, the catalyst for the co-production of propylene by catalytic de-olefin reforming of light gasoline still needs to be further improved. Summary of the Invention

[0007] One of the objectives of this invention is to provide a composite multi-level porous ZSM-5 and ZSM-11 eutectic molecular sieve and its preparation method, which solves the problem that existing ZSM-5 and ZSM-11 eutectic molecular sieve catalysts have narrow pore sizes that easily lead to side reactions.

[0008] The second objective of this invention is to provide a modified catalytic material, its preparation method, and its application, which can not only effectively reduce the olefin content in light gasoline but also increase the yield of propylene.

[0009] This invention is achieved through the following technical solution: This invention discloses a method for preparing a composite multi-level porous ZSM-5 and ZSM-11 eutectic molecular sieve, comprising the following steps: Preparation of stepwise porous ZSM-5 molecular sieve: Mix the aluminum source, phosphorus source and deionized water evenly to form solution A; Then, the silicon source, deionized water, calcium source, inorganic base, seed crystal and first template agent are mixed and stirred evenly to prepare solution B; Mix solution B with solution A, adjust the pH to 10.5-12, add organic pore guiding agent and stir evenly. After dynamic crystallization of the mixed solution, separate the solid and liquid products. The solid product is filtered, washed, dried and calcined to obtain stepwise porous ZSM-5 molecular sieve. Preparation of ZSM-11 molecular sieve precursor: Aluminum source, inorganic alkali, deionized water, second template agent, seed crystal, and silicon source were mixed evenly, and the pH was adjusted to 10.5-12 to obtain a mixed solution. After dynamic crystallization, the mixed solution was used to synthesize the ZSM-11 molecular sieve precursor. A stepped-pore ZSM-5 molecular sieve was added to a ZSM-11 molecular sieve precursor, the pH was adjusted to 10.5–12, and the mixture was ball-milled at 150–170°C for 72–96 h. After filtration, washing, drying, and calcination, a composite multi-level porous ZSM-5 and ZSM-11 eutectic molecular sieve was obtained.

[0010] Furthermore, in the preparation of the small-crystal, stepwise porous ZSM-5 molecular sieve, tetrapropylammonium hydroxide was used as the first template agent; the specific molar ratio of each raw material was as follows: SiO2 / Al2O3=30~600, Na2O / SiO2=0.01~0.4, TPA + / SiO2 = 0.01~1.0, H2O / SiO2 = 5~60; TPA + The cation representing tetrapropylammonium hydroxide; The amount of seed crystal added is 0.5% to 15% of the mass of SiO2 in the silicon source, the amount of phosphorus source added is 0.5% to 10% of the mass of SiO2 in the silicon source, the amount of calcium source added is 2% to 15% of the mass of SiO2 in the silicon source, and the amount of organosilane added is 0.2% to 10% of the mass of SiO2 in the silicon source.

[0011] Furthermore, in the preparation of ZSM-5 molecular sieve with small crystallite step-pores, the mixed solution was dynamically pre-crystallized at 80~120℃ for 3~6h, and then dynamically crystallized at 150~170℃ for 20~80h. In the preparation of ZSM-11 molecular sieve precursor, the mixed solution was dynamically crystallized at 80–100 °C for 20–80 h. The dynamic crystallization process is carried out in a rotary oven reactor at a speed of 10-100 rpm.

[0012] Furthermore, the molar ratio of each raw material in the preparation of the ZSM-11 molecular sieve precursor is as follows: SiO2 / Al2O3=30~600, Na2O / SiO2=0.01~0.4, TBA + / SiO2 = 0.01~1.0, H2O / SiO2 = 5~60; TBA + This represents the cation of tetrabutylammonium hydroxide.

[0013] This invention also discloses the composite hierarchical porous ZSM-5 and ZSM-11 eutectic molecular sieve prepared by the aforementioned method, wherein the total pore volume in the composite hierarchical channels is 0.25–0.50 cm³. 3 / g, micropore volume is 0.13~0.16cm³ 3 / g, mesopore volume is 0.12~0.34cm³ 3 / g; specific surface area is 360-420m² 2 / g, the particle size of the eutectic molecular sieve is 0.05μm~10μm.

[0014] Furthermore, in the eutectic molecular sieve, the mass ratio of ZSM-5 to ZSM-11 is between 5:1 and 1:5.

[0015] This invention also discloses a method for preparing a modified catalytic material, comprising the following steps: The composite multi-level porous ZSM-5 and ZSM-11 eutectic molecular sieves were added to an NH4Cl solution and stirred thoroughly under water bath conditions. After filtration and washing until neutral, the mixture was repeated several times. After washing and drying, NH4-type molecular sieves are obtained, and after calcination, hydrogen-type molecular sieves are obtained. After grinding the hydrogen-type molecular sieve, it is mixed with γ-Al2O3 at a mass ratio of 9:1 to 1:9, and 2% to 3% of Tianqing powder is added. The mixture is then mixed evenly, and dilute nitric acid is added to bind the molecular sieve, γ-Al2O3, and Tianqing powder into agglomerates. The mixture is then extruded, dried, and calcined to obtain a catalyst material for catalytic cracking of light gasoline.

[0016] The present invention also discloses the modified catalytic material prepared by the aforementioned preparation method.

[0017] This invention also discloses the application of the modified catalyst material, which uses catalytic cracking light gasoline as feedstock and the modified catalyst material as catalyst to carry out a non-hydrogenated olefins modification and propylene co-production reaction to prepare propylene.

[0018] Furthermore, the reaction conditions are as follows: reaction temperature 360℃~500℃, reaction pressure 0.1~2.0MPa, and liquid hourly space velocity 0.5~3.0h⁻¹. -1 Water vapor is used as a diluent, and the mass ratio of water vapor to catalytic cracking light gasoline is 0.1-0.3. The reaction products are heat exchanged, cooled, and separated to obtain liquid and gaseous products. The liquid product is modified gasoline, and the gaseous product is a mixture of gases containing propylene and ethylene.

[0019] Compared with the prior art, the present invention has the following beneficial technical effects: This invention discloses a method for preparing a composite multi-level porous ZSM-5 and ZSM-11 eutectic molecular sieve catalyst. The method involves preparing ZSM-5 and ZSM-11 molecular sieve precursors separately. By mixing the metal (non-metal) salt precursor with a silicon or aluminum source in a certain proportion under appropriate pH conditions, the precipitation process of the metal (non-metal) ions with the silicon or aluminum source during hydrothermal synthesis is synchronized with the crystallization of the silica-alumina gel. This ensures that the size of the metal (non-metal) salt hydrolysis and condensation products is small enough to enter the zeolite channels and achieve uniform dispersion, thus eliminating the agglomeration of metal (non-metal) oxides.

[0020] In the preparation of ZSM-5 molecular sieve with hierarchical pores, by using appropriate ratios of silica-alumina gel, organic pore-directing agents and crystallization conditions, molecular sieves with nanoscale hierarchical pore structures can be generated. On the one hand, this increases the size and number of metal oxide formation spaces during the synthesis process, and on the other hand, it improves the problem of pore blockage caused by the presence of metals and the interior of zeolite channels, thereby enhancing the performance of the catalyst.

[0021] Finally, the ball milling crystallization method was used to co-crystallize ZSM-11 and ZSM-5 molecular sieves. The impact and shearing forces of the balls made it easier for ZSM-11 molecular sieve nanocrystals to enter the mesoporous channels of ZSM-5 molecular sieves. At the same time, the surface of the mesoporous molecular sieves was easily formed with new "growth points" due to the high-speed impact of the balls, thus avoiding the independent growth of ZSM-11 and ZSM-5 molecular sieves.

[0022] This invention also discloses a composite hierarchical porous ZSM-5 and ZSM-11 eutectic molecular sieve, which has a high metal content and a large number of hierarchical channels, with a total pore volume of 0.28–0.50 cm³. 3 / g, micropore volume is 0.14~0.5cm³ 3 / g, mesopore volume is 0.12~0.32cm³ 3 / g; specific surface area is 380-420m² 2 / g, the eutectic molecular sieve has a particle size of 0.28μm~0.45μm. Its hierarchical porous structure facilitates the diffusion of macromolecular reactants or products and increases the accessibility of catalytic active centers. When applied to catalytic reforming of light gasoline, it achieves an olefin conversion rate of no less than 85%, demonstrating good ability to selectively convert olefins to high-octane products.

[0023] This invention further prepares a hydrogen-form molecular sieve based on composite hierarchical porous ZSM-5 and ZSM-11 eutectic molecular sieves, and then calcines the hydrogen-form molecular sieve to obtain a catalytic material for reforming light gasoline in catalytic cracking. The reforming catalytic material provided by this invention is used in the non-hydrogenated olefin reforming reaction of FCC light gasoline, which can not only effectively reduce the olefin content in light gasoline, but also improve the yield of propylene.

[0024] The modified gasoline obtained by upgrading catalytic cracking gasoline using this invention has an olefin content of 4-20% (v) in the fraction, a gasoline yield of 40%-65%, and a research octane number of 92.5-95.5. The propylene yield in the gaseous components is 10%-18%. This modified gasoline not only meets the requirements of the China VI standard for clean gasoline blending components but also co-produces high-quality chemical raw materials such as propylene. Attached Figure Description

[0025] Figure 1 The XRD pattern of the composite hierarchical porous ZSM-5 and ZSM-11 eutectic molecular sieve prepared in Example 1 of this invention; Figure 2 SEM image of the composite hierarchical porous ZSM-5 and ZSM-11 eutectic molecular sieve prepared in Example 1 of this invention; Figure 3 The image shows the BET plot of the composite multi-level porous ZSM-5 and ZSM-11 eutectic molecular sieve prepared in Example 1 of this invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the present invention clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention; that is, the described embodiments are only a part of the embodiments of the present invention, and not all of them.

[0027] The detailed description of the embodiments of the present invention provided in the following figures is not intended to limit the scope of the claimed invention, but merely to illustrate one selected embodiment of the invention. All other embodiments obtained by those skilled in the art based on the figures and embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0028] It should be noted that the terms “comprising,” “including,” or any other variations are intended to cover non-exclusive inclusion, such that a process, element, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to the process, element, method, article, or apparatus.

[0029] This invention discloses a method for preparing a catalyst for the co-production of propylene from non-hydrogenated olefins in catalytic cracking of light gasoline, comprising the following steps: (1) Preparation of ZSM-5 molecular sieve with small grain size and stepped pores: Aluminum source, phosphorus source (calculated as P2O5), and deionized water are added slowly and sequentially to the reaction vessel to mix them evenly and form solution A. Then, the silicon source, deionized water, calcium source (calculated as CaO), inorganic base, seed crystal and first template agent are mixed and stirred evenly to prepare solution B.

[0030] Under rapid stirring, solution B is slowly added dropwise to solution A to adjust the pH to 10.5–12. The mixed solution is stirred at room temperature for 2–3 hours, then organosilane is added and stirred until homogeneous. The mixed solution is then dynamically pre-crystallized at 80–120℃ for 3–6 hours, and then dynamically crystallized at 150–170℃ for 20–80 hours. Hydrothermal crystallization is used to synthesize small-crystal, stepwise porous ZSM-5 molecular sieve.

[0031] The prepared ZSM-5 molecular sieves had particle sizes ranging from 0.1 μm to 0.5 μm and total pore volumes ranging from 0.28 to 0.42 cm³. 3 / g, micropore volume of 0.10~0.12cm³ 3 / g, mesopore volume is 0.18~0.30cm³ 3 / g.

[0032] The dynamic crystallization process is carried out in a reactor within a rotary oven, with the rotary oven rotating at a speed of 10-100 rpm.

[0033] The reactor was rapidly cooled to separate the solid and liquid products. The solid product was then filtered, washed, dried, and calcined to obtain ZSM-5 molecular sieve with small crystal cascade pores.

[0034] The molar composition of the raw material mixture is as follows: SiO2 / Al2O3 = 30–600, Na2O / SiO2 = 0.01–0.4, TBA+ / SiO2 = 0.01–1.0, H2O / SiO2 = 5–60. The amount of seed crystal added is 0.5–15% of the mass of SiO2 in the silicon source, the amount of phosphorus source (calculated as P2O5) added is 0.5–10% of the mass of SiO2 in the silicon source, the amount of calcium source (calculated as CaO) added is 2–15% of the mass of SiO2 in the silicon source, and the amount of organosilane added is 0.2–10% of the mass of SiO2 in the silicon source.

[0035] (2) Preparation of small-grained ZSM-11 precursor Aluminum source, inorganic alkali, deionized water, second template agent, seed crystal, and silicon source are added slowly and sequentially to the reactor under stirring, and thoroughly mixed until homogeneous. The molar composition of the raw material mixture is: SiO2 / Al2O3 = 30–600, Na2O / SiO2 = 0.01–0.4, TBA+ / SiO2 = 0.01–1.0, H2O / SiO2 = 5–60, and the amount of seed crystal added is 0.5%–15% of the mass of SiO2 in the silicon source. The homogeneous solution is dynamically crystallized at 80–100℃ for 20–80 hours, followed by hydrothermal crystallization to synthesize small-crystal ZSM-11 molecular sieve precursors. The dynamic crystallization treatment is carried out in a rotary oven reactor with a rotation speed of 10–100 rpm.

[0036] (3) Add the ZSM-5 molecular sieve obtained in step (1) to the ZSM-11 molecular sieve molecular sieve nanocrystal precursor obtained in step (2), adjust the pH value of the mixed slurry to 10.5-12, add it to a heated ball mill and ball mill crystallize it for 72-96 hours at 150-170℃ and ball mill speed of 7000 r / min. After filtration, washing, drying and calcination, the composite multi-level porous ZSM-5 and ZSM-11 eutectic molecular sieve is obtained.

[0037] Crystallization is an essential process for the preparation of molecular sieves, and it can be divided into static crystallization and dynamic crystallization. This invention uses dynamic crystallization to prepare ZSM-5 molecular sieve and ZSM-11 molecular sieve precursors separately, forming hierarchical ZSM-5. In the preparation of hierarchical ZSM-5, in addition to seed crystals and template agents, there are also organic pore guide agents. The co-crystallization process of ZSM-5 and ZSM-11 adopts ball milling crystallization. The impact and shearing forces of the balls make it easier for ZSM-11 molecular sieve nanocrystals to enter the mesoporous channels of ZSM-5 molecular sieve. At the same time, the surface of the mesoporous molecular sieve is prone to forming new "growth points" due to the high-speed impact of the balls, thereby avoiding the independent growth of ZSM-11 and ZSM-5 molecular sieves.

[0038] The reactor in the above steps is a reactor with a polytetrafluoroethylene liner.

[0039] The silicon source, aluminum source, phosphorus source, calcium source, and organosilane used in this invention are not particularly limited, and any commonly used in this technical field may be used. The silicon source is preferably tetraethyl orthosilicate or macroporous silica gel; the aluminum source is preferably aluminum isopropoxide or sodium aluminate; the phosphorus source is preferably ammonium phosphate or phosphoric acid; the calcium source is preferably calcium nitrate or calcium carbonate; the organosilane is preferably 3,4-epoxycyclohexylethyltrimethoxysilane or di-(trimethoxysilylpropyl)amine; the first template agent is preferably tetrapropylammonium hydroxide; the second template agent is preferably tetrabutylammonium hydroxide; and the molar ratio of the second template agent to the first template agent is 1:1 to 2.

[0040] The silicon source and aluminum source are mixed uniformly in an inorganic alkaline solution system at room temperature to form a silicon-aluminum gel, which is then crystallized at different temperature stages.

[0041] This invention also provides a catalyst using the aforementioned ZSM-5 and ZSM-11 eutectic molecular sieves as supports. Specifically, the ZSM-5 and ZSM-11 eutectic molecular sieves are added to a 1 mol / L NH4Cl solution, with a mass ratio of molecular sieve to NH4Cl solution of 1:10. The mixture is stirred thoroughly in a water bath at 85°C for 2 hours. The mixture is then filtered, washed until neutral, and this process is repeated three times, followed by washing and drying to obtain an NH4-type molecular sieve. This NH4-type molecular sieve is then calcined in a muffle furnace at 550°C for 6 hours to obtain a hydrogen-type molecular sieve. After grinding the above-mentioned hydrogen-type molecular sieve, it was mixed with γ-Al₂O₃ at a mass ratio of 9:1 to 1:9, and 2-3% (by weight, based on the molecular sieve) of Tianqing powder was added. The mixture was stirred evenly, and 2-4% dilute nitric acid was added dropwise to bind the molecular sieve, γ-Al₂O₃, and Tianqing powder into agglomerates. The agglomerates were then extruded in an extruder, and the strip-shaped catalyst was dried in an oven at 120°C for 4 hours and calcined at 550°C for 6 hours to obtain a catalytic cracking catalyst for upgrading light gasoline. Because this catalyst uses the above-mentioned ZSM-5 and ZSM-11 eutectic molecular sieves as a support, it can exhibit excellent catalytic performance.

[0042] This invention also provides a method for catalytic cracking light gasoline to reduce olefins, comprising the following steps: loading the above-mentioned catalyst into a fixed-bed reactor; and, under the action of the catalyst, carrying out a non-hydrogenated olefins reduction and propylene co-production reaction in the fixed-bed reactor. The reaction conditions are: reaction temperature 360℃~500℃, reaction pressure 0.1~2.0MPa, and liquid hourly space velocity 0.5~3.0h. -1 Water vapor is used as a diluent, with a mass ratio of water vapor to catalytic cracking light gasoline of 0.1-0.3. The reaction products are subjected to heat exchange, cooling, and separation. The liquid product is modified gasoline, and the gaseous product is a mixture of propylene and ethylene.

[0043] The catalytic light gasoline is a light fraction (<80~120℃ fraction) obtained by cutting and separating catalytic cracking gasoline, and the olefin content in the catalytic cracking gasoline can be ≤60%. Other types of gasoline, such as coking gasoline and thermal cracking gasoline, can also be used in the method of this invention.

[0044] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0045] In the following embodiments, unless otherwise specified, each step can be completed using conventional methods, devices / instruments / structures / components in the art, and the reagents and chemicals used can be commercially available or prepared using conventional methods in the art.

[0046] Example 1 (1) Preparation of small-crystal, stepwise porous ZSM-5 molecular sieve: Sodium aluminate (41 wt%), ammonium phosphate (99 wt%), and deionized water were added sequentially to a reaction vessel at room temperature and mixed thoroughly to form solution A. Macroporous silica gel, deionized water, calcium nitrate, sodium hydroxide, ZSM-5 seed crystals (M1), and tetrapropylammonium hydroxide (TPA) were added to a beaker. + Mix 25wt%) to form solution B.

[0047] Solution B was added to solution A and stirred at room temperature for 2 hours. The pH was adjusted to 11.0, and then the organosilane di-(trimethoxysilylpropyl)amine was added and stirred until homogeneous. The mixture was dynamically pre-crystallized in a rotary oven at 100℃ for 4 hours, and then dynamically crystallized at 170℃ for 72 hours. The rotary oven speed was 80 rpm. The reaction vessel was rapidly cooled, and the product was separated into solid and liquid phases. The solid product was filtered, washed, dried at 120℃ for 3 hours, and calcined at 600℃ to obtain ZSM-5 molecular sieve with small-crystal stepwise pores.

[0048] The composition (molar ratio) is: SiO2 / Al2O3 = 30, Na2O / SiO2 = 0.04, TPA + / SiO2=0.1, H2O / SiO2=5; The amount of seed crystal M1 added is 10% of the mass of SiO2, the amount of ammonium phosphate (99wt%) (calculated as P2O5) added is 5% of the mass of SiO2, the amount of calcium nitrate (calculated as CaO) added is 10% of the mass of SiO2, and the amount of organosilane added is 2% of the mass of SiO2.

[0049] (2) Preparation of small-grained ZSM-11 precursor: Sodium aluminate (41 wt%), sodium hydroxide, deionized water, ZSM-11 seed crystals (M2), and tetrabutylammonium hydroxide (TBA) were prepared at room temperature. + 25 wt% of silica gel and macroporous silica gel were added sequentially to a stainless steel reactor and stirred thoroughly to ensure homogeneity. The pH was then adjusted to 11.0. The homogeneous solution was then subjected to dynamic crystallization in a rotary oven at 100°C for 72 h at a rotation speed of 80 rpm to synthesize the ZSM-11 molecular sieve precursor.

[0050] The composition (molar ratio) is: SiO2 / Al2O3 = 30, Na2O / SiO2 = 0.04, TBA + / SiO2=0.1, H2O / SiO2=5; The amount of seed crystal M2 added is 10% of the mass of SiO2.

[0051] (3) The ZSM-5 molecular sieve obtained in step (1) is added to the ZSM-11 molecular sieve molecular sieve nanocrystal precursor obtained in step (2), the pH value of the mixed slurry is adjusted to 11.0, and it is added to a heated ball mill and ball milled and crystallized for 72 hours at 170°C and 7000 r / min. After filtration, washing, drying at 120°C for 3 hours, and calcination at 550°C, the composite multi-level porous ZSM-5 and ZSM-11 eutectic molecular sieve is obtained.

[0052] In steps (1) and (2), TPA + :TBA + (mol) = 1:1, and the reactor in the above steps is a reactor with a polytetrafluoroethylene liner.

[0053] In this embodiment, a composite multi-level porous ZSM-5 and ZSM-11 eutectic molecular sieve was prepared. The mass ratio of ZSM-5 to ZSM-11 in the eutectic molecular sieve was 1.05:1; the total pore volume was 0.28 cm³. 3 / g, micropore volume is 0.153cm³ 3 / g, mesopore volume is 0.127cm³ 3 / g, specific surface area is 383m² 2 / g, with a particle size of 0.3μm~0.4μm.

[0054] like Figure 1 As shown, the XRD pattern of the composite multi-level porous ZSM-5 and ZSM-11 eutectic molecular sieve prepared in this embodiment can be clearly seen from the figure. The characteristic peaks of ZSM-5 and ZSM-11 are obvious, and the crystallinity is 98%.

[0055] like Figure 2 As shown, the SEM image of the molecular sieve catalyst obtained in Example 1 of the present invention has a particle size of approximately 0.30 μm to 0.40 μm.

[0056] like Figure 3 As shown, the BET diagram of the molecular sieve catalyst obtained in Example 1 of the present invention shows the NH3-TPD adsorption-desorption isotherm. A significant hysteresis loop exists in the relative pressure range of 0.5~0.95, indicating the presence of mesopores and a specific surface area of ​​383 m². 2 / g, total pore volume is 0.28cm³ 3 / g, micropore volume is 0.153cm³ 3 / g, mesopore volume is 0.127cm³ 3 / g.

[0057] Example 2 The steps in this embodiment are the same as those in Embodiment 1. The difference is: In step (1), after mixing solution A and solution B, the mixed solution is dynamically pre-crystallized in a rotary oven at 120℃ for 3 hours, and then dynamically crystallized at 170℃ for 80 hours. The pH value of the mixed solution is 11.0, and the composition (molar ratio) of the mixed solution is: SiO2 / Al2O3 = 200, Na2O / SiO2 = 0.04, TPA + / SiO2=0.2, H2O / SiO2=40; In step (2), during the preparation of the small-grained ZSM-11 precursor, the uniformly stirred solution was dynamically crystallized in a rotary oven reactor at 100°C for 80 hours. The pH of the mixed solution was 11.0, and the composition (molar ratio) of the mixed solution was: SiO2 / Al2O3 = 200, Na2O / SiO2 = 0.04, TBA + / SiO2=0.2, H2O / SiO2=40; In step (3), the ball milling crystallization temperature is 170℃, and the dynamic crystallization time is 84h. The pH value of the mixed solution is 11.0.

[0058] In steps (1) and (2), TPA + :TBA + (mol) = 1.4:1.

[0059] In this embodiment, a composite multi-level porous ZSM-5 and ZSM-11 eutectic molecular sieve was prepared. The mass ratio of ZSM-5 to ZSM-11 in the eutectic molecular sieve was 1.65:1; the total pore volume was 0.335 cm³. 3 / g, micropore volume is 0.158cm³ 3 / g, mesopore volume is 0.177cm³ 3 / g, specific surface area is 412m² 2 / g, with a particle size of 0.32μm~0.4μm.

[0060] Example 3 The steps in this embodiment are the same as those in Embodiment 1. The difference is: The silicon source is tetraethyl orthosilicate, and the aluminum source is aluminum isopropoxide.

[0061] In step (1), after mixing solution A and solution B, the mixed solution is dynamically pre-crystallized at 100℃ for 6 hours and then dynamically crystallized at 160℃ for 60 hours in a rotary oven. The pH value of the mixed solution is 10.5, and the composition (molar ratio) of the mixed solution is: SiO2 / Al2O3 = 200, Na2O / SiO2 = 0.01, TPA + / SiO2=0.3, H2O / SiO2=40; In step (2), during the preparation of the small-grained ZSM-11 precursor, the uniformly stirred solution was dynamically crystallized in a rotary oven reactor at 90°C for 60 hours. The pH of the mixed solution was 10.5, and the composition (molar ratio) of the mixed solution was: SiO2 / Al2O3 = 200, Na2O / SiO2 = 0.01, TBA + / SiO2=0.3, H2O / SiO2=40; In step (3), the ball milling crystallization temperature is 160℃, and the dynamic crystallization time is 84h. The pH value of the mixed solution is 10.5.

[0062] In steps (1) and (2), TPA + :TBA + (mol) = 1.1:1.

[0063] In this embodiment, a composite multi-level porous ZSM-5 and ZSM-11 eutectic molecular sieve was prepared. The mass ratio of ZSM-5 to ZSM-11 in the eutectic molecular sieve was 1.25:1; the total pore volume was 0.314 cm³. 3 / g, micropore volume is 0.148cm³ 3 / g, mesopore volume is 0.166cm³ 3 / g, specific surface area is 388m² 2 / g, with a particle size of 0.28μm~0.42μm.

[0064] Example 4 The steps in this embodiment are the same as those in Embodiment 1. The difference is: The silicon source is tetraethyl orthosilicate, the aluminum source is sodium aluminate, the phosphorus source is phosphoric acid, the calcium source is calcium carbonate, and the organosilane is di-(trimethoxysilylpropyl)amine.

[0065] In step (1), after solution A and solution B are mixed, the mixed solution is dynamically pre-crystallized in a rotary oven at 90℃ for 4 hours and then dynamically crystallized at 160℃ for 20 hours. The pH value of the mixed solution is 11.8.

[0066] In step (2), during the preparation of the small-crystal ZSM-11 precursor, the solution after being stirred evenly was dynamically crystallized in a rotary oven reactor at 80°C for 20 hours. The pH of the mixed solution was 11.8.

[0067] In step (3), the ball milling crystallization temperature is 160℃, and the dynamic crystallization time is 96h. The pH value of the mixed solution is 11.8.

[0068] The composition (molar ratio) of step (1) is: SiO2 / Al2O3 = 300, Na2O / SiO2 = 0.2, TPA + / SiO2=0.01, H2O / SiO2=50; The amount of seed crystal M1 added is 15% of the mass of SiO2, the amount of phosphoric acid (99wt%) (calculated as P2O5) added is 4% of the mass of SiO2, the amount of calcium carbonate (calculated as CaO) added is 10% of the mass of SiO2, and the amount of organosilane added is 2% of the mass of SiO2.

[0069] The composition (molar ratio) of step (2) is: SiO2 / Al2O3 = 300, Na2O / SiO2 = 0.2, TBA + / SiO2 = 0.01, H2O / SiO2 = 50; The amount of seed crystal M2 added is 15% of the mass of SiO2.

[0070] In steps (1) and (2), TPA + :TBA + (mol) = 1.6:1.

[0071] In this embodiment, a composite hierarchical porous ZSM-5 and ZSM-11 eutectic molecular sieve was prepared. The mass ratio of ZSM-5 to ZSM-11 in the eutectic molecular sieve was 1.76:1; the total pore volume was 0.293 cm³. 3 / g, micropore volume is 0.152cm³ 3 / g, mesopore volume is 0.159cm³ 3 / g, specific surface area is 410m² 2 / g, with a particle size of 0.3μm~0.38μm.

[0072] Example 5 The steps in this embodiment are the same as those in Embodiment 1. The difference is: The silicon source is macroporous silica gel, the aluminum source is sodium aluminate, the phosphorus source is phosphoric acid, the calcium source is calcium nitrate, and the organosilane is 3,4-epoxycyclohexylethyltrimethoxysilane.

[0073] In step (1), after mixing solution A and solution B, the mixed solution is dynamically pre-crystallized in a rotary oven at 80℃ for 5 hours and then dynamically crystallized at 150℃ for 50 hours. The pH value of the mixed solution is 12.0. In step (2), during the preparation of the small-crystal ZSM-11 precursor, the homogenized solution was dynamically crystallized in a rotary oven at 80°C for 50 hours. The pH of the mixed solution was 12.0. In step (3), the ball milling crystallization temperature is 150℃, and the dynamic crystallization time is 96 hours. The pH value of the mixed solution is 12.0. The composition (molar ratio) of step (1) is: SiO2 / Al2O3 = 100, Na2O / SiO2 = 0.3, TPA + / SiO2=1, H2O / SiO2=30; the amount of seed crystal M1 added is 15% of the mass of SiO2, the amount of phosphoric acid (99wt%) (calculated as P2O5) added is 5% of the mass of SiO2, the amount of calcium carbonate (calculated as CaO) added is 15% of the mass of SiO2, and the amount of organosilane added is 5% of the mass of SiO2.

[0074] Step (2) Composition (molar ratio): SiO2 / Al2O3 = 100, Na2O / SiO2 = 0.3, TBA + / SiO2=1, H2O / SiO2=30; the amount of seed crystal M2 added is 15% of the mass of SiO2.

[0075] In steps (1) and (2), TPA + :TBA + (mol) = 1.2:1.

[0076] In this embodiment, a composite multi-level porous ZSM-5 and ZSM-11 eutectic molecular sieve was prepared. The mass ratio of ZSM-5 to ZSM-11 in the eutectic molecular sieve was 1.42:1; the total pore volume was 0.454 cm³. 3 / g, micropore volume is 0.147cm³ 3 / g, mesopore volume is 0.312cm³ 3 / g, specific surface area is 392m² 2 / g, with a particle size of 0.35μm~0.45μm.

[0077] Example 6 The steps in this embodiment are the same as those in Embodiment 1. The difference is: The silicon source is tetraethyl orthosilicate, the aluminum source is sodium aluminate, the phosphorus source is ammonium phosphate, the calcium source is calcium carbonate, and the organosilane is 3,4-epoxycyclohexylethyltrimethoxysilane.

[0078] In step (1), after solution A and solution B are mixed, the mixed solution is dynamically pre-crystallized at 110℃ for 4 hours and dynamically crystallized at 170℃ for 72 hours in a rotary oven. The pH value of the mixed solution is 12.0.

[0079] In step (2), during the preparation of the small-crystal ZSM-11 precursor, the uniformly stirred solution was dynamically crystallized in a rotary oven reactor at 100°C for 72 hours. The pH of the mixed solution was 12.0.

[0080] In step (3), the ball milling crystallization temperature is 170℃, and the dynamic crystallization time is 96h. The pH value of the mixed solution is 12.0.

[0081] Step (1) Composition (molar ratio): SiO2 / Al2O3 = 600, Na2O / SiO2 = 0.4, TPA+ / SiO2=0.01, H2O / SiO2=60; the amount of seed crystal M1 added is 15% of the mass of SiO2, the amount of ammonium phosphate (99wt%) (calculated as P2O5) added is 10% of the mass of SiO2, the amount of calcium carbonate (calculated as CaO) added is 5% of the mass of SiO2, and the amount of organosilane added is 8% of the mass of SiO2.

[0082] Step (2) Composition (molar ratio): SiO2 / Al2O3 = 600, Na2O / SiO2 = 0.4, TBA + / SiO2=0.01, H2O / SiO2=60; the amount of seed crystal M2 added is 15% of the mass of SiO2.

[0083] In steps (1) and (2), TPA + :TBA + (mol) = 1:1.

[0084] In this embodiment, a composite hierarchical porous ZSM-5 and ZSM-11 eutectic molecular sieve was prepared. The mass ratio of ZSM-5 to ZSM-11 in the eutectic molecular sieve was 1.10:1; the total pore volume was 0.367 cm³. 3 / g, micropore volume is 0.13cm 3 / g, mesopore volume is 0.237cm³ 3 / g, specific surface area is 386m² 2 / g, with a particle size of 0.35μm~0.42μm.

[0085] Comparative Example 1 Preparation of small-crystal, stepwise porous ZSM-5 molecular sieve: Sodium aluminate (41 wt%), ammonium phosphate (99 wt%), and deionized water were sequentially added to a stainless steel reactor with a polytetrafluoroethylene liner at room temperature and mixed thoroughly to form solution A. Macroporous silica gel, deionized water, calcium nitrate, sodium hydroxide, ZSM-5 seed crystals, and tetrapropylammonium hydroxide (TPA) were then added to a beaker. + Solution B was formed by mixing 25 wt% of the product with solution A. Solution B was added to solution A and stirred at room temperature for 2 hours. Then, organosilane di-(trimethoxysilylpropyl)amine was added and stirred until homogeneous. The mixture was then dynamically crystallized in a rotary oven at 170°C for 72 hours at a rotation speed of 80 rpm. The reaction vessel was then rapidly cooled, and the product was separated into solid and liquid phases. The solid product was filtered, washed, dried at 120°C for 3 hours, and calcined at 600°C to obtain ZSM-5 molecular sieve with small-crystal stepped pores.

[0086] The molecular sieve composition (molar): SiO2 / Al2O3 = 200, Na2O / SiO2 = 0.2, TPA + / SiO2=0.6, H2O / SiO2=40; the amount of seed crystal added is 10% of the mass of SiO2, the amount of ammonium phosphate (99wt%) (calculated as P2O5) added is 5% of the mass of SiO2, the amount of calcium nitrate (calculated as CaO) added is 10% of the mass of SiO2, and the amount of organosilane added is 6% of the mass of SiO2.

[0087] Comparative Example 2 Preparation of ZSM-11 small-crystal stepwise porous molecular sieve: At room temperature, sodium aluminate (41 wt%), sodium hydroxide (99 wt%), and tetrabutylammonium hydroxide (TBA) were prepared. + 25wt% of HCl, deionized water, macroporous silica gel, and ZSM-11 seed crystals were sequentially added to a stainless steel reactor lined with polytetrafluoroethylene (PTFE) and stirred thoroughly to ensure homogeneity. The homogeneous solution was then subjected to dynamic crystallization at 100℃ for 24 hours and at 170℃ for 72 hours in a rotary oven at a speed of 80 rpm. The molecular sieve composition (molar): SiO2 / Al2O3 = 200, Na2O / SiO2 = 0.2, TBA + / SiO2=0.6, H2O / SiO2=40, and the amount of seed crystal added is 6% of the mass of SiO2.

[0088] Comparative Example 3 (1) Preparation of small-grained ZSM-11 precursor: At room temperature, sodium aluminate (41 wt%), sodium hydroxide (99 wt%), and tetrabutylammonium hydroxide (TBA) were prepared. + 25 wt% of silane, deionized water, ZSM-11 seed crystals, and macroporous silica gel were sequentially added to a stainless steel reactor lined with polytetrafluoroethylene (PTFE) and stirred thoroughly to ensure homogeneity. The homogenized solution was then subjected to dynamic crystallization at 100°C for 24 hours in a rotary oven at 80 rpm. The molecular sieve composition (molar): SiO2 / Al2O3 = 200, Na2O / SiO2 = 0.02, TBA + / SiO2=0.6, H2O / SiO2=40; the amount of seed crystal added is 6% of the mass of SiO2.

[0089] (2) Commercially available micron-sized ZSM-5 (SiO2 / Al2O3=200) molecular sieves were added to the ZSM-11 molecular sieve precursor obtained in step (1). The pH value of the mixed slurry was adjusted to 10.5-12. The mixture was then added to a heated ball mill and ball-milled at 170°C and 7000 r / min for 72 h. After filtration, washing, drying at 120°C for 3 h, and calcination at 550°C, ZSM-5 and ZSM-11 eutectic molecular sieves were obtained.

[0090] The crystallinity of the samples was determined by X-ray diffraction using a D / max-3C X-ray powder diffractometer. XRD analysis of each molecular sieve sample was performed using a polycrystalline / D8 Advance X-ray diffractometer. The specific surface area, pore size, and pore structure of each molecular sieve sample were analyzed using an ASAP2460 multifunctional adsorption analyzer (nitrogen adsorption-desorption method). The apparent morphology and grain size of the catalyst were observed using a Hitachi SU8010 (SEM) instrument.

[0091] Table 1 shows the structure and physical parameters of the molecular sieves synthesized in Examples 1-6 and Comparative Examples 1-3.

[0092] Table 1 shows that the small-crystal, hierarchical porous ZSM-5 molecular sieve prepared in Comparative Example 1; the small-crystal, hierarchical porous ZSM-11 molecular sieve prepared in Comparative Example 2; and the ZSM-5 / ZSM-11 eutectic molecular sieve catalyst prepared in Comparative Example 3 by crystallizing ordinary micron-sized ZSM-5 (SiO2 / Al2O3=200) molecular sieve with a small-crystal ZSM-11 precursor. None of these formulations have the same physical parameters as the composite multi-level porous ZSM-5 / ZSM-11 eutectic molecular sieves prepared in Examples 1-6 of this invention.

[0093] The molecular sieves prepared in the above examples and comparative examples were added to a 1 mol / L NH4Cl solution at a mass ratio of 1:10. The mixture was stirred thoroughly in a water bath at 85°C for 2 hours. The mixture was then filtered, washed until neutral, and repeated three times, followed by washing and drying to obtain an NH4-type molecular sieve. This sieve was then calcined in a muffle furnace at 550°C for 6 hours to obtain a hydrogen-type molecular sieve. The hydrogen-type molecular sieve was ground and then mixed with γ-Al2O3 at a mass ratio of 7:3. 2-3% (based on molecular sieve weight) of Tianqing powder was added and mixed evenly. 4% dilute nitric acid was added dropwise to bind the molecular sieve, γ-Al2O3, and Tianqing powder into clumps. The clumps were then extruded using an extruder. The strip catalyst was then dried in an oven at 120°C for 4 hours and calcined at 550°C for 6 hours to obtain a catalytic cracking catalyst for light gasoline reforming. After crushing and sieving, 20-40 mesh catalyst particles were obtained.

[0094] The above-mentioned catalyst material for catalytic cracking of light gasoline was loaded into a 100ml fixed-bed reactor with a catalyst loading of 80ml. Using catalytic cracking light gasoline as feedstock, the reaction of non-hydrogenated olefins of catalytic cracking light gasoline and co-production of propylene was carried out under the action of the above-mentioned catalyst.

[0095] The reaction conditions were as follows: reaction temperatures of 360℃, 420℃, and 480℃; reaction pressure of 0.5 MPa; and liquid hourly space velocity of 2.0 h⁻¹. -1The mass ratio of water vapor to catalytic cracked light gasoline is 0.2.

[0096] The reaction products are subjected to heat exchange, cooling, and separation. The liquid product is modified gasoline, and the gaseous product is a mixture of propylene and ethylene.

[0097] The light gasoline fraction with a distillation range of less than 120℃ was used for catalytic cracking. The properties of the feedstock gasoline are shown in Table 2.

[0098] Table 3 Composition of feedstock for catalytic cracking gasoline

[0099] The reaction results are shown in Table 3.

[0100] Table 3 Reaction Results

[0101] As shown in Table 3, the modified catalytic material prepared based on the composite multi-level porous ZSM-5 and ZSM-11 eutectic molecular sieves of this invention, when applied to the catalytic cracking of light gasoline, yielded gasoline fractions with olefin content of 4.21-16.24% (v)%, a gasoline yield of 40.21-72.28%, and a propylene yield of 9.86-17.95% in the gaseous components. The modified gasoline not only meets the requirements of the National VI standard for clean gasoline blending components but also co-produces high-quality chemical raw materials such as propylene.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a composite multi-level porous ZSM-5 and ZSM-11 eutectic molecular sieve, characterized in that, The process includes the following: Preparation of stepwise porous ZSM-5 molecular sieve: Mix the aluminum source, phosphorus source and deionized water evenly to form solution A; Then, the silicon source, deionized water, calcium source, inorganic base, seed crystal and first template agent are mixed and stirred evenly to prepare solution B; Mix solution B with solution A, adjust the pH to 10.5-12, add organic pore guiding agent and stir evenly. After dynamic crystallization of the mixed solution, separate the solid and liquid products. The solid product is filtered, washed, dried and calcined to obtain stepwise porous ZSM-5 molecular sieve. Preparation of ZSM-11 molecular sieve precursor: Aluminum source, inorganic alkali, deionized water, second template agent, seed crystal, and silicon source were mixed evenly, and the pH was adjusted to 10.5-12 to obtain a mixed solution. After dynamic crystallization, the mixed solution was used to synthesize the ZSM-11 molecular sieve precursor. A stepped-pore ZSM-5 molecular sieve was added to a ZSM-11 molecular sieve precursor, the pH was adjusted to 10.5–12, and the mixture was ball-milled at 150–170°C for 72–96 h. After filtration, washing, drying, and calcination, a composite multi-level porous ZSM-5 and ZSM-11 eutectic molecular sieve was obtained.

2. The method for preparing a composite multi-level porous ZSM-5 and ZSM-11 eutectic molecular sieve according to claim 1, characterized in that, In the preparation of ZSM-5 molecular sieves with small crystallites and hierarchical pores, tetrapropylammonium hydroxide was used as the first template agent; the specific molar ratio of each raw material was as follows: SiO2 / Al2O3=30~600, Na2O / SiO2=0.01~0.4, TPA + / SiO2 = 0.01~1.0, H2O / SiO2 = 5~60; TPA + The cation representing tetrapropylammonium hydroxide; The amount of seed crystal added is 0.5% to 15% of the mass of SiO2 in the silicon source, the amount of phosphorus source added is 0.5% to 10% of the mass of SiO2 in the silicon source, the amount of calcium source added is 2% to 15% of the mass of SiO2 in the silicon source, and the amount of organosilane added is 0.2% to 10% of the mass of SiO2 in the silicon source.

3. The method for preparing a composite multi-level porous ZSM-5 and ZSM-11 eutectic molecular sieve according to claim 1, characterized in that, In the preparation of ZSM-5 molecular sieve with small crystallite step-hole, the mixed solution was dynamically pre-crystallized at 80~120℃ for 3~6h, and then dynamically crystallized at 150~170℃ for 20~80h. In the preparation of ZSM-11 molecular sieve precursor, the mixed solution was dynamically crystallized at 80–100 °C for 20–80 h. The dynamic crystallization process is carried out in a rotary oven reactor at a speed of 10-100 rpm.

4. The method for preparing a composite multi-level porous ZSM-5 and ZSM-11 eutectic molecular sieve according to claim 1, characterized in that, In the preparation of the ZSM-11 molecular sieve precursor, the specific molar ratio of each raw material is as follows: SiO2 / Al2O3=30~600, Na2O / SiO2=0.01~0.4, TBA + / SiO2 = 0.01~1.0, H2O / SiO2 = 5~60; TBA + This represents the cation of tetrabutylammonium hydroxide.

5. A composite multi-level porous ZSM-5 and ZSM-11 eutectic molecular sieve prepared by the preparation method according to any one of claims 1-4, characterized in that, In the composite multi-level channel, the total pore volume is 0.25–0.50 cm³. 3 / g, micropore volume is 0.13~0.16cm³ 3 / g, mesopore volume is 0.12~0.34cm³ 3 / g; specific surface area is 360-420m² 2 / g, the particle size of the eutectic molecular sieve is 0.05μm~10μm.

6. The composite multi-level porous ZSM-5 and ZSM-11 eutectic molecular sieve according to claim 5, characterized in that, In eutectic molecular sieves, the mass ratio of ZSM-5 to ZSM-11 is between 5:1 and 1:

5.

7. A method for preparing a modified catalytic material, characterized in that, Includes the following steps: Add the composite multi-level porous ZSM-5 and ZSM-11 eutectic molecular sieves as described in claim 5 or 6 to an NH4Cl solution, stir thoroughly under water bath conditions, filter and wash until neutral, and repeat several times. After washing and drying, NH4-type molecular sieves are obtained, and after calcination, hydrogen-type molecular sieves are obtained. After grinding the hydrogen-type molecular sieve, it is mixed with γ-Al2O3 at a mass ratio of 9:1 to 1:9, and 2% to 3% of Tianqing powder is added. The mixture is then mixed evenly, and dilute nitric acid is added to bind the molecular sieve, γ-Al2O3, and Tianqing powder into agglomerates. The mixture is then extruded, dried, and calcined to obtain a catalyst material for catalytic cracking of light gasoline.

8. The modified catalytic material prepared by the method of claim 7.

9. The application of the modified catalytic material according to claim 7, characterized in that, Propylene was produced by using catalytic cracking light gasoline as feedstock and reforming catalytic materials as catalysts to carry out non-hydrogenated olefins reforming and propylene co-production reaction.

10. The application according to claim 9, characterized in that, The reaction conditions are as follows: reaction temperature 360℃~500℃, reaction pressure 0.1~2.0MPa, and liquid hourly space velocity 0.5~3.0h⁻¹. -1 Water vapor is used as a diluent, and the mass ratio of water vapor to catalytic cracking light gasoline is 0.1-0.

3. The reaction products are heat exchanged, cooled, and separated to obtain liquid and gaseous products. The liquid product is modified gasoline, and the gaseous product is a mixture of gases containing propylene and ethylene.

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