Light gasoline cracking propylene yield increasing catalyst containing porous vermiculite-containing silica gel mesoporous composite material, and preparation method and application thereof

Abstract

The present application relates to the field of petrochemical industry, and discloses a light gasoline cracking yield-increasing propylene catalyst containing porous vermiculite-containing silica gel mesoporous composite material, a preparation method and application thereof. The catalyst comprises zeolite molecular sieve, porous vermiculite-containing silica gel mesoporous composite material, adhesive oxide and modified oxide, wherein, based on the total weight of the catalyst, the zeolite molecular sieve is 45-65 wt%, the porous vermiculite-containing silica gel mesoporous composite material is 15-35 wt%, the adhesive oxide is 10-20 wt%, and the modified oxide is 1-9 wt%. The average particle size of the porous vermiculite-containing silica gel mesoporous composite material is 20-60 μm, the specific surface area is 100-800 m 2 / g, the pore volume is 1-2 mL / g, and the pore size is in four-peak distribution, wherein the first most probable pore size corresponding to the four peaks is 1-2 nm, 2-3 nm, 3-5 nm and 20-40 nm, respectively. When the catalyst is used in light gasoline catalytic cracking reaction, not only propylene can be obtained, but also the olefin content of the light gasoline product can be reduced.

Description

Technical Field

[0001] This invention relates to the field of petrochemicals, specifically to a light gasoline cracking catalyst for increasing propylene production containing a porous vermiculite-silica mesoporous composite material, its preparation method, and its application. Background Technology

[0002] Propylene is a very important organic chemical raw material. With the continuous growth in demand for downstream propylene products (including polypropylene, acrylic acid, and acrylonitrile), the demand for propylene has also increased year by year. To date, my country's propylene supply is still insufficient to meet demand, and traditional methods of ethylene co-production and refinery propylene recovery are increasingly unable to meet market needs.

[0003] The catalysts used in the catalytic cracking of light gasoline to increase propylene production are mainly zeolite molecular sieve catalysts. Compared with metal oxides, zeolite molecular sieves have advantages such as ordered pore structure, large specific surface area, and adjustable number and strength of acidic centers. Therefore, most researchers focus on zeolite molecular sieve catalysts. The main components of existing light gasoline catalytic cracking catalysts are ZSM-5, ZSM-11, ZRP, or ZSM-35 molecular sieves. Research results show that the pore structure, surface acidity, and structural stability of the catalyst are key factors affecting the catalytic cracking of olefins. Unmodified acidic ZSM-5 molecular sieves have good initial activity in the light gasoline cracking reaction, but poor stability. To improve catalyst performance, many researchers have conducted in-depth studies on the synthesis and modification of zeolite molecular sieves.

[0004] Existing light gasoline catalytic cracking catalysts primarily consist of zeolite molecular sieves or modified zeolite molecular sieves. Because zeolite molecular sieves are microporous with narrow pore structures, they are prone to side reactions, leading to reduced selectivity for the target product, propylene.

[0005] Therefore, the propylene selectivity of existing light gasoline catalytic cracking catalysts for increasing propylene production needs to be further improved. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing light gasoline catalytic cracking catalysts for increasing propylene production, namely, low propylene yield and poor stability. This invention provides a light gasoline cracking catalyst for increasing propylene production containing a porous vermiculite-silica mesoporous composite material, its preparation method, and its application. Using the catalyst provided by this invention in the light gasoline catalytic cracking reaction can not only produce propylene but also reduce the olefin content of the light gasoline product.

[0007] To achieve the above objectives, the first aspect of the present invention provides a catalyst for increasing propylene production through light gasoline cracking, wherein the catalyst comprises a zeolite molecular sieve, a porous vermiculite-containing silica gel mesoporous composite material, a binder oxide, and a modified oxide, and based on the total weight of the catalyst, the content of the zeolite molecular sieve is 45-65% by weight, the content of the porous vermiculite-containing silica gel mesoporous composite material is 15-35% by weight, the content of the binder oxide is 10-20% by weight, and the content of the modified oxide is 1-9% by weight;

[0008] The porous vermiculite-containing silica gel mesoporous composite material has an average particle size of 20-60 μm and a specific surface area of ​​100-800 m². 2 / g, pore volume is 1-2mL / g, pore size is distributed in four peaks, and the first most probable pore size corresponding to the four peaks is 1-2nm, the second most probable pore size is 2-3nm, the third most probable pore size is 3-5nm, and the fourth most probable pore size is 20-40nm.

[0009] A second aspect of the present invention provides a method for preparing the aforementioned light gasoline cracking catalyst for increasing propylene production, wherein the preparation method comprises:

[0010] (1) In the presence of dilute nitric acid, zeolite molecular sieve, porous vermiculite-containing silica gel mesoporous composite material, binder and extrusion aid are mixed, extruded and subjected to a first calcination treatment to obtain catalyst precursor;

[0011] (2) The catalyst precursor is immersed in an aqueous solution of the modified oxide precursor and then dried and calcined to obtain a light gasoline cracking catalyst for increasing propylene production.

[0012] A third aspect of the present invention provides the application of the aforementioned light gasoline cracking catalyst for increasing propylene production in catalytic cracking.

[0013] The technical solution of the present invention has the following advantages through the above technical solution:

[0014] (1) The light gasoline cracking catalyst provided by the present invention is mainly composed of hydrogen-type high-silica ZSM-5 zeolite molecular sieve and porous vermiculite-containing silica gel mesoporous composite material. The raw materials are inexpensive and the preparation method is simple.

[0015] (2) The light gasoline cracking catalyst for increasing propylene production provided by the present invention can not only effectively improve the conversion rate of olefins in light gasoline and the selectivity of the target product propylene, but also effectively reduce the olefin content in light gasoline.

[0016] (3) The preparation method of the light gasoline cracking catalyst for increasing propylene production described in this invention is simple, the conditions are easy to control, and the product has good repeatability.

[0017] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof.

[0019] Figure 1 This is the X-ray diffraction pattern of the porous vermiculite-containing silica gel mesoporous composite material A prepared in Example 1 of this invention;

[0020] Figure 2 This is a SEM image of the porous vermiculite-containing silica gel mesoporous composite material A prepared in Example 1 of this invention. Detailed Implementation

[0021] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0022] The first aspect of this invention provides a catalyst for increasing propylene production through light gasoline cracking, wherein the catalyst comprises a zeolite molecular sieve, a porous vermiculite-silica mesoporous composite material, a binder oxide, and a modified oxide, and based on the total weight of the catalyst, the content of the zeolite molecular sieve is 45-65% by weight, the content of the porous vermiculite-silica mesoporous composite material is 15-35% by weight, the content of the binder oxide is 10-20% by weight, and the content of the modified oxide is 1-9% by weight.

[0023] The porous vermiculite-containing silica gel mesoporous composite material has an average particle size of 20-60 μm and a specific surface area of ​​100-800 m². 2 / g, pore volume is 1-2mL / g, pore size is distributed in four peaks, and the first most probable pore size corresponding to the four peaks is 1-2nm, the second most probable pore size is 2-3nm, the third most probable pore size is 3-5nm, and the fourth most probable pore size is 20-40nm.

[0024] The inventors of this invention have discovered that the main components of existing light gasoline cracking catalysts are microporous zeolite molecular sieves (including ZSM-5, ZSM-11, ZSM-35, or ZRP). While microporous molecular sieves have an ordered and stable structure, their pore sizes are relatively narrow, typically between 0.4 and 0.7 nm. During olefin cracking reactions, larger reactant and product molecules have difficulty diffusing within these narrow pores, which not only affects the contact between reactants and active sites but also easily leads to side reactions such as deep dehydrogenation.

[0025] The inventors of this invention discovered during their research on the preparation of light gasoline cracking catalysts that mixing and modifying a certain amount of porous vermiculite-containing silica mesoporous composite material with hydrogen-type high-silica ZSM-5 molecular sieves, and then using it as the main component of the catalyst in the catalytic cracking reaction of light gasoline, can not only effectively improve propylene selectivity but also increase the conversion rate of olefins in light gasoline. Compared with the narrow-pore HZSM-5 molecular sieve, the porous vermiculite-containing silica mesoporous composite material simultaneously possesses four different pore sizes (1-2 nm, 2-3 nm, 3-5 nm, and 20-40 nm, respectively). Mixing an appropriate amount of the porous vermiculite-containing silica mesoporous composite material with ZSM-5 molecular sieves facilitates the smooth diffusion of larger reactant and product molecules, effectively preventing the occurrence of side reactions.

[0026] According to the present invention, in a preferred embodiment, the specific surface area of ​​the porous vermiculite-containing silica gel mesoporous composite material is 100-200 m². 2 / g, with a more preferred specific surface area of ​​104-168m² 2 The pore volume is 1.4-1.8 mL / g, and the pore size exhibits a four-peak distribution, with the first most probable pore size corresponding to the four peaks being 1.2-1.9 nm, the second most probable pore size being 2.6-2.7 nm, the third most probable pore size being 3.5-3.9 nm, and the fourth most probable pore size being 31-37 nm. Under these conditions, the diffusion of reactant and product molecules during the reaction is more favorable, and the occurrence of side reactions caused by the narrow pores of the zeolite molecular sieve is more effectively suppressed.

[0027] According to the present invention, based on the total weight of the light gasoline cracking catalyst for increasing propylene production, the content of the zeolite molecular sieve is 51-58% by weight, the content of the porous vermiculite-silica mesoporous composite material is 23-28% by weight, the content of the binder oxide is 11-19% by weight, and the content of the modified oxide is 3-7% by weight. Controlling the content of each component in the catalyst provided by the present invention within this range can effectively improve the olefin conversion rate and propylene selectivity in light gasoline.

[0028] In this invention, it should be noted that, based on the total weight of the light gasoline cracking catalyst for increasing propylene production, the total content of the zeolite molecular sieve, the porous vermiculite-containing silica gel mesoporous composite material, the binding oxide, and the modified oxide is 100%.

[0029] According to the present invention, the zeolite molecular sieve is a hydrogen-type high-silica ZSM-5 molecular sieve; preferably, the SiO2 / Al2O3 molar ratio of the hydrogen-type high-silica ZSM-5 molecular sieve is 100-800, more preferably 200-500, and even more preferably 200-300.

[0030] According to the present invention, the weight ratio of the hydrogen-type high-silica ZSM-5 molecular sieve to the porous vermiculite-containing silica gel mesoporous composite material is (1.5-4.5):1, preferably (2-4):1, and more preferably (2.2-3.76):1.

[0031] According to the present invention, the adhesive oxide is a product of the adhesive after calcination, preferably silicon oxide and / or aluminum oxide; more preferably, the adhesive is selected from one or more of silica sol, aluminum sol, pseudoboehmite and diatomite.

[0032] According to the present invention, the modified oxide is selected from one or more of magnesium oxide, calcium oxide, strontium oxide, barium oxide, zinc oxide, boron oxide, cerium oxide, lanthanum oxide, zirconium dioxide and phosphorus-containing oxides.

[0033] According to the present invention, the preparation method of the porous vermiculite-containing silica gel mesoporous composite material includes:

[0034] (a) In the presence of a first template agent, a second template agent, trimethylpentane and ethanol, tetramethoxysilane is first contacted with an acidic aqueous solution, and the mixture after the first contact is crystallized, washed and filtered to obtain mesoporous molecular sieve filter cake 1.

[0035] (b) The third template agent, tetraethyl orthosilicate and ammonia are brought into a second contact, and the mixture after the second contact is crystallized and filtered to obtain mesoporous molecular sieve filter cake 2.

[0036] (c) The water glass, inorganic acid and n-butanol are brought into a third contact, and the mixture after the third contact is filtered to obtain a silica gel filter cake;

[0037] (d) The mesoporous molecular sieve filter cake 1, the mesoporous molecular sieve filter cake 2, vermiculite, and the silica gel filter cake are mixed and ball-milled. The solid powder after ball milling is slurried with water to obtain a slurry. The slurry is then spray-dried and calcined to obtain a porous mesoporous composite material containing vermiculite and silica gel.

[0038] According to the present invention, in step (a), both the first template agent and the second template agent are triblock copolymers of polyethylene oxide-propylene oxide-ethylene oxide; preferably, the first template agent is P123 and the second template agent is F127; the first template agent is P123 (molecular formula EO). 20 PO 70 EO 20 The second template agent is F127 (molecular formula EO). 106 PO 70 EO 106 ).

[0039] According to the present invention, the pH value of the acidic aqueous solution is 1-6, preferably 3-5; more preferably, the acidic aqueous solution is a 1-5 mol / L acetic acid and sodium acetate buffer solution.

[0040] According to the present invention, the molar ratio of the first template agent, the second template agent, ethanol, the acidic aqueous solution, trimethylpentane and tetramethoxysilane is 1:(0.1-2):(100-500):(150-900):(200-500):(50-200), preferably 1:(0.2-1):(200-400):(300-600):(250-400):(70-150).

[0041] According to the present invention, the conditions for the first contact include: a temperature of 10-40°C and a time of 10-48 hours.

[0042] According to the present invention, in step (a), the crystallization conditions include a temperature of 30-80°C and a time of 10-48h.

[0043] According to the present invention, in step (a), the washing conditions are not particularly limited. For example, the washing process may include: after filtration, obtaining a solid product, repeatedly washing the solid product with distilled water (the number of washing times may be 2-10), and then performing vacuum filtration.

[0044] According to the present invention, the filtration separation is a method of separating liquid and solid particles well known to those skilled in the art, which uses air pressure to separate liquid and solid particles or mixtures of liquid and liquid.

[0045] According to the present invention, in step (b), the third template agent is hexadecyltrimethylammonium bromide.

[0046] According to the present invention, the molar ratio of the tetraethyl orthosilicate, the third template agent, ammonia in the ammonia solution, and water in the ammonia solution is 1:(0.1-1):(0.1-5):(100-200), preferably 1:(0.2-0.5):(1.5-3.5):(120-180).

[0047] According to the present invention, the conditions for the second contact include: a temperature of 10-60°C and a time of 1-5 hours.

[0048] According to the present invention, in step (c), the inorganic acid is selected from one or more of sulfuric acid, nitric acid and hydrochloric acid; preferably, the weight ratio of the inorganic acid: n-butanol: water glass is 1:(0.5-2):(3-6).

[0049] According to the present invention, the third contact conditions include: a temperature of 10-60°C, a time of 1-5 hours, and a pH value of 2-4.

[0050] According to the present invention, in step (d), based on 100 parts by weight of the mesoporous molecular sieve filter cake 1, the amount of the mesoporous molecular sieve filter cake 2 is 20-300 parts by weight, preferably 50-200 parts by weight; the amount of the silica gel filter cake is 50-500 parts by weight, preferably 100-300 parts by weight; and the amount of the vermiculite is 50-500 parts by weight, preferably 100-300 parts by weight.

[0051] According to the present invention, in step (d), the ball milling method is as follows: Mesoporous molecular sieve filter cake 1, mesoporous molecular sieve filter cake 2, vermiculite, and silica gel filter cake are added to the ball mill jar of a ball mill. The inner wall of the ball mill jar is made of agate. The diameter of the grinding balls is 2-3 mm, and the rotation speed is 300-500 r / min. Grinding is carried out continuously for 2-50 hours at a temperature of 20-100℃ inside the ball mill jar, after which the solid powder is removed. The number of grinding balls depends on the size of the ball mill jar; for a ball mill jar with a size of 50-150 mL, one grinding ball can be used. The grinding balls are made of agate.

[0052] According to the present invention, in step (d), the conditions for spray drying include: a temperature of 150-220°C and a rotation speed of 10000-15000 r / min.

[0053] According to the present invention, in step (d), the calcination conditions include: a temperature of 400-600°C, preferably 450-550°C; and a time of 10-60 h, preferably 20-30 h.

[0054] A second aspect of the present invention provides a method for preparing the aforementioned light gasoline cracking catalyst for increasing propylene production, wherein the preparation method comprises:

[0055] (1) In the presence of dilute nitric acid, zeolite molecular sieve, porous vermiculite-containing silica gel mesoporous composite material, binder and extrusion aid are mixed, extruded and subjected to a first calcination treatment to obtain catalyst precursor;

[0056] (2) The catalyst precursor is immersed in an aqueous solution of the modified oxide precursor and then dried and calcined to obtain a light gasoline cracking catalyst for increasing propylene production.

[0057] According to the present invention, in step (1), relative to 500 mL of dilute nitric acid, the amount of the zeolite molecular sieve is 1000-1400 parts by weight, the amount of the porous vermiculite-silica mesoporous composite material is 400-600 parts by weight, the amount of the binder is 300-500 parts by weight, and the amount of the extrusion aid is 100-300 parts by weight; preferably, relative to 500 mL of dilute nitric acid, the amount of the zeolite molecular sieve is 1100-1200 parts by weight, the amount of the porous vermiculite-silica mesoporous composite material is 500-550 parts by weight, the amount of the binder is 350-400 parts by weight, and the amount of the extrusion aid is 150-200 parts by weight.

[0058] According to the present invention, in step (2), the amount of the catalyst precursor is 70-100 parts by weight relative to 100 mL of water, and the amount of the oxide precursor is 10-30 parts by weight; preferably, the amount of the catalyst precursor is 95-100 parts by weight relative to 100 mL of water, and the amount of the oxide precursor is 10-20 parts by weight.

[0059] According to the present invention, the modified oxide precursor comprises an inorganic salt of a metal and / or an inorganic acid of a nonmetal; preferably, the metal is selected from one or more of magnesium, calcium, strontium, barium, zinc, cerium, lanthanum and zirconium, and the nonmetal is boron and / or phosphorus;

[0060] According to the present invention, the extrusion aid is selected from one or more of guar gum powder, cellulose, polyethylene glycol, polyvinyl alcohol and starch, more preferably guar gum powder and / or polyethylene glycol.

[0061] According to the present invention, in step (1), the conditions for the first calcination include: a temperature of 500-600°C and a time of 3-20h.

[0062] According to the present invention, in step (1), the drying conditions include: a temperature of 70-160°C and a time of 4-10 hours.

[0063] According to the present invention, in step (2), the conditions for the second calcination include: a temperature of 500-600°C and a time of 4-10 hours.

[0064] According to the present invention, in step (2), the drying conditions include: a temperature of 60-120°C and a time of 5-20h.

[0065] A third aspect of the present invention provides the application of the aforementioned light gasoline cracking catalyst for increasing propylene production in catalytic cracking.

[0066] According to the present invention, the specific operation of this application is as follows: at a temperature of 450-580℃, a pressure of 0.01-0.5MPa, and a weight hourly space velocity of 1-30h. -1 Under certain conditions, feedstock containing light gasoline is contacted with a light gasoline cracking catalyst for propylene production in a fixed-bed adiabatic reactor to generate a reaction mixture containing propylene and ethylene. Propylene is obtained through heat exchange, cooling, and separation, while the separated ethylene and lighter components are returned to the reactor.

[0067] In this invention, a method for applying a catalyst for enhancing propylene production through light gasoline cracking is disclosed, wherein the light gasoline feedstock can be selected from:

[0068] (1) Light gasoline fraction obtained from catalytic cracking unit;

[0069] (2) C5 and above fractions from methanol-to-olefins.

[0070] The method provided by this invention can be used as a standalone method for propylene preparation, or it can be used in conjunction with an FCC unit or a methanol-to-olefins unit in an oil refinery.

[0071] Microporous zeolite molecular sieve catalysts with low silica-to-alumina ratios are characterized by fast reaction rates, poor propylene selectivity, and short service life in light gasoline catalytic cracking reactions. In contrast, high silica-to-alumina ratio zeolite molecular sieve catalysts with added modifiers show some improvement in propylene selectivity and stability, but they are still prone to secondary reactions during the reaction process. The light gasoline cracking propylene-enhancing catalyst provided by this invention uses a mixture of hydrogen-form high silica-to-alumina ratio ZSM-5 zeolite molecular sieve and porous vermiculite-silica mesoporous composite material as the main active component, and introduces an appropriate amount of oxides as modifiers, which can significantly improve the conversion rate of olefins in light gasoline, the selectivity of propylene, and the stability of the catalyst.

[0072] The present invention will be described in detail below through embodiments.

[0073] In the following examples and comparative examples:

[0074] X-ray diffraction analysis of the samples was performed on a Bruker AXS D8 Advance X-ray diffractometer (Germany); pore structure parameter analysis was performed on an ASAP2020-M+C adsorption analyzer (Micromeritics, USA). Before analysis, the samples were degassed under vacuum at 350℃ for 4 hours. The specific surface area was calculated using the BET method, and the pore volume was calculated using the BJH model. SEM images of the samples were obtained using an XL-30 field emission environmental scanning electron microscope (FEI, USA); elemental analysis of the catalyst samples was performed on an Eagle III energy-dispersive X-ray fluorescence spectrometer (EDAX, USA).

[0075] The drying oven was manufactured by Shanghai Yiheng Scientific Instruments Co., Ltd., model DHG-9030A.

[0076] The muffle furnace is manufactured by CARBOLITE, model CWF1100.

[0077] The polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymers P123 and F127 used in the examples and comparative examples were purchased from Aldrich; ZSM-5 molecular sieves with different silica-alumina ratios were purchased from Shanghai Fuxu Molecular Sieve Co., Ltd.; alumina sol was purchased from Zibo Jiarun Chemical Co., Ltd.; and boehmite was purchased from Zibo Hengqi Powder New Materials Co., Ltd.

[0078] All other reagents used in the examples and comparative examples were purchased from Sinopharm Chemical Reagent Co., Ltd., and the reagent purity was analytical grade.

[0079] Example 1

[0080] This embodiment illustrates the propylene-enhancing catalyst for light gasoline cracking prepared according to the present invention, which contains a porous vermiculite-containing silica gel mesoporous composite material.

[0081] (1) Preparation of porous vermiculite-containing silica gel mesoporous composite materials

[0082] 0.002 mol of triblock copolymer P123, 0.001 mol of triblock copolymer F127 and 0.6 mol of ethanol were added to 300 mL of a buffer solution of acetic acid and sodium acetate (pH = 4.4). The mixture was stirred at 20 °C until P123 was completely dissolved. Then, 0.52 mol of trimethylpentane was added to the above solution and stirred at 20 °C for 6 hours. Then, 0.2 mol of tetramethoxysilane was added to the above solution and stirred at 20 °C for 20 hours. The solution was then transferred to a polytetrafluoroethylene-lined reactor and crystallized at 60 °C for 24 hours. After filtration and washing with distilled water, mesoporous molecular sieve filter cake 1 was obtained.

[0083] 0.35 mol of cetyltrimethylammonium bromide and 1.0 mol of tetraethyl orthosilicate were added to a 25% ammonia solution containing 3.0 mol of ammonia water, and diluted with 2880 g of deionized water. The mixture was stirred at 30°C until dissolved, and stirring was continued at 30°C for 3 h. The solution was filtered to obtain a mesoporous material filter cake, which was washed until the pH reached 7 to obtain mesoporous molecular sieve filter cake 2.

[0084] A mixture of 15% by weight water glass, 12% by weight sulfuric acid solution, and n-butanol in a weight ratio of 5:1:1 was reacted at 30°C for 2 hours. The pH was then adjusted to 3 with 98% by weight sulfuric acid. The resulting reaction mixture was then filtered and washed with distilled water until the sodium ion content was below 0.02% by weight, yielding a silica gel filter cake.

[0085] The prepared mesoporous molecular sieve filter cakes 1 and 2 (5g), vermiculite powder, and silica gel filter cake were placed together in a 100mL ball mill jar and sealed. The ball mill jar and grinding balls were made of agate, with a diameter of 3mm, and one ball was used at a rotation speed of 400 rpm. After ball milling at 60℃ for 3 hours, a solid powder was obtained. This solid powder was dissolved in 30g of deionized water and spray-dried at 200℃ and a rotation speed of 12000 rpm. The spray-dried product was then calcined in a muffle furnace at 500℃ for 24 hours to remove the template agent, yielding a porous vermiculite-containing silica gel mesoporous composite material A. The structural parameters of the porous vermiculite-containing silica gel mesoporous composite material A are listed in Table 1.

[0086] Figure 1 This is the X-ray diffraction pattern of porous vermiculite-containing silica gel mesoporous composite material A, where the horizontal axis represents 2θ (°) and the vertical axis represents intensity; from Figure 1 It can be seen that the porous vermiculite-containing silica gel mesoporous composite material A has the 2D hexagonal channel structure characteristic of mesoporous materials.

[0087] Figure 2 This is a SEM image of porous mesoporous composite material A containing vermiculite and silica gel. Figure 2 It can be seen that the microstructure of the porous vermiculite-containing silica gel mesoporous composite material A is mesoporous spheres with a particle size of 20-60 μm.

[0088] (2) Preparation of catalyst for increasing propylene production through light gasoline cracking

[0089] 27g of the porous vermiculite-silica mesoporous composite material A prepared in the above steps was mixed with 54g of ZSM-5 molecular sieve with a SiO2 / Al2O3 ratio of 300, 20g of pseudoboehmite with a water content of 30%, and 6g of guar gum powder. Then, 70mL of 5% dilute nitric acid was added, and the mixture was stirred until homogeneous before extrusion molding. The mixture was dried at 110℃ for 10 hours and finally calcined at 550℃ for 8 hours to obtain catalyst precursor A. 95g of catalyst precursor A was impregnated with 100mL of an aqueous solution containing calcium nitrate, cerium nitrate, and phosphoric acid, dried at 110℃ for 16 hours, and calcined at 580℃ for 8 hours to obtain catalyst A.

[0090] The composition of catalyst A is listed in Table 2.

[0091] (3) Catalyst performance testing

[0092] The performance of catalyst A in the catalytic cracking of light gasoline was evaluated in a fixed-bed reactor. The feedstock was C5-C8 light gasoline with the following composition: 7.71g n-alkanes, 40.49g isoalkanes, 51.46g olefins, and 0.36g cycloalkanes. The catalyst A charge was 5.0g, the reaction temperature was 540℃, the reaction pressure was 0.05MPa, and the feedstock weight hourly space velocity (WHSV) was 16h⁻¹. -1 After cooling and gas-liquid separation, the gas composition was analyzed using an Agilent 6890 gas chromatograph equipped with an Al2O3-S capillary column and a flame ionization detector (FID), with programmed temperature ramping and quantitative analysis using correction factors. The liquid composition was analyzed using an Agilent 6890 gas chromatograph equipped with a PONA column, with programmed temperature ramping and quantitative analysis using light gasoline standards. The reaction results are shown in Table 3.

[0093] Example 2-3

[0094] This embodiment illustrates the propylene-enhancing catalyst for light gasoline cracking prepared according to the present invention, which contains a porous vermiculite-containing silica gel mesoporous composite material.

[0095] Examples 2 and 3 were carried out in the same manner as steps (1) and (2) in Example 1, except that the preparation process of the porous vermiculite-containing silica mesoporous composite material in step (1) and the preparation process of the catalyst in step (2) were changed, as detailed in Table 1, and porous vermiculite-containing silica mesoporous composite materials B and C, as well as catalyst B and catalyst C were obtained respectively.

[0096] Table 1 lists the components, dosage, and preparation conditions of porous vermiculite-containing silica mesoporous composites B and C, as well as the structural parameters of the resulting porous vermiculite-containing silica mesoporous composites B and C.

[0097] Table 2 lists the composition of catalysts B and C.

[0098] The performance of catalysts B and C was evaluated using the same method as step (3) in Example 1, and the test results are listed in Table 3.

[0099] Example 4

[0100] This embodiment illustrates the propylene-enhancing catalyst for light gasoline cracking prepared according to the present invention, which contains a porous vermiculite-containing silica gel mesoporous composite material.

[0101] Catalyst D was prepared using the same method as in Example 1, except that the amounts of porous vermiculite-silica mesoporous composite material A, ZSM-5 molecular sieve, pseudoboehmite, guar gum powder, dilute nitric acid, and aqueous solution containing calcium nitrate, cerium nitrate, and phosphoric acid were changed, and the "aqueous solution containing calcium nitrate, cerium nitrate, and phosphoric acid" was replaced with "aqueous solution containing calcium nitrate, lanthanum nitrate, and boric acid".

[0102] The results showed that, based on the total weight of catalyst D, the content of ZSM-5 zeolite molecular sieve was 63 wt%, the content of porous vermiculite-silica mesoporous composite material A was 15 wt%, the content of alumina from the binder was 20 wt%, the content of calcium oxide was 0.5 wt%, the content of lanthanum oxide was 1.1 wt%, and the content of boron trioxide was 0.4 wt%.

[0103] The performance of catalyst D was evaluated using the same method as step (3) in Example 1, and the test results are listed in Table 3.

[0104] Comparative Example 1

[0105] Catalyst D1 was prepared using the same method as in Example 1, except that step (1) was omitted, and in step (2) the porous vermiculite-containing silica gel mesoporous composite material A was not used; instead, 160g of ZSM-5 molecular sieve with a SiO2 / Al2O3 ratio of 300 was used. Furthermore, the amounts of each component were changed, and the modified oxide precursor was modified. The results are shown in Table 2.

[0106] The performance of catalyst D1 was evaluated using the same method as step (3) in Example 1, and the test results are listed in Table 3.

[0107] Comparative Example 2

[0108] Catalyst D2 was prepared using the same method as in Example 1, except that step (1) was omitted, and in step (2) “50g of porous vermiculite-containing silica mesoporous composite material A” was replaced with “50g of commercially available silica”; and the amounts of each component were changed, as well as the modified oxide precursor was changed. The results are shown in Table 2.

[0109] The performance of catalyst D2 was evaluated using the same method as step (3) in Example 1, and the test results are listed in Table 3.

[0110] Comparative Example 3

[0111] Catalyst D3 was prepared using the same method as in Example 1, except that “high silica-alumina ratio ZSM-5 zeolite molecular sieve (SiO2 / Al2O3 is 300)” in step (1) was replaced with “low silica-alumina ratio ZSM-5 zeolite molecular sieve (SiO2 / Al2O3 is 50)”.

[0112] The performance of catalyst D3 was evaluated using the same method as step (3) in Example 1, and the test results are listed in Table 3.

[0113] Comparative Example 4

[0114] Catalyst D4 was prepared using the same method as in Example 1, except that the amounts of porous vermiculite-silica mesoporous composite material A, ZSM-5 molecular sieve, pseudoboehmite, guar gum powder, dilute nitric acid, and aqueous solution containing calcium nitrate, cerium nitrate, and phosphoric acid were changed, and the "aqueous solution containing calcium nitrate, cerium nitrate, and phosphoric acid" was replaced with "aqueous solution containing calcium nitrate, lanthanum nitrate, and phosphoric acid".

[0115] The results showed that, based on the total weight of catalyst D4, the content of ZSM-5 zeolite molecular sieve was 73 wt%, the content of porous vermiculite-silica mesoporous composite material A was 7 wt%, the content of alumina from the binder was 7 wt%, the content of calcium oxide was 5.1 wt%, the content of lanthanum oxide was 4.3 wt%, and the content of phosphorus pentoxide was 3.6 wt%.

[0116] The performance of catalyst D4 was evaluated using the same method as step (3) in Example 1, and the test results are listed in Table 3.

[0117] Table 1

[0118]

[0119]

[0120] Table 2

[0121]

[0122]

[0123] Table 3

[0124]

[0125] Table 3 shows that the catalyst provided by this invention exhibits excellent performance in the catalytic cracking of light gasoline to propylene. Comparing the data of catalyst A with catalysts D1 and D2 reveals that catalyst A contains a portion of porous vermiculite-silica mesoporous composite material, while catalysts D1 and D2 do not. Compared to catalysts D1 and D2, catalyst A shows significantly improved light gasoline olefin conversion, propylene selectivity, and catalyst stability. These results indicate that the superior performance of the light gasoline cracking propylene-enhancing catalyst provided by this invention is due to the presence of an appropriate amount of porous vermiculite-silica mesoporous composite material.

[0126] Comparing the data of catalysts A and D3 reveals that the light gasoline cracking catalyst for propylene production enhancement prepared using the hydrogen-form ZSM-5 molecular sieve with a low silica-to-alumina ratio exhibits poor performance. Although the olefin conversion rate in light gasoline is high in the initial stage of the reaction, the propylene selectivity is low. Furthermore, as the reaction progresses, the conversion rate and selectivity of catalyst D3 decrease significantly, while catalyst A maintains stable performance throughout the 100-hour reaction period. Moreover, the introduction of vermiculite and the extended reaction time are more conducive to improving the olefin conversion rate and propylene selectivity of light gasoline.

[0127] Comparing the data of catalyst A and catalyst D4, it can be seen that: if the content of zeolite molecular sieve is too high, the content of porous vermiculite-silica mesoporous composite material is too low, the content of binder oxide is too low, and the content of modified oxide is too high, the conversion rate and selectivity of catalyst D4 will be significantly reduced.

[0128] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. The application of a light gasoline cracking catalyst for enhancing propylene production in catalytic cracking, the application comprising: The process involves contacting a feedstock containing light gasoline with a light gasoline cracking catalyst for enhancing propylene production. The catalyst comprises a zeolite molecular sieve, a porous vermiculite-silica mesoporous composite material, a binding oxide, and a modified oxide; wherein the specific surface area of ​​the porous vermiculite-silica mesoporous composite material is 100-200 m² / g. 2 / g, pore volume is 1.4-1.8mL / g, pore size is distributed in four peaks, and the first most probable pore size corresponding to the four peaks is 1.2-1.9nm, the second most probable pore size is 2.6-2.7nm, the third most probable pore size is 3.5-3.9nm, and the fourth most probable pore size is 31-37nm. Based on the total weight of the light gasoline cracking catalyst for increasing propylene production, the content of the zeolite molecular sieve is 51-58% by weight, the content of the porous vermiculite-containing silica gel mesoporous composite material is 23-28% by weight, the content of the binder oxide is 11-19% by weight, and the content of the modified oxide is 3-7% by weight. The zeolite molecular sieve is a hydrogen-type high-silica ZSM-5 molecular sieve; the SiO2 / Al2O3 molar ratio of the hydrogen-type high-silica ZSM-5 molecular sieve is 100-800. The preparation method of the porous vermiculite-containing silica gel mesoporous composite material includes: (a) In the presence of a first template agent, a second template agent, trimethylpentane and ethanol, tetramethoxysilane is first contacted with an acidic aqueous solution, and the mixture after the first contact is crystallized, washed and filtered to obtain mesoporous molecular sieve filter cake 1; (b) The third template agent, tetraethyl orthosilicate and ammonia are brought into a second contact, and the mixture after the second contact is crystallized and filtered to obtain mesoporous molecular sieve filter cake 2; (c) Water glass, inorganic acid and n-butanol are brought into a third contact, and the mixture after the third contact is filtered to obtain silica gel filter cake; (d) The mesoporous molecular sieve filter cake 1, the mesoporous molecular sieve filter cake 2, vermiculite, and the silica gel filter cake are mixed and ball-milled. The solid powder after ball milling is slurried with water to obtain a slurry. The slurry is then spray-dried and calcined to obtain a porous mesoporous composite material containing vermiculite and silica gel.

2. The application according to claim 1, wherein, The SiO2 / Al2O3 molar ratio of the hydrogen-type high-silica ZSM-5 molecular sieve is 200-500.

3. The application according to claim 1, wherein, The weight ratio of the hydrogen-type high-silica ZSM-5 molecular sieve to the porous vermiculite-containing silica gel mesoporous composite material is (1.5-4.5):

1.

4. The application according to claim 1, wherein, The adhesive oxide is the product of the adhesive after calcination.

5. The application according to claim 4, wherein, The adhesive oxide is silicon oxide and / or aluminum oxide.

6. The application according to claim 4, wherein, The adhesive is selected from one or more of silica sol, alumina sol, pseudoboehmite, and diatomite.

7. The application according to claim 1, wherein, The modified oxide is selected from one or more of magnesium oxide, calcium oxide, strontium oxide, barium oxide, zinc oxide, boron oxide, cerium oxide, lanthanum oxide, zirconium dioxide, and phosphorus-containing oxides.

8. The application according to claim 1, wherein, In step (a), both the first template agent and the second template agent are triblock copolymers of polyethylene oxide-propylene oxide-ethylene oxide.

9. The application according to claim 1, wherein, The first template agent is P123, with the molecular formula EO. 20 PO 70 EO 20 The second template agent is F127, with the molecular formula EO. 106 PO 70 EO 106 .

10. The application according to claim 1, wherein, The molar ratio of the first template agent, the second template agent, ethanol, the acidic aqueous solution, trimethylpentane and tetramethoxysilane is 1:(0.1-2):(100-500):(150-900):(200-500):(50-200).

11. The application according to claim 10, wherein, The molar ratio of the first template agent, the second template agent, ethanol, the acidic aqueous solution, trimethylpentane and tetramethoxysilane is 1:(0.2-1):(200-400):(300-600):(250-400):(70-150).

12. The application according to claim 1, wherein, The conditions for the first contact include: a temperature of 10-40℃ and a time of 10-48h.

13. The application according to claim 1, wherein, In step (b), the third template agent is hexadecyltrimethylammonium bromide.

14. The application according to claim 1, wherein, The molar ratio of the tetraethyl orthosilicate, the third template agent, ammonia in the ammonia solution, and water in the ammonia solution is 1:(0.1-1):(0.1-5):(100-200).

15. The application according to claim 14, wherein, The molar ratio of the tetraethyl orthosilicate, the third template agent, ammonia in the ammonia solution, and water in the ammonia solution is 1:(0.2-0.5):(1.5-3.5):(120-180).

16. The application according to claim 1, wherein, The conditions for the second contact include: a temperature of 10-60°C and a time of 1-5 hours.

17. The application according to claim 1, wherein, In step (c), the inorganic acid is selected from one or more of sulfuric acid, nitric acid and hydrochloric acid.

18. The application according to claim 17, wherein, The weight ratio of the inorganic acid, n-butanol, and water glass is 1:(0.5-2):(3-6).

19. The application according to claim 1, wherein, The third contact conditions include: a temperature of 10-60℃, a time of 1-5h, and a pH value of 2-4.

20. The application according to claim 1, wherein, In step (d), based on 100 parts by weight of the mesoporous molecular sieve filter cake 1, the amount of the mesoporous molecular sieve filter cake 2 is 20-300 parts by weight, the amount of the silica gel filter cake is 50-500 parts by weight, and the amount of the vermiculite is 50-500 parts by weight.

21. The application according to claim 20, wherein, In step (d), based on 100 parts by weight of the mesoporous molecular sieve filter cake 1, the amount of the mesoporous molecular sieve filter cake 2 is 50-200 parts by weight, the amount of the silica gel filter cake is 100-300 parts by weight, and the amount of the vermiculite is 100-300 parts by weight.

22. The application according to claim 1, wherein, The roasting conditions include a temperature of 400-600℃ and a time of 10-60h.

23. The application according to claim 1, wherein, The preparation method of the light gasoline cracking catalyst for increasing propylene production includes: (1) In the presence of dilute nitric acid, zeolite molecular sieve, porous vermiculite-containing silica gel mesoporous composite material, binder and extrusion aid are mixed, extruded and subjected to a first calcination treatment to obtain catalyst precursor; (2) The catalyst precursor is immersed in an aqueous solution of the modified oxide precursor and then dried and calcined to obtain a light gasoline cracking catalyst for increasing propylene production.

24. The application according to claim 23, wherein, In step (1), relative to 500 mL of dilute nitric acid, the amount of the zeolite molecular sieve is 1000-1400 parts by weight, the amount of the porous vermiculite-silica mesoporous composite material is 400-600 parts by weight, the amount of the binder is 300-500 parts by weight, and the amount of the extrusion aid is 100-300 parts by weight.

25. In the application according to claim 23, in step (2), the amount of the catalyst precursor is 70-100 parts by weight relative to 100 mL of water, and the amount of the oxide precursor is 10-30 parts by weight.

26. The application according to claim 23, wherein, The modified oxide precursors include inorganic salts of metals and / or inorganic acids of nonmetals.

27. The application according to claim 26, wherein, The metal is selected from one or more of magnesium, calcium, strontium, barium, zinc, cerium, lanthanum, and zirconium, and the nonmetal is boron and / or phosphorus.

28. The application according to claim 23, wherein, The extrusion aid is selected from one or more of guar gum powder, cellulose, polyethylene glycol, polyvinyl alcohol, and starch.

29. The application according to claim 28, wherein, The extrusion aid is guar gum powder and / or polyethylene glycol.

30. The application according to claim 23, wherein, In step (1), the conditions for the first calcination include: a temperature of 500-600℃ and a time of 3-20h.

31. The application according to claim 23, wherein, In step (2), the conditions for the second calcination include: a temperature of 500-600℃ and a time of 4-10h.

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