Catalytic cracking catalysts, their preparation methods, and catalytic cracking methods

Abstract

This disclosure relates to a catalytic cracking catalyst, its preparation method, and a catalytic cracking method. The catalytic cracking method includes contacting a feedstock oil with the catalytic cracking catalyst to react, wherein the feedstock oil is a full-range oil or intermediate-base heavy oil, and the catalytic cracking catalyst contains a modified hollow ZSM-5 hierarchical porous molecular sieve, a nano-molecular sieve, a Y-type molecular sieve, and a support. The catalytic cracking method of this disclosure has a higher yield of low-carbon olefins.

Description

Technical Field

[0001] This disclosure relates to a catalytic cracking catalyst, its preparation method, and a catalytic cracking method. Background Technology

[0002] Low-carbon olefins, represented by ethylene and propylene, are important basic organic chemical raw materials and are hailed as the cornerstone of modern chemical industry. While many technologies exist both domestically and internationally for producing low-carbon olefins using catalytic cracking or catalytic pyrolysis units, processes for directly catalytically cracking crude oil into small-molecule olefins are rarely reported. Due to the significant differences in the cracking properties of reactant molecules in different fractions of whole-range crude oil, although the crude oil can be pre-divided to change the feed positions of light and heavy components, thereby altering the reaction conditions of the light and heavy fractions, achieving efficient conversion of light and heavy components within the same catalytic reaction system using the same catalyst remains the biggest challenge.

[0003] Heavy oil catalytic cracking is a process that converts heavy oil under more demanding conditions by using catalysts that produce more low-carbon olefins and adjusting reaction conditions, such as increasing the reaction temperature, based on catalytic cracking. The catalyst is a key factor affecting heavy oil catalytic cracking. Based on hydrocarbon composition, petroleum is generally classified into paraffinic, intermediate, and naphthenic types. In reality, all crude oil is a mixture of paraffinic and naphthenic crude oils; if the content of both is roughly equal, it is called intermediate-based crude oil. Intermediate-based heavy oils, with properties between paraffinic and naphthenic heavy oils, have similar alkane and cycloalkane contents, therefore the catalysts required to achieve satisfactory processing results often differ.

[0004] In catalysts for producing low-carbon olefins, ZSM-5 molecular sieves with MFI topology and β molecular sieves with BEA topology are commonly used. Although ZSM-5 molecular sieves have shape-selective properties, their small pore size is not conducive to the diffusion and adsorption of large molecular reactants, especially cyclic hydrocarbons, resulting in low yields of low-carbon olefins. Summary of the Invention

[0005] The purpose of this disclosure is to provide a catalytic cracking catalyst and its preparation method and catalytic cracking method, which can achieve efficient conversion of whole distillate oil or intermediate heavy oil and significantly improve the yield of low carbon olefins using a single catalyst.

[0006] To achieve the above objectives, the first aspect of this disclosure provides a catalytic cracking method, the method comprising: contacting a feedstock oil with a catalytic cracking catalyst to react, wherein the feedstock oil is a full-fraction oil or an intermediate-base heavy oil, and the catalytic cracking catalyst contains a modified hollow ZSM-5 hierarchical porous molecular sieve, a nano-molecular sieve, a Y-type molecular sieve, and a support.

[0007] Based on the dry weight of the catalytic cracking catalyst, the content of the modified hollow ZSM-5 hierarchical porous molecular sieve is 15-40% by weight, the content of the nano molecular sieve is 1-10% by weight, the content of the Y-type molecular sieve is 5-15% by weight, and the content of the support is 40-80% by weight.

[0008] The modified hollow ZSM-5 hierarchical porous molecular sieve contains a molecular sieve and phosphorus and metal components supported on the molecular sieve; the phosphorus-aluminum molar ratio of the modified hollow ZSM-5 hierarchical porous molecular sieve is 0.1-1.5; the content of the metal component, based on the dry basis weight of the modified hollow ZSM-5 hierarchical porous molecular sieve and calculated by the oxide content of the metal component, is 0.1-5 wt%; the modified hollow ZSM-5 hierarchical porous molecular sieve has a closed hollow structure, the average grain size of the modified hollow ZSM-5 hierarchical porous molecular sieve is 0.2-3.0 μm, and the ratio of bulk silicon-aluminum molar ratio to surface silicon-aluminum molar ratio is 1.0-1.5; the total specific surface area of ​​the modified hollow ZSM-5 hierarchical porous molecular sieve is 250-350 m² / s. 2 / g, mesoporous specific surface area is 20-100m² 2 / g, wherein the mesoporous specific surface area accounts for 15-40% of the total specific surface area, the strong Brønsted acid content accounts for 55-70% of the total Brønsted acid content, and the strong Leucite content accounts for 50-70% of the total Leucite content.

[0009] The pore size of the nanomolecular sieve is 0.56-0.75 nm.

[0010] Optionally, the feedstock oil is a full-fraction oil, and the reaction conditions include: a reaction temperature of 550-600℃; based on the dry weight of the catalytic cracking catalyst, the content of the modified hollow ZSM-5 hierarchical porous molecular sieve is 20-40% by weight, the content of the nano-molecular sieve is 1-5% by weight, the content of the Y-type molecular sieve is 5-15% by weight, and the content of the support is 40-80% by weight.

[0011] Optionally, the feedstock oil is intermediate-base heavy oil, and the reaction conditions include: a reaction temperature of 550-600℃; based on the dry weight of the catalytic cracking catalyst, the content of the modified hollow ZSM-5 hierarchical porous molecular sieve is 15-30% by weight, the content of the nano-molecular sieve is 5-10% by weight, the content of the Y-type molecular sieve is 5-10% by weight, and the content of the support is 50-75% by weight.

[0012] In a second aspect, this disclosure provides a catalytic cracking catalyst comprising a modified hollow ZSM-5 hierarchical porous molecular sieve, a nano-molecular sieve, a Y-type molecular sieve, and a support. Based on the dry weight of the catalytic cracking catalyst, the content of the modified hollow ZSM-5 hierarchical porous molecular sieve is 15-40% by weight, the content of the nano-molecular sieve is 1-10% by weight, the content of the Y-type molecular sieve is 5-15% by weight, and the content of the support is 40-80% by weight.

[0013] The modified hollow ZSM-5 hierarchical porous molecular sieve contains a molecular sieve and phosphorus and metal components supported on the molecular sieve; the phosphorus-aluminum molar ratio of the modified hollow ZSM-5 hierarchical porous molecular sieve is 0.1-1.5; the content of the metal component, based on the dry basis weight of the modified hollow ZSM-5 hierarchical porous molecular sieve and calculated by the oxide content of the metal component, is 0.1-5 wt%; the modified hollow ZSM-5 hierarchical porous molecular sieve has a closed hollow structure, the average grain size of the modified hollow ZSM-5 hierarchical porous molecular sieve is 0.2-3.0 μm, and the ratio of bulk silicon-aluminum molar ratio to surface silicon-aluminum molar ratio is 1.0-1.5; the total specific surface area of ​​the modified hollow ZSM-5 hierarchical porous molecular sieve is 250-350 m² / s. 2 / g, mesoporous specific surface area is 20-100m² 2 / g, wherein the mesoporous specific surface area accounts for 15-40% of the total specific surface area, the strong Brønsted acid content accounts for 55-70% of the total Brønsted acid content, and the strong Leucite content accounts for 50-70% of the total Leucite content.

[0014] The pore size of the nanomolecular sieve is 0.56-0.75 nm.

[0015] Optionally, the phosphorus-aluminum molar ratio of the modified hollow ZSM-5 hierarchical porous molecular sieve is 0.2-1.3;

[0016] The content of the metal component is 0.5-4% by weight, based on the dry basis weight of the modified hollow ZSM-5 multi-level porous molecular sieve and the oxide content of the metal component.

[0017] Optionally, the average grain size of the modified hollow ZSM-5 hierarchical porous molecular sieve is 0.5-3.0 μm, the ratio of the bulk silicon-aluminum molar ratio to the surface silicon-aluminum molar ratio is 1.0-1.3, and the relative crystallinity is 80-90%.

[0018] Optionally, the total specific surface area of ​​the modified hollow ZSM-5 hierarchical porous molecular sieve is 260-340 m². 2 / g, mesoporous specific surface area is 25-100m² 2 / g, wherein the mesoporous specific surface area accounts for 18-35% of the total specific surface area.

[0019] Optionally, the metal component is selected from one or more of lanthanum, cerium, tungsten, iron, cobalt, nickel, copper, manganese, zinc, tin, bismuth and gallium;

[0020] The nano-molecular sieve is one or more of the molecular sieves having AET, AFR, AFS, AFI, BEA, BOG, CFI, CON, GME, IFR, ISV, LTL, MEI, MOR, OFF and SAO structures; preferably at least one of Beta, SAPO-5, SAPO-40, SSZ-13, CIT-1, ITQ-7, ZSM-18, mordenite and sodium chalcogenide;

[0021] The Y-type molecular sieve is selected from one or more of the following: REY molecular sieve, DASY molecular sieve, USY molecular sieve, phosphorus-containing DASY molecular sieve, phosphorus-containing USY molecular sieve, PSRY molecular sieve, HRY molecular sieve, HSY molecular sieve, SCY molecular sieve, and RSCY molecular sieve.

[0022] Optionally, the carrier is selected from one or more of natural clay, alumina carrier, silica carrier, aluminum phosphate carrier and silica-alumina oxide carrier;

[0023] Preferably, the silica support is one or more of neutral silica sol, acidic silica sol, or alkaline silica sol; the alumina support is one or more of alumina sol, acidified boehmite, hydrated alumina, and activated alumina; the aluminum phosphate support is aluminum phosphate gel; and the aluminosilicate support is selected from one or more of solid aluminosilicate materials, aluminosilicate sol, and aluminosilicate gel.

[0024] Optionally, the support comprises a silica support; based on the dry weight of the catalytic cracking catalyst, the silica support contains 1-20% by weight of SiO2.

[0025] A third aspect of this disclosure provides a method for preparing the catalytic cracking catalyst described in the second aspect of this disclosure, the method comprising: drying and optionally calcining a slurry containing a support, a modified hollow ZSM-5 hierarchical porous molecular sieve, a nano-molecular sieve, a Y-type molecular sieve, and water.

[0026] Optionally, the preparation steps of the modified hollow ZSM-5 hierarchical porous molecular sieve include:

[0027] A first solution containing a first phosphorus source and a first metal source is mixed with hollow ZSM-5 multi-level porous molecular sieve raw material, and the resulting first slurry is subjected to a first drying and a first calcination, wherein the weight ratio of the first solution to the hollow ZSM-5 multi-level porous molecular sieve raw material is 1:(0.5-2.0).

[0028] Alternatively, the preparation steps of the modified hollow ZSM-5 hierarchical porous molecular sieve include:

[0029] S1. The second solution containing the second phosphorus source is mixed with the hollow ZSM-5 multi-level porous molecular sieve raw material, and the resulting second slurry is subjected to a second drying and a second calcination to obtain the first solid product; wherein, the weight ratio of the second solution containing the second phosphorus source to the hollow ZSM-5 multi-level porous molecular sieve raw material is 1:(0.5-2.0);

[0030] S2. The first solid product is subjected to hydrothermal treatment to obtain the second solid product;

[0031] S3. The third solution containing the second metal source is mixed with the second solid product, and the resulting third slurry is subjected to a third drying and a third calcination, wherein the weight ratio of the third solution containing the second metal source to the second solid product is 1:(0.5-2.0).

[0032] Optionally, the first phosphorus source and the second phosphorus source are each independently selected from one or more of phosphoric acid, ammonium dihydrogen phosphate, diammonium hydrogen phosphate and ammonium phosphate;

[0033] The first metal source and the second metal source are each independently selected from one or more of the nitrates, chlorides and sulfates of metals, and the metals are selected from one or more of lanthanum, cerium, tungsten, iron, cobalt, nickel, copper, manganese, zinc, tin, bismuth and gallium;

[0034] The hollow ZSM-5 multi-stage porous molecular sieve raw material is an H-type hollow ZSM-5 multi-stage porous molecular sieve.

[0035] Optionally, the conditions for the hydrothermal treatment include: a temperature of 400-800℃ and a time of 1-12 hours;

[0036] The conditions for the first drying, the second drying, and the third drying each independently include: a temperature of 90-120℃ and a time of 2-24 hours;

[0037] The conditions for the first roasting, the second roasting, and the third roasting each independently include: a temperature of 450-600℃ and a time of 2-6 hours.

[0038] Through the above technical solution, this disclosure uses modified hollow ZSM-5 hierarchical porous molecular sieve combined with nano molecular sieve and Y-type molecular sieve as the main active component of the catalyst. When used in the catalytic cracking of whole distillate oil or intermediate heavy oil, it can achieve efficient conversion of multiple components and improve the yield of target products.

[0039] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0040] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings:

[0041] Figure 1 Here is a SEM image of the phosphorus hollow ZSM-5 hierarchical porous molecular sieve prepared in Example 1 of this disclosure;

[0042] Figure 2 Here is a SEM image of the phosphorus hollow ZSM-5 hierarchical porous molecular sieve prepared in Example 2 of this disclosure;

[0043] Figure 3 These are SEM images of the nano-molecular sieves in Examples 4-6 of this disclosure;

[0044] Figure 4 These are SEM images of the Y-type molecular sieves in Examples 4-6 of this disclosure. Detailed Implementation

[0045] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0046] In a first aspect, this disclosure provides a catalytic cracking method, the method comprising: contacting a feedstock oil with a catalytic cracking catalyst to react, wherein the feedstock oil is a full-fraction oil or an intermediate-base heavy oil, and the catalytic cracking catalyst contains a modified hollow ZSM-5 hierarchical porous molecular sieve, a nano-molecular sieve, a Y-type molecular sieve, and a support.

[0047] Based on the dry weight of the catalytic cracking catalyst, the modified hollow ZSM-5 hierarchical porous molecular sieve comprises 15-40% by weight, the nano-molecular sieve comprises 1-10% by weight, the Y-type molecular sieve comprises 5-15% by weight, and the support comprises 40-80% by weight; the modified hollow ZSM-5 hierarchical porous molecular sieve contains molecular sieves and phosphorus and metal components supported on the molecular sieves; the phosphorus-aluminum molar ratio of the modified hollow ZSM-5 hierarchical porous molecular sieve is 0.1-1.5. The content of the metal component, calculated based on the oxide content of the metal component and using the dry basis weight of the modified hollow ZSM-5 hierarchical porous molecular sieve, is 0.1-5% by weight. The modified hollow ZSM-5 hierarchical porous molecular sieve has a closed hollow structure, an average grain size of 0.2-3.0 μm, and a bulk silicon-aluminum molar ratio to surface silicon-aluminum molar ratio of 1.0-1.5. The total specific surface area of ​​the modified hollow ZSM-5 hierarchical porous molecular sieve is 250-350 m² / s. 2 / g, mesoporous specific surface area is 20-100m² 2 / g, wherein the mesoporous specific surface area accounts for 15-40% of the total specific surface area, the strong Brønsted acid content accounts for 55-70% of the total Brønsted acid content, and the strong Lewis acid content accounts for 50-70% of the total Lewis acid content; the pore size of the nanomolecular sieve is 0.56-0.75nm.

[0048] In one specific embodiment of this disclosure, the feedstock oil is a full-fraction oil, and the reaction conditions include: a reaction temperature of 550-600℃; based on the dry weight of the catalytic cracking catalyst, the content of the modified hollow ZSM-5 hierarchical porous molecular sieve is 20-40% by weight, the content of the nano-molecular sieve is 1-5% by weight, the content of the Y-type molecular sieve is 5-15% by weight, and the content of the support is 40-80% by weight. The full-fraction oil catalytic cracking method of this disclosure uses a special catalyst containing modified hollow ZSM-5 hierarchical porous molecular sieve, which can achieve efficient conversion of light and heavy components and improve the yield of the target product.

[0049] In another specific embodiment of this disclosure, the feedstock oil is intermediate-based heavy oil, and the reaction conditions include: a reaction temperature of 550-600℃; based on the dry weight of the catalytic cracking catalyst, the content of the modified hollow ZSM-5 hierarchical porous molecular sieve is 15-30% by weight, the content of the nano-molecular sieve is 5-10% by weight, the content of the Y-type molecular sieve is 5-10% by weight, and the content of the support is 50-75% by weight. The intermediate-based heavy oil catalytic cracking method of this disclosure uses a special catalyst containing modified hollow ZSM-5 hierarchical porous molecular sieve, which can achieve efficient conversion of multiple components such as alkanes and cycloalkanes, and improve the yield of the target product.

[0050] In a second aspect, this disclosure provides the aforementioned catalytic cracking catalyst, which comprises a modified hollow ZSM-5 hierarchical porous molecular sieve, a nano-molecular sieve, a Y-type molecular sieve, and a support. Based on the dry weight of the catalytic cracking catalyst, the content of the modified hollow ZSM-5 hierarchical porous molecular sieve is 15-40% by weight, the content of the nano-molecular sieve is 1-10% by weight, the content of the Y-type molecular sieve is 5-15% by weight, and the content of the support is 40-80% by weight. The modified hollow ZSM-5 hierarchical porous molecular sieve comprises a molecular sieve and phosphorus and metal components supported on the molecular sieve. The modified hollow ZSM-5 hierarchical porous molecular sieve has a phosphorus-aluminum molar ratio of 0.1-1.5; the content of the metal component, based on the dry basis weight of the modified hollow ZSM-5 hierarchical porous molecular sieve and calculated as oxides of the metal component, is 0.1-5% by weight; the modified hollow ZSM-5 hierarchical porous molecular sieve has a closed hollow structure, the average grain size of the modified hollow ZSM-5 hierarchical porous molecular sieve is 0.2-3.0 μm, and the ratio of bulk silicon-aluminum molar ratio to surface silicon-aluminum molar ratio is 1.0-1.5; the total specific surface area of ​​the modified hollow ZSM-5 hierarchical porous molecular sieve is 250-350 m² / s. 2 / g, mesoporous specific surface area is 20-100m² 2 / g, wherein the mesoporous specific surface area accounts for 15-40% of the total specific surface area, the strong Brønsted acid content accounts for 55-70% of the total Brønsted acid content, and the strong Lewis acid content accounts for 50-70% of the total Lewis acid content; the pore size of the nanomolecular sieve is 0.56-0.75nm.

[0051] The catalytic cracking catalyst disclosed herein contains a modified hollow ZSM-5 hierarchical porous molecular sieve, which has a multi-level porous structure of micropores-mesopores-mesopores, providing multi-directional diffusion pathways, expanding the confined space, improving the accessibility of active centers, and optimizing the diffusion performance of the molecular sieve. It also contains phosphorus and metal components, which further effectively modify the active sites. When combined with nano-molecular sieves and Y-type molecular sieves, its application in the catalytic cracking of whole-fraction oil or intermediate-base heavy oil can effectively improve the yield of low-carbon olefins.

[0052] In one specific embodiment of this disclosure, the phosphorus-aluminum molar ratio (P / Al) of the modified hollow ZSM-5 hierarchical porous molecular sieve is 0.2-1.3; the content of the metal component, based on the dry weight of the metal-modified hollow ZSM-5 hierarchical porous molecular sieve composite material and calculated as the oxide content of the metal component, is 0.5-4% by weight. In this disclosure, the phosphorus-aluminum molar ratio of the modified hollow ZSM-5 hierarchical porous molecular sieve is determined by XRF fluorescence method, and the content of the metal component is determined by XRF fluorescence method.

[0053] In one specific embodiment of this disclosure, the average grain size of the modified hollow ZSM-5 hierarchical porous molecular sieve crystals is 0.5-3.0 μm, the ratio of the bulk silicon-aluminum molar ratio (based on SiO2 / Al2O3) to the surface silicon-aluminum molar ratio (based on SiO2 / Al2O3) is 1.0-1.3, and the relative crystallinity is 80-90%. In this disclosure, grain size refers to the size of the widest part of the grain, which can be obtained by measuring the widest part of the grain projection plane in the SEM or TEM image of the sample. The average grain size is obtained by selecting any 10 molecular sieves from the SEM or TEM image and calculating their average value. The bulk silicon-aluminum molar ratio refers to the overall silicon-aluminum molar ratio of the ZSM-5 nanocrystalline material, which is determined by the XRF method. The surface silicon-aluminum molar ratio is determined by the XPS method. The specific testing methods are well known to those skilled in the art and will not be elaborated here. The bulk silicon-aluminum molar ratio is 15-200. In this disclosure, the relative crystallinity of the molecular sieve is based on the XRD standard ZSM-5 molecular sieve standard from the China Petroleum and Chemical Research Institute, and the crystallinity of the standard is considered to be 100%.

[0054] In one specific embodiment of this disclosure, the modified hollow ZSM-5 hierarchical porous molecular sieve has a total specific surface area of ​​260-340 m². 2 / g, mesoporous specific surface area is 25-100m² 2 / g, wherein the mesoporous specific surface area accounts for 18-35% of the total specific surface area, and the N2 adsorption-desorption curve exhibits an H4-type hysteresis loop. In this disclosure, the total specific surface area and mesoporous specific surface area are obtained using BET analysis.

[0055] In one specific embodiment of this disclosure, the proportion of the strong Brønsted acid to the total Brønsted acid is 55-68%, and the proportion of the strong Leucine to the total Leucine is 50-65%. The amounts of the strong Brønsted acid and the total Brønsted acid are prepared using a pyridine infrared acidic method, and the amounts of the strong Leucine and the total Leucine are also prepared using a pyridine infrared acidic method.

[0056] According to this disclosure, the metal component is selected from one or more of Group VIIB, Group VIII, Group IIIB, Group IIIA, and Group IIB metals. In one specific embodiment of the invention, the metal component is selected from one or more of lanthanum, cerium, tungsten, iron, cobalt, nickel, copper, manganese, zinc, tin, bismuth, and gallium.

[0057] According to this disclosure, the nano-molecular sieve can be one or more of the molecular sieves having AET, AFR, AFS, AFI, BEA, BOG, CFI, CON, GME, IFR, ISV, LTL, MEI, MOR, OFF and SAO structures; preferably at least one of Beta, SAPO-5, SAPO-40, SSZ-13, CIT-1, ITQ-7, ZSM-18, mordenite and sodium chalcogenide.

[0058] According to this disclosure, the Y-type molecular sieve can be a hydrothermally stabilized or gas-phase stabilized Y-type molecular sieve. The Y-type molecular sieve may contain rare earth elements or not; specifically, the rare earth content of the Y-type molecular sieve, calculated as rare earth element oxides (RE2O3), is 0-25% by weight, and the rare earth element can be lanthanum and / or cerium. The Y-type molecular sieve may contain phosphorus or not; specifically, the phosphorus content of the Y-type molecular sieve, calculated as P2O5, is 0-10% by weight. The Y-type molecular sieve can be selected from one or more of REY molecular sieves, DASY molecular sieves, USY molecular sieves, phosphorus-containing DASY molecular sieves, phosphorus-containing USY molecular sieves, PSRY molecular sieves, HRY molecular sieves, HSY molecular sieves, SCY molecular sieves, and RSCY molecular sieves.

[0059] According to this disclosure, the carrier is selected from one or more of natural clay, alumina carrier, silica carrier, aluminum phosphate carrier, and aluminosilicate carrier. In one embodiment, the silica carrier is one or more of neutral silica sol, acidic silica sol, or alkaline silica sol; the alumina carrier is one or more of alumina sol, acidified boehmite, hydrated alumina, and activated alumina; the aluminum phosphate carrier is aluminum phosphate gel; and the aluminosilicate carrier is selected from one or more of solid aluminosilicate materials, aluminosilicate sol, and aluminosilicate gel.

[0060] In one specific embodiment of this disclosure, the support comprises a silica support; based on the dry weight of the catalytic cracking catalyst, the silica support has a SiO2 content of 1-20% by weight.

[0061] In one specific embodiment of this disclosure, based on the dry weight of the catalytic cracking catalyst, the catalytic cracking catalyst contains 20-40 wt% modified hollow ZSM-5 hierarchical porous molecular sieve, 1-5 wt% nano-molecular sieve, 5-15 wt% Y-type molecular sieve, 20-60 wt% (e.g., 25-50 wt%) clay, 5-35 wt% (e.g., 10-30 wt%) acidified pseudoboehmite, 3-25 wt% (e.g., 5-15 wt% or 3-20 wt%) alumina sol, and 0-15 wt% (e.g., 3-10 wt% or 5-15 wt%) silica sol.

[0062] In one specific embodiment of this disclosure, based on the dry weight of the catalytic cracking catalyst, the sodium oxide content in the catalytic cracking catalyst is preferably less than 0.15% by weight.

[0063] A third aspect of this disclosure provides a method for preparing the aforementioned catalytic cracking catalyst, the method comprising: drying and optionally calcining a slurry containing a support, a modified hollow ZSM-5 hierarchical porous molecular sieve, a nano-molecular sieve, a Y-type molecular sieve, and water. This disclosure does not limit the specific form of drying, which can be conventionally used by those skilled in the art. In a preferred embodiment, the drying is spray drying, which can simultaneously dry the material and shape the catalyst. Spray drying is well known to those skilled in the art, and specific methods will not be described in detail here.

[0064] In one specific embodiment of this disclosure, the preparation steps of the modified hollow ZSM-5 hierarchical porous molecular sieve include: mixing a first solution containing a first phosphorus source and a first metal source with hollow ZSM-5 hierarchical porous molecular sieve raw material; subjecting the resulting first slurry to a first drying and a first calcination; wherein the weight ratio of the first solution to the hollow ZSM-5 hierarchical porous molecular sieve raw material is 1:(0.5-2.0). In a preferred specific embodiment, this step includes: adding the first solution containing the first phosphorus source and the first metal source dropwise to the flatly spread hollow ZSM-5 hierarchical porous molecular sieve raw material, making the molecular sieve raw material appear as a "viscous paste".

[0065] According to this disclosure, the weight ratio of the first solution to the hollow ZSM-5 multi-level porous molecular sieve raw material can vary within a wide range, for example, it can be 1:(0.5-2.0), preferably 1:(0.8-1.5).

[0066] In another embodiment, the preparation steps of the modified hollow ZSM-5 hierarchical porous molecular sieve include: S1, mixing a second solution containing a second phosphorus source with hollow ZSM-5 hierarchical porous molecular sieve raw material, and subjecting the resulting second slurry to a second drying and a second calcination to obtain a first solid product, wherein the weight ratio of the second solution containing the second phosphorus source to the hollow ZSM-5 hierarchical porous molecular sieve raw material is 1:(0.5-2.0), and the second solution containing the second phosphorus source is calculated as P; S2, subjecting the first solid product to hydrothermal treatment to obtain a second solid product; S3, mixing a third solution containing a second metal source with the second solid product, and subjecting the resulting third slurry to a third drying and a third calcination, wherein the weight ratio of the third solution containing the second metal source to the second solid product is 1:(0.5-2.0), and the third solution containing the second metal source is calculated as a metal oxide. In a preferred embodiment, step S1 includes: adding a second solution containing a second phosphorus source dropwise to a flat, hollow ZSM-5 multi-level porous molecular sieve raw material, so that the molecular sieve raw material is in the form of a "viscous paste".

[0067] According to this disclosure, the first phosphorus source and the second phosphorus source are each independently selected from one or more of phosphoric acid, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, and ammonium phosphate; the first metal source and the second metal source are each independently selected from one or more of nitrates, chlorides, and sulfates of metals, wherein the metal can be selected from one or more of Group VIIB, Group VIII, Group IIIB, Group IIIA, and Group IIB metals, preferably one or more of lanthanum, cerium, tungsten, iron, cobalt, nickel, copper, manganese, zinc, tin, bismuth, and gallium; the hollow ZSM-5 hierarchical porous molecular sieve raw material can be commercially available or prepared by the manufacturer. In one embodiment, the ratio of the bulk silicon-aluminum molar ratio to the surface silicon-aluminum molar ratio of the hollow ZSM-5 hierarchical porous molecular sieve raw material can be 1.0-1.5, and the total specific surface area can be 340-420 m². 2 / g, mesoporous specific surface area can be 15-150m² 2 / g; Preferably, the hollow ZSM-5 multi-level porous molecular sieve raw material is an H-type hollow ZSM-5 multi-level porous molecular sieve, and the sodium oxide content of the H-type hollow ZSM-5 multi-level porous molecular sieve is less than 0.1% by weight.

[0068] According to this disclosure, hydrothermal treatment is well known to those skilled in the art, and can be carried out, for example, in a heat-resistant, sealed container. The conditions for the hydrothermal treatment include: a temperature of 400-800°C and a time of 1-12 hours. This invention does not limit the pressure of the hydrothermal treatment; it can be carried out under the autogenous pressure of the reaction system or under an applied pressure, preferably under autogenous pressure.

[0069] According to this disclosure, drying is a technique conventionally employed by those skilled in the art, and can be carried out, for example, in a constant temperature drying oven. The conditions for the first drying, the second drying, and the third drying can each independently include: a temperature of 90-120°C and a time of 2-24 hours.

[0070] According to this disclosure, roasting is a conventional technique used by those skilled in the art, and can be carried out in a muffle furnace, tube furnace, etc. The conditions for the first roasting, the second roasting, and the third roasting can each independently include: a temperature of 450-600°C and a time of 2-6 hours. This invention does not impose specific limitations on the roasting atmosphere; for example, it can be an air atmosphere, an inert gas atmosphere, etc.

[0071] In one specific embodiment of this disclosure, hollow ZSM-5 hierarchical porous molecular sieve raw material is prepared by a method including the following steps: (1) mixing and stirring a first organosilicon source and a first solvent at 30-50°C for 0.5-5 hours, then heating to 70-100°C and mixing and stirring for 2-10 hours, and mixing the resulting mixed liquid with a first template agent at 20-30°C for 0.5-3.0 hours to obtain a first mixed product; (2) mixing a first alkali metal hydroxide (calculated as alkali metal oxide), a second solvent, and a first aluminum source (calculated as Al2O3) in a molar ratio of (1.5-5):(60-350):1 at 20-80°C for 0.5-2.0 hours. (3) The first mixed product and the second mixed product are mixed and then subjected to dynamic crystallization. The resulting solid is taken out and subjected to a fourth calcination to obtain a third solid product. (4) The third solid product is mixed with an alkaline first solution and heated to the reaction temperature at a heating rate of 1-5℃ / min. The reaction is carried out at the reaction temperature for 10-90min to obtain a fourth solid product. The reaction temperature is 60-90℃ and the alkaline content in the alkaline first solution is 0.45-2mol / L. (5) The fourth solid product is subjected to a first ammonium exchange and optionally subjected to a sixth calcination to obtain hollow ZSM-5 multi-level porous molecular sieve raw material.

[0072] According to this disclosure, the total amount of the first template agent, the first solvent, and the second solvent, and the molar ratio of the first alkali metal hydroxide to the first organosilicon source can vary within a wide range, for example, it can be (0.06-0.55):(10-100):(0.02-1.5):1, preferably (0.1-0.50):(15-85):(0.03-1.2):1, and the molar ratio of the first organosilicon source to the first aluminum source can be (20-500):1; wherein, the first organosilicon source is calculated as SiO2, the first alkali metal hydroxide is calculated as an alkali metal oxide (for example, when the first alkali metal hydroxide is NaOH, it is calculated as Na2O), and the first aluminum source is calculated as Al2O3. In one embodiment, the first template agent and the first alkali metal hydroxide contain OH. - The ratio of the total molar amount to the molar amount of the first organosilicon source, calculated as SiO2, is (0.01-1.5):1, preferably (0.02-1.2):1.

[0073] According to this disclosure, in step (2), the molar ratio of the first alkali metal hydroxide (calculated as alkali metal oxide), the second solvent, and the first aluminum source (calculated as Al2O3) is preferably (2.0-4.5):(80-350):1.

[0074] According to this disclosure, in step (3), dynamic crystallization is well known to those skilled in the art, and the conditions for dynamic crystallization may include: a temperature of 80-200°C and a time of 4-80 hours; preferably, a temperature of 160-180°C and a time of 12-60 hours.

[0075] According to this disclosure, in step (4), the weight ratio of the third solid product to the amount of the first alkali-containing solution can be 1:(2-10), preferably 1:(8-10); the ratio of the bulk silicon-aluminum molar ratio and the surface silicon-aluminum molar ratio of the third solid product can be 1.2-5.0.

[0076] According to this disclosure, in step (5), the first ammonium exchange of the fourth solid product includes: mixing the fourth solid product, the first ammonium source, and the fifth solvent in a weight ratio of 1:(0.5-1.0):(8-10), and reacting the resulting mixture at 70-90°C for 0.5-5 hours. The first ammonium source is selected from one or more of ammonium chloride, ammonium sulfate, and ammonium nitrate. Optionally, the product obtained from the first ammonium exchange is filtered, washed, and dried; optionally, the product obtained from the first ammonium exchange is subjected to a sixth calcination; preferably, the product obtained from the first ammonium exchange is filtered, washed, and dried before undergoing a sixth calcination; the temperature of the sixth calcination can be 400-600°C, and the time can be 1-24 hours, preferably 1-10 hours or 1.5-6 hours, more preferably, the temperature is 450-580°C, and the time is 2-4.5 hours.

[0077] In one embodiment, compared with the third solid product, the hollow ZSM-5 multi-level porous molecular sieve raw material has a 100-500% increase in mesopore specific surface area, a 150-600% increase in mesopore volume, and a 50-250% increase in total acidity.

[0078] In another specific embodiment of this disclosure, hollow ZSM-5 hierarchical porous molecular sieve raw material is prepared by a method including the following steps: S1, mixing a second template agent, a second inorganic silicon source, and a third solvent at 30-50°C for 0.5-3.0 hours, and subjecting the resulting third mixed product to a first hydrothermal treatment and a second hydrothermal treatment in sequence to obtain a fourth mixed product; wherein, the conditions for the first hydrothermal treatment include: a temperature of 80-150°C and a time of 1-6 hours; the conditions for the second hydrothermal treatment include: a temperature of 160-180°C and a time of 12-60 hours; S2, mixing a second alkali metal hydroxide (calculated as alkali metal oxide), a fourth solvent, and a third solvent (calculated as Al2O3) in a molar ratio of (1.5-5):(60-350):1. Two aluminum sources are mixed at 20-80℃ for 0.5-2.0 hours to obtain a fifth mixed product; S3, the fourth mixed product and the fifth mixed product are mixed, and the resulting mixture is subjected to a third hydrothermal treatment. The resulting solid is taken out and subjected to a fifth calcination to obtain a fifth solid product; S4, the fifth solid product is mixed with a second alkaline solution, and the temperature is raised to the reaction temperature at a heating rate of 1-5℃ / min. The reaction is carried out at the reaction temperature for 10-90 min to obtain a sixth solid product, wherein the reaction temperature is 60-90℃ and the alkaline content in the second alkaline solution is 0.45-2 mol / L; S5, the sixth solid product is subjected to a second ammonium exchange and optionally a seventh calcination to obtain hollow ZSM-5 multi-level porous molecular sieve raw material.

[0079] According to this disclosure, the molar ratio of the total amount of the second template agent, the third solvent, and the fourth solvent, and the amount of the second alkali metal hydroxide and the second inorganic silicon source is (0.06-0.55):(10-100):(0.02-1.5):1, preferably (0.10-0.50):(15-85):(0.03-1.2):1, and the molar ratio of the second inorganic silicon source to the second aluminum source is (20-500):1; wherein the second inorganic silicon source is calculated as SiO2, the second alkali metal hydroxide is calculated as an alkali metal oxide (for example, when the second alkali metal hydroxide is NaOH, the second alkali metal hydroxide is calculated as Na2O), and the second aluminum source is calculated as Al2O3. In one embodiment, the second template agent and the second alkali metal hydroxide contain OH. - The ratio of the total molar amount to the molar amount of the second inorganic silicon source in terms of SiO2 (abbreviated as OH / SiO2) is (0.01-1.5):1, preferably (0.02-1.2):1.

[0080] According to this disclosure, hydrothermal treatment is well known to those skilled in the art, and can be carried out, for example, in a heat-resistant, sealed container. The present invention does not limit the conditions of hydrothermal treatment; it can be carried out under the autogenous pressure of the reaction system or under applied pressure, preferably under autogenous pressure.

[0081] According to this disclosure, in step S2, the molar ratio of the second alkali metal hydroxide (calculated as alkali metal oxide), the fourth solvent, and the second aluminum source (calculated as Al2O3) is preferably (2.0-4.5):(80-350):1.

[0082] In one embodiment, in step S3, the conditions for the third hydrothermal treatment include: 160-180°C for 12-60 hours.

[0083] According to this disclosure, in step S4, the weight ratio of the fifth solid product to the second alkali-containing solution is 1:(2-10), preferably 1:(8-10), and the ratio of the bulk silicon-aluminum molar ratio to the surface silicon-aluminum molar ratio of the fifth solid product is 1.2-5.0.

[0084] According to this disclosure, in step S5, the second ammonium exchange of the sixth solid product includes: mixing the sixth solid product, the second ammonium source, and the sixth solvent in a weight ratio of 1:(0.5-1.0):(8-10), and reacting the resulting mixture at 70-90°C for 0.5-2 hours. The second ammonium source is selected from one or more of ammonium chloride, ammonium sulfate, and ammonium nitrate. Optionally, the product obtained from the second ammonium exchange is filtered, washed, and dried; alternatively, the product obtained from the second ammonium exchange is subjected to a seventh calcination; preferably, the product obtained from the second ammonium exchange is filtered, washed, and dried before undergoing a seventh calcination; the temperature of the seventh calcination can be 400-600°C, and the time can be 1-24 hours, preferably 1-10 hours or 1.5-6 hours, more preferably, the temperature is 450-580°C, and the time is 2-4.5 hours.

[0085] According to this disclosure, compared with the fifth solid product, the hollow ZSM-5 hierarchical porous molecular sieve has a mesopore specific surface area increased by 100-500%, a mesopore volume increased by 150-600%, and a total acid content increased by 50-250%.

[0086] In one embodiment, the conditions for the fourth and fifth calcinations each independently include: a temperature of 400-600°C and a time of 2-6 hours, preferably a temperature of 450-580°C and a time of 3-5 hours.

[0087] According to this disclosure, the first organosilicon source is selected from one or more of methyl orthosilicate and tetraethyl orthosilicate; the second inorganic silicon source is selected from one or more of silica sol, water glass, and solid silica gel; the first template agent and the second template agent are each independently selected from one or more of tetrapropylammonium bromide, tetrapropylammonium hydroxide, n-butylamine, and hexamethylenediamine; the first aluminum source and the second aluminum source are each independently selected from one or more of sodium aluminate, aluminum sulfate, aluminum nitrate, aluminum isopropoxide, and aluminum sol; the first alkali metal hydroxide and the second alkali metal hydroxide are each independently selected from one or more of lithium hydroxide, sodium hydroxide, and potassium hydroxide; the first alkaline solution and the second alkaline solution are each independently selected from one or more of sodium hydroxide solution, potassium hydroxide solution, lithium hydroxide, and barium hydroxide.

[0088] According to this disclosure, in one embodiment, the first solvent, the second solvent, the third solvent, the fourth solvent, the fifth solvent, and the sixth solvent are each water.

[0089] The present disclosure will be further illustrated by the following examples, but the present disclosure is not limited thereto.

[0090] Unless otherwise specified, all raw materials used in the following examples and comparative examples were commercially available. Kaolin was an industrial product of China Kaolin Corporation, with a solid content of 75% by weight; boehmite was produced by Shandong Aluminum Plant, with an alumina content of 65% by weight; alumina sol was produced by Qilu Branch of Sinopec Catalyst Co., Ltd., with an alumina content of 21% by weight; silica sol was produced by Beijing Chemical Plant, with a silica content of 25% by weight (acidic silica sol, pH 3.0); concentrated hydrochloric acid was chemically pure and produced by Beijing Chemical Plant. β-molecular sieve, grade BETA-25-NKC, with a pore size of 0.59 nm, was produced by Tianjin Nanhua Catalyst Co., Ltd., and its SEM image is shown below. Figure 3 As shown. Y-type molecular sieve, grade SCY-12, rare earth content 12% by weight, produced by Qilu Branch of Sinopec Catalyst Co., Ltd., its SEM image is shown below. Figure 4 As shown.

[0091] In the examples and comparative examples, the crystal size of the molecular sieve was measured by SEM. Ten crystal sizes were randomly measured, and the average value was taken to obtain the average crystal size of the molecular sieve sample.

[0092] The bulk silica-alumina ratio of the samples was determined by XRF using a ZSX Primus II (Rigaku) ​​X-ray fluorescence spectrometer. Test conditions included an excitation voltage of 50 kV, an excitation current of 50 mA, and rhodium and palladium. The elemental composition of the molecular sieve was analyzed by measuring the peak intensity of each element using a scintillation counter and a proportional counter.

[0093] The surface silicon-to-aluminum molar ratio of the samples was determined by XPS using a Thermo Fisher ESCALab 250 X-ray photoelectron spectrometer. The testing conditions were: monochromatic Al Kα X-rays as the excitation source, excitation energy 1496.6 eV, and power 150 W. The electron binding energy was corrected using the C1s peak (284.8 eV) of the contaminating carbon.

[0094] The total specific surface area, mesoporous specific surface area, and N2 adsorption-desorption curves of the samples were determined using the BET adsorption-desorption total analysis method. Instrument: Micromeritics ASAP 2420 adsorption analyzer (USA). Test conditions: The samples were degassed under vacuum at 100℃ and 300℃ for 0.5 h and 6 h, respectively, and then N2 adsorption-desorption tests were conducted at 77.4 K. The adsorption and desorption amounts of nitrogen in the purified samples under different specific pressures were measured, and N2 adsorption-desorption isotherms were obtained. The BET specific surface area was calculated using the BET formula, the micropore area was calculated using t-plot, and the pore size distribution was calculated using the BJH method.

[0095] The relative crystallinity of the samples was determined by X-ray diffraction. Instrument: Empyrean. Test conditions: tube voltage 40kV, tube current 40mA, Cu target Kα radiation, 2θ scan range 5°-35°, scan rate 2 (°) / min.

[0096] The phosphorus-aluminum molar ratio of the sample was determined using X-ray fluorescence spectrometry. Instrument: ZSX Primus II (Rigaku) ​​X-ray fluorescence spectrometer. Test conditions: excitation voltage 50 kV, excitation current 50 mA, rhodium-palladium. The intensity of each elemental peak was determined using a scintillation counter and a proportional counter to analyze the elemental composition of the molecular sieve.

[0097] The content of metal components in the sample was determined by X-ray fluorescence method, under the same detection conditions as above.

[0098] The amounts of strong Brønsted acid and total Brønsted acid in the samples were determined using pyridine infrared adsorption. The amounts of strong Lewis acid and total Lewis acid were also determined using the same method. Instrument: NICOLET 6700 Fourier transform infrared spectrometer (BIQ-RAD, USA). Test method: The samples were compressed into pellets and sealed in the in-situ cell of the infrared spectrometer. Adsorption and desorption were performed according to the set program. The amount of pyridine-adsorbed acid was calculated based on the peak area.

[0099] Examples 1-3 are examples of preparing modified hollow ZSM-5 hierarchical porous molecular sieves.

[0100] Example 1

[0101] (1) Weigh 456.0 g of tetraethyl orthosilicate, add 3115.7 g of deionized water, stir and heat in a water bath at 40°C for 2 h, then raise the water bath temperature to 70°C and stir and heat for 4 h to remove the ethanol produced by the hydrolysis of the silicon source. During this process, water that evaporates at the same time as the ethanol is intermittently added to the system. The resulting mixed liquid is mixed and stirred with 558.3 ​​g of tetrapropylammonium hydroxide aqueous solution (mass fraction of 25.0%) at 25°C for 1 h to obtain the first mixed product.

[0102] (2) Weigh 17.2 g of sodium hydroxide granules, add 384.0 g of deionized water to completely dissolve the sodium hydroxide, then add 40.8 g of aluminum nitrate nonahydrate, stir at room temperature for 1.0 h to obtain the second mixed product (i.e. aluminum source solution);

[0103] (3) The second mixed product is slowly added to the first mixed product and mixed evenly. Stirred at room temperature for 4.0 h. The resulting precursor liquid is transferred into the synthesis vessel and dynamically crystallized at 170 °C for 48 h. After crystallization, the product is centrifuged, filtered, washed, dried, and calcined at 550 °C for 4 h to obtain the third solid product (denoted as molecular sieve I-M1).

[0104] (4) Mix the third solid product with a sodium hydroxide solution with a concentration of 0.5 mol / L. The mass ratio of the third solid product to the alkaline solution is 1:10. Heat the product to 80°C at a heating rate of 2°C / min and stir at that temperature for 30 min. Filter, wash and dry to obtain the fourth solid product (denoted as molecular sieve I-S1-Na).

[0105] (5) Mix the fourth solid product: ammonium chloride: deionized water in a weight ratio of 1:1:10 evenly, stir and heat in an 80°C water bath for 30 min, filter, wash and dry, mix the obtained solid product: ammonium chloride: deionized water in a weight ratio of 1:0.5:10 evenly, perform a second ammonium exchange, filter, wash and dry, calcine at 550°C for 2 h to obtain hydrogen-type hollow ZSM-5 multi-level porous molecular sieve, denoted as I-S1-H.

[0106] (6) The hydrogen-type hollow ZSM-5 hierarchical porous molecular sieve I-S1-H was modified to obtain a molecular sieve solid content of 96.65% by weight. 2.69g of H3PO4 solution (concentration 85% by weight) was dissolved in 46.25g of deionized water and stirred until fully dissolved to obtain a phosphorus-containing solution. 50g of hollow ZSM-5 hierarchical porous molecular sieve I-S1-H was spread in a petri dish, and the phosphorus-containing solution was slowly added dropwise and mixed thoroughly to obtain a slurry with the molecular sieve in a "viscous paste" state. The slurry was then dried in air at 115℃ for 4h and then calcined at 550℃ for 2h to obtain the first solid product.

[0107] (7) The first solid product was subjected to hydrothermal treatment at 600℃ and 100% water vapor for 4 hours to obtain the second solid product.

[0108] (8) Dissolve 2.48g of lanthanum chloride in 46.26g of deionized water, stir until fully dissolved to obtain a metal salt solution. Add the metal salt solution to the second solid product and mix thoroughly to obtain a slurry with a "viscous paste" consistency. Then dry the slurry in air at 110℃ for 4h and calcine at 550℃ for 2h to obtain modified hollow ZSM-5 hierarchical porous molecular sieve SS-1. Its SEM image is shown below. Figure 1 As shown, the properties of the samples are listed in Table 1.

[0109] Example 2

[0110] (1) Weigh 550.0 g of methyl orthosilicate, add 2975.0 g of deionized water, stir and heat in a water bath at 30°C for 5 h, then raise the water bath temperature to 70°C and stir for 4 h to remove the ethanol produced by the hydrolysis of the silicon source. During this process, water that evaporates at the same time as the ethanol is intermittently added to the system. The resulting mixed liquid is mixed and stirred with 241.5 g of tetrapropylammonium bromide aqueous solution (mass fraction of 25.0%) at 20°C for 0.5 h to obtain the first mixed product.

[0111] (2) Weigh 9.1 g of sodium hydroxide granules, add 217.0 g of deionized water to completely dissolve the sodium hydroxide, then add 6.0 g of sodium aluminate (alumina content is 62.0%), stir at 20°C for 2.0 h to obtain the second mixed product;

[0112] (3) The second mixed product is slowly added to the first mixed product and mixed evenly. Stirred at room temperature for 4.0 h. The resulting precursor liquid is transferred to the synthesis vessel and dynamically crystallized at 180 °C for 24 h. After crystallization, it is centrifuged, filtered, washed, dried, and calcined at 550 °C for 4 h to obtain the third solid product (denoted as molecular sieve I-M2).

[0113] (4) Mix the third solid product and a sodium hydroxide alkaline solution with a concentration of 0.6 mol / L evenly. The mass ratio of the third solid product to the alkaline solution is 1:10. Heat the product to 80°C at a heating rate of 4°C / min, and then heat and stir at 80°C for 30 min. Filter, wash and dry to obtain the fourth solid product (denoted as molecular sieve I-S2-Na).

[0114] (5) Mix the fourth solid product: ammonium chloride: deionized water in a weight ratio of 1:1:10 evenly, stir and heat in an 80°C water bath for 30 min, filter, wash and dry, mix the obtained solid product: ammonium chloride: deionized water in a weight ratio of 1:0.5:10 evenly, perform a second ammonium exchange, filter, wash and dry, calcine at 550°C for 2 h to obtain hydrogen-type hollow ZSM-5 multi-level porous molecular sieve, denoted as I-S2-H.

[0115] (6) The hollow ZSM-5 hierarchical porous molecular sieve I-S2-H was modified, and the solid content of the molecular sieve was 94.21% by weight. 2.68g of ammonium dihydrogen phosphate was dissolved in 44.21g of deionized water and fully dissolved. Then, 4.25g of Fe(NO3)3·6H2O was added and stirred evenly to obtain a solution containing phosphorus source and metal source. 50g of hollow ZSM-5 hierarchical porous molecular sieve I-S2-H was spread evenly in a petri dish, and the solution containing phosphorus source and metal source was slowly added dropwise and mixed evenly to obtain a slurry with the molecular sieve in the form of a "viscous paste". The slurry was then dried in air at 110℃ for 4h and calcined at 550℃ for 2h to obtain the modified hollow ZSM-5 hierarchical porous molecular sieve SS-2. Its SEM image is shown below. Figure 2 As shown, the properties of the samples are listed in Table 1.

[0116] Example 3

[0117] (1) Weigh 455.9 g of tetrapropylammonium hydroxide aqueous solution (mass fraction of 25.0%), add 3238.3 g of deionized water, stir at room temperature for 10 min, then add 1156.4 g of silica sol (SiO2 content of 25%), stir at 50℃ water bath for 1.0 h, transfer the obtained third mixed product into the reaction vessel, crystallize at 80℃ for 2 h, then raise the temperature to 170℃ and crystallize for 12 h to obtain the fourth mixed product;

[0118] (2) Weigh 9.7 g of sodium hydroxide granules, add 277.9 g of deionized water to completely dissolve the sodium hydroxide, then add 33.3 g of aluminum nitrate nonahydrate, stir at 25°C for 1.0 h to obtain the fifth mixed product;

[0119] (3) Add the fourth mixed product to the fifth mixed product, stir evenly, and continue to crystallize at 170℃ for 36h; after crystallization, centrifuge, filter, wash, dry, and calcine at 550℃ for 4h to obtain the fifth solid product (denoted as molecular sieve I-M3).

[0120] (4) Mix the fifth solid product with a sodium hydroxide solution with a concentration of 1.0 mol / L. The mass ratio of the fourth solid product to the alkaline solution is 1:10. Heat the product to 80°C at a heating rate of 5°C / min and stir at that temperature for 30 min. Filter, wash and dry to obtain the sixth solid product (denoted as molecular sieve I-S3-Na).

[0121] (5) Mix the sixth solid product: ammonium chloride: deionized water in a weight ratio of 1:1:10 evenly, stir and heat in an 80°C water bath for 30 min, filter, wash and dry, then mix the obtained solid product: ammonium chloride: deionized water in a weight ratio of 1:0.5:10 evenly, perform a second ammonium exchange, filter, wash and dry, and calcine at 550°C for 2 h to obtain hollow ZSM-5 multi-level porous molecular sieve, denoted as I-S3-H.

[0122] (6) The hollow ZSM-5 hierarchical porous molecular sieve I-S3-H was modified to obtain a solid content of 92.75% by weight. 1.71g of H3PO4 solution (concentration 85% by weight) was dissolved in 42.49g of deionized water and stirred until fully dissolved to obtain a phosphorus-containing solution. 50g of hollow ZSM-5 hierarchical porous molecular sieve I-S3-H was spread in a petri dish, and the phosphorus-containing solution was slowly added dropwise and mixed thoroughly to obtain a slurry with the molecular sieve in the form of a "viscous paste". The slurry was then dried in air at 115℃ for 4h and then calcined at 550℃ for 2h to obtain the first solid product.

[0123] (7) The first solid product was subjected to hydrothermal treatment at 600℃ and 100% water vapor for 4 hours to obtain the second solid product.

[0124] (8) Dissolve 4.48g gallium nitrate nonahydrate in 46.26g deionized water and stir until fully dissolved to obtain a metal salt solution. Add the metal salt solution to the second solid product and mix thoroughly to obtain a slurry with the molecular sieve in the form of a "viscous paste". Then dry the slurry in air at 110℃ for 4h and calcine it at 550℃ for 2h to obtain modified hollow ZSM-5 multi-level porous molecular sieve SS-3. Its properties are listed in Table 1.

[0125] Comparative Example 1

[0126] The conventional ZSM-5 molecular sieve DSS-1 was purchased from Sinopec Catalyst Company Qilu Branch, with a silicon-aluminum molar ratio (SiO2 / Al2O3) of 25. Its properties are listed in Table 1.

[0127] Table 1

[0128]

[0129]

[0130]

[0131] In Table 1, R represents the template agent, and the ratio of bulk to surface silicon-aluminum molar ratio represents the ratio of bulk silicon-aluminum molar ratio to surface silicon-aluminum molar ratio.

[0132] Increase in mesoporous specific surface area = 100% × [Mesoporous specific surface area of ​​hollow ZSM-5 hierarchical molecular sieve (or hollow hierarchical ZSM-5 nanocrystalline material, hydrogen-type hollow ZSM-5 hierarchical molecular sieve before the introduction of phosphorus) / mesoporous specific surface area of ​​the first solid product (or the fourth solid product) - 1];

[0133] Mesoporous volume increase = 100% × [Mesoporous volume of hollow ZSM-5 hierarchical molecular sieve (or hollow hierarchical ZSM-5 nanocrystalline material, hydrogen-type hollow ZSM-5 hierarchical molecular sieve before the introduction of phosphorus) / mesoporous volume of the first solid product (or the fourth solid product) - 1];

[0134] Total acid content increase = 100% × [total acid content of hollow ZSM-5 hierarchical porous molecular sieve (or hollow hierarchical porous ZSM-5 nanocrystalline material, hydrogen-type hollow ZSM-5 hierarchical porous molecular sieve before the introduction of phosphorus) / total acid content of the first solid product (or the fourth solid product) - 1].

[0135] Examples 4-9 illustrate the preparation of catalytic cracking catalysts.

[0136] Examples 4-9

[0137] Catalysts were prepared using the modified hollow ZSM-5 hierarchical porous molecular sieves prepared in Examples 1-3, and the catalyst numbers are A1-A6 respectively.

[0138] Methods for preparing catalytic cracking catalysts include:

[0139] (1) Mix boehmite and water evenly, and add concentrated hydrochloric acid with a concentration of 36% by weight while stirring. The acid-aluminum molar ratio is 0.2 (the weight ratio of HCl to boehmite calculated as Al2O3). The resulting mixture is aged at 70°C for 1.5 hours to obtain an aged boehmite slurry. The alumina content of the aged boehmite slurry is 12% by weight.

[0140] (2) The modified hollow ZSM-5 hierarchical pore molecular sieve, β molecular sieve, Y-type molecular sieve, alumina sol, silica sol, kaolin, and the above-prepared aged pseudoboehmite slurry and deionized water are mixed evenly to form a slurry with a solid content of 30% by weight, and spray-dried to obtain catalyst microspheres.

[0141] (3) The catalyst microspheres were calcined at 550℃ for 4 hours;

[0142] (4) The calcined catalyst microspheres were exchanged at 80°C for 1 hour according to the weight ratio of catalyst microspheres: ammonium salt: H2O = 1:1:10, filtered, and the above exchange and filtration process was repeated once. The catalyst was then dried. The ammonium salt was ammonium chloride. The sodium oxide content in the obtained catalytic cracking catalyst was less than 0.15% by weight. The composition of the prepared catalyst is shown in Table 2.

[0143] Comparative Examples 2-3

[0144] Catalysts DA1 and DA2 were prepared using the same method as in Example 4, except that molecular sieve DSS-1 from Comparative Example 1 was used instead of molecular sieve SS-1 prepared in Example 1. The composition of the prepared catalysts is shown in Table 2.

[0145] Table 2

[0146]

[0147] Test Example 1

[0148] The catalytic cracking catalysts prepared in Examples 7-9 and Comparative Example 3 were aged at 820°C and 100% vol% steam for 30 hours. Their performance in the catalytic cracking of whole-fraction oil was then evaluated in a small fixed fluidized bed reactor under the following conditions: reaction temperature 580°C and weight hourly space velocity (WHSV) 20 h⁻¹. -1 The ratio of reactant to oil by weight is 8. The properties of the full-fraction oil are shown in Table 3, and the reaction results are shown in Table 4. The product mass distribution was calculated based on the feedstock.

[0149] Table 3

[0150]

[0151] Table 4

[0152]

[0153]

[0154] As shown in Table 4, the catalytic cracking catalyst provided in this disclosure has higher cracking capacity and higher yield of low-carbon olefins.

[0155] Test Example 2

[0156] The catalytic cracking catalysts prepared in Examples 4-6 and Comparative Example 2 were aged at 820°C and 100% vol% steam for 30 hours. Their intermediate-based heavy oil catalytic cracking performance was then evaluated in a small fixed fluidized bed reactor under the following conditions: reaction temperature 580°C and weight hourly space velocity (WHSV) 20 h⁻¹. -1 The ratio of the agent to the oil by weight is 8. The properties of the intermediate heavy oil are shown in Table 5, and the reaction results are shown in Table 6.

[0157] The product quality distribution mentioned above is calculated based on the raw material feed.

[0158] Table 5

[0159] intermediate base heavy oil properties Carbon content, % by weight 86.43 Hydrogen content, % by weight 12.88 <![CDATA[Density at 20 °C, kg / m 3 > 901 Residual char, % by weight 4.8 Freezing point, ℃ 42 Initial boiling point, ℃ 278.8 Final boiling point, ℃ 540.2 Saturated hydrocarbons, % by weight 40 Aromatics, % by weight 22.6 Gel, weight % 37.3 Asphalt, % by weight 0.1 Alkanes, % by weight 29.4 Monocycloalkanes, % by weight 8.4 Bicycloalkanes, % by weight 9.5 Tricyclic alkanes, % by weight 6.7 Total cycloalkanes, % by weight 26.4 Total bicyclic aromatic hydrocarbons, % by weight 10.2

[0160] Table 6

[0161]

[0162]

[0163] As shown in Table 6, the heavy oil catalytic cracking catalyst provided in this disclosure has a higher catalytic cracking capacity for intermediate-based heavy oil and a higher yield of low-carbon olefins.

[0164] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0165] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0166] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A catalytic cracking method, characterized in that, The method includes: contacting feedstock oil with a catalytic cracking catalyst to react, wherein the feedstock oil is a full-fraction oil or intermediate-base heavy oil, and the catalytic cracking catalyst contains modified hollow ZSM-5 hierarchical porous molecular sieve, nano molecular sieve, Y-type molecular sieve and support; Based on the dry weight of the catalytic cracking catalyst, the content of the modified hollow ZSM-5 hierarchical porous molecular sieve is 15-40% by weight, the content of the nano-molecular sieve is 1-10% by weight, the content of the Y-type molecular sieve is 5-15% by weight, the content of the support is 40-80% by weight, and the total amount of the catalytic cracking catalyst is 100% by weight. The modified hollow ZSM-5 hierarchical porous molecular sieve contains a molecular sieve and phosphorus and metal components supported on the molecular sieve; the phosphorus-aluminum molar ratio of the modified hollow ZSM-5 hierarchical porous molecular sieve is 0.1-1.5; the content of the metal component, based on the dry basis weight of the modified hollow ZSM-5 hierarchical porous molecular sieve and calculated by the oxide content of the metal component, is 0.1-5% by weight; the modified hollow ZSM-5 hierarchical porous molecular sieve has a closed hollow structure, the average grain size of the modified hollow ZSM-5 hierarchical porous molecular sieve is 0.2-3.0 μm, and the ratio of bulk silicon-aluminum molar ratio to surface silicon-aluminum molar ratio is 1.0-1.5; the total specific surface area of ​​the modified hollow ZSM-5 hierarchical porous molecular sieve is 250-350 m² / s. 2 / g, mesoporous specific surface area is 20-100m² 2 / g, wherein the mesoporous specific surface area accounts for 15-40% of the total specific surface area, the strong Brønsted acid content accounts for 55-70% of the total Brønsted acid content, and the strong Lewis acid content accounts for 50-70% of the total Lewis acid content; The pore size of the nanomolecular sieve is 0.56-0.75 nm.

2. The method according to claim 1, wherein, The feedstock oil is a full-fraction oil, and the reaction conditions include: a reaction temperature of 550-600℃; based on the dry weight of the catalytic cracking catalyst, the content of the modified hollow ZSM-5 hierarchical porous molecular sieve is 20-40% by weight, the content of the nano-molecular sieve is 1-5% by weight, the content of the Y-type molecular sieve is 5-15% by weight, the content of the support is 40-80% by weight, and the total amount of the catalytic cracking catalyst is 100% by weight.

3. The method according to claim 1, wherein, The feedstock oil is intermediate-base heavy oil, and the reaction conditions include: a reaction temperature of 550-600℃; based on the dry weight of the catalytic cracking catalyst, the content of the modified hollow ZSM-5 hierarchical porous molecular sieve is 15-30% by weight, the content of the nano-molecular sieve is 5-10% by weight, the content of the Y-type molecular sieve is 5-10% by weight, the content of the support is 50-75% by weight, and the total amount of the catalytic cracking catalyst is 100% by weight.

4. A catalytic cracking catalyst, characterized in that, This catalytic cracking catalyst contains modified hollow ZSM-5 hierarchical porous molecular sieve, nano-molecular sieve, Y-type molecular sieve, and a support. Based on the dry weight of the catalytic cracking catalyst, the content of the modified hollow ZSM-5 hierarchical porous molecular sieve is 15-40% by weight, the content of the nano-molecular sieve is 1-10% by weight, the content of the Y-type molecular sieve is 5-15% by weight, the content of the support is 40-80% by weight, and the total amount of the catalytic cracking catalyst is 100% by weight. The modified hollow ZSM-5 hierarchical porous molecular sieve contains a molecular sieve and phosphorus and metal components supported on the molecular sieve; the phosphorus-aluminum molar ratio of the modified hollow ZSM-5 hierarchical porous molecular sieve is 0.1-1.5; the content of the metal component, based on the dry basis weight of the modified hollow ZSM-5 hierarchical porous molecular sieve and calculated by the oxide content of the metal component, is 0.1-5% by weight; the modified hollow ZSM-5 hierarchical porous molecular sieve has a closed hollow structure, the average grain size of the modified hollow ZSM-5 hierarchical porous molecular sieve is 0.2-3.0 μm, and the ratio of bulk silicon-aluminum molar ratio to surface silicon-aluminum molar ratio is 1.0-1.5; the total specific surface area of ​​the modified hollow ZSM-5 hierarchical porous molecular sieve is 250-350 m² / s. 2 / g, mesoporous specific surface area is 20-100m² 2 / g, wherein the mesoporous specific surface area accounts for 15-40% of the total specific surface area, the strong Brønsted acid content accounts for 55-70% of the total Brønsted acid content, and the strong Lewis acid content accounts for 50-70% of the total Lewis acid content; The pore size of the nanomolecular sieve is 0.56-0.75 nm.

5. The catalytic cracking catalyst according to claim 4, wherein, The modified hollow ZSM-5 hierarchical porous molecular sieve has a phosphorus-aluminum molar ratio of 0.2-1.3; The content of the metal component is 0.5-4% by weight, based on the dry basis weight of the modified hollow ZSM-5 multi-level porous molecular sieve and the oxide content of the metal component.

6. The catalytic cracking catalyst according to claim 4, wherein, The modified hollow ZSM-5 hierarchical porous molecular sieve has an average grain size of 0.5-3.0 μm, a bulk silicon-aluminum molar ratio to a surface silicon-aluminum molar ratio of 1.0-1.3, and a relative crystallinity of 80-90%.

7. The catalytic cracking catalyst according to claim 4, wherein, The modified hollow ZSM-5 multi-level porous molecular sieve has a total specific surface area of ​​260-340 m². 2 / g, mesoporous specific surface area is 25-100m² 2 / g, wherein the mesoporous specific surface area accounts for 18-35% of the total specific surface area.

8. The catalytic cracking catalyst according to claim 4, wherein, The metal component is selected from one or more of lanthanum, cerium, tungsten, iron, cobalt, nickel, copper, manganese, zinc, tin, bismuth and gallium; The nano-molecular sieve is one or more of the following molecular sieves having the structures AET, AFR, AFS, AFI, BEA, BOG, CFI, CON, GME, IFR, ISV, LTL, MEI, MOR, OFF, and SAO; The Y-type molecular sieve is selected from one or more of REY molecular sieve, DASY molecular sieve, USY molecular sieve, phosphorus-containing DASY molecular sieve, phosphorus-containing USY molecular sieve, PSRY molecular sieve, HRY molecular sieve, HSY molecular sieve, and SCY molecular sieve.

9. The catalytic cracking catalyst according to claim 8, wherein, The nano-molecular sieve is at least one of Beta, SAPO-5, SAPO-40, SSZ-13, CIT-1, ITQ-7, ZSM-18, mordenite, and sodium chalcogenide.

10. The catalytic cracking catalyst according to claim 4, wherein, The carrier is selected from one or more of the following: natural clay, alumina carrier, silica carrier, aluminum phosphate carrier, and silica-alumina oxide carrier.

11. The catalytic cracking catalyst according to claim 10, wherein, The silica carrier is one or more of neutral silica sol, acidic silica sol, or alkaline silica sol; the alumina carrier is one or more of alumina sol, acidified boehmite, hydrated alumina, and activated alumina; the aluminum phosphate carrier is aluminum phosphate gel; and the aluminosilicate carrier is selected from one or more of solid aluminosilicate materials, aluminosilicate sol, and aluminosilicate gel.

12. The catalytic cracking catalyst according to claim 4, wherein, The support includes a silica support; based on the dry weight of the catalytic cracking catalyst, the silica support has a SiO2 content of 1-20% by weight.

13. A method for preparing the catalytic cracking catalyst according to any one of claims 4-12, the method comprising: The slurry containing a carrier, modified hollow ZSM-5 hierarchical porous molecular sieve, nano molecular sieve, Y-type molecular sieve and water is dried and optionally calcined.

14. The method according to claim 13, wherein, The preparation steps of the modified hollow ZSM-5 hierarchical porous molecular sieve include: A first solution containing a first phosphorus source and a first metal source is mixed with hollow ZSM-5 multi-level porous molecular sieve raw material, and the resulting first slurry is subjected to a first drying and a first calcination, wherein the weight ratio of the first solution to the hollow ZSM-5 multi-level porous molecular sieve raw material is 1:(0.5-2.0). Alternatively, the preparation steps of the modified hollow ZSM-5 hierarchical porous molecular sieve include: S1. The second solution containing the second phosphorus source is mixed with the hollow ZSM-5 multi-level porous molecular sieve raw material, and the resulting second slurry is subjected to a second drying and a second calcination to obtain the first solid product; wherein, the weight ratio of the second solution containing the second phosphorus source to the hollow ZSM-5 multi-level porous molecular sieve raw material is 1:(0.5-2.0). S2. The first solid product is subjected to hydrothermal treatment to obtain the second solid product; S3. The third solution containing the second metal source is mixed with the second solid product, and the resulting third slurry is subjected to a third drying and a third calcination, wherein the weight ratio of the third solution containing the second metal source to the second solid product is 1:(0.5-2.0).

15. The method according to claim 14, wherein, The first phosphorus source and the second phosphorus source are each independently selected from one or more of phosphoric acid, ammonium dihydrogen phosphate, diammonium hydrogen phosphate and ammonium phosphate; The first metal source and the second metal source are each independently selected from one or more of the nitrates, chlorides and sulfates of metals, and the metals are selected from one or more of lanthanum, cerium, tungsten, iron, cobalt, nickel, copper, manganese, zinc, tin, bismuth and gallium; The hollow ZSM-5 multi-stage porous molecular sieve raw material is an H-type hollow ZSM-5 multi-stage porous molecular sieve.

16. The method of claim 14, wherein, The conditions for the hydrothermal treatment include: a temperature of 400-800℃ and a time of 1-12 hours; The conditions for the first drying, the second drying, and the third drying each independently include: a temperature of 90-120℃ and a time of 2-24 hours; The conditions for the first roasting, the second roasting, and the third roasting each independently include: a temperature of 450-600℃ and a time of 2-6 hours.

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