Catalytic cracking catalyst, process for its preparation and use

Abstract

The present application relates to a kind of catalytic cracking catalyst and its preparation method and application, the catalytic cracking catalyst contains carrier and phosphorus-containing hollow ZSM-5 hierarchical pore molecular sieve, with the dry basis weight of the catalytic cracking catalyst as benchmark, the content of the carrier is 50-85 wt%, the content of the phosphorus-containing hollow hierarchical pore ZSM-5 molecular sieve is 15-50 wt%. The catalytic cracking catalyst of the present application has relatively optimal molecular diffusion performance, and has higher low carbon olefin yield when it is used in catalytic cracking process of naphtha.

Description

TECHNICAL FIELD

[0001] The present application relates to a catalytic cracking catalyst and its preparation method and application. BACKGROUND

[0002] Low carbon olefins (mainly refers to ethylene, propylene, butene) are very important chemical raw materials, with the development of society, the market demand of low carbon olefins in China increases sharply, the import volume of ethylene, propylene, butene and their downstream products increases year by year. At present, the world mainly uses naphtha steam cracking to produce low carbon olefins. This method has many shortcomings such as high reaction temperature and high energy consumption. In order to overcome these problems, a large number of catalytic cracking technology researches have been carried out at home and abroad, hoping to introduce catalysis, on the one hand, to appropriately reduce the reaction temperature, reduce coking and energy consumption, on the other hand, to improve the yield of low carbon olefins and more flexible product distribution.

[0003] CN101491772A discloses a catalyst for catalytic cracking of naphtha, which comprises the following active components by weight percentage: a) 80-99.5% of at least one selected from the group consisting of ZSM-5 and mordenite, ZSM-5 and beta zeolite, or ZSM-5 and Y zeolite; and b) the balance of at least one element selected from the group consisting of VA elements of the periodic table of elements or its oxide supported thereon, but the catalyst can obtain a lower diene yield of ethylene and propylene.

[0004] CN102861604A discloses a catalyst for catalytic cracking of naphtha to produce olefins, wherein, by weight content of the final catalyst, 60-90% of EU-1 / ZSM-5 composite molecular sieve and 0.5-3% of heteropoly acid are contained. When the catalyst is actually used for catalytic cracking of naphtha, although the diene yield of ethylene and propylene is high, the propylene / ethylene ratio is still low, and the yield of propylene and butene is small. SUMMARY

[0005] The purpose of the present application is to provide a catalytic cracking catalyst and its preparation method and application, which has a better molecular diffusion performance, and has a higher yield of low carbon olefins when used in the catalytic cracking process of naphtha.

[0006] In order to achieve the above purpose, the first aspect of the present application provides a catalytic cracking catalyst, which contains a carrier and a phosphorus-containing hollow ZSM-5 hierarchical pore molecular sieve, the content of the carrier is 50-85% by weight based on the dry basis weight of the catalytic cracking catalyst, and the content of the phosphorus-containing hollow ZSM-5 hierarchical pore molecular sieve is 15-50% by weight.

[0007] The phosphorus-containing hollow ZSM-5 hierarchical porous molecular sieve has a closed hollow structure. The average grain size of the phosphorus-containing 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 phosphorus-aluminum molar ratio of the phosphorus-containing hollow ZSM-5 hierarchical porous molecular sieve is 0.1-1.5.

[0008] The N2 adsorption-desorption curve of the phosphorus-containing hollow ZSM-5 multi-level porous molecular sieve exhibits an H4-type hysteresis loop, with strong Brønsted acid accounting for 65-80% of the total Brønsted acid content and strong Lewis acid accounting for 50-75% of the total Lewis acid content.

[0009] Optionally, the phosphorus-aluminum molar ratio of the phosphorus-containing hollow ZSM-5 hierarchical porous molecular sieve is 0.2-1.3.

[0010] Optionally, the average grain size of the phosphorus-containing hollow ZSM-5 hierarchical porous molecular sieve crystals is 0.4-2.5 μm, the ratio of the bulk silicon-aluminum molar ratio to the surface silicon-aluminum molar ratio is 1.1-1.4, and the relative crystallinity is 75-90%.

[0011] Optionally, the total specific surface area of ​​the phosphorus-containing hollow ZSM-5 hierarchical porous molecular sieve before phosphorus modification is 350-400 m². 2 / g, mesoporous specific surface area is 45-140m² 2 / g, the mesoporous specific surface area accounts for 20-35% of the total specific surface area, and the N2 adsorption-desorption curve exhibits an H4-type hysteresis loop.

[0012] Optionally, the proportion of the strong Brønsted acid to the total Brønsted acid is 70-80%, and the proportion of the strong Leucine to the total Leucine is 55-70%.

[0013] Optionally, the carrier is selected from one or more of natural clay, alumina carrier, silica carrier, aluminum phosphate carrier and silica-alumina oxide carrier;

[0014] 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.

[0015] Optionally, the support is a silica support; based on the dry weight of the catalyst, the silica support has a SiO2 content of 1-25% by weight.

[0016] Optionally, based on the dry weight of the catalytic cracking catalyst, the content of the support is 55-80% by weight, and the content of the phosphorus-containing hollow hierarchical ZSM-5 molecular sieve is 20-45% by weight.

[0017] The second aspect of the present invention provides a method for preparing the catalytic cracking catalyst provided in the first aspect of the present invention, the method comprising: subjecting a slurry containing a support and a phosphorus-containing hollow ZSM-5 hierarchical porous molecular sieve to a first drying and optionally a first calcination.

[0018] Optionally, the phosphorus-containing hollow ZSM-5 hierarchical porous molecular sieve is prepared by a method comprising the following steps:

[0019] (1) Mix and stir the first organosilicon source and the first solvent at 30-50°C for 0.5-5 hours, then heat to 70-100°C and mix and stir for 2-10 hours. Mix the resulting mixed liquid with the first template agent at 20-30°C for 0.5-3.0 hours to obtain the first mixed product.

[0020] (2) Mix the first alkali metal hydroxide (calculated as alkali metal oxide), the second solvent, and the 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 to obtain the second mixed product;

[0021] (3) The first mixed product and the second mixed product are mixed and then dynamically crystallized. The resulting solid is taken out and subjected to a second calcination to obtain the first solid product.

[0022] (4) The first solid product is mixed with the first alkaline solution, and the temperature is raised to the reaction temperature at a rate of 1-5℃ / min. The reaction is carried out at the reaction temperature for 10-90 min to obtain the second solid product. The reaction temperature is 60-90℃, and the alkaline content in the first alkaline solution is 0.45-2 mol / L.

[0023] (5) The second solid product is subjected to a first ammonium exchange and optionally a sixth calcination to obtain a third solid product;

[0024] (6) The third solid product is mixed with a second solution containing a phosphorus source, and the resulting first slurry is subjected to a second drying and a third calcination; or,

[0025] The method includes:

[0026] S1. The second template agent, the second inorganic silicon source, and the third solvent are mixed at 30-50°C for 0.5-3.0 hours. The resulting third mixed product is subjected to a first hydrothermal treatment and a second hydrothermal treatment in sequence to obtain a fourth mixed product. The conditions for the first hydrothermal treatment are: temperature 80-150°C and time 1-6 hours; the conditions for the second hydrothermal treatment are: temperature 160-180°C and time 4-60 hours.

[0027] S2. Mix the second alkali metal hydroxide (calculated as alkali metal oxide), the fourth solvent, and the second 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 to obtain the fifth mixed product.

[0028] S3. Mix the fourth mixed product and the fifth mixed product, subject the resulting mixture to a third hydrothermal treatment, remove the resulting solid and subject it to a fourth calcination to obtain a fourth solid product;

[0029] S4. The fourth solid product is mixed with the second alkaline solution, and the temperature is increased to the reaction temperature at a rate of 1-5℃ / min. The mixture is then reacted at the reaction temperature for 10-90 min to obtain the fifth solid product. The reaction temperature is 60-90℃, and the alkaline content in the second alkaline solution is 0.45-2 mol / L.

[0030] S5. The fifth solid product is subjected to a second ammonium exchange, and optionally a seventh calcination is performed to obtain the sixth solid product.

[0031] S6. The sixth solid product is mixed with the fourth solution containing a phosphorus source, and the resulting second slurry is subjected to a third drying and a fifth calcination.

[0032] Optionally, the first organosilicon source is selected from one or more of methyl orthosilicate and ethyl orthosilicate;

[0033] The second inorganic silicon source is selected from one or more of silica sol, water glass, and solid silica gel;

[0034] 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;

[0035] 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;

[0036] 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;

[0037] 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 solution and barium hydroxide solution;

[0038] The phosphorus source is selected from at least one or more of phosphoric acid, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, and ammonium phosphate.

[0039] Optionally, the total amount of the first template agent, the first solvent, and the second solvent, the molar ratio of the first alkali metal hydroxide to the first organosilicon source is (0.06-0.55):(10-100):(0.02-1.5):1, and the molar ratio of the first organosilicon source to the first aluminum source is (20-500):1; wherein the first organosilicon source is calculated as SiO2, the first alkali metal hydroxide is calculated as alkali metal oxide, and the first aluminum source is calculated as Al2O3;

[0040] Preferably, 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 (2-4.5):(80-350):1;

[0041] Preferably, in step (4), the weight ratio of the first solid product to the first alkaline solution is 1:(2-10); the ratio of the bulk silicon-aluminum molar ratio to the surface silicon-aluminum molar ratio of the first solid product is 1.2-5.0.

[0042] Preferably, in step (6), the weight ratio of the second solution containing the phosphorus source to the third solid product is 1:(0.5-2.0);

[0043] The total amount of the second template agent, the third solvent, and the fourth solvent, and the molar ratio of the amount of the second alkali metal hydroxide and the second inorganic silicon source are (0.06-0.55):(10-100):(0.02-1.5):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 alkali metal oxide, and the second aluminum source is calculated as Al2O3;

[0044] Preferably, 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 (2-4.5):(80-350):1;

[0045] Preferably, in step S4, the weight ratio of the fourth solid product to the second alkali-containing solution is 1:(2-10), and the ratio of the bulk silicon-aluminum molar ratio to the surface silicon-aluminum molar ratio of the fourth solid product is 1.2-5.0.

[0046] Preferably, in step S6, the weight ratio of the fourth solution containing the phosphorus source to the sixth solid product is 1:(0.5-2.0).

[0047] Optionally, the conditions for dynamic crystallization include: a temperature of 160-180°C and a time of 12-60 hours;

[0048] The conditions for the third hydrothermal treatment include: a temperature of 160-180℃ and a time of 12-60 hours;

[0049] The conditions for the second, third, fourth, and fifth calcinations each independently include: a temperature of 400-600℃ and a time of 2-6 hours;

[0050] The conditions for the second drying and the third drying each independently include: a temperature of 90-120°C and a time of 2-24 hours.

[0051] Optionally, the method further includes: mixing catalyst particles obtained from the first drying and optionally the first calcination, ammonium salt and a fifth solvent in a weight ratio of 1:(0.1-1):(5-15) for a third ammonium exchange, and optionally washing;

[0052] The conditions for the third ammonium exchange include: a temperature of 50-100℃ and a time of 0.5-2 hours;

[0053] The ammonium salt is selected from one or more of ammonium chloride, ammonium sulfate, and ammonium nitrate.

[0054] The third aspect of the present invention provides an application of the catalytic cracking catalyst provided in the first aspect of the present invention in the catalytic cracking of naphtha.

[0055] Through the above technical solution, the outer surface of the catalytic cracking catalyst of the present invention is mainly composed of microporous structure, while also rich in mesoporous and macroporous structures. It has a large outer surface area and can provide multi-directional diffusion paths, thus exhibiting superior molecular diffusion performance. When used in the catalytic cracking process of naphtha, it results in a higher yield of low-carbon olefins.

[0056] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0057] 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. In the drawings:

[0058] Figure 1 Here is a SEM image of the phosphorus hollow ZSM-5 hierarchical porous molecular sieve prepared in Example 2 of this invention;

[0059] Figure 2 This is a SEM image of the phosphorus hollow ZSM-5 hierarchical porous molecular sieve prepared in Example 1 of this invention. Detailed Implementation

[0060] The specific embodiments of the present invention 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 the present invention.

[0061] The first aspect of this invention provides a catalytic cracking catalyst comprising a support and a phosphorus-containing hollow ZSM-5 hierarchical porous molecular sieve. Based on the dry weight of the catalytic cracking catalyst, the content of the support is 50-85% by weight, and the content of the phosphorus-containing hollow ZSM-5 hierarchical porous molecular sieve is 15-50% by weight. The phosphorus-containing hollow ZSM-5 hierarchical porous molecular sieve has a closed hollow structure. The average grain size of the sieve crystals 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 phosphorus-aluminum molar ratio of the phosphorus-containing hollow ZSM-5 hierarchical porous molecular sieve is 0.1-1.5. The N2 adsorption-desorption curve of the phosphorus-containing hollow ZSM-5 hierarchical porous molecular sieve exhibits an H4-type hysteresis loop, the proportion of strong Brønsted acid to total Brønsted acid is 65-80%, and the proportion of strong Lewis acid to total Lewis acid is 50-75%.

[0062] The catalytic cracking catalyst of the present invention contains phosphorus-containing hollow ZSM-5 hierarchical porous molecular sieve. Its hierarchical porous structure gives the catalyst better accessibility of active centers and diffusion performance of reactant molecules, and can reduce the secondary conversion of low-carbon olefins. When used in the catalytic cracking process of naphtha, it can effectively improve the yield of low-carbon olefins.

[0063] In one specific embodiment of the present invention, the phosphorus-aluminum molar ratio of the phosphorus-containing hollow ZSM-5 hierarchical porous molecular sieve is 0.2-1.3. In this invention, the phosphorus-aluminum molar ratio of the phosphorus-containing hollow ZSM-5 hierarchical porous molecular sieve is determined by XRF fluorescence method, and the content of the metal component is also determined by XRF fluorescence method.

[0064] In one specific embodiment of the present invention, the average grain size of the phosphorus-containing hollow ZSM-5 hierarchical porous molecular sieve crystals is 0.4-2.5 μm, preferably 0.6-2.5 μm, the ratio of the bulk silicon-aluminum molar ratio (as SiO2 / Al2O3) to the surface silicon-aluminum molar ratio (as SiO2 / Al2O3) is 1.1-1.4, and the relative crystallinity is 75-90%. In this invention, grain size refers to the size of the widest part of the grain, which can be obtained by measuring the size of 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 in 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, and 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 described in detail here. The bulk silicon-aluminum molar ratio is 15-200. In this invention, 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%.

[0065] In one specific embodiment of the present invention, the total specific surface area of ​​the phosphorus-containing hollow ZSM-5 hierarchical porous molecular sieve before phosphorus modification is 350-420 m². 2 / g, mesoporous specific surface area is 45-140m² 2 / g, wherein the mesoporous specific surface area accounts for 20-40% of the total specific surface area, and the N2 adsorption-desorption curve exhibits an H4-type hysteresis loop. In this invention, the total specific surface area and mesoporous specific surface area are obtained using BET analysis.

[0066] In one specific embodiment of the present invention, the proportion of the strong Brønsted acid to the total Brønsted acid is 70-80%, and the proportion of the strong Leucine to the total Leucine is 55-70%. The strong Brønsted acid and the total Brønsted acid are prepared using a pyridine infrared acidic method, and the strong Leucine and the total Leucine are prepared using a pyridine infrared acidic method.

[0067] According to the present invention, 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.

[0068] In one specific embodiment of the present invention, the support is a silica support; based on the dry weight of the catalyst, the silica support has a SiO2 content of 1-25% by weight.

[0069] According to the present invention, based on the dry weight of the catalytic cracking catalyst, the content of the support can be 55-80% by weight, and the content of the phosphorus-containing hollow hierarchical ZSM-5 molecular sieve can be 20-45% by weight.

[0070] In one specific embodiment of the present invention, based on the dry weight of the catalyst, the catalytic cracking catalyst contains 15-50 wt% phosphorus-containing hollow ZSM-5 hierarchical porous 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.

[0071] In one specific embodiment of the present invention, 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.

[0072] The second aspect of the present invention provides a method for preparing the catalytic cracking catalyst provided in the first aspect of the present invention, the method comprising: subjecting a slurry containing a support and a phosphorus-containing hollow ZSM-5 hierarchical porous molecular sieve to a first drying and optionally a first calcination.

[0073] This invention does not limit the specific form of the first drying process, 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.

[0074] In one specific embodiment of the present invention, the phosphorus-containing hollow ZSM-5 hierarchical porous molecular sieve is prepared by a method comprising 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 to obtain a second mixed product; (3) (3) Mix the first mixed product with the second mixed product and perform dynamic crystallization. Take out the obtained solid and perform a second calcination to obtain a first solid product; (4) Mix the first solid product with a first solution containing alkali and raise the temperature to the reaction temperature at a heating rate of 1-5℃ / min. React at the reaction temperature for 10-90min to obtain a second solid product. The reaction temperature is 60-90℃ and the alkali content in the first solution containing alkali is 0.45-2mol / L; (5) Perform a first ammonium exchange on the second solid product to obtain a third solid product; (6) Mix the third solid product with a second solution containing phosphorus source and perform a second drying and a third calcination on the obtained first slurry.

[0075] According to the present invention, 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 and the first organosilicon source to the amount of solvent can vary within a wide range, for example, it can be (0.06-0.55):(10-100):(0.02-1.5):1, preferably (0.08-0.50):(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, preferably (23-200):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, the first alkali metal hydroxide 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.

[0076] According to the present invention, 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.

[0077] According to the present invention, 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.

[0078] According to the present invention, in step (4), the weight ratio of the first solid product to the amount of the first alkali-containing solution can be 1:(2-10); the ratio of the bulk silicon-aluminum molar ratio and the surface silicon-aluminum molar ratio of the first solid product is 1.2-5.0.

[0079] According to the present invention, in step (5), the first ammonium exchange of the second solid product includes: mixing the second solid product, the first ammonium source, and the fifth solvent in a weight ratio of 1:(0.5-2.0):(5-20), and reacting the resulting mixture at 50-100°C, preferably 60-90°C, for 0.5-2 hours. The first ammonium source is selected from one or more of ammonium chloride, ammonium sulfate, and ammonium nitrate. The ammonium exchange can be performed once or multiple times. 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.

[0080] According to the present invention, in step (6), the weight ratio of the second solution containing the phosphorus source to the third solid product can be 1:(0.2-2.5), preferably 1:(0.5-2.0). The mass content of the phosphorus source in the second solution is, for example, 1-10%.

[0081] According to the present invention, compared with the first solid product, the hollow ZSM-5 multi-level porous molecular sieve (third solid product) 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%.

[0082] In another specific embodiment of the present invention, the phosphorus-containing hollow ZSM-5 hierarchical porous molecular sieve is prepared by a method comprising 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 sequentially 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; and the conditions for the second hydrothermal treatment include: a temperature of 160-180°C and a time of 4-60 hours; S2, mixing a second alkali metal hydroxide (calculated as alkali metal oxide), a fourth solvent, and a second aluminum source (calculated as Al2O3) in a molar ratio of (1.5-5):(60-350):1 at 20-80°C. S3. After 0.5-2.0 hours, a fifth mixed product is obtained; S4. 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 fourth calcination to obtain a fourth solid product; S5. The fourth 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 fifth solid product; wherein the reaction temperature is 60-90℃, and the alkaline content in the second alkaline solution is 0.45-2 mol / L; S6. The fifth solid product is subjected to a second ammonium exchange to obtain a sixth solid product; S7. The sixth solid product is mixed with a fourth solution containing a phosphorus source, and the resulting second slurry is subjected to a third drying and a fifth calcination.

[0083] According to the present invention, the total amount of the second template agent, the third solvent, and the fourth solvent, and the molar ratio of the second alkali metal hydroxide to the second inorganic silicon source can vary within a wide range, for example, it can be (0.06-0.55):(10-100):(0.02-1.5):1, preferably (0.08-0.50):(15-85):(0.03-1.2):1, and the molar ratio of the second inorganic silicon source to the second aluminum source can be (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.

[0084] According to the present invention, 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 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.

[0085] According to the present invention, 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.

[0086] In one embodiment, the conditions for the third hydrothermal treatment include: a temperature of 160-180°C and a time of 12-60 hours.

[0087] According to the present invention, in step S4, the weight ratio of the fourth solid product to the second alkali-containing solution can be 1:(2-10), and the ratio of the bulk silicon-aluminum molar ratio to the surface silicon-aluminum molar ratio of the fourth solid product is 1.2-5.0.

[0088] According to the present invention, in step S5, the second ammonium exchange of the fifth solid product includes: mixing the fifth solid product, the second ammonium source, and the sixth solvent in a weight ratio of 1:(0.5-2):(5-20), and reacting the resulting mixture at 50-100°C, preferably 60-90°C, for 0.5-2 hours. The second ammonium source is selected from one or more of ammonium chloride, ammonium sulfate, and ammonium nitrate. The ammonium exchange can be performed once or multiple times. 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.

[0089] According to the present invention, in step S6, the weight ratio of the fourth solution containing the phosphorus source to the sixth solid product can be 1:(0.2-2.5), preferably 1:(0.5-2.0). The mass content of the phosphorus source in the fourth solution is, for example, 1-10%.

[0090] According to the present invention, compared with the fourth solid product, the hollow ZSM-5 multi-level porous molecular sieve (sixth solid product) 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%.

[0091] According to the present invention, roasting is a technical means conventionally employed by those skilled in the art, and roasting can be carried out in a muffle furnace, tube furnace, etc. The conditions for the second, third, fourth, and fifth roastings 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 2.5-4.5 hours.

[0092] According to the present invention, drying is a technique conventionally employed by those skilled in the art, and calcination can be carried out in a constant temperature drying oven. The conditions for the second drying and the third drying each independently include: a temperature of 90-120°C and a time of 2-24 hours.

[0093] According to the present invention, 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; and the phosphorus source is selected from at least one or more of phosphoric acid, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, and ammonium phosphate.

[0094] In one specific embodiment of the present invention, the method further includes: mixing catalyst particles obtained from the first drying and optionally the first calcination, ammonium salt, and a fifth solvent in a weight ratio of 1:(0.1-1):(5-15) and then performing a third ammonium exchange, and optionally washing; the conditions for the third ammonium exchange include: a temperature of 50-100°C and a time of 0.5-2 hours; the solution containing ammonium salt is calculated as ammonium salt, and the ammonium salt is selected from one or more of ammonium chloride, ammonium sulfate, and ammonium nitrate. The ammonium exchange can be performed multiple times.

[0095] According to one embodiment of the present invention, the first solvent, the second solvent, the third solvent, the fourth solvent, the fifth solvent, and the sixth solvent are each water.

[0096] A third aspect of the present invention provides the application of the catalytic cracking catalyst provided by the present invention in the catalytic cracking of naphtha.

[0097] The present invention will be further illustrated by the following examples, but the present invention is not limited thereto.

[0098] Unless otherwise specified, all raw materials used in the following examples and comparative examples were commercially available. Among them, 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); and concentrated hydrochloric acid was chemically pure and produced by Beijing Chemical Plant.

[0099] In the examples and comparative examples, the crystal size of the molecular sieve was measured by TEM. Ten crystal sizes were randomly measured, and the average value was taken to obtain the average crystal size of the molecular sieve sample.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] Examples 1-4 are examples of preparing phosphorus-containing hollow ZSM-5 hierarchical porous molecular sieves.

[0107] Example 1

[0108] (1) Weigh 91.2 g of tetraethyl orthosilicate, add 639.14 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 111.65 g of tetrapropylammonium hydroxide aqueous solution (mass fraction of 25.0%) at 25°C for 1 h to obtain the first mixed product.

[0109] (2) Weigh 3.44 g of sodium hydroxide particles, add 60.8 g of deionized water to completely dissolve the sodium hydroxide, then add 8.16 g of aluminum nitrate nonahydrate, stir at room temperature for 1.0 h to obtain the second mixed product (i.e. aluminum source solution);

[0110] (3) The second mixed product is slowly added to the first mixed product and mixed evenly. The mixture is stirred at room temperature for 4.0 h. The resulting precursor liquid is transferred to 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 first solid product (denoted as molecular sieve I-M1).

[0111] (4) Mix the first solid product with a sodium hydroxide solution with a concentration of 0.65 mol / L until homogeneous. The mass ratio of the first solid product to the alkaline solution is 1:10. Heat the solution 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 second solid product (denoted as molecular sieve I-S1-Na).

[0112] (5) Mix the second solid product, ammonium chloride, and deionized water at a weight ratio of 1:1:10, stir and heat in an 80°C water bath for 30 min, filter, wash, and dry. Mix the obtained solid product, ammonium chloride, and deionized water at a weight ratio of 1:0.5:10, perform a second ammonium exchange, filter, wash, dry, and calcine at 550°C for 2 h to obtain the third solid product (a hydrogen-type hollow ZSM-5 multi-level porous molecular sieve, denoted as I-S1-H).

[0113] (6) Dissolve 2.69 g of H3PO4 solution (concentration 85% by weight) in 46.25 g of deionized water, stir until fully dissolved, to obtain a phosphorus-containing solution; spread 50 g of the third solid product in a petri dish, slowly add the phosphorus-containing solution dropwise, mix thoroughly until the molecular sieve is in a "viscous paste" state, dry in air at 115 °C for 4 h, and then calcine at 550 °C for 2 h to obtain the phosphorus-containing hollow ZSM-5 hierarchical porous molecular sieve of the present invention, denoted as SS-1, and its SEM image is shown below. Figure 2 As shown.

[0114] Example 2

[0115] (1) Weigh 60.0 g of methyl orthosilicate, add 425.0 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 34.5 g of tetrapropylammonium bromide aqueous solution (mass fraction of 25.0%) at 20°C for 0.5 h to obtain the first mixed product;

[0116] (2) Weigh 1.30 g of sodium hydroxide granules, add 31.0 g of deionized water to completely dissolve the sodium hydroxide, then add 0.85 g of sodium aluminate (alumina content is 62.0%), stir at 20°C for 2.0 h to obtain the second mixed product;

[0117] (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 first solid product (denoted as molecular sieve I-M2).

[0118] (4) Mix the first solid product and a sodium hydroxide alkaline solution with a concentration of 0.6 mol / L evenly. The mass ratio of the first 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 second solid product (denoted as molecular sieve I-S2-Na).

[0119] (5) The second solid product: ammonium chloride: deionized water were mixed evenly in a weight ratio of 1:1:10. The mixture was stirred and heated in an 80°C water bath for 30 min. After filtration, washing and drying, the resulting solid product: ammonium chloride: deionized water were mixed evenly in a weight ratio of 1:0.5:10. The mixture was subjected to a second ammonium exchange, filtered, washed and dried, and calcined at 550°C for 2 h to obtain the third solid product (hydrogen-type hollow ZSM-5 multi-level porous molecular sieve, denoted as I-S2-H).

[0120] (6) Dissolve 2.68g of ammonium dihydrogen phosphate in 44.21g of deionized water until fully dissolved and stirred until homogeneous to obtain a phosphorus-containing solution; spread 50g of the third solid product in a petri dish, slowly add the prepared phosphorus-containing solution dropwise, and mix thoroughly until the molecular sieve becomes a "viscous paste"; dry in air at 110℃ for 4h, and calcine at 550℃ for 2h to obtain the phosphorus-containing hollow ZSM-5 hierarchical porous molecular sieve of the present invention, denoted as SS-2, and its SEM image is shown below. Figure 1 As shown.

[0121] Example 3

[0122] (1) Weigh 65.13 g of tetrapropylammonium hydroxide aqueous solution (mass fraction of 25.0%), add 476.62 g of deionized water, stir at room temperature for 10 min, then add 165.20 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;

[0123] (2) Weigh 1.39 g of sodium hydroxide granules, add 27.2 g of deionized water to completely dissolve the sodium hydroxide, then add 4.76 g of aluminum nitrate nonahydrate, stir at 25°C for 1.0 h to obtain the fifth mixed product;

[0124] (3) Add the fourth mixed product to the fifth mixed product, stir evenly, and continue to crystallize at 170℃ for 36h; after crystallization, centrifuge and filter, wash, dry, and calcine at 550℃ for 4h to obtain the fourth solid product (denoted as molecular sieve I-M3).

[0125] (4) Mix the fourth 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 solution to 80°C at a heating rate of 5°C / min and stir it at that temperature for 30 min. Filter, wash and dry to obtain the fifth solid product (denoted as molecular sieve I-S3-Na).

[0126] (5) Mix the fifth solid product, ammonium chloride, and deionized water in a weight ratio of 1:1:10. Stir and heat in an 80°C water bath for 30 min. Filter, wash, and dry. Then mix the obtained solid product, ammonium chloride, and deionized water in a weight ratio of 1:0.5:10. Perform a second ammonium exchange, filter, wash, and dry. Calcine at 550°C for 2 h to obtain the sixth solid product (denoted as I-S3-H).

[0127] (6) Dissolve 1.71g of H3PO4 solution (concentration 85% by weight) in 42.49g of deionized water, stir until fully dissolved, and obtain a phosphorus-containing solution; spread 50g of the sixth solid product in a petri dish, slowly add the prepared phosphorus-containing solution, mix thoroughly until the molecular sieve is in the form of a "viscous paste"; dry in air at 115℃ for 4h, and then calcine at 550℃ for 2h to obtain the phosphorus-containing hollow ZSM-5 multi-level porous molecular sieve of the present invention, denoted as SS-3.

[0128] Example 4

[0129] (1) Weigh 134.4 g of tetraethyl orthosilicate, add 833.60 g of deionized water, stir and heat in a water bath at 50°C for 1 h, then raise the water bath temperature to 80°C and stir and heat for 3 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 65.13 g of tetrapropylammonium hydroxide aqueous solution (mass fraction of 25.0%) at 30°C for 1.5 h to obtain the first mixed product;

[0130] (2) Weigh 2.0 g of sodium hydroxide granules, add 26.0 g of deionized water to completely dissolve the sodium hydroxide, then add 4.76 g of aluminum nitrate nonahydrate, stir at 20°C for 1.0 h to obtain the second mixed product;

[0131] (3) The second mixed product is slowly added to the first mixed product and mixed evenly. The mixture is stirred at room temperature for 4.0 h. The resulting precursor liquid is transferred to the synthesis vessel and dynamically crystallized at 160 °C for 60 h. After crystallization, the product is centrifuged, filtered, washed, dried, and calcined at 550 °C for 4 h to obtain the first solid product (denoted as molecular sieve I-M4).

[0132] (4) Mix the first solid product and a sodium hydroxide alkaline solution with a concentration of 0.7 mol / L evenly. The mass ratio of the first 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 this temperature for 30 min. Filter, wash and dry to obtain the second solid product (denoted as molecular sieve I-S4-Na).

[0133] (5) Mix the second solid product, ammonium chloride, and deionized water at a weight ratio of 1:1:10, stir and heat in an 80°C water bath for 30 min, filter, wash, and dry. Mix the obtained solid product, ammonium chloride, and deionized water at a weight ratio of 1:0.5:10, perform a second ammonium exchange, filter, wash, and dry, and calcine at 550°C for 2 h to obtain the third solid product (hydrogen-type hollow ZSM-5 multi-level porous molecular sieve, denoted as I-S4-H).

[0134] (6) Dissolve 2.61g of diammonium hydrogen phosphate in 43.0g of deionized water, stir until fully dissolved, and obtain a phosphorus-containing solution; spread 50g of the third solid product in a petri dish, slowly add the phosphorus-containing solution, mix thoroughly until the molecular sieve is in the form of a "viscous paste"; dry in air at 110℃ for 4h, and calcine at 550℃ for 2h to obtain the phosphorus-containing hollow ZSM-5 multi-level porous molecular sieve of the present invention, and the sample is designated as SS-4.

[0135] Comparative Example 1

[0136] 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.

[0137] Table 1

[0138]

[0139]

[0140]

[0141] 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.

[0142] 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];

[0143] 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];

[0144] 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].

[0145] Examples 5-8 and Comparative Example 2 are examples of preparing catalytic cracking catalysts.

[0146] Examples 5-8

[0147] Catalysts were prepared using the phosphorus-containing hollow ZSM-5 hierarchical porous molecular sieves prepared in Examples 1-4, respectively. The catalyst numbers are A1, A2, A3, and A4.

[0148] Methods for preparing catalytic cracking catalysts include:

[0149] (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.

[0150] (2) The phosphorus-containing hollow ZSM-5 multi-level porous molecular sieve, alumina sol, silica sol, kaolin, the aged pseudoboehmite slurry and deionized water prepared above are mixed evenly to form a slurry with a solid content of 30% by weight, and spray-dried to obtain catalyst microspheres.

[0151] (3) The catalyst microspheres were calcined at 550℃ for 4 hours;

[0152] (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 and characteristic parameters of the prepared catalyst are shown in Table 2.

[0153] Comparative Example 2

[0154] Catalyst DA1 was prepared using the same method as in Example 5, except that molecular sieve DSS-1 prepared in Comparative Example 1 was used instead of molecular sieve SS-1 prepared in Example 1.

[0155] Table 2

[0156]

[0157] Test case

[0158] The catalytic cracking catalysts prepared in the examples and comparative examples were aged at 820°C and 100% (v / v) water vapor for 30 hours, and their catalytic cracking performance was evaluated in a small fixed-bed reactor. The evaluation conditions were: reaction temperature 675°C, nitrogen flow rate 100 mL / min, oil feed time 600 s, catalyst-to-oil ratio 7.2 (w / w), oil feed rate 1.0 g, and oil feed rate 0.10 g / min. The naphtha properties are shown in Table 3, and the reaction results are shown in Table 4.

[0159] The yield mentioned above is calculated based on the raw material feed.

[0160] Product yield = Product output (by weight) / Light hydrocarbon feed rate (by weight) × 100%,

[0161] The conversion rate is the sum of the yields of hydrocarbon products with 4 or fewer carbon atoms in the molecule, the yields of hydrogen, and the yield of coke.

[0162] The thermal decomposition index is (C1+C2) / iC4.

[0163] The hydrogen transfer coefficient is (C3) 0 +C4 0 ) / (C3 ＝ +C4 ＝ ).

[0164] Table 3

[0165]

[0166]

[0167] Table 4

[0168]

[0169] As shown in Table 4, the catalytic cracking catalyst provided by this invention has higher naphtha cracking capacity, higher yields of ethylene, propylene, and butene, and significantly higher total yields of propylene and butene. Under the condition of comparable hydrogen transfer coefficient, the thermal cracking index is significantly lower, indicating that the phosphorus-containing hollow ZSM-5 hierarchical porous molecular sieve has a shell structure that matches the microporous-mesoporous-macroporous structure of the hollow structure, and has excellent diffusion performance.

[0170] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0171] 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, the present invention will not describe the various possible combinations separately.

[0172] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A catalytic cracking catalyst, comprising a carrier and a phosphorus-containing hollow ZSM-5 hierarchical pore molecular sieve, wherein the content of the carrier is 50-85 wt%, and the content of the phosphorus-containing hollow ZSM-5 hierarchical pore molecular sieve is 15-50 wt%, based on the dry basis weight of the catalytic cracking catalyst; The phosphorus-containing hollow ZSM-5 hierarchical pore molecular sieve has a closed hollow structure, the average crystal size of the phosphorus-containing hollow ZSM-5 hierarchical pore molecular sieve crystal is 0.4-2.5 μm, the ratio of the bulk phase silicon-aluminum molar ratio to the surface silicon-aluminum molar ratio is 1.0-1.4, and the relative crystallinity is 75-90%;The phosphorus-aluminum molar ratio of the phosphorus-containing hollow ZSM-5 hierarchical pore molecular sieve is 0.2-1.3; The N2 adsorption-desorption curve of the phosphorus-containing hollow ZSM-5 hierarchical pore molecular sieve shows a H4 type hysteresis loop, the proportion of strong B acid amount to total B acid amount is 70-80%, and the proportion of strong L acid amount to total L acid amount is 55-70%;The carrier is selected from one or more of natural clay, alumina carrier, silica carrier, aluminum phosphate carrier and silicon-aluminum oxide carrier.

2. The catalytic cracking catalyst of claim 1, wherein, The silica carrier is one or more of neutral silica sol, acidic silica sol or basic silica sol;The alumina carrier is one or more of aluminum sol, acidified pseudo-boehmite, hydrated alumina and activated alumina;The aluminum phosphate carrier is aluminum phosphate sol;The silicon-aluminum oxide carrier is selected from one or more of solid silicon-aluminum material, silicon-aluminum sol and silicon-aluminum gel.

3. The catalytic cracking catalyst of claim 1, wherein, The content of the carrier is 55-80 wt%, and the content of the phosphorus-containing hollow ZSM-5 hierarchical pore molecular sieve is 20-45 wt%, based on the dry basis weight of the catalytic cracking catalyst.

4. A process for preparing the catalytic cracking catalyst of any one of claims 1-3, the process comprising: The slurry containing the carrier and the phosphorus-containing hollow ZSM-5 hierarchical pore molecular sieve is subjected to first drying and optional first calcination; The phosphorus-containing hollow ZSM-5 hierarchical pore molecular sieve is prepared by a method comprising the following steps, which comprises: (1) mixing and stirring a first organic silicon source and a first solvent at 30-50℃ for 0.5-5 hours, then increasing the temperature to 70-100℃ and mixing and stirring for 2-10 hours, mixing the obtained mixed liquid with a first template agent at 20-30℃ for 0.5-3.0 hours to obtain a first mixed product; (2) mixing a first alkali hydroxide in terms of alkali metal oxide, a second solvent and a first aluminum source in terms of Al2O3 in a molar ratio of (1.5-5) : (60-350) : 1 at 20-80℃ for 0.5-2.0 hours to obtain a second mixed product; (3) mixing the first mixed product with the second mixed product and then performing dynamic crystallization, taking out the obtained solid and performing second calcination to obtain a first solid product; (4) mixing the first solid product with a first solution containing alkali, increasing the temperature to the reaction temperature at a temperature increasing rate of 1-5℃ / min, and then reacting at the reaction temperature for 10-90 min to obtain a second solid product;Wherein, the reaction temperature is 60-90℃, and the content of alkali in the first solution containing alkali is 0.45-2 mol / L. (5) subjecting the second solid product to a first ammonium exchange, optionally a sixth calcination, to obtain a third solid product; (6) mixing the third solid product with a second solution containing a phosphorus source, and subjecting the obtained first slurry to a second drying and a third calcination; or, The method comprises: S1, mixing a second template agent, a second inorganic silicon source and a third solvent at 30-50℃ for 0.5-3.0 hours, and then subjecting the obtained third mixed product to a first hydrothermal treatment and a second hydrothermal treatment in sequence to obtain a fourth mixed product; wherein the first hydrothermal treatment is carried out at a temperature of 80-150℃ for 1-6 hours; and the second hydrothermal treatment is carried out at a temperature of 160-180℃ for 4-60 hours; S2, mixing a second alkali metal hydroxide in terms of alkali metal oxide, a fourth solvent and a second aluminum source in terms of Al2O3 at a molar ratio of (1.5-5):(60-350):1 at 20-80℃ for 0.5-2.0 hours to obtain a fifth mixed product; S3, mixing the fourth mixed product and the fifth mixed product, and then subjecting the obtained mixture to a third hydrothermal treatment, taking out the obtained solid product and subjecting it to a fourth calcination to obtain a fourth solid product; S4, mixing the fourth solid product with a second solution containing alkali, and then raising the temperature to a reaction temperature at a temperature raising rate of 1-5℃ / min, and then reacting at the reaction temperature for 10-90min to obtain a fifth solid product; wherein the reaction temperature is 60-90℃, and the content of alkali in the second solution containing alkali is 0.45-2mol / L; S5, subjecting the fifth solid product to a second ammonium exchange, optionally a seventh calcination, to obtain a sixth solid product; S6, mixing the sixth solid product with a fourth solution containing a phosphorus source, and then subjecting the obtained second slurry to a third drying and a fifth calcination.

5. The method of claim 4, wherein, The first organic silicon source is selected from one or more of methyl orthosilicate and ethyl 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 hexanediamine; 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 isopropyl alcohol 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 solution containing alkali and the second solution containing alkali are each independently selected from one or more of sodium hydroxide solution, potassium hydroxide solution, lithium hydroxide solution and barium hydroxide solution; The phosphorus source is selected from at least one or more of phosphoric acid, ammonium dihydrogen phosphate, diammonium hydrogen phosphate and ammonium phosphate.

6. The method of claim 4, wherein, The total amount of the first template agent, the first solvent and the second solvent, the mole ratio of the amount of the first alkali metal hydroxide and the first organic silicon source is (0.06-0.55):(10-100):(0.02-1.5):1, the mole ratio of the amount of the first organic silicon source and the first aluminum source is (20-500):1; wherein the first organic silicon source is calculated as SiO2, the first alkali metal hydroxide is calculated as alkali metal oxide, and the first aluminum source is calculated as Al2O3.

7. The method of claim 6, wherein, In step (2), the mole ratio of the amount of the first alkali metal hydroxide calculated as alkali metal oxide, the second solvent and the first aluminum source calculated as Al2O3 is (2-4.5):(80-350):1; In step (4), the weight ratio of the amount of the first solid product and the first solution containing alkali is 1:(2-10); the ratio of the bulk silicon-aluminum molar ratio and the surface silicon-aluminum molar ratio of the first solid product is 1.2-5.0; In step (6), the weight ratio of the amount of the second solution containing a phosphorus source and the third solid product is 1:(0.5-2.0); The total amount of the second template agent, the third solvent and the fourth solvent, the mole ratio of 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, the mole ratio of the second inorganic silicon source and 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 alkali metal oxide, and the second aluminum source is calculated as Al2O3; In step S2, the mole ratio of the amount of the second alkali metal hydroxide calculated as alkali metal oxide, the fourth solvent and the second aluminum source calculated as Al2O3 is (2-4.5):(80-350):1; In step S4, the weight ratio of the amount of the fourth solid product and the second solution containing alkali is 1:(2-10), the fourth solid product is calculated as SiO2, and the ratio of the bulk silicon-aluminum molar ratio and the surface silicon-aluminum molar ratio of the fourth solid product is 1.2-5.0; In step S6, the weight ratio of the amount of the fourth solution containing a phosphorus source and the sixth solid product is 1:(0.5-2.0).

8. The method of claim 4, wherein, The conditions of the dynamic crystallization include: temperature of 160-180℃, time of 12-60 hours; The conditions of the third hydrothermal treatment include: temperature of 160-180℃, time of 12-60 hours; The conditions of the second calcination, the third calcination, the fourth calcination and the fifth calcination each independently include: temperature of 400-600℃, time of 2-6 hours; The conditions of the second drying and the third drying each independently include: temperature of 90-120℃, time of 2-24 hours.

9. The method of claim 4, wherein, The method further comprises: mixing the catalyst particles obtained from the first drying and optional first calcination, the ammonium salt and a fifth solvent in a weight ratio of 1:(0.1-1):(5-15) to perform a third ammonium exchange, and optionally washing; The conditions of the third ammonium exchange comprise: a temperature of 50-100°C, and a time of 0.5-2 hours. The ammonium salt is selected from one or more of ammonium chloride, ammonium sulfate and ammonium nitrate.

10. Use of the catalytic cracking catalyst according to any one of claims 1-3 in catalytic cracking of naphtha.

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