CN113578299B - A silicon-aluminum-zirconium composite oxide, catalytic cracking catalyst and preparation method and application thereof - Google Patents

Abstract

The invention relates to a silicon-aluminum-zirconium composite oxide, a catalytic cracking catalyst and a preparation method and application thereof. Based on the dry weight of the silicon-aluminum-zirconium composite oxide, the silicon-aluminum-zirconium composite oxide contains 40-90% by weight of Al. ₂ O ₃ , 15-55 wt% ZrO ₂ and 2-20 wt% SiO ₂ , the pore volume with a pore diameter of 10-60nm accounts for more than 70% of the total pore volume, and the microreactivity index is more than 30. The catalytic cracking catalyst containing the silicon-aluminum-zirconium composite oxide of the present invention has good heavy oil cracking ability, carbon tetraolefin selectivity and heavy metal pollution resistance.

Description

A silicon-aluminum-zirconium composite oxide, a catalytic cracking catalyst, and its preparation method and application

Technical Field

The invention relates to a silicon-aluminum-zirconium composite oxide, a catalytic cracking catalyst, and a preparation method and application thereof.

Background Art

With the increase of environmental awareness, the quality standards of automotive gasoline are constantly upgraded. The new standard for automotive gasoline, GB17930-2016, clearly stipulates that the National VI standard gasoline will be implemented in stages across the country from 2019. Compared with the National V standard, the benzene, aromatics and olefin contents of gasoline under the National VI standard will be reduced. At present, my country's gasoline blending component scheme has been difficult to meet the requirements. Due to the high octane number of alkylated gasoline and zero olefin, alkylated gasoline is a good gasoline blending component relative to traditional catalytic gasoline and reforming gasoline under the National VI standard, and its proportion in gasoline blending components will be greatly increased. The main raw materials of the alkylation unit are isobutane and C4 olefins. Nearly 70% of the world's C4 olefins come from catalytic cracking units, and the technology of producing C4 olefin fractions from catalytic cracking units has the advantages of low investment and low cost. Many companies are trying to obtain a larger amount of C4 olefin yield from the catalytic cracking process.

Catalytic cracking catalyst directly affects the conversion of reactants and the distribution of products, and plays an important role in the catalytic cracking process. Y-type molecular sieve is the main active component of catalytic cracking catalyst, which is composed of hexagonal prism cage, sodalite cage (also known as β cage) and super cage. Since the kinetic diameter of hexagonal prism cage and sodalite cage is only 0.26nm, except for water molecules, the kinetic diameters of _N2 , _O2 and all organic molecules are greater than 0.26nm and cannot enter the hexagonal prism cage and sodalite cage. Therefore, only the acid center in the super cage (kinetic diameter 0.81nm) is available for the adsorption, activation and reaction of organic molecules. Conventional Y-type molecular sieve is extracted with aluminum and/or supplemented with silicon by various methods to obtain ultra-stable Y-type molecular sieve (USY). The number of skeleton aluminum of USY molecular sieve is reduced, the unit cell constant is reduced, the distance between acid centers is increased, the acid strength is improved, and the acid density is reduced, which is not conducive to the hydrogen transfer reaction of bimolecules, but is relatively conducive to cracking reaction. The ratio of cracking reaction to hydrogen transfer reaction is improved, so compared with rare earth modified Y type molecular sieve, USY has high gasoline octane number, low dry gas and coke yield, and high selectivity of C4 olefins. The introduction of rare earth into USY can increase the activity of USY, but the olefin selectivity suffers a certain loss. This is mainly due to the presence of rare earth ions that increase the number of B acid centers and make the molecular sieve unit cell constant difficult to shrink. Generally, rare earth-free USY molecular sieve has lower hydrogen transfer reaction performance and higher C4 olefin selectivity, and high rare earth conventional Y type molecular sieve has high hydrogen transfer reaction activity and low C4 olefin selectivity.

In order to increase the production of low-carbon olefins, people usually add zeolites with MFI structure to the catalyst. Compared with Y-type molecular sieves, MFI structure zeolites can selectively crack and isomerize the straight-chain and short-branched alkanes in the FCC gasoline fraction in its pores to generate C3-C5 olefins, thereby increasing the yield of low-carbon olefins. In 1993, Engelhard Company of the United States first disclosed a cracking catalyst for increasing the production of isobutylene and isopentene in US Patent USP5243121. By reducing the unit cell size of Y zeolite in the cracking catalyst through hydrothermal treatment, the selectivity of the catalyst for olefins in the product during hydrocarbon cracking can be improved. A considerable amount of ZSM-5 zeolite can also be added to the catalyst as an additive, which can not only reduce the amount of coke, but also improve the activity. US3758403 discloses a catalyst with ZSM-5 and large-pore zeolite (mainly Y-type zeolite) as active components, which increases the yield of C3 and C4 olefins while improving the octane number of gasoline. The large-pore zeolite cracks the raw materials to produce gasoline and diesel, and the ZSM-5 shape-selective molecular sieve further cracks them into low-carbon olefins. Phosphorus modification can improve the surface acidity of zeolite and improve shape selectivity. USP5171921 discloses a phosphorus-modified ZSM-5 zeolite, which has a silicon-aluminum ratio of 20 to 60. After being impregnated with a phosphorus-containing compound and treated with 500 to 700°C steam, it is used for the reaction of converting C3 to C20 hydrocarbons into C2 to C5 olefins. It has higher activity than HZSM-5 that is not treated with phosphorus.

Due to the particularity of its structure, β zeolite has both acid catalytic properties and structural selectivity, and has rapidly developed into a new type of catalytic material in recent years. There are also many reports on the application of β zeolite in catalytic cracking catalysts to produce light olefins. U.S. Patent No. 4,837,396 discloses a catalyst containing β zeolite and Y zeolite, and a metal ion compound is used as a stabilizer to improve the hydrothermal stability and mechanical strength of the catalyst. The stabilizer can directly act on the β zeolite or be introduced during the preparation process. CN1055105C discloses a cracking catalyst for producing more isobutylene and isopentene, containing 6 to 30% by weight of a five-membered ring high-silicon zeolite containing phosphorus and rare earth, 5 to 20% by weight of USY zeolite, 1 to 5% by weight of β zeolite, 30 to 60% by weight of clay and 15 to 30% by weight of an inorganic oxide. The catalyst has the characteristics of producing more isobutylene and isopentene under the process conditions of catalytic cracking, and can also co-produce high-octane gasoline. CN104998681A discloses a catalytic cracking aid for increasing the concentration of light olefins and a preparation method thereof, wherein the aid comprises a boron-modified phosphorus- and metal-containing beta molecular sieve, an inorganic oxide binder, a Group VIII metal additive, a phosphorus additive, and optional clay. The catalytic cracking aid is applied to the catalytic cracking of petroleum hydrocarbons, can increase the concentration of isobutylene in the catalytic cracking liquefied gas, and reduce the yield of coke.

The active components of the catalyst are important, but the role of the matrix cannot be ignored. It is generally believed that the catalyst matrix should have a large pore size, suitable activity and good hydrothermal stability so that the catalyst can withstand harsh hydrothermal operating conditions and pre-cracking heavy crude oil.

Alumina has a simple preparation process, high specific surface area, good mechanical strength, and suitable pore size. It is one of the most widely used catalyst carriers. Zirconium oxide has both acidic and alkaline surface centers, oxidizing and reducing properties, and good ion exchange properties. As a carrier or catalyst, it shows unique catalytic activity and selectivity in the field of catalysis. CN00123133.2 discloses a zirconium-containing alumina carrier and a preparation method thereof. The zirconium-containing alumina carrier is prepared by adding a zirconium-containing compound in the form of kneading during the molding process of the carrier; the acidity of the carrier is maintained at a relatively stable stage, the infrared acidity is 0.25-0.32 mmol/g, and the pore distribution is concentrated in the mesopore range. CN200710158366.1 discloses a composite oxide carrier and a preparation method. The precursors of alumina, silicon dioxide and zirconium oxide are co-precipitated with an alkaline solution, and a surfactant is added to improve the pore structure and acidity and alkalinity. The obtained precipitate is washed, filtered, and high-temperature calcined to obtain a composite oxide powder, and then extruded to obtain the carrier. The pore structure and acidity and alkalinity of the obtained carrier are adjustable in a wide range, with a specific surface area of ^200-500m2 /g, a pore volume of 0.4-1.2mL/g, and a total NH3 _- TPD acid content of 0.2-0.8mmol/g. CN200710158368.0 discloses a method for preparing a silicon- and zirconium-containing alumina dry gel powder, wherein after the aluminum-containing compound solution and the precipitant are gelled, the zirconium-containing compound solution is added under conditions such as controlling an appropriate pH value, and the silicon-containing compound is added before, after or simultaneously with the zirconium-containing compound, and then the silicon- and zirconium-containing alumina dry gel is obtained after washing, filtering, and drying.

It can be seen that the various catalysts/auxiliaries prepared by the above-mentioned prior art are used in the catalytic cracking process to a certain extent to achieve the purpose of increasing the production of light olefins, but often have the following problems: first, while increasing propylene and butene, the yield of liquefied gas also increases, resulting in little change in the concentration of propylene or butene in the liquefied gas; on the other hand, while increasing butene, the yield of propylene also increases, resulting in poor butene selectivity.

From the analysis of the formation and conversion mechanism of C4 olefins in the catalytic cracking process, the formation of C4 olefins in the catalytic cracking process mainly comes from two aspects: one is the product of the cracking of active intermediates generated by the monomolecular cracking reaction or bimolecular cracking reaction of hydrocarbon macromolecules in the raw materials, and the other is the product of the secondary reaction of low-carbon olefins formed in the cracking reaction. The C4 olefins generated in the catalytic cracking process can further undergo cracking reactions, isomerization reactions, dimerization reactions and hydrogen transfer reactions.

Summary of the invention

The purpose of the present invention is to provide a silicon-aluminum-zirconium composite oxide, a catalytic cracking catalyst, and a preparation method and application thereof. The catalytic cracking catalyst of the present invention has good heavy oil cracking ability, C4 olefin selectivity and resistance to heavy metal pollution.

In order to achieve the above-mentioned object, the first aspect of the present invention provides a silicon-aluminum-zirconium composite oxide, which contains 30-80 weight % of Al ₂ O ₃ , 15-55 weight % of ZrO ₂ and 2-20 weight % of SiO ₂ based on the dry weight of the silicon-aluminum-zirconium composite oxide, the pore volume with a pore diameter range of 10-60 nm accounts for more than 70% of the total pore volume, and the micro-reaction activity index is more than 30, and the pore diameter refers to the pore diameter.

Optionally, based on the dry weight of the silicon-aluminum-zirconium composite oxide, the silicon-aluminum-zirconium composite oxide contains 40-75 wt % of Al ₂ O ₃ , 15-50 wt % of ZrO ₂ and 5-15 wt % of SiO ₂ .

Optionally, the pore volume of the silicon-aluminum-zirconium composite oxide with a pore diameter range of 10-60 nm accounts for 75-85% of the total pore volume.

Optionally, the micro-reaction activity index of the silicon-aluminum-zirconium composite oxide is 35-50.

A second aspect of the present invention provides a catalytic cracking catalyst, which contains, based on the dry weight of the catalytic cracking catalyst, 10-50 weight % of Y-type zeolite, 1-30 weight % of β zeolite, 1-20 weight % of ZSM-5 zeolite, 3-40 weight % of silicon-aluminum-zirconium composite oxide, 10-70 weight % of clay and 5-30 weight % of binder, wherein the silicon-aluminum-zirconium composite oxide is the silicon-aluminum-zirconium composite oxide according to claim 1 or 2.

Optionally, the catalytic cracking catalyst contains 10-40 wt% of the Y-type zeolite, 5-30 wt% of the β zeolite, 2-15 wt% of the ZSM-5 zeolite, 5-35 wt% of the silicon-aluminum-zirconium composite oxide, 10-55 wt% of the clay and 5-25 wt% of the binder.

Optionally, the Y-type zeolite is selected from one or more of a Y-type zeolite containing phosphorus and/or rare earth, an ultrastable Y zeolite, and an ultrastable Y zeolite containing phosphorus and/or rare earth;

The beta zeolite is selected from hydrogen beta zeolite and/or modified beta zeolite, and the modified beta zeolite contains one or more of phosphorus, iron and rare earth metal elements;

The ZSM-5 zeolite is selected from hydrogen-type ZSM-5 zeolite and/or ZSM-5 zeolite containing a modifying element, and the modifying element is one or more of phosphorus, rare earth and iron;

The clay is selected from one or more of kaolin, rectorite, diatomaceous earth, montmorillonite, bentonite and sepiolite;

The binder is selected from one or more of aluminum sol, silica sol, silica-aluminum composite sol, aluminum phosphate sol and acidified pseudo-boehmite.

The third aspect of the present invention provides a method for preparing the silicon-aluminum-zirconium composite oxide provided by the first aspect of the present invention, the method comprising:

(1) mixing a zirconium-containing compound, a carbon source and a first solvent, adjusting the pH value of the mixture to 5-10, and stirring at 15-40° C. for 0.5-4 hours to obtain a first slurry; the carbon source comprises a natural high molecular organic compound and/or a semi-synthetic high molecular organic compound;

(2) mixing the aluminum source, the second solvent and the acid solution at 15-60° C. for 0.5-4 hours to obtain a second slurry;

(3) Mixing the first slurry, the second slurry and the silicon source at 0-40° C. for 0.1-2 hours, and performing a first drying and/or a first calcination.

Optionally, in step (1), the weight ratio of the zirconium-containing compound, the carbon source and the first solvent is 1:(0.01-0.20):(4-20), preferably 1:(0.05-0.20):(5-15); the zirconium-containing compound is calculated as zirconium oxide.

Optionally, in step (1), the pH value of the mixture is adjusted to 5-9.

Optionally, in step (2), the concentration of the acid solution is 2-45 wt %; the weight ratio of the aluminum source to the acid solution is 1:(0.01-0.3), preferably (0.06-0.25), and the aluminum source is calculated as alumina.

Optionally, step (3) comprises: stirring and mixing the first slurry and the second slurry at 15-40° C. for 0.1-1 hour, adding the silicon source to the obtained mixture, and continuing to stir at 15-40° C. for 0.1-1 hour.

Optionally, the zirconium-containing compound is selected from one or more of zirconium tetrachloride, zirconium sulfate, zirconium nitrate, zirconium oxychloride, zirconium acetate and zirconium isopropoxide;

The carbon source is selected from one or more of starch, lignin, viscose fiber, methyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose and carboxymethyl cellulose;

The aluminum source is selected from one or more of pseudo-boehmite, boehmite, aluminum hydroxide and aluminum oxide;

The silicon source is selected from one or more of silica sol, silica gel and water glass;

The first solvent and the second solvent are each independently selected from one or more of deionized water, ethanol and acetone;

The acid solution is selected from one or more of hydrochloric acid solution, sulfuric acid solution, nitric acid solution, phosphoric acid solution, formic acid solution, acetic acid solution, oxalic acid solution and citric acid solution.

Optionally, the temperature of the first drying is 80-200° C.; the temperature of the first calcining is 300-700° C., and the time is 0.5-5 hours.

The fourth aspect of the present invention provides a method for preparing the catalytic cracking catalyst provided by the second aspect of the present invention, the method comprising: mixing the Y-type zeolite, the β zeolite, the ZSM-5 zeolite, the silica-aluminum-zirconium composite oxide, the clay, the binder and the third solvent, granulating the obtained third slurry, and performing a second drying and/or a second calcination; the silica-aluminum-zirconium composite oxide is the silica-aluminum-zirconium composite oxide provided by the first aspect of the present invention.

Optionally, the solid content of the third slurry is 15-60% by weight, and the silicon-aluminum-zirconium composite oxide is calculated as the sum of silicon oxide, zirconium oxide and aluminum oxide;

The third solvent is deionized water and/or decationized water.

Optionally, the second drying temperature is 60-200° C.; the second calcining temperature is 350-650° C., and the time is 0.5-5 hours.

The fifth aspect of the present invention provides an application of the silicon-aluminum-zirconium composite oxide provided in the first aspect of the present invention or the catalytic cracking catalyst provided in the second aspect in the catalytic cracking of heavy oil.

Through the above technical scheme, the silicon-aluminum-zirconium composite oxide of the present invention has excellent pore size distribution and activity, and the catalytic cracking catalyst containing the silicon-aluminum-zirconium composite oxide has good heavy oil cracking performance and can improve the selectivity and yield of C4 olefins.

The method of the invention can prepare silicon-aluminum-zirconium composite oxide and catalytic cracking catalyst with good catalytic performance.

Other features and advantages of the present invention will be described in detail in the following detailed description.

DETAILED DESCRIPTION

The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

The first aspect of the present invention provides a silicon-aluminum-zirconium composite oxide, which contains 30-80 wt% Al ₂ O ₃ , 15-55 wt% ZrO ₂ and 2-20 wt% SiO ₂ based on the dry weight of the silicon-aluminum-zirconium composite oxide, the pore volume with a pore diameter range of 10-60 nm accounts for more than 70% of the total pore volume, and the micro-reaction activity index is more than 30, and the pore diameter refers to the pore diameter. The micro-reaction activity index is measured according to the ASTM D3907 standard method.

The silicon-aluminum-zirconium composite oxide of the present invention has excellent pore size distribution and activity as well as good resistance to heavy metal pollution, can effectively capture heavy metals in raw materials, avoid heavy metal damage to the active components of molecular sieves, and can improve the pre-cracking reaction of heavy oil macromolecules during the catalytic cracking reaction. Combining it with the molecular sieve component of the catalytic cracking catalyst is beneficial to provide more precursors for the production of C4 olefins, thereby improving the selectivity and yield of C4 olefins.

In a preferred embodiment, the silicon-aluminum-zirconium composite oxide contains 40-75 wt% Al ₂ O ₃ , 15-50 wt% ZrO ₂ and 5-15 wt% SiO ₂ , based on the dry weight of the silicon-aluminum-zirconium composite oxide.

In a specific embodiment, the pore volume of the silicon-aluminum-zirconium composite oxide with a pore diameter ranging from 10 to 60 nm may account for 75 to 85% of the total pore volume.

In a specific embodiment, the micro-reaction activity index of the silicon-aluminum-zirconium composite oxide may be 35-50.

The second aspect of the present invention provides a catalytic cracking catalyst, which contains, based on the dry weight of the catalytic cracking catalyst, 10-50 weight % of Y-type zeolite, 1-30 weight % of β zeolite, 1-20 weight % of ZSM-5 zeolite, 3-40 weight % of silicon-aluminum-zirconium composite oxide, 10-70 weight % of clay and 5-30 weight % of binder, and the silicon-aluminum-zirconium composite oxide is the silicon-aluminum-zirconium composite oxide provided by the first aspect of the present invention.

The catalytic cracking catalyst of the present invention has good catalytic performance and heavy metal pollution resistance, can improve the selectivity and yield of C4 olefins, can promote the cracking process of heavy oil macromolecules, reduce the yield of slurry oil and diesel, and improve the yield of gasoline. When the catalytic cracking catalyst of the present invention is used in the catalytic cracking process of heavy oil, the conversion rate of heavy oil is high, and the yield and selectivity of C4 olefins are high.

In a preferred embodiment, the catalytic cracking catalyst contains 10-40 wt% of Y-type zeolite, 5-30 wt% of β zeolite, 2-15 wt% of ZSM-5 zeolite, 5-35 wt% of silicon-aluminum-zirconium composite oxide, 10-55 wt% of clay and 5-25 wt% of binder.

According to the present invention, Y-type zeolite, beta zeolite and ZSM-5 zeolite are well known to those skilled in the art, for example, Y-type zeolite can be selected from one or more of Y-type zeolite containing phosphorus and/or rare earth, ultrastable Y zeolite, and ultrastable Y zeolite containing phosphorus and/or rare earth. Beta zeolite can be selected from hydrogen beta zeolite and/or modified beta zeolite, and the modified beta zeolite can contain one or more of phosphorus, iron and rare earth metal elements. ZSM-5 zeolite can be selected from hydrogen ZSM-5 zeolite and/or ZSM-5 zeolite containing modifying elements, and the modifying elements are one or more of phosphorus, rare earth and iron.

According to the present invention, the clay is commonly used by those skilled in the art, and can be selected from, for example, kaolin, rectorite, diatomaceous earth, montmorillonite, bentonite and sepiolite, or a mixture of several thereof.

According to the present invention, the binder is conventionally used by those skilled in the art, and can be purchased commercially or prepared according to existing methods. Preferably, the binder is selected from one or more of aluminum sol, silica sol, silica-aluminum composite sol, aluminum phosphate sol and acidified pseudo-boehmite. Among them, the preparation method of acidified pseudo-boehmite is well known to those skilled in the art. For example, when hydrochloric acid is used to acidify pseudo-boehmite, the mass of hydrochloric acid (calculated as 36% hydrochloric acid) and pseudo-boehmite (calculated as alumina) is 0.10-0.20. Aluminum phosphate sol can be prepared according to the methods provided in patents CN1008974C and CN1083512A, and silica sol can be prepared according to the methods provided in US Pat. Nos. 3,957,689 and 3,867,308.

The third aspect of the present invention provides a method for preparing the silicon-aluminum-zirconium composite oxide provided by the first aspect of the present invention, the method comprising:

(1) mixing a zirconium-containing compound, a carbon source and a first solvent, adjusting the pH value of the mixture to 5-10, and stirring at 15-40° C. for 0.5-4 hours to obtain a first slurry; the carbon source comprises a natural high molecular organic compound and/or a semi-synthetic high molecular organic compound;

(2) mixing the aluminum source, the second solvent and the acid solution at 15-60° C. for 0.5-4 hours to obtain a second slurry;

(3) The first slurry, the second slurry and the silicon source are mixed at 0-40° C. for 0.1-2 hours, and a first drying and/or a first calcination is performed.

According to the present invention, the mixing time in step (1) refers to the time for mixing the slurry obtained after the first slurry, the second slurry and the silicon source are added.

According to the present invention, in step (1), the weight ratio of the zirconium-containing compound, the carbon source and the first solvent can vary within a large range, for example, it can be 1: (0.01-0.20): (4-20), where the zirconium-containing compound is calculated as zirconium oxide; preferably, the weight ratio of the zirconium-containing compound, the carbon source and the first solvent is 1: (0.05-0.2): (5-15).

According to the present invention, the zirconium-containing compound can be selected from one or more of zirconium tetrachloride, zirconium sulfate, zirconium nitrate, zirconium oxychloride, zirconium acetate and zirconium isopropoxide. The first solvent and the second solvent can be independently selected from one or more of deionized water, ethanol and acetone, preferably deionized water.

According to the present invention, the carbon source is a natural high molecular organic compound and/or a semi-synthetic high molecular organic compound. In a specific embodiment, the carbon source is selected from one or more of starch, lignin, viscose fiber, methyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose and carboxymethyl cellulose. The inventors of the present invention have found that the carbon source is not only conducive to the uniform dispersion of the zirconium-containing substance in the first slurry, avoiding its aggregation to form larger particles, but also after the first calcination, due to its own decomposition, a good pore structure will be formed in the resulting composite.

According to the present invention, in step (1), a zirconium-containing compound, a carbon source and a first solvent are formed into a mixture, and then the pH value of the mixture is adjusted to 5-10, preferably 5-8.5. There is no specific restriction on the way to adjust the pH value of the mixture. For example, the pH value of the first slurry can be ^adjusted by adding an alkaline solution, and the alkaline solution can be one or more of ammonia water, water glass aqueous solution, sodium metaaluminate aqueous solution and sodium hydroxide aqueous solution, preferably ammonia water. The concentration of the alkaline solution can vary over a large range. In one embodiment, the concentration of the alkaline solution in terms of OH- can be 2-20% by weight, preferably 3-15% by weight. In another embodiment, the alkaline solution is dilute ammonia water, and the concentration of the dilute ammonia water in terms of _NH3 is 2-20% by weight, preferably 3-15% by weight.

In a specific embodiment, in step (1), after adjusting the pH value of the mixture, the mixture is stirred at 15-30° C. for 0.5-2 hours to obtain a first slurry.

According to the present invention, in step (2), the concentration of the acid solution can vary in a wide range. For example, it can be 2-45% by weight, preferably 5-15% by weight; the weight ratio of the aluminum source and the acid solution can also vary in a wide range, for example, it can be 1: (0.01-0.3), preferably 1: (0.05-0.25), more preferably 1: (0.06-0.25), and further preferably 1: (0.1-0.2), the aluminum source is calculated as aluminum oxide. In a specific embodiment, the acid solution is preferably hydrochloric acid, the weight ratio of the aluminum source and the acid solution is preferably 1: (0.05-0.25), more preferably 1: (0.06-0.25), and further preferably 1: (0.1-0.2), the aluminum source is calculated as aluminum oxide, and the acid solution is calculated as 36% by weight of hydrochloric acid.

In a specific embodiment, the aluminum source and the acid solution are mixed and then stirred at 15-60° C. for 0.5-4 hours to obtain a second slurry. The solid content of the second slurry is preferably 15-45% by weight.

In a specific embodiment, the acid solution can be selected from one or more of hydrochloric acid solution, sulfuric acid solution, nitric acid solution, phosphoric acid solution, formic acid solution, acetic acid solution, oxalic acid solution and citric acid solution, preferably hydrochloric acid solution and/or nitric acid solution.

According to the present invention, step (3) may include: stirring and mixing the first slurry and the second slurry at 15-40° C. for 0.1-1 hour, preferably at 15-30° C. for 10-30 minutes, adding a silicon source to the obtained mixture, and continuing to stir the mixture at 15-40° C. for 10-60 minutes, preferably at 15-30° C. for 10-30 minutes. The silicon source is well known to those skilled in the art, and may be an organic silicon source and/or an inorganic silicon source, preferably one or more of silica sol, silica gel and water glass, and more preferably silica sol.

According to the present invention, the temperature of the first drying can be 80-200°C, preferably, the temperature is 80-120°C, and the time of the first drying can vary within a large range without specific limitation; the temperature of the first roasting can be 350-700°C, the time can be 0.5-5 hours, the temperature is 350-600°C, and the time is 1.0-3.0 hours.

The above-mentioned drying and calcining are well known to those skilled in the art. For example, the drying can be carried out in a constant temperature drying oven, and the calcining can be carried out in a muffle furnace or a tubular furnace.

The fourth aspect of the present invention provides a method for preparing the catalytic cracking catalyst provided by the second aspect of the present invention, the method comprising: mixing Y-type zeolite, β zeolite, ZSM-5 zeolite, silica-aluminum-zirconium composite oxide, clay, a binder and a third solvent, granulating the obtained third slurry, and performing a second drying and/or a second calcination; the silica-aluminum-zirconium composite oxide is the silica-aluminum-zirconium composite oxide provided by the first aspect of the present invention.

According to the present invention, the clay can be selected from one or more of kaolin, rectorite, diatomaceous earth, montmorillonite, bentonite and sepiolite; the binder can be selected from one or more of aluminum sol, silica sol, silica-aluminum composite sol, aluminum phosphate sol and acidified pseudo-boehmite; the third solvent can be water, for example, selected from deionized water and/or decationized water.

A preferred specific embodiment is to mix and slurry the third solvent, clay, silicon-aluminum-zirconium composite oxide and a binder, mix and stir the obtained slurry with Y-type zeolite, β-zeolite and ZSM-5 zeolite, spray granulate, roast, and optionally wash and dry to obtain the catalytic cracking catalyst of the present invention. Preferably, an acid is added during slurrying, or an acid is added after slurrying to adjust the pH value of the slurry to 1-5, preferably 2-4, and age at 30-90°C for 0.5-5 hours. The acid can be a water-soluble inorganic acid or organic acid, preferably one or more of hydrochloric acid, nitric acid and phosphoric acid. Among them, the method and conditions of spray drying are well known to those skilled in the art and will not be repeated here.

According to the present invention, the solid content of the third slurry may be 15-60% by weight, preferably 15-50% by weight, and the silicon-aluminum-zirconium composite oxide is calculated as the sum of silicon oxide, zirconium oxide and aluminum oxide.

According to the present invention, the temperature of the second drying is 80-200°C, preferably, the temperature is 80-120°C, and the time of the second drying can be selected according to actual needs, without specific restrictions; the temperature of the second calcination is 350-800°C, and the time is 0.5-6 hours, preferably, the temperature is 400-650°C, and the time is 1-4 hours, and the calcination can be carried out in any atmosphere, such as air.

The fifth aspect of the present invention provides use of the silicon-aluminum-zirconium composite oxide provided by the first aspect of the present invention or the catalytic cracking catalyst provided by the second aspect of the present invention in catalytic cracking of heavy oil.

The present invention is further described below by way of examples, but the present invention is not limited thereto.

The raw materials used in the preparation of the catalyst are as follows: kaolin produced by Suzhou Kaolin Company, with a solid content of 76% by weight; the aluminum oxide content in the aluminum sol is 21.5% by weight; the silicon oxide content in the silica sol is 25% by weight; pseudo-boehmite is produced by Shandong Aluminum Plant, with a solid content of 62.0% by weight; hydrochloric acid is produced by Beijing Chemical Plant, with a specification of analytical grade and a mass concentration of 36%; the ultra-stable Y zeolite USY used has a solid content of 94.7% and a unit cell constant of In terms of weight percentage, the Na ₂ O content is 1.3%; the solid content of the rare earth ultrastable Y zeolite REUSY is 84.8%, and the unit cell constant is In terms of weight percentage, the Na ₂ O content is 1.6%, and the RE ₂ O ₃ content is 12.0%; the solid content of hydrogen beta zeolite is 75%, SiO ₂ /Al ₂ O ₃ = 25, and the Na ₂ O content is 0.15%. The solid content of phosphorus-modified beta zeolite is 82.5%, SiO ₂ /Al ₂ O ₃ = 25, the Na ₂ O content is 0.15%, and the P ₂ O ₅ content is 7.0%. HZSM-5 zeolite, SiO ₂ /Al ₂ O ₃ = 40-50, the Na ₂ O content is 3.5%, and the solid content is 75% by weight. Phosphorus-modified ZSM-5 zeolite, SiO ₂ /Al ₂ O ₃ = 40-50, the Na ₂ O content is 0.12%, the P ₂ O ₅ content is 2.1%, and the solid content is 83% by weight.

The above-mentioned Y-type zeolite, β-zeolite and ZSM-5 zeolite are all produced by Sinopec Catalyst Co., Ltd., and the remaining reagents are produced by Sinopharm Chemical Reagent Co., Ltd., and the specifications are all analytically pure.

Micro-reaction activity index: The standard method of RIPP92-90 (see "Petrochemical Analysis Method" (RIPP Test Method) edited by Yang Cuiding et al., Science Press, published in 1990) was used to evaluate the light oil micro-reaction activity of the sample. The catalyst loading was 5.0 g, the reaction temperature was 460°C, the feed oil was straight-run light diesel with a distillation range of 235-337°C, and the product composition was analyzed by gas chromatography. The light oil micro-reaction activity was calculated based on the product composition.

Pore volume: The nitrogen adsorption-desorption method was used to test according to ASTM D4365 to calculate the specific surface area and pore volume of the sample.

Catalyst composition analysis: The X-ray fluorescence spectroscopy (XRF) method was used, and the results of catalyst composition analysis are shown in Table 2-4.

Examples 1-8 are examples of preparing silicon-aluminum-zirconium composite oxides, and Comparative Examples 1-4 are comparative examples of preparing comparative silicon-aluminum-zirconium composite oxides:

Example 1

(1) 915 g of zirconium oxychloride (ZrOCl ₂ ·8H ₂ O) and 17.5 g of hydroxypropyl methylcellulose were slurried with 1400 g of deionized water, the pH value of the mixture was adjusted to 7.0 with dilute ammonia water, and stirred at 15° C. for 3.0 hours to obtain a first slurry; wherein the concentration of the dilute ammonia water in terms of NH ₃ was 12% by weight; and the weight ratio of the zirconium oxychloride, hydroxypropyl methylcellulose and deionized water was 1:0.05:4;

(2) 806 g of pseudo-boehmite, 3144 g of deionized water and 50 g of hydrochloric acid (hydrochloric acid with a concentration of 36 wt %) were mixed under stirring, and the obtained mixture was stirred at 50° C. for 1 hour to obtain a second slurry;

(3) The first slurry and the second slurry were mixed at 15°C, and then stirred at 15°C for 20 minutes. Then, 600 g of silica sol was added, and stirring was continued at 15°C for 20 minutes. The solid was filtered to obtain a solid. After the solid was dried at 120°C for 4 hours, it was calcined at 550°C for 2 hours to obtain a silicon-aluminum-zirconium composite oxide SAZ-1, in which aluminum oxide accounted for 50%, zirconium oxide accounted for 35%, and silicon oxide accounted for 15% (weight content, the same below).

Example 2

(1) 392 g of zirconium isopropoxide and 7.5 g of methyl cellulose were slurried with 600 g of deionized water, the pH value of the mixture was adjusted to 5.5 with sodium hydroxide solution, and stirred at 40° C. for 1.0 hour to obtain a first slurry; wherein the concentration of the sodium hydroxide solution in terms of ^OH- is 5% by weight; and the weight ratio of the zirconium isopropoxide, methyl cellulose and deionized water is 1:0.05:4;

(2) 1161 g of pseudo-boehmite, 4269 g of deionized water and 108 g of hydrochloric acid (hydrochloric acid with a concentration of 36 wt %) were mixed under stirring, and the obtained mixture was stirred at 17° C. for 4 hours to obtain a second slurry;

(3) The first slurry and the second slurry were mixed at 40°C, and then stirred at 40°C for 15 minutes. Then, 520 g of water glass was added, and the stirring was continued at 40°C for 25 minutes. The solid was filtered to obtain a solid. After the solid was dried at 120°C for 4 hours, it was calcined at 550°C for 2 hours to obtain a silicon-aluminum-zirconium composite oxide SAZ-2, in which aluminum oxide accounted for 72%, zirconium oxide accounted for 15%, and silicon oxide accounted for 13%.

Example 3

(1) 523 g of zirconium nitrate and 30 g of lignin were taken, and after pulping with 1114 g of deionized water, the pH value of the mixture was adjusted to 8.0 with dilute ammonia water, and stirred at 25° C. for 0.5 hour to obtain a first slurry; the concentration of the dilute ammonia water in terms of NH ₃ was 5% by weight, and the weight ratio of the zirconium nitrate, lignin and deionized water was 1:0.15:6;

(2) 1129 g of pseudo-boehmite, 4331 g of deionized water and 140 g of hydrochloric acid (hydrochloric acid with a concentration of 36 wt %) were mixed under stirring, and the obtained mixture was stirred at 60° C. for 0.5 hour to obtain a second slurry;

(3) The second slurry is cooled to 25°C, added to the first slurry, and stirred at 25°C for 15 minutes. Then, 400 g of silica sol is added, and stirring is continued at 25°C for 30 minutes. The solid is filtered to obtain a solid. The solid is dried at 120°C for 4 hours, and then calcined at 550°C for 2 hours to obtain a silicon-aluminum-zirconium composite oxide SAZ-3, in which aluminum oxide accounts for 70%, zirconium oxide accounts for 20%, and silicon oxide accounts for 10%.

Example 4

(1) 837 g of zirconium nitrate and 32 g of viscose fiber were pulped with 1130 g of deionized water, the pH value of the mixture was adjusted to 7.5 with dilute ammonia water, and the mixture was stirred at 15° C. for 1.5 hours to obtain a first slurry; wherein the concentration of the dilute ammonia water in terms of NH ₃ was 12% by weight; and the weight ratio of the zirconium nitrate, viscose fiber and deionized water was 1:0.1:4;

(2) 1016 g of pseudo-boehmite, 3792 g of deionized water and 38 g of hydrochloric acid (hydrochloric acid with a concentration of 36 wt %) were stirred and mixed, and the obtained mixture was stirred at 60° C. for 1.5 hours to obtain a second slurry;

(3) The second slurry was cooled to 22°C, added to the first slurry, and stirred at 22°C for 30 minutes. Then, 320 g of silica sol was added, and stirring was continued at 22°C for 30 minutes. The solid was filtered to obtain a solid. After drying at 120°C for 4 hours, it was calcined at 550°C for 2 hours to obtain a silicon-aluminum-zirconium composite oxide SAZ-4, in which aluminum oxide accounted for 63%, zirconium oxide accounted for 32%, and silicon oxide accounted for 5%.

Example 5

(1) 1308 g of zirconium oxychloride (ZrOCl ₂ ·8H ₂ O) and 100 g of lignin were slurried with 2400 g of deionized water, the pH value of the mixture was adjusted to 9.0 with dilute ammonia water, and stirred at 15° C. for 2.0 hours to obtain a first slurry; wherein the concentration of the dilute ammonia water NH ₃ was 12% by weight; and the weight ratio of the zirconium oxychloride, lignin and deionized water was 1:0.2:5;

(2) 484 g of pseudo-boehmite, 1880 g of deionized water and 36 g of hydrochloric acid (hydrochloric acid with a concentration of 36 wt %) were stirred and mixed; the obtained mixture was stirred at room temperature (25° C.) for 1 hour to obtain a second slurry;

(3) The first slurry and the second slurry were mixed at 15°C, and then stirred at 15°C for 20 minutes. Then, 800 g of silica sol was added, and the mixture was stirred at 15°C for 40 minutes. The solid was filtered to obtain a solid. After drying at 120°C for 4 hours, the solid was calcined at 550°C for 2 hours to obtain a silicon-aluminum-zirconium composite oxide SAZ-4, in which aluminum oxide accounted for 30%, zirconium oxide accounted for 51%, and silicon oxide accounted for 19%.

Example 6

Silicon-aluminum-zirconium composite oxide SAZ-6 was prepared by the same method as in Example 1, except that in step (1), 915 g of zirconium oxychloride (ZrOCl ₂ ·8H ₂ O) and 2.4 g of hydroxypropyl methylcellulose were slurried with 1400 g of deionized water, the pH value of the mixture was adjusted to 9.5 with dilute ammonia water, and stirred at room temperature (15°C) for 3.0 hours to obtain a first slurry. The concentration of the dilute ammonia water in terms of NH ₃ was 12% by weight; the weight ratio of zirconium oxychloride, hydroxypropyl methylcellulose and deionized water was 1:0.008:4.

The prepared silicon-aluminum-zirconium composite oxide contains 54% aluminum oxide, 30% zirconium oxide and 16% silicon oxide.

Example 7

Silicon-aluminum-zirconium composite oxide SAZ-7 was prepared by the same method as in Example 1, except that in step (2), 806 g of pseudo-boehmite, 3144 g of deionized water and 10 g of hydrochloric acid (36 wt % hydrochloric acid concentration) were stirred and mixed; the obtained mixture was stirred at 50° C. for 1 hour to obtain a second slurry.

The prepared silicon-aluminum-zirconium composite oxide contains 48% aluminum oxide, 37% zirconium oxide and 15% silicon oxide.

Example 8

The silicon-aluminum-zirconium composite oxide SAZ-8 was prepared in the same manner as in Example 1, except that in step (3), the first slurry and the second slurry were mixed with 1000 g of silica sol and stirred at 15° C. for 20 minutes. The prepared silicon-aluminum-zirconium composite oxide contained 46% aluminum oxide, 34% zirconium oxide, and 20% silicon oxide.

Comparative Example 1

270mL 2mol/L aluminum nitrate, 3000mL 0.05mol/L zirconium nitrate and 35mL silica gel (containing ₂₅ % SiO2) were mixed, mixed surfactant 1 (polyglycerol 200: polyglycerol 2000: polyglycerol 600 = 1:0.8:1 (weight ratio)), ammonia water and mixed surfactant 1' (mixed surfactant 1 and polyvinyl alcohol 50000 = 30:1 (weight ratio)) were added, wherein ammonia water: mixed surfactant 1' = 20:1 (weight ratio); pH value was adjusted to 7.5, reacted at 80℃ and aged at 40℃ for 1.5 hours, filtered, washed with deionized water 3 times, dried at 120℃ for 3 hours, extruded after adding extrusion aid, and calcined at 600℃ for 3 hours to obtain composite oxide carrier SAZ-D1. The SAZ-D1 composite oxide carrier contains 50% aluminum oxide, 35% zirconium oxide and 15% silicon oxide.

Comparative Example 2

Add 1L of deionized water to the container, heat it to 62°C, add 1.5L of aluminum chloride solution containing 3g/100mL _{of Al2O3} and 5g/100mL of ammonia solution containing _NH3 , control the pH value to 7.0, and add the material for 80min. After stopping the feeding, age the system at the above temperature and pH conditions for 60min, add 300mL of sodium metasilicate solution with a _SiO2 content of 10%, continue aging for 10min, then add 175mL of zirconium oxychloride solution with a _ZrO2 content of 8%, add it in 10min, control the pH value of the material to 6.5, continue aging for 60min, and then wash it ₄ times until Cl/ _Al2O3 <0.5%. After drying the filter cake at 100°C for 15h, crush it to a particle size of less than 180 mesh, accounting for more than 95%, to obtain dry rubber powder SAZ-D2. The dry rubber powder contains 50% aluminum oxide, 35% zirconium oxide and 15% silicon oxide.

Comparative Example 3

270mL 2mol/L aluminum nitrate was mixed with 35mL silica gel (containing 25wt% SiO ₂ ), ammonia water was added, pH value was adjusted to 8.5, and the reaction was carried out at 60°C to obtain sol A. 3000mL 0.05mol/L zirconium nitrate solution was mixed with theoretical complexing amount of ammonium tartrate to obtain complex solution B. Sol A and complex solution B were mixed and stirred vigorously, 30wt% hydrogen peroxide was added at room temperature to make Zr ₄ ⁺ :H ₂ O ₂ =1:3 (molar ratio), after reacting for 3 hours, the temperature was raised to 60°C and aged for 1 hour, filtered, washed with deionized water 3 times, dried at 120°C for 3 hours and crushed to obtain composite oxide dry gel. The composite oxide dry gel was calcined at 600°C for 3 hours to obtain composite oxide SAZ-D3. In SAZ-D3 composite oxide, aluminum oxide is 50%, zirconium oxide is 35%, and silicon oxide is 15%.

Comparative Example 4

The silicon-aluminum-zirconium composite oxide SAZ-D4 was prepared by the same method as in Example 1, except that no carbon source was added in step (1). The silicon-aluminum-zirconium composite oxide contained 50% aluminum oxide, 35% zirconium oxide and 15% silicon oxide.

Comparative Example 5

The silicon-aluminum-zirconium composite oxide SAZ-D5 was prepared by the same method as in Example 1, except that no carbon source was added in step (1), and 17.5 g of tartrate, a complexing agent, was added. The silicon-aluminum-zirconium composite oxide contained 50% aluminum oxide, 35% zirconium oxide, and 15% silicon oxide.

Examples 9-22 are examples of catalytic cracking catalysts containing the silicon-aluminum-zirconium composite oxide of the present invention, and comparative examples 6-10 and 12-13 are comparative examples of catalytic cracking catalysts containing comparative silicon-aluminum-zirconium composite oxides:

Examples 9-16

289g of kaolin and 1580g of deionized water are added to a slurrying tank and slurried for 60 minutes, and then 200g of silicon-aluminum-zirconium composite oxides SAZ-1 to SAZ-8 are added and stirred for 60 minutes; then 271g of REUSY zeolite, 133g of hydrogen-type β zeolite and 67g of phosphorus-modified ZSM-5 zeolite are added and slurried with 530g of deionized water to form a slurry, and after stirring for 30 minutes, 930g of aluminum sol is added, and the mixture is homogenously dispersed (stirred) for 30 minutes. Then, the obtained slurry is spray-dried and formed, and calcined at 500°C for 2 hours to obtain the cracking catalysts C1 to C8 provided by the present invention.

Embodiment 17

447 g of kaolin and 1980 g of deionized water are added to a slurrying tank and slurried for 60 minutes. Then, 200 g of silicon-aluminum-zirconium composite oxide SAZ-5 is added and stirred for 30 minutes. Then, 105 g of USY zeolite, 236 g of REUSY, 67 g of Hβ zeolite and 40 g of HZSM-5 zeolite are added and slurried with 551 g of deionized water to form a slurry. After stirring for 30 minutes, 372 g of aluminum sol is added and homogenized (stirred) for 30 minutes. Then, the obtained slurry is spray-dried and formed, and calcined at 500°C for 2 hours to obtain the cracking catalyst C9 of the present invention.

Embodiment 18

371g of kaolin and 1996g of deionized water are added to a slurrying tank and slurried for 60 minutes. Then, 250g of silicon-aluminum-zirconium composite oxide SAZ-5 is added and stirred for 30 minutes. Then, 271g of REUSY, 133g of Hβ zeolite and 67g of HZSM-5 zeolite are added and slurried with 528g of deionized water to form a slurry. After stirring for 30 minutes, 372g of aluminum sol is added and homogenized (stirred) for 30 minutes. Then, the obtained slurry is spray-dried and formed, and calcined at 500°C for 2 hours to obtain the cracking catalyst C10 of the present invention.

Embodiment 19

300 g of silicon-aluminum-zirconium composite oxide SAZ-5, 289 g of kaolin and 1945 g of deionized water are added to a slurrying tank and slurried for 60 minutes. Then, 64 g of USY zeolite, 177 g of REUSY, 133 g of Hβ zeolite and 93 g of P-ZSM-5 zeolite are added and slurried with 533 g of deionized water to form a slurry. After stirring for 30 minutes, 465 g of aluminum sol is added and homogenized (stirred) for 30 minutes. Then, the obtained slurry is spray-dried and formed, and calcined at 500°C for 2 hours to obtain the cracking catalyst C11 provided by the present invention.

Embodiment 20

526g of kaolin and 1856g of deionized water are added to a slurrying tank and slurried for 60 minutes, and then 100g of silicon-aluminum-zirconium composite oxide SAZ-5 is added and stirred for 30 minutes; then 53g of USY zeolite, 177g of REUSY, 181g of phosphorus-modified β zeolite and 70g of P-ZSM-5 zeolite are added and slurried with 591g of deionized water to form a slurry, and after stirring for 30 minutes, 465g of aluminum sol is added, and the mixture is homogenously dispersed (stirred) for 30 minutes. Then, the obtained slurry is spray-dried and formed, and calcined at 500°C for 2 hours to obtain the cracking catalyst C12 provided by the present invention.

Embodiment 21

350g of silicon-aluminum-zirconium composite oxide SAZ-5, 197g of kaolin and 1935g of deionized water are added to a slurrying tank and slurried for 30 minutes. Then, 212g of REUSY, 242g of phosphorus-modified β zeolite and 26g of P-Fe-ZSM-5 zeolite are added and slurried with 578g of deionized water to form a slurry. After stirring for 30 minutes, 465g of aluminum sol is added and homogenously dispersed (stirred) for 30 minutes. Then, the obtained slurry is spray-dried and formed, and calcined at 500°C for 2 hours to obtain the cracking catalyst C13 provided by the present invention.

Example 22

250g of kaolin and 466g of deionized water are added to a slurrying tank and slurried for 60 minutes. Then, 30g of silicon-aluminum-zirconium composite oxide SAZ-5 is added and stirred for 30 minutes. Then, 316g of USY zeolite, 177g of REUSY, 27g of Hβ zeolite and 13g of HZSM-5 zeolite are added and slurried with 466g of deionized water to form a slurry. After stirring for 30 minutes, 1395g of aluminum sol is added and homogenized (stirred) for 30 minutes. Then, the obtained slurry is spray-dried and formed, and calcined at 500°C for 2 hours to obtain the cracking catalyst C14 of the present invention.

Comparative Examples 6-10

Catalytic cracking catalysts DC1 to DC5 were prepared in the same manner as in Example 9, except that the silicon-aluminum-zirconium composite oxides used in the preparation of Comparative Examples 6 to 10 were the silicon-aluminum-zirconium composite oxides SAZ-D1 to SAZ-D5 prepared in Comparative Examples 1 to 5, respectively.

Comparative Example 11

This comparative example prepares a catalytic cracking catalyst that does not contain silicon-aluminum-zirconium composite oxide.

According to the method of Example 9, 289g of kaolin and 1583g of deionized water were added to a slurrying tank and slurried for 60 minutes, and then 271g of REUSY zeolite, 133g of hydrogen-type β zeolite and 67g of phosphorus-modified ZSM-5 zeolite were added with 530g of deionized water to form a slurry. After stirring for 30 minutes, 930g of aluminum sol was added and homogenously dispersed (stirred) for 30 minutes. Then, the obtained slurry was spray-dried and formed, and calcined at 500°C for 2 hours to obtain a comparative catalyst DC6.

Comparative Example 12

This comparative example prepares a catalytic cracking catalyst that does not contain beta zeolite.

The catalyst was prepared according to the method of Example 19. 300 g of silicon-aluminum-zirconium composite oxide SAZ-5, 289 g of kaolin and 1945 g of deionized water were added to a slurrying tank and slurried for 30 minutes. 169 g of USY zeolite, 177 g of REUSY and 70 g of P-ZSM-5 zeolite were added and slurried with 584 g of deionized water. After stirring for 30 minutes, 465 g of aluminum sol was added and homogenized (stirred) for 30 minutes. The obtained slurry was then spray-dried and formed, and calcined at 500°C for 2 hours to obtain a comparative catalytic cracking catalyst DC7.

Comparative Example 13

This comparative example prepares a catalytic cracking catalyst that does not contain ZSM-5 zeolite.

A catalyst was prepared according to the method of Example 19. 300 g of silicon-aluminum-zirconium composite oxide SAZ-5, 289 g of kaolin and 1945 g of deionized water were added to a slurrying tank and slurried for 30 minutes. 137 g of USY zeolite, 177 g of REUSY and 133 g of Hβ zeolite were added and slurried with 556 g of deionized water to form a slurry. After stirring for 30 minutes, 465 g of aluminum sol was added and homogenized (stirred) for 30 minutes. The obtained slurry was then spray-dried and formed, and calcined at 500°C for 2 hours to obtain a comparative catalytic cracking catalyst DC8.

Comparative Example 14

This comparative example prepares a catalytic cracking catalyst that does not contain silicon-aluminum-zirconium composite oxide.

A catalyst was prepared according to the method of Example 19. 2500 g of acidified pseudo-boehmite and 289 g of kaolin were added to a slurrying tank and slurried for 30 minutes. 64 g of USY zeolite, 177 g of REUSY, 133 g of Hβ zeolite and 93 g of P-ZSM-5 zeolite were added and slurried with 533 g of deionized water to form a slurry. After stirring for 30 minutes, 465 g of aluminum sol was added and homogenously dispersed (stirred) for 30 minutes. The obtained slurry was then spray-dried and formed, and calcined at 500°C for 2 hours to obtain a comparative catalytic cracking catalyst DC9.

Catalytic Cracking Catalyst Evaluation

(1) Catalytic cracking catalysts C1-C8 and DC1-DC6 were pre-aged in a fixed bed aging device at 800°C and 100% steam for 12 hours and then evaluated in a small fixed fluidized bed device. The properties of the reaction feed oil are shown in Table 8. The reaction temperature was 500°C, the catalyst-oil weight ratio was 5.92, and the reaction time was 75 seconds.

Among them, conversion rate = gasoline yield + liquefied gas yield + dry gas yield + coke yield;

Heavy oil selectivity = heavy oil yield/conversion rate;

C4 olefin concentration = C4 olefin yield / liquefied gas yield;

C4 olefin selectivity = C4 olefin yield / C4 fraction yield. The evaluation results are shown in Table 5 and Table 7.

(2) Catalysts C9-C14 and DC7-DC9 were immersed in kerosene solutions of nickel cyclopentaneate (1000ppm), vanadium cyclopentaneate (1000ppm) and calcium cyclopentaneate (1000ppm) respectively, so that the nickel, vanadium and calcium on catalysts C9-C14 all reached 1000ppm. The impregnated samples were aged at 800°C and 100% steam for 4 hours and then evaluated on an ACE (fixed fluidized bed) device. The feedstock oil was Wuhan mixed feedstock oil (properties are shown in Table 9), the reaction temperature was 500°C, and the catalyst-oil weight ratio was 8. The evaluation results are shown in Tables 6 and 7.

Table 1 Properties of silicon-aluminum-zirconium composite oxides

The results in Table 1 show that compared with Comparative Examples 1-4, the silicon-aluminum-zirconium composite oxides prepared by the present invention all have higher micro-reaction activity indexes.

Table 2 Catalytic cracking catalyst composition

Table 3 Catalytic cracking catalyst composition

Table 4 Catalytic cracking catalyst composition

Table 5 Evaluation results

The results in Table 5 and Table 7 show that, compared with the catalysts DC1-DC6 prepared in Comparative Examples 6-11, the catalysts C1-C8 prepared in Examples 9-16 of the present invention are used in the catalytic cracking process, the C4 olefin yield is improved, the C4 olefin concentration in the liquefied gas is improved, and the C4 olefin selectivity is increased. The silicon-aluminum-zirconium composite oxide of the present invention has excellent heavy oil cracking ability, is conducive to providing more C4 olefin precursors for increasing production, and is beneficial to increasing production of C4 olefins.

Table 6 Evaluation results

The results in Tables 6 and 7 show that, compared with Comparative Example 14, the cracking catalyst C9-C14 provided by the present invention has good resistance to heavy metal pollution and higher C4 olefin concentration and C4 olefin selectivity; compared with Comparative Example 13, the cracking catalyst provided by the present invention has a comparable total yield of liquefied gas and gasoline, but the C4 olefin concentration in the liquefied gas and the C4 olefin selectivity are significantly improved; compared with Comparative Example 12, the cracking catalyst provided by the present invention has a higher total yield of liquefied gas and gasoline, and a higher C4 olefin selectivity.

Table 7 Evaluation results

Table 8

Raw oil properties Density (20℃)/(kg·cm ^-3 ) 919.3 w(residual carbon value)/% 2.62 w(C)/％ 87.42 w(H)/％ 11.5 w(S)/％ 0.26 w(N)/％ 0.0616 Metal mass fraction/(μg·g ^-1 ) Fe 3.2 Ni 3.8 V 3.8 Four components mass fraction/% Saturated hydrocarbons 62.1 Aromatics 26.6 Gel 10.7 Asphaltene 0.6 Vacuum distillation range/℃ Initial distillation point 226.7 5% 280.9 10% 317 30% 400.7 50% 454.4 70% 527 Final distillation point 540 Distillation endpoint volume yield/% 72.6

Table 9

In summary, the cracking catalyst provided by the present invention not only has excellent heavy oil cracking ability and heavy metal pollution resistance, but also has excellent C4 olefin selectivity and yield.

The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

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 further describe various possible combinations.

In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims (19)

1. A catalytic cracking catalyst comprising, based on the dry weight of the catalytic cracking catalyst, 10 to 50 wt% of a Y-type zeolite, 1 to 30 wt% of a beta zeolite, 1 to 20 wt% of a ZSM-5 zeolite, 3 to 40 wt% of a silicoaluminozirconium composite oxide, 10 to 70 wt% of a clay, and 5 to 30 wt% of a binder;

the silicon aluminum zirconium composite oxide contains 30 to 80 weight percent of Al based on the dry weight of the silicon aluminum zirconium composite oxide ₂ O ₃ 15-55 wt.% ZrO ₂ And 2 to 20% by weight of SiO ₂ The pore volume of the pores with the pore diameter range of 10-60nm accounts for more than 70% of the total pore volume, the micro-reactivity index is more than 30, and the pore diameter refers to the pore diameter.

2. The catalytic cracking catalyst according to claim 1, wherein the sialyl composite oxide contains 40 to 75 wt.% Al based on the dry weight of the sialyl composite oxide ₂ O ₃ 15-50 weight portionsZrO in% by weight ₂ And 5 to 15% by weight of SiO ₂ 。

3. The catalytic cracking catalyst of claim 1, wherein the pore volume of the sialyl composite oxide having a pore size in the range of 10-60nm is 75-85% of the total pore volume.

4. The catalytic cracking catalyst of claim 1, wherein the micro-reactivity index of the sialyl composite oxide is 35-50.

5. The catalytic cracking catalyst of claim 1, wherein the catalytic cracking catalyst comprises 10-40 wt% of the Y-zeolite, 5-30 wt% of the beta zeolite, 2-15 wt% of the ZSM-5 zeolite, 5-35 wt% of the silicoaluminozirconium composite oxide, 10-55 wt% of the clay, and 5-25 wt% of the binder.

6. The catalytic cracking catalyst according to claim 1, wherein the Y-type zeolite is selected from one or more of a phosphorus-and/or rare earth-containing Y-type zeolite, a ultrastable Y-zeolite, and a phosphorus-and/or rare earth-containing ultrastable Y-zeolite;

the beta zeolite is selected from hydrogen beta zeolite and/or modified beta zeolite, and the modified beta zeolite contains one or more of phosphorus, iron and rare earth metal elements;

the ZSM-5 zeolite is selected from hydrogen type ZSM-5 zeolite and/or ZSM-5 type zeolite containing modified elements, wherein the modified elements are one or more of phosphorus, rare earth and iron;

the clay is one or more selected from kaolin, rectorite, diatomite, montmorillonite, bentonite and sepiolite;

the binder is one or more selected from aluminum sol, silica sol, silicon-aluminum composite sol, aluminum phosphate sol and acidified pseudo-boehmite.

7. The catalytic cracking catalyst according to claim 1, wherein the method for producing the sialyl composite oxide comprises:

(1) Mixing a zirconium-containing compound, a carbon source and a first solvent, adjusting the pH value of the mixture to 5-10, and stirring at 15-40 ℃ for 0.5-4 hours to obtain a first slurry; the carbon source comprises natural high molecular organic compounds and/or semisynthetic high molecular organic compounds;

(2) Mixing an aluminum source, a second solvent and an acid solution for 0.5-4 hours at 15-60 ℃ to obtain second slurry;

(3) Mixing the first slurry, the second slurry and the silicon source for 0.1-2 hours at 15-40 ℃ and performing first drying and/or first roasting.

8. The catalytic cracking catalyst of claim 7, wherein in step (1), the weight ratio of the zirconium-containing compound, the carbon source and the first solvent amount is 1: (0.01-0.20): (4-20); the zirconium-containing compound is calculated as zirconium oxide.

9. The catalytic cracking catalyst of claim 8, wherein in step (1), the weight ratio of the zirconium-containing compound, the carbon source and the first solvent is 1: (0.05-0.20): (5-15), the zirconium-containing compound being in the form of zirconium oxide.

10. The catalytic cracking catalyst according to claim 7, wherein in step (1), the pH of the mixture is adjusted to 5 to 9.

11. The catalytic cracking catalyst according to claim 7, wherein in step (2), the concentration of the acid solution is 2 to 45% by weight; the weight ratio of the aluminum source to the acid solution is 1: (0.01-0.3), the aluminum source being calculated as aluminum oxide.

12. The catalytic cracking catalyst of claim 11, wherein in step (2), the weight ratio of the aluminum source to the acid solution is 1: (0.06-0.25), the aluminium source being calculated as aluminium oxide.

13. The catalytic cracking catalyst of claim 7, wherein step (3) comprises: mixing the first slurry and the second slurry at 15-40 ℃ for 0.1-1 hour, adding the silicon source into the obtained mixture, and continuing stirring at 15-40 ℃ for 0.1-1 hour.

14. The catalytic cracking catalyst according to claim 7, wherein the zirconium-containing compound is selected from one or more of zirconium tetrachloride, zirconium sulfate, zirconium nitrate, zirconium oxychloride, zirconium acetate and zirconium isopropoxide;

the carbon source is one or more selected from starch, lignin, viscose, methylcellulose, hydroxypropyl methylcellulose, hydroxyethyl cellulose and carboxymethyl cellulose;

The aluminum source is selected from one or more of pseudo-boehmite, aluminum hydroxide and aluminum oxide;

the silicon source is selected from one or more of silica sol, silica gel and water glass;

the first solvent and the second solvent are respectively and independently selected from one or more of deionized water, ethanol and acetone;

the acid solution is one or more selected from hydrochloric acid solution, sulfuric acid solution, nitric acid solution, phosphoric acid solution, formic acid solution, acetic acid solution, oxalic acid solution and citric acid solution.

15. The catalytic cracking catalyst of claim 7, wherein the first drying temperature is 80-200 ℃; the temperature of the first roasting is 300-700 ℃ and the time is 0.5-5 hours.

16. A process for preparing the catalytic cracking catalyst of any one of claims 1-15, the process comprising: mixing the Y-type zeolite, the beta zeolite, the ZSM-5 zeolite, the silicon-aluminum-zirconium composite oxide, the clay, the binder and a third solvent, granulating the obtained third slurry, and performing second drying and/or second roasting.

17. The method of claim 16, wherein the third slurry has a solids content of 15-60 wt% based on the sum of silica, zirconia and alumina;

The third solvent is deionized water and/or deionized water.

18. The method of claim 16, wherein the second drying temperature is 60-200 ℃; the temperature of the second roasting is 350-650 ℃ and the time is 0.5-5 hours.

19. Use of a catalytic cracking catalyst according to any one of claims 1 to 15 in the catalytic cracking of heavy oils.