A catalytic cracking co-catalyst with high resistance to thermal wear and its preparation method

Abstract

This invention discloses a catalytic cracking co-catalyst with high resistance to thermal abrasion, comprising a molecular sieve, a matrix, a binder, and a binder modifier. The molecular sieve has an MFI structure, and the molecular sieve with a pore diameter less than 0.7 nm accounts for 50 wt% to 100 wt% of the total molecular sieve. The matrix is ​​composed of a γ-alumina precursor with a colloidal index ≤ 50% and clay. The binder is prepared from phosphorus-containing and aluminum-containing compounds. The raw materials for the binder modifier include multi-chelate ligands, precursors of at least two coordination metals, alcohols, and organic acids. The binder, binder modifier, and matrix are all mixed in a high-shear emulsifier. Compared with existing catalytic cracking co-catalysts for propylene and octane number, the catalytic cracking co-catalyst provided by this invention has higher resistance to thermal abrasion, larger pore volume, and higher molecular sieve content.

Description

Technical Field

[0001] This invention belongs to the field of catalyst and co-catalyst technology, specifically relating to a catalytic cracking co-catalyst with high resistance to thermal abrasion and its preparation method. Background Technology

[0002] In catalytic cracking, the content of the target product varies significantly depending on the cracking catalyst and process technology used. Using a co-catalyst can effectively improve the yield of the target product. Propylene co-catalysts commonly use MFI-type zeolites, such as ZSM-5 molecular sieves, as the active component, kaolin as the support, and various silica-alumina gels as binders. Introducing phosphorus oxides into propylene and octane number co-catalysts can significantly improve the activity stability of MFI-type zeolites and the selectivity of propylene in liquefied petroleum gas (LPG), while also having a certain effect on improving the octane number of gasoline. Therefore, to improve the activity stability and propylene selectivity of co-catalysts, phosphorus-alumina gel is currently widely used as a binder. Besides its excellent propylene selectivity, phosphorus-alumina gel also has good binding properties, meeting the industrial requirements for catalyst strength.

[0003] However, existing catalytic cracking propylene and octane number co-catalysts prepared using phosphorus-aluminum glue as a binder suffer from low molecular sieve content, small pore volume, low specific surface area, and poor strength, especially poor resistance to thermal abrasion. This leads to problems such as insignificant increase in target yield, decreased gasoline yield, deteriorated system activity, and significant strength differences compared to the main catalyst when applied in the catalytic cracking process. Consequently, these issues cause fluidization fluctuations in the unit, affecting its long-term stable operation. Increasing the content of the active component ZSM-5 molecular sieve and improving the pore volume of the catalytic cracking propylene and octane number co-catalyst often results in a deterioration in the co-catalyst's resistance to abrasion, leading to abnormal fluidization, catalyst loss, fouling in the exhaust system, and increased solids content in the slurry, all of which negatively impact the long-term operation of the catalytic cracking unit.

[0004] For example, Chinese patent document CN102794194B discloses a method for preparing a propylene co-catalyst for catalytic cracking, including steps of molecular sieve exchange, preparation of the propylene co-catalyst, and washing of the propylene co-catalyst. The molecular sieve exchange step includes: contacting the molecular sieve with an aqueous solution containing inorganic and organic acids at 0-5°C for 0.5-2 hours; the weight ratio of H2O to molecular sieve is 5-10:1; and using H2O to prepare the propylene co-catalyst. + The concentration of organic acid in the aqueous solution is 0.009-0.9 mol / L, and the concentration of inorganic acid is 0.001-0.1 mol / L. The washing step of the propylene co-catalyst includes: contacting the propylene co-catalyst with an aqueous solution containing inorganic and organic acids at 0-5°C for 10-100 minutes, wherein the weight ratio of H₂O to propylene co-catalyst is 5-9:1, with H₂O as the solvent. +The concentration of organic acid in the aqueous solution is calculated to be 0.0001-0.2 mol / L, and the concentration of inorganic acid is 0.0001-0.1 mol / L. In this scheme, the co-catalyst is treated with acid after preparation to optimize the pore structure and acidity distribution of the co-catalyst. However, this method will reduce the cracking activity of the co-catalyst, especially the cracking activity of low-carbon olefins, and reduce the yield of the target product.

[0005] Chinese patent document CN103254925B discloses a catalytic cracking propylene co-catalyst and its preparation method. The co-catalyst, by total weight, comprises 20-60% HZSM-5 molecular sieve, 5-25% aluminum phosphate oxide, 6-12% silica-alumina gel carrier, and the remainder being kaolin. The molar ratio of SiO2 to Al2O3 in the HZSM-5 molecular sieve is (25-500):1. The aluminum phosphate oxide is aluminum phosphate, and the silica-alumina gel carrier is silica-alumina gel. The silica-alumina sol co-catalyst prepared by this method can clog the pores of the molecular sieve, and the co-catalyst has a low pore volume and small specific surface area.

[0006] Chinese patent document CN102049284B discloses a catalytic cracking propylene co-catalyst. Based on 100% of the total weight of the co-catalyst, it contains 30-80% by weight of molecular sieves, of which ZSM-5 zeolite content is 28-78% by weight, and clay content is 10-65% by weight. The co-catalyst contains P, specifically 7.0-15.0% by weight (P2O5), and 0-1.0% by weight of La2O3. Aluminum phosphate sol is used as a binder, which improves the wear resistance of the co-catalyst and the solid content of the spray slurry, while avoiding chlorine content in the spray slurry and co-catalyst. The co-catalyst prepared by this method uses aluminum phosphate binder. Compared with conventional binders such as silica-alumina sol, this binder results in a smaller mesopore volume in the co-catalyst, but also increases the thermal abrasion index, generating a large amount of fine powder during equipment operation, affecting the stable operation of the equipment.

[0007] Chinese patent document CN107970983A discloses a co-catalyst comprising 10-75 wt% (dry weight) of a phosphorus-containing MFI structured molecular sieve, 3-40 wt% (dry weight) of a phosphorus-aluminum inorganic binder, 1-30 wt% (oxides) of other inorganic binders, 0-60 wt% (dry weight) of a second clay, and 0.5-15 wt% (oxides) of a metal additive selected from at least one of Group VIII metals and manganese, zinc, and gallium. In this method, when using an aluminum phosphate binder and modifying the molecular sieve with phosphorus, excessive phosphorus introduction in the co-catalyst can form stable PO-Al bonds with the aluminum on the molecular sieve, blocking the pores of the molecular sieve, causing a decrease in specific surface area, and affecting the reaction performance of the co-catalyst.

[0008] Chinese patent document CN104549445A discloses a method for preparing a catalytic cracking co-catalyst. This method includes preparing a high-silica ZSM-5 molecular sieve, mixing the obtained high-silica ZSM-5 molecular sieve with a binder and clay, slurrying, and granulating. The preparation of the high-silica ZSM-5 molecular sieve includes: introducing NaZSM-5 molecular sieve powder into a gas-phase ultrastable reactor; moving the NaZSM-5 molecular sieve powder from the molecular sieve inlet to the molecular sieve outlet of the gas-phase ultrastable reactor without carrier gas transport; and allowing the NaZSM-5 molecular sieve powder to react with gas-phase SiCl4 in the gas-phase ultrastable reactor. This preparation method can continuously prepare ZSM-5 molecular sieves with a high silica-to-alumina ratio, thereby preparing a catalytic cracking propylene co-catalyst. However, this method first performs ultrastabilization treatment on the molecular sieve, followed by acid-base treatment, which severely damages the molecular sieve framework and affects the reaction performance of the co-catalyst.

[0009] Chinese patent document CN102847551B discloses a cracking co-catalyst with high and low carbon olefin concentrations. This co-catalyst contains a phosphorus-aluminum inorganic binder containing a first clay, modified MFI molecular sieves, other inorganic binders, and Group VIII metal additives, with or without a second clay. The phosphorus-aluminum inorganic binder containing the first clay comprises 15-40 wt% aluminum (based on Al2O3), 45-80 wt% phosphorus (based on P2O5), and 1-40 wt% first clay (on a dry basis). In the preparation of this co-catalyst, the molecular sieve is treated with acid and alkali to expand its pore structure, which is beneficial for increasing the pore volume and specific surface area of ​​the co-catalyst. However, this mesoporization process reduces the crystallinity of the molecular sieve and causes a significant loss of surface acidic sites, leading to a decrease in cracking reaction performance. Furthermore, the molecular sieve is modified with transition metals such as phosphorus to improve its stability and reaction performance, and an aluminum phosphate binder is used. However, excessive phosphorus further reduces the reaction performance of the molecular sieve. On the other hand, conventional aluminum phosphate has poor thermal abrasion resistance.

[0010] As mentioned earlier, existing technologies generally use a certain amount of ZSM-5 molecular sieve, silica sol, or aluminum-containing compounds as the aluminum source, and then add phosphorus-containing compounds, clay, and other components to prepare propylene co-catalysts. When preparing co-catalysts using the above methods, although the silica, aluminum sol, or partial aluminum-containing compounds and phosphorus-containing compounds forming a partial aluminum phosphate binder can increase the catalyst's wear resistance to some extent, its wear resistance is still insufficient when the molecular sieve content in the catalyst is high or the catalyst pore volume is large. The underlying mechanism is currently unclear; however, it has been found that when the molecular sieve content in the co-catalyst is high or the co-catalyst pore volume is large, the co-catalyst particles undergo varying degrees of breakage when prepared using existing methods, especially after high-temperature steam aging. It is speculated that these ions may have a stable bond with the binding components, keeping the binding components in an inactive state. During the preparation of the co-catalyst, it remains in an inactive state. On the one hand, this stable bond reduces the binding effect of the binding components. On the other hand, during the spray drying process of the co-catalyst, especially during steam aging, the chloride, ammonium, and nitrate ions, which are stably bonded to the binding components, become unstable, generating gases such as hydrogen chloride, ammonia, nitrogen, and oxygen, respectively. The generation of these gases causes a large number of "bubbles" to form inside the co-catalyst particles. When the temperature rises, these bubbles will burst out from inside the co-catalyst, leading to damage to the shape of the co-catalyst particles, and in severe cases, even rupture. This reduces the binding effect of various binders and significantly decreases the wear resistance of the co-catalyst. Furthermore, existing propylene octane number co-catalyst preparation processes use large amounts of phosphoric acid to modify the molecular sieve to improve its activity and stability. However, the use of phosphorus reacts with the non-framework aluminum of the ZSM-5 molecular sieve, forming a firmly bonded PO-Al bond, blocking the pores of the molecular sieve, and causing a decrease in the crystallinity, specific surface area, and activity of the ZSM-5 molecular sieve. A large amount of phosphorus is discharged with wastewater during the co-catalyst preparation process, causing excessive phosphorus content in the wastewater and impacting the environment. Summary of the Invention

[0011] To address the problems and areas for improvement in existing technologies, this invention provides a catalytic cracking co-catalyst with high resistance to thermal abrasion and its preparation method. Compared with existing catalytic cracking co-catalysts for propylene and octane number, the catalytic cracking co-catalyst provided by this invention has higher resistance to thermal abrasion, larger pore volume, and higher molecular sieve content.

[0012] To achieve the above objectives, the present invention provides the following technical solution:

[0013] A catalytic cracking co-catalyst with high resistance to thermal abrasion includes a molecular sieve, a matrix, a binder, and a binder modifier;

[0014] The molecular sieve having an MFI structure and a pore diameter of less than 0.7 nm accounts for 50 wt% to 100 wt% of the total molecular sieve.

[0015] The matrix consists of γ-alumina precursors with a colloidal index ≤50% and clay;

[0016] The binder is made from phosphorus-containing compounds and aluminum-containing compounds;

[0017] The raw materials for the binder modifier include multi-chelating ligands, precursors of at least two coordination metals, alcohols, and organic acids;

[0018] The binder, the binder modifier, and the matrix are all mixed in a high-shear emulsifier.

[0019] Optionally, the catalytic cracking co-catalyst with high resistance to thermal abrasion provided by the present invention further includes a molecular sieve modifier, wherein the molecular sieve modifier is the same as or different from the binder modifier; preferably, the raw materials of the molecular sieve modifier include multi-chelate ligands, rare earth coordination metal precursors, alcohols and organic acids.

[0020] Optionally, the catalytic cracking cocatalyst with high resistance to thermal abrasion provided by the present invention comprises a multi-gnawing chelating ligand having at least two coordinating atoms, wherein the coordinating atoms are P, O, or N and O; preferably, the multi-gnawing chelating ligand is selected from any one of aminotrimethylphosphonic acid, hydroxyethylidene diphosphonic acid, ethylenediaminetetramethylidene phosphonic acid, diethylenetriaminepentamethylidene phosphonic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, 2-hydroxyphosphonoacetic acid, bis(1,6-hexylenetriaminepentamethylidene phosphonic acid), hexamethylenediaminetetramethylidene phosphonic acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, and 1,2-ethylenediamine; more preferably, the coordinating atoms in the multi-gnawing chelating ligand are P and O.

[0021] Optionally, in the catalytic cracking cocatalyst with high resistance to thermal abrasion provided by the present invention, the precursor of the coordinating metal in the binder modifier is selected from chlorides, sulfates, or nitrates of rare earth metals and transition metals; preferably, the rare earth metal is selected from light rare earth metals, such as lanthanum, cerium, neodymium, samarium, etc.; the transition metal is selected from copper, silver, nickel, zinc, cobalt, cadmium, etc. The ratio of rare earth metal to transition metal in the coordinating metal is not specifically limited, and can be adjusted according to the actual situation. The molar ratio of the transition metal to the rare earth metal recommended by the present invention is 1:5 to 10; the molar ratio of the multi-chelating ligand to the coordinating metal (rare earth metal and transition metal) is 2 to 5:1.

[0022] Optionally, in the catalytic cracking co-catalyst with high resistance to thermal abrasion provided by the present invention, the molar ratio of the multi-meshing chelating ligand to the rare earth coordination metal in the molecular sieve modifier is 2 to 5:1.

[0023] Optionally, in the catalytic cracking co-catalyst with high resistance to thermal abrasion provided by the present invention, the organic acid in the molecular sieve modifier and the binder modifier is one or more of benzoic acid, lactic acid, propionic acid, formic acid, acetic acid, sorbic acid and malic acid;

[0024] The alcohol is selected from C1 to C3 monohydric alcohols, preferably one or more of methanol, ethanol and propanol.

[0025] Optionally, in the catalytic cracking co-catalyst with high resistance to thermal abrasion provided by the present invention, the molar ratio of phosphorus in the phosphorus-containing compound to aluminum in the aluminum-containing compound is 2-10:1, preferably 4-8:1. The aluminum-containing compound and the phosphorus-containing compound are not specifically limited and can be conventional in the industry. The aluminum-containing compound includes, but is not limited to, aluminum oxides, aluminum hydroxides, and aluminum-containing organic compounds, such as aluminum oxide, aluminum hydroxide, sodium aluminate monohydrate, aluminum chloride, and aluminum isopropoxide; preferably, aluminum oxides and aluminum hydroxides. The phosphorus-containing compound includes, but is not limited to, phosphorus oxides, phosphorus oxyacids, phosphoric acid, phosphates, or phosphorus-containing organic compounds, such as phosphoric acid, diammonium hydrogen phosphate, phosphorus pentoxide, organophosphonic acid, sodium phosphate, and calcium phosphate. Preferably, phosphorus oxyacids, phosphoric acid, and phosphorus ammonium salts are used.

[0026] Optionally, in the catalytic cracking cocatalyst with high resistance to thermal abrasion provided by the present invention, the γ-alumina precursor in the matrix has a colloidal index of 20% to 30%; preferably, the XRD pattern of the γ-alumina precursor shows characteristic peaks near 2θ of 14°, 28°, 38°, and 49°; such as boehmite, boehmite, boehmite, etc.

[0027] Optionally, in the catalytic cracking co-catalyst with high resistance to thermal abrasion provided by the present invention, the mass ratio of the γ-alumina precursor to the clay in the matrix is ​​1:0.5 to 15, preferably 1:2 to 9.

[0028] Optionally, the high thermal abrasion resistance catalytic cracking co-catalyst provided by the present invention uses clay in the matrix that is commonly used in the art, all of which meet the requirements of the present invention. Examples include kaolin, hydrous kaolin, montmorillonite, diatomaceous earth, bentonite, vellum, etc., commonly used as co-catalysts for catalytic cracking of propylene, octane, and other catalytic cracking co-catalyst components, or one or more of these. Preferably, the clay is selected from kaolin, vellum, hydrous kaolin, or mixtures thereof.

[0029] Optionally, the catalytic cracking co-catalyst with high resistance to thermal abrasion provided by the present invention further includes at least one of BEA, FER, MWW, MOR, AST, and FAU structured molecular sieves; preferably, the molecular sieve is a mixed molecular sieve composed of two different structures (i.e., a mixture of MFI structured molecular sieve and any other type of molecular sieve), and the specific surface area of ​​the mixed molecular sieve is not less than 400-500 m². 2 / g, the Si / Al molar ratio in the MFI structured molecular sieve is 10-200.

[0030] Specifically, any molecular sieve with a different structure can be a standard one used in the industry, without any specific limitations. For example, molecular sieves with an MFI structure can be selected from high-silica ZSM-5, low-silica ZSM-5, phosphorus-modified ZSM-5, phosphorus-iron modified ZSM-5 molecular sieves, or TS-1 molecular sieves, etc.; molecular sieves with a BEA structure can be selected from high-silica Beta molecular sieves, low-silica Beta molecular sieves, and various metal-modified Beta molecular sieves, etc.; molecular sieves with an FER structure can be selected from ZSM-35 molecular sieves, etc.; molecular sieves with an MWW structure can be selected from MCM-22, MCM-41, etc.; molecular sieves with an MOR structure can be selected from mordenite, etc.; molecular sieves with an AST structure can be selected from pure silica AST molecular sieves, etc.; and molecular sieves with a FAU structure can be selected from Y-type molecular sieves, rare earth Y-type molecular sieves, dealulated Y-type molecular sieves, ultrastable Y-type molecular sieves, etc.

[0031] Optionally, the catalytic cracking co-catalyst with high resistance to thermal abrasion provided by the present invention, based on the total dry weight of the catalytic cracking co-catalyst (100%), comprises the following contents: the molecular sieve content is 20wt%–70wt%, the matrix content is 10wt%–40wt%, the binder content is 10wt%–30wt%, the binder modifier (based on the total mass of multi-meshing chelating ligands and coordination metal oxides) content is 1.5wt%–10wt%, and the molecular sieve modifier (based on the total mass of multi-meshing chelating ligands and rare earth coordination metal oxides) content is 0wt%–2wt%.

[0032] The present invention also provides a method for preparing the above-mentioned high-temperature-wear-resistant catalytic cracking co-catalyst, comprising the following steps:

[0033] Acid treatment: Molecular sieves with Na2O content ≤0.1wt% are mixed with deionized water to form a molecular sieve slurry. Then, a mixture of organic and inorganic acids is added until the pH of the molecular sieve slurry is ≤2.0 and the reaction is carried out. After the reaction is completed, the slurry is dried and calcined to obtain the acid-treated molecular sieve.

[0034] Mixed slurry: The binder and binder modifier are mixed evenly in a high-shear emulsifier, and then the mixture of the acid-treated molecular sieve and deionized water is added and mixed evenly to obtain the mixed slurry;

[0035] Calcination and molding: Add matrix slurry to the mixed slurry and continue to mix in a high-shear emulsifier for 5 minutes, then perform spray molding and drying, and calcination to obtain the catalytic cracking co-catalyst with high thermal abrasion resistance.

[0036] Optionally, in the acid treatment step of the preparation method of the above-mentioned high thermal wear resistance catalytic cracking co-catalyst provided by the present invention, when the Na2O content in the molecular sieve is greater than 0.1wt%, the method further includes an ammonium exchange step of the molecular sieve, including the following steps: exchanging the molecular sieve with ammonium salt until the Na2O content in the molecular sieve is ≤0.1wt%, separating, and drying to obtain a molecular sieve with a Na2O content ≤0.1wt% after ammonium exchange; ammonium exchange of molecular sieve is a conventional processing technology in the field, and existing conventional ammonium exchange processes can meet the implementation of the technical solution of the present invention, and are not specifically limited or described in detail here.

[0037] Optionally, in the acid treatment step of the method for preparing the high-heat-wear-resistant catalytic cracking co-catalyst provided by the present invention, the organic and inorganic acids in the mixed acid can be conventional in the industry and are not specifically limited, such as hydrochloric acid, nitric acid, sulfuric acid, oxalic acid, citric acid, tartaric acid, etc. Preferably, the pH of the system after adding the mixed acid is ≤1.0, and more preferably, the molar ratio of organic acid to inorganic acid is 2 to 5:1. The reaction apparatus involved in this step is not specifically limited, as long as it has a reflux device, such as a heated kettle with a reflux device.

[0038] Optionally, in the acid treatment step of the method for preparing the above-mentioned catalytic cracking co-catalyst with high resistance to thermal abrasion provided by the present invention, 100% water vapor is introduced during the first 2 / 3 of the calcination time, and air is introduced during the last 1 / 3 of the time. Calcination under water vapor conditions during the first 2 / 3 of the time is beneficial for stabilizing the molecular sieve and improving its stability; calcination under water vapor-free conditions during the last 1 / 3 of the time can quickly and thoroughly calcine the organic matter in the co-catalyst. Due to the occupancy effect of the organic matter, complete calcination is beneficial for forming a large number of pores within the co-catalyst.

[0039] Optionally, in the acid treatment step of the preparation method of the above-mentioned high thermal wear resistance catalytic cracking co-catalyst provided by the present invention, the calcination parameters are not specifically limited, and conventional parameters in the industry can be used, such as limiting the calcination temperature to 400-800℃ and the time to 2-5h.

[0040] Optionally, in the acid treatment step of the method for preparing the high thermal wear resistance catalytic cracking co-catalyst provided by the present invention, after the reaction is completed, a step of adding a molecular sieve modifier is also included; the reaction parameters after adding the molecular sieve modifier are not specifically limited, and conventional parameters in the industry can be used, such as reacting at 60-100℃ for 0.5-12h, preferably for 3-10h.

[0041] The preparation of the molecular sieve modifier recommended in this invention includes the following steps:

[0042] An alcohol is added to an organic acid solution containing a multi-chelating ligand, and the mixture is stirred to obtain a multi-chelating ligand solution; preferably, the molar concentration of the multi-chelating ligand in the multi-chelating ligand solution is 0.1 to 1.0 mol / L, the concentration of the organic acid is 10 wt% to 30 wt%, and the concentration of the alcohol is 5 wt% to 20 wt%.

[0043] An alcohol is added to an organic acid solution of a rare earth metal precursor and mixed to obtain a rare earth metal precursor solution; preferably, the concentration of the organic acid in the rare earth metal precursor solution is 10wt% to 30wt%, and the concentration of the alcohol is 5wt% to 20wt%.

[0044] The multi-chelate ligand solution and the rare earth metal precursor solution were added to a high-shear dispersing emulsifier, and the pH of the system was adjusted to 5-8 to obtain a molecular sieve modifier.

[0045] Optionally, the present invention also provides a method for preparing the adhesive modifier, comprising the following steps:

[0046] An alcohol is added to an organic acid solution containing a multi-chelating ligand, and the mixture is stirred to obtain a multi-chelating ligand solution; preferably, the molar concentration of the multi-chelating ligand in the multi-chelating ligand solution is 0.15-1.0 mol / L, the concentration of the organic acid is 10 wt%-30 wt%, and the concentration of the alcohol is 5 wt%-20 wt%.

[0047] An alcohol is added to an organic acid solution containing at least two coordination metal precursors, and the mixture is stirred to obtain a coordination metal precursor solution; preferably, the concentration of the organic acid in the coordination metal precursor solution is 10 wt% to 30 wt%, and the concentration of the alcohol is 5 wt% to 20 wt%.

[0048] The multi-chelating ligand solution and the precursor solution of the coordinating metal were added to a high-shear dispersing emulsifier, and the pH of the system was adjusted to 5-8 to obtain a binder modifier.

[0049] Optionally, the present invention also provides a method for preparing the above-mentioned adhesive, comprising the following steps:

[0050] A mixed aqueous solution of phosphorus-containing and aluminum-containing compounds is added to a high-shear emulsifier, heated to 60-80°C, and the pH is adjusted to ≤4.0 to carry out the reaction, thereby obtaining the binder.

[0051] Optionally, in the calcination and molding step of the preparation method of the above-mentioned high-heat-wear-resistant catalytic cracking co-catalyst provided by the present invention, the preparation of the matrix slurry is a well-known operation in the art. Specifically, it is sufficient to mix and slurry the γ-alumina precursor, clay, and deionized water, without special requirements. By controlling the mixing time of the molecular sieve, the in-situ formed aluminum phosphate binder, and the in-situ formed binder modifier in the high-shear emulsifier to be no more than 5 minutes, it is equivalent to achieving instantaneous and thorough mixing. After mixing, the mixture is immediately output and spray-dried, realizing the continuous process of "mixing, conveying, drying and molding". This avoids prolonged contact between the mixed slurry and the binder, which could lead to phosphorus migration and a reduction in the surface area and pore volume of the molecular sieve. Preferably, the mixing time of the mixed slurry and the matrix slurry in the high-shear emulsifier is no more than 3 minutes.

[0052] Optionally, in the calcination and molding step of the preparation method of the above-mentioned high heat-wear resistant catalytic cracking co-catalyst provided by the present invention, the spray molding drying refers to the granulation and drying of the material, which is a technology known to those skilled in the art. Existing parameters can be used. For example, the process conditions for spray molding drying in the preparation of catalytic cracking co-catalyst are generally as follows: the temperature of the spray tower furnace is controlled at 450-600℃, and the temperature of the spray tail gas is controlled at 150-300℃.

[0053] Preferably, the preparation method of the catalytic cracking co-catalyst with high resistance to thermal abrasion provided by the present invention specifically includes the following steps:

[0054] S1: Preparation of multi-chelating ligand solution

[0055] A multi-gnawing chelating ligand is mixed with an organic acid solution to prepare an organic acid solution of the multi-gnawing chelating ligand. Then, an alcohol solution is added and mixed evenly to obtain a multi-gnawing chelating ligand solution.

[0056] S2: Preparation of Coordination Metal Precursor Solution

[0057] At least two coordination metal precursors are added to an organic acid solution. After they are completely dissolved, an alcohol solution is added and mixed evenly to obtain a coordination metal precursor solution.

[0058] S3: Preparation of rare earth metal precursor solution

[0059] Rare earth metal precursors are added to an organic acid solution, and after complete dissolution, an alcohol solution is added. After mixing evenly, a rare earth metal precursor solution is obtained.

[0060] S4: Acid treatment of molecular sieves

[0061] Molecular sieves with a Na2O content ≤0.1wt% are mixed with deionized water to form a molecular sieve slurry. A mixed acid of organic and inorganic acids is added to adjust the pH of the molecular sieve slurry to ≤2.0, and the reaction is carried out. After the reaction is completed, the multi-gnawing chelate ligand solution prepared in S1 is added, and the mixture is stirred evenly. Then, the rare earth metal precursor solution prepared in S3 is added to carry out the reaction. After the reaction is completed, the mixture is dried and calcined to obtain the acid-treated molecular sieve. (When the Na2O content in the molecular sieve is greater than 0.1wt%, ammonium exchange can be performed first to reduce the Na2O content in the molecular sieve to below 0.1wt%).

[0062] S5: Preparation of Mixed Slurry

[0063] The multi-chelate ligand solution prepared in S1 is added to a high-shear dispersing emulsifier, and the temperature is maintained at 30-50°C. The coordination metal precursor solution prepared in S2 is added, and the pH of the system is adjusted to 5-8. After the reaction is complete, a binder modifier solution is obtained. Then, a mixed aqueous solution containing phosphorus and aluminum compounds is added to the high-shear dispersing emulsifier, heated to 60-80°C, and the pH is adjusted to ≤4.0 for reaction. After the reaction is complete, a modified phosphorus-aluminum binder colloid is obtained. Then, the mixture of the acid-treated molecular sieve and deionized water prepared in S4 is added to a high-shear emulsifier and mixed evenly to obtain a mixed slurry.

[0064] S6: Preparation of matrix slurry

[0065] The matrix slurry is obtained by mixing and pulping γ-alumina precursor, clay and deionized water, with no special requirements.

[0066] S7: Baking and Shaping

[0067] The matrix slurry is added to the mixed slurry and mixed for 5 minutes in a high-shear emulsifier. Then, it is spray-dried and calcined to obtain the catalytic cracking co-catalyst with high thermal abrasion resistance.

[0068] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0069] Beneficial Effect 1: The catalytic cracking co-catalyst provided by this invention modifies the aluminum phosphate binder by using a modifier containing at least two metals and multi-chelated ligands, replacing existing binders such as aluminum sol, silica sol, and acidified boehmite. On the one hand, this prevents the high content of binder during co-catalyst preparation from clogging the pores in the co-catalyst; on the other hand, it reduces the amount of acid added during co-catalyst preparation, increases the pH value of the slurry, thereby reducing acid corrosion of the molecular sieve structure and improving the activity of the co-catalyst. Using a low-colloidal-index γ-alumina precursor as one of the matrix materials reduces the colloidal solubility of the γ-alumina precursor by the acidic medium during co-catalyst preparation, reducing the clogging of the co-catalyst and zeolite molecular sieve pores by colloidal alumina. Simultaneously, it precisely controls the presence of free aluminum in the co-catalyst system, avoiding excessive reaction with the effective components of the binder, which would affect the binder's bonding performance. A small portion of the colloidal γ-alumina precursor can react with phosphorus-containing compounds in the binder under specific conditions to form a binder. On the other hand, γ-alumina precursors with low colloidal index can form a large number of mesopores during the co-catalyst curing process, thereby increasing the pore volume of the co-catalyst.

[0070] Beneficial Effect 2: The preparation method of the catalytic cracking co-catalyst provided by this invention involves mixing inorganic and organic acids to treat the active component molecular sieve, thereby controlling its pore structure and morphology, increasing the pore volume and specific surface area of ​​the molecular sieve; simultaneously, it regulates the surface acidity of the molecular sieve, reducing strong acid centers and the proportion of Brønsted acid and Lewis acid. This significantly improves propylene selectivity while increasing LPG yield, enhances aromatization ability, and increases gasoline octane number. By pre-stabilizing the molecular sieve, the pore size and specific surface area are increased, significantly improving the activity stability and retention rate under high-temperature hydrothermal conditions. Therefore, excessive phosphorus is not required to modify the molecular sieve during catalyst preparation, reducing the reaction between phosphorus and the non-framework aluminum of the molecular sieve (excessive phosphorus introduced during preparation will react with the non-framework aluminum to form stable PO-Al bonds, thus clogging the pores and reducing the crystallinity, specific surface area, and activity of the molecular sieve). Furthermore, since excessive phosphorus is not introduced during catalyst preparation, large amounts of phosphorus are effectively prevented from being discharged with wastewater (causing excessive phosphorus content in wastewater), thus avoiding environmental impact. Furthermore, by further employing multi-gnawing chelating ligand solution to form metal chelates in situ with rare earth metal precursor solution, rare earth metals can be uniformly distributed on the surface of molecular sieve, thereby modulating the acid distribution on the surface of molecular sieve and preventing the strong acid centers on the surface of molecular sieve from weakening during acid treatment, which would affect the reaction performance. At the same time, due to the occupancy effect of metal chelates, abundant mesoporous structures can be formed in the catalyst during the preparation process.

[0071] Beneficial Effect 3: The catalytic cracking catalyst provided by this invention employs a metal central ligand composed of a multi-meshing chelate ligand and at least two coordinating metals. Under the promotion of organic acids and alcohols, a multi-metal chelate binder modifier is prepared in situ for modifying the binder. Compared with directly using commercially available metal chelates, the in-situ prepared multi-metal chelate modifier has better water solubility, promoting the binding of the modifier with aluminum phosphate sol and resulting in better modification effects. Furthermore, the use of multi-meshing chelate ligands allows for chelation with various metal ions to form multi-metal chelate ligands, reducing dissolution problems between different solvents during binder preparation and minimizing interactions between different chelate ligands. Simultaneously, the proportions of different metals can be flexibly controlled to achieve precise regulation of binder performance. Moreover, the in-situ preparation of the multi-metal chelate modifier overcomes the limitation of a limited variety of commercially available metal chelates, expanding the applicability of binder preparation. Finally, the preferred use of multi-meshing chelate ligands with N, P, and O coordinating atoms reduces the introduction of excessive heteroatoms into the binder, affecting binder performance and minimizing the impact on catalyst performance.

[0072] Beneficial Effect 4: The preparation method of the catalytic cracking co-catalyst provided by the present invention involves the in-situ synthesis of a binder modifier (metal chelate) and a binder, and the use of the binder modifier to modify the binder. On the one hand, it can effectively avoid the introduction of impurities from the molecular sieve or other heteroatoms into the binder, that is, avoid the impurities introduced during the formation of aluminum phosphate crystals from affecting the crystallinity of aluminum phosphate crystals, causing collapse under high temperature hydrothermal conditions (that is, causing chloride, ammonium, nitrate ions to fail to form a strong bond with the binder, reducing the bubbles formed during the curing and calcination process, and thus forming defect sites in the co-catalyst leading to collapse). On the other hand, and more importantly, the in-situ synthesis of the binder and binder modifier allows the metal ions (transition metal ions and rare earth metal ions, etc.) in the binder to modify the aluminum phosphate binder, strengthening the interaction between aluminum phosphate and the matrix material and molecular sieve, and improving the bonding strength between the binder and other components. Experiments show that the metal ions in the binder provided in this invention can significantly reduce thermal collapse under high-temperature hydrothermal conditions, thereby greatly improving the thermal wear performance of the co-catalyst; at the same time, it can avoid premature hardening of the colloid during the later stage of co-catalyst molding and drying, preventing the reduction in reaction performance caused by clogging the co-catalyst pores, and increasing the pore volume of the co-catalyst. Numerous experimental results show that adding this binder modifier to the aluminum phosphate binder can form micropores and mesopores inside the binder during the preparation process, thereby increasing the pore volume of the co-catalyst without affecting the binding performance of the binder.

[0073] Beneficial Effect 5: The preparation method of the catalytic cracking co-catalyst provided by this invention does not specifically limit the reaction apparatus for the acid treatment step, as long as it can be implemented. In the preparation step of the mixed slurry and the calcination and molding step, when the binder and binder modifier are synthesized in situ and mixed with the acid-treated molecular sieve, and then emulsified with the matrix slurry, a high-shear emulsifier is required. On the one hand, it can disperse the low colloidal index γ-alumina precursor into a uniform and viscous emulsion slurry and efficiently mix it with the molecular sieve, overcoming the technical problem that the low colloidal index γ-alumina precursor has poor solubility and cannot form a uniform slurry; at the same time, the γ-alumina precursor exists in a non-free state, avoiding the over-reaction with phosphorus-containing compounds in the binder. On the other hand, the application of the high-shear emulsifier solves the problem that the binder modifier and aluminum phosphate binder cannot be fully mixed, promotes the mutual reaction between the aluminum phosphate binder and the binder modifier, effectively controls the microenvironment such as the supersaturation distribution in the reactor, and enhances the role of the metal chelate of the binder modifier component. More importantly, the application of the high-shear emulsifier enables efficient and short-time mixing of the binder modifier, binder, molecular sieve, and matrix slurry. This achieves rapid emulsification of the low-solubility γ-alumina precursor and thorough homogenization of the binder, binder modifier, molecular sieve, and matrix slurry. After uniform mixing, spray drying is immediately performed to prevent phosphorus migration caused by prolonged contact between the binder and molecular sieve, thus achieving the encapsulation and positioning of phosphorus in the aluminum phosphate binder. This plays an irreplaceable role in improving the reaction performance of the co-catalyst. Detailed Implementation

[0074] The present invention will now be described in detail through embodiments. It should be noted that the following embodiments are only for further illustration of the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above description.

[0075] For any experimental steps or conditions not specified in the examples and comparative examples, the procedures and conditions described in the literature in this field can be followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0076] The raw materials and equipment involved in this invention are all commercially available and can all meet the requirements for implementing the technical solution of this invention. However, for ease of comparison, the raw materials from the following sources are used in the following embodiments:

[0077] Y-type molecular sieve, ZSM-5 molecular sieve, Beta molecular sieve, and MCM-22 molecular sieve were sourced from Lanzhou Petrochemical Company.

[0078] Hydrochloric acid, citric acid, nitric acid, oxalic acid, phosphoric acid, aluminum hydroxide, aluminum oxide, aluminum dihydrogen phosphate, diammonium hydrogen phosphate, aluminum chloride, phosphonic acid, aluminum nitrate, aluminum isopropoxide, hexamethylenediaminetetramethylenephosphonic acid, benzoic acid, 1-propanol, nickel nitrate, zinc sulfate, neodymium sulfate, lactic acid, cobalt chloride, samarium chloride, 1,2-ethylenediamine, ethylenediaminetetraacetic acid, hydroxyethylidene diphosphonic acid, hexamethylenediaminetetramethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, formic acid, acetic acid, ethanol, copper nitrate, lanthanum chloride, lanthanum nitrate, silver nitrate, cerium nitrate, propionic acid, methanol, ethylenediaminetetraacetic acid chelated copper, hydroxyethylethylenediaminetriacetic acid chelated lanthanum; all are analytical grade and manufactured by Sinopharm Group.

[0079] Boehmite, boehmite, kaolin, halloysite, diatomite, and bentonite are produced by Chalco Shandong Aluminum Industry.

[0080] Evaluation and analysis methods:

[0081] The surface area of ​​the co-catalyst was determined by the low-temperature nitrogen adsorption-desorption method (NB / SH / T 0959);

[0082] The pore volume of the catalyst was tested using the water droplet method (NB / SH / T 0955);

[0083] The wear index of the catalyst was determined using the straight tube method (NB / SH / T 0964);

[0084] The thermal collapse rate of the co-catalyst was tested on a small-scale fixed fluidized bed abrasion system (all parts are made of stainless steel) in the laboratory. The specific steps are as follows:

[0085] The co-catalyst in the fluidized bed undergoes continuous fluidization and abrasion under the action of fluidizing air. The extremely fine particles abraded are carried out of the fluidized bed by the gas through a filter element, while larger particles are blocked by the filter element and remain in the fluidized bed for further abrasion. The gas inlet pipe has five evenly distributed air inlets with a diameter of 1 mm at its front end and around its perimeter, and the filter element has a filtration accuracy of 1 μm. In the experiment, 100 g of the prepared co-catalyst was first weighed and recorded as w1, then added to the fluidized bed. The preheater was heated to 150℃, and the fluidized bed temperature was raised to 200℃. The air generator was turned on, and the gas flow rate was adjusted to 40 m / s. The apparent gas velocity inside the reactor was 0.8 m / s. After 4 hours of fluidization and abrasion, the remaining catalyst mass in the reactor was weighed and recorded as w2. The preheater temperature was changed to 650℃, and the fluidized bed temperature to 680℃, while keeping other conditions unchanged. The remaining co-catalyst weight was measured again and recorded as w3. The thermal collapse rate L is then calculated as follows:

[0086] L=(w2-w3) / w2×100%

[0087] The catalyst reaction performance was tested using a small fixed fluidized bed microreactor device according to the method in NB / SH / T0952-2017.

[0088] Example 1

[0089] The catalytic cracking co-catalyst provided in this embodiment, based on the total dry weight of the catalytic cracking co-catalyst as 100%, contains 10wt% ZSM-5 molecular sieve (Si / Al (mol) = 10), 10wt% Y-type molecular sieve, 9wt% binder modifier (based on the total mass of multi-chelate ligands and coordination metal oxides), 26.5wt% boehmite (gel solubility index of 20%), 13.5wt% kaolin, 30wt% binder (P / Al molar ratio of 2:1), and 1wt% molecular sieve modifier (based on the total mass of multi-chelate ligands and rare earth metal oxides).

[0090] The specific preparation method is as follows:

[0091] S1: The bidentate chelating ligand 1,2-ethylenediamine was mixed with formic acid solution to prepare a formic acid solution of the bidentate chelating ligand. After thorough mixing, methanol solution was added to obtain a 1,2-ethylenediamine ligand solution. The molar concentration of 1,2-ethylenediamine in this solution was 0.2 mol / L, the concentration of formic acid was 30 wt%, and the concentration of methanol was 20 wt%.

[0092] S2: Lanthanum chloride and copper nitrate were added to a formic acid solution. After complete dissolution, a methanol solution was added and mixed thoroughly to obtain a precursor solution of mixed coordination metals. The formic acid concentration in this precursor solution was 30 wt%, the methanol concentration was 20 wt%, the total molar concentration of the coordination metals (lanthanum and copper) was 0.1 mol / L, and the molar ratio of lanthanum chloride to copper nitrate was 5:1.

[0093] S3: Lanthanum chloride is added to a formic acid solution. After complete dissolution, an ethanol solution is added and mixed thoroughly to obtain a lanthanum chloride solution. The concentration of formic acid in this solution is 30 wt%, the concentration of ethanol is 20 wt%, and the molar concentration of lanthanum is 0.1 mol / L.

[0094] S4: After exchanging ZSM-5 molecular sieve with Y-type molecular sieve using ammonium chloride, the molar content of Na2O in the mixed molecular sieve is reduced to below 0.1wt%.

[0095] S5: The above-mentioned ammonium-exchanged mixed molecular sieve is mixed with deionized water to obtain a molecular sieve slurry. Then, a mixture of dilute hydrochloric acid and citric acid (molar ratio of hydrochloric acid to citric acid is 2:1) is added to the molecular sieve slurry. After the acid is added, the pH of the system is 2.0. The temperature is raised to 60°C and reacted in a reactor with a reflux device for 12 hours. After the reaction is completed, the 1,2-ethylenediamine ligand solution prepared in S1 is added and stirred evenly. Then, the lanthanum chloride solution prepared in S3 is added and stirred at the same temperature for another hour. The material obtained after the reaction is dried at 120°C for 12 hours and then calcined at 400°C for 5 hours (100% steam is introduced for the first 200 minutes of calcination and air is introduced for the last 100 minutes of calcination) to obtain the acid-treated molecular sieve.

[0096] The molar ratio of 1,2-ethylenediamine to lanthanum chloride is 2:1.

[0097] S6: The 1,2-ethylenediamine ligand solution obtained in S1 is added to a high-shear dispersing emulsifier, and the temperature is maintained at 30℃. An equal volume of the mixed coordination metal precursor solution obtained in S2 is added, and the pH of the system is adjusted to 5 to obtain a binder modifier solution. Then, a mixed aqueous solution of aluminum hydroxide and aluminum dihydrogen phosphate (P / Al molar ratio of 2:1) is added to this binder modifier solution, and the mixture is heated to 60℃ in a high-shear dispersing emulsifier. The pH is then adjusted to 4.0 to carry out the reaction. After the reaction is completed, the modified aluminum phosphate binder colloid is obtained. Then, the acid-treated molecular sieve obtained in S5 is mixed with deionized water and added to a high-shear emulsifier. After mixing evenly, a mixed slurry is obtained.

[0098] S7: Mix boehmite (colloidal index of 20%), kaolin, and deionized water to prepare a matrix slurry.

[0099] S8: Add the mixed slurry obtained in S6 to the matrix slurry obtained in S7, and continue mixing in a high-shear emulsifier for 2 minutes. Then, perform spray molding. The spray molding conditions are that the furnace temperature of the spray tower is controlled at 580℃ and the temperature of the spray exhaust gas is controlled at 160℃. After the obtained material is calcined at 600℃ for 2 hours, it becomes the catalytic cracking co-catalyst.

[0100] The physicochemical properties and catalytic performance of the catalytic cracking co-catalyst are shown in Table 1.

[0101] Example 2

[0102] The catalytic cracking co-catalyst provided in this embodiment, based on the total dry weight of the catalytic cracking co-catalyst as 100%, contains 49wt% ZSM-5 molecular sieve (Si / Al(mol)=50), 21wt% Beta molecular sieve, 1.5wt% binder modifier (based on the total mass of multi-chelate ligands and coordination metal oxides), 3.5wt% boehmite (colloidal index 30%), 6.5wt% halloysite, and 18wt% binder (P / Al molar ratio of 10:1); the molecular sieve modifier (based on the total mass of multi-chelate ligands and rare earth metal oxides) contains 0.5wt%.

[0103] The specific preparation method is as follows:

[0104] S1: Ethylenediaminetetraacetic acid (EDTA), a hexa-chelating ligand, is mixed with an acetic acid solution to prepare an acetic acid solution containing EDTA multi-chelating ligands. After thorough mixing, an ethanol solution is added to obtain an EDTA ligand solution. The molar concentration of EDTA in this ligand solution is 1 mol / L, the concentration of the organic acid is 10 wt%, and the concentration of ethanol is 5 wt%.

[0105] S2: Cerium nitrate and silver nitrate are added to an acetic acid solution. After complete dissolution, an ethanol solution is added and mixed thoroughly to obtain a precursor solution of mixed coordination metals. The concentration of acetic acid in this precursor solution is 10 wt%, the concentration of ethanol is 5 wt%, the total molar concentration of coordination metals (cerium and silver) is 0.2 mol / L, and the molar ratio of cerium nitrate to silver nitrate is 10:1.

[0106] S3: Add cerium nitrate to an acetic acid solution. After it is completely dissolved, add an ethanol solution and mix thoroughly to obtain a cerium nitrate solution. The concentration of acetic acid in this solution is 30 wt%, the concentration of ethanol is 20 wt%, and the molar concentration of cerium is 0.2 mol / L.

[0107] S4: Mix ZSM-5 and Beta molecular sieve with deionized water to obtain molecular sieve slurry. Then add a mixture of dilute nitric acid and oxalic acid (molar ratio of dilute nitric acid to oxalic acid is 5:1) to the molecular sieve slurry. After adding the acid, the pH of the system is 0.5. Heat to 80℃ and react in a reactor with a reflux device for 3 hours until the reaction is complete. Add the ethylenediaminetetraacetic acid ligand solution prepared in S1 and stir evenly. Then add an equal volume of cerium nitrate solution prepared in S3 and continue stirring at the same temperature for 1 hour. Dry the material obtained after the reaction at 120℃ for 12 hours and then calcine at 800℃ for 2 hours (100% steam is introduced for the first 80 minutes of calcination and air is introduced for the last 40 minutes of calcination) to obtain the acid-treated molecular sieve.

[0108] The molar ratio of ethylenediaminetetraacetic acid to cerium nitrate is 5:1.

[0109] S5: The ethylenediaminetetraacetic acid solution obtained in S1 is added to a high-shear dispersing emulsifier, and the temperature is maintained at 50℃. An equal volume of the mixed coordination metal precursor solution obtained in S2 is added, and the pH of the system is adjusted to 5 to obtain a binder modifier solution. Then, a mixed aqueous solution of aluminum oxide and phosphoric acid (P / Al molar ratio = 10:1) is added to this binder modifier solution, and the mixture is heated to 80℃ in a high-shear dispersing emulsifier. The pH is then adjusted to 3.0 to carry out the reaction. After the reaction is completed, the modified aluminum phosphorus binder colloid is obtained. Then, the acid-treated molecular sieve obtained in S4 is mixed with deionized water and added to a high-shear emulsifier. After mixing evenly, a mixed slurry is obtained.

[0110] S6: Boehmite (colloidal index 30%), malachite and deionized water are mixed to prepare a matrix slurry.

[0111] S7: Add the mixed slurry obtained in S5 to the matrix slurry obtained in S6, and continue mixing in a high-shear emulsifier for 4 minutes. Then, perform spray molding. The spray molding conditions are that the furnace temperature of the spray tower is controlled at 580℃ and the temperature of the spray exhaust gas is controlled at 160℃. After the obtained material is calcined at 600℃ for 2 hours, it becomes the catalytic cracking co-catalyst.

[0112] The physicochemical properties and catalytic performance of the catalytic cracking co-catalyst are shown in Table 1.

[0113] Example 3

[0114] The catalytic cracking co-catalyst provided in this embodiment, based on the total dry weight of the catalytic cracking co-catalyst as 100%, contains 26wt% ZSM-5 molecular sieve (Si / Al (mol) = 200), 11wt% MCM-22 molecular sieve, 6.4wt% binder modifier (based on the total mass of multi-chelate ligands and coordination metal oxides), 2.2wt% boehmite (colloidal index 25%), 32.8wt% diatomaceous earth, and 20wt% binder (P / Al molar ratio of 5:1); the molecular sieve modifier (based on the total mass of multi-chelate ligands and rare earth metal oxides) contains 1.6wt%.

[0115] The specific preparation method is as follows:

[0116] S1: A propionic acid solution containing the tetraglycated ligand hydroxyethylidene diphosphonic acid (HEDDI) was prepared by mixing HEDDI with a propionic acid solution. After thorough mixing, methanol solution was added to obtain a HEDDI ligand solution. The molar concentration of HEDDI in this ligand solution was 0.6 mol / L, the concentration of propionic acid was 20 wt%, and the concentration of methanol was 10 wt%.

[0117] S2: Neodymium sulfate and zinc sulfate are added to a propionic acid solution. After complete dissolution, an ethanol solution is added and mixed thoroughly to obtain a precursor solution of mixed coordination metals. The concentration of propionic acid in this precursor solution is 20 wt%, the concentration of ethanol is 10 wt%, the total molar concentration of coordination metals (neodymium and zinc) is 0.2 mol / L, and the molar ratio of zinc sulfate to neodymium sulfate is 1:8.

[0118] S3: Add neodymium sulfate to a propionic acid solution. After it is completely dissolved, add an ethanol solution and mix thoroughly to obtain a neodymium sulfate solution. The concentration of propionic acid in this solution is 20 wt%, the concentration of ethanol is 10 wt%, and the molar concentration of neodymium is 0.2 mol / L.

[0119] S4: Mix the ZSM-5 and MCM-22 molecular sieves with deionized water to obtain a molecular sieve slurry. Then, add a mixture of dilute nitric acid and citric acid (molar ratio of nitric acid to citric acid is 3:1) to the molecular sieve slurry. After adding the acid, the pH of the system is 1.0. The temperature is raised to 80℃ and reacted in a reactor with a reflux device for 6 hours until the reaction is complete. Then, add the hydroxyethylidene diphosphonic acid ligand solution prepared in S1 and stir evenly. Then, add an equal volume of neodymium sulfate solution prepared in S3 and continue stirring at this temperature for 0.5 hours. After that, dry the material obtained after the reaction at 120℃ for 12 hours and then calcine it at 600℃ for 3 hours (100% steam is introduced for the first 120 minutes of calcination and air is introduced for the last 60 minutes of calcination) to obtain the acid-treated molecular sieve.

[0120] The molar ratio of hydroxyethylidene diphosphonic acid to neodymium sulfate is 3:1.

[0121] S5: The hydroxyethylidene diphosphonic acid ligand solution obtained in S1 is added to a high-shear dispersing emulsifier, and the temperature is maintained at 40℃. An equal volume of the mixed coordination metal precursor solution obtained in S2 is added, and the pH of the system is adjusted to 7 to obtain the binder modifier solution. A mixed aqueous solution of aluminum chloride and organophosphonic acid (P / Al molar ratio = 5:1) is added to the high-shear dispersing emulsifier, heated to 80℃, and the pH is adjusted to 3.0 to carry out the reaction. After the reaction is completed, the modified aluminum phosphate binder colloid is obtained. Then, the acid-treated molecular sieve obtained in S4 is mixed with deionized water and added to a high-shear emulsifier. After mixing evenly, a mixed slurry is obtained.

[0122] S6: Mix boehmite (colloidal index 25%), diatomaceous earth and deionized water to prepare a matrix slurry.

[0123] S7: Add the mixed slurry obtained in S5 to the matrix slurry obtained in S6, and continue mixing in a high-shear emulsifier for 1 minute. Then, perform spray molding. The spray molding conditions are that the furnace temperature of the spray tower is controlled at 580℃ and the temperature of the spray exhaust gas is controlled at 160℃. After the obtained material is calcined at 600℃ for 2 hours, it becomes the catalytic cracking co-catalyst.

[0124] The physicochemical properties and catalytic performance of the catalytic cracking co-catalyst are shown in Table 1.

[0125] Example 4

[0126] The catalytic cracking co-catalyst provided in this embodiment, based on the total dry weight of the catalytic cracking co-catalyst as 100%, contains 35wt% ZSM-5 molecular sieve (Si / Al(mol)=100), 9wt% Y-type molecular sieve, 2.8wt% binder modifier (based on the total mass of multi-chelate ligands and coordination metal oxides), 3.6wt% boehmite (gel solubility index of 25%), 33.4wt% bentonite, and 15wt% binder (P / Al molar ratio of 8:1); the molecular sieve modifier (based on the total mass of multi-chelate ligands and rare earth metal oxides) contains 0.8wt%.

[0127] The specific preparation method is as follows:

[0128] S1: A benzoic acid solution containing hexamethylenediaminetetramethylenephosphonic acid (HDMA) as a tetra-chelating ligand was prepared by mixing the HDMA chelating ligand with a benzoic acid solution. After thorough mixing, an ethanol solution was added to obtain a HDMA chelating ligand solution. The molar concentration of HDMA in this solution was 0.6 mol / L, the concentration of benzoic acid was 20 wt%, and the concentration of ethanol was 10 wt%.

[0129] S2: Nickel nitrate and neodymium sulfate were added to a benzoic acid solution. After complete dissolution, a 1-propanol solution was added and mixed thoroughly to obtain a precursor solution of mixed coordination metals. The concentration of benzoic acid in this precursor solution was 20%, the concentration of 1-propanol was 10%, the total molar concentration of the coordination metals (nickel and neodymium) was 0.2 mol / L, and the molar ratio of nickel nitrate to neodymium sulfate was 1:6.

[0130] S3: Neodymium sulfate is added to a benzoic acid solution. After complete dissolution, a 1-propanol solution is added and mixed thoroughly to obtain a rare earth metal precursor solution. The concentration of benzoic acid in this precursor solution is 20%, the concentration of 1-propanol is 10%, and the molar concentration of neodymium sulfate is 0.2 mol / L.

[0131] S4: After exchanging ZSM-5 molecular sieve with Y-type molecular sieve using ammonium chloride, the molar content of Na2O in the mixed molecular sieve is reduced to below 0.1wt%.

[0132] S5: Mix ZSM-5 molecular sieve and Y-type molecular sieve with deionized water to obtain molecular sieve slurry. Then add a mixture of dilute hydrochloric acid and tartaric acid (molar ratio of hydrochloric acid to tartaric acid is 3:1) to the molecular sieve slurry. After adding the acid, the pH of the system is 0.5. Heat to 80℃ and react in a reactor with a reflux device for 10 hours. After the reaction is completed, add the hexamethylenediaminetetramethylenephosphonic acid ligand solution prepared in S1. After stirring evenly, add an equal volume of rare earth metal precursor solution prepared in S3. Continue stirring at this temperature for 0.5 hours. Dry the material obtained after the reaction at 80℃ for 10 hours. Then calcine at 600℃ for 3 hours (100% steam is introduced for the first 120 minutes of calcination, and air is introduced for the last 60 minutes of calcination) to obtain the acid-treated molecular sieve.

[0133] The molar ratio of hexamethylenediaminetetramethylenephosphonic acid to neodymium sulfate is 3:1.

[0134] S6: The hexamethylenediaminetetramethylenephosphonic acid solution obtained in S1 is added to a high-shear dispersing emulsifier, and the temperature is maintained at 40℃. An equal volume of the mixed coordination metal precursor solution obtained in S2 is added, and the pH of the system is adjusted to 7 to obtain the binder modifier solution. A mixed aqueous solution of aluminum nitrate and diammonium hydrogen phosphate (P / Al molar ratio = 8:1) is added to the high-shear dispersing emulsifier, heated to 70℃, and the pH is adjusted to 3.0 to carry out the reaction. After the reaction is completed, the modified aluminum phosphate binder colloid is obtained. Then, the acid-treated molecular sieve obtained in S5 is mixed with deionized water and added to the high-shear emulsifier. After mixing evenly, a mixed slurry is obtained.

[0135] S7: Boehmite (colloidal index of 25%), bentonite and deionized water are mixed to prepare matrix slurry.

[0136] S8: Add the mixed slurry obtained in S6 to the matrix slurry obtained in S7, and continue mixing in a high-shear emulsifier for 1 minute. Then, perform spray molding. The spray molding conditions are that the furnace temperature of the spray tower is controlled at 580℃ and the temperature of the spray exhaust gas is controlled at 160℃. After the obtained material is calcined at 600℃ for 2 hours, it becomes the catalytic cracking co-catalyst.

[0137] The physicochemical properties and catalytic performance of the catalytic cracking co-catalyst are shown in Table 1.

[0138] Example 5

[0139] The catalytic cracking co-catalyst provided in this embodiment, based on the total dry weight of the catalytic cracking co-catalyst as 100%, contains 45wt% ZSM-5 molecular sieve, 11wt% Y-type molecular sieve, 2.4wt% binder modifier (based on the total mass of multi-chelate ligands and coordination metal oxides), 4wt% boehmite (gel solubility index of 25%), 27wt% kaolin, 10wt% binder (P / Al molar ratio of 6:1), and 0.6wt% molecular sieve modifier (based on the total mass of multi-chelate ligands and rare earth metal oxides).

[0140] The specific preparation method is as follows:

[0141] S1: The octetral chelating ligand diethylenetriaminepentamethylphosphonic acid (DMEPA) was mixed with a lactic acid solution to prepare a lactic acid solution containing DMEPA as a multi-chelating ligand. After thorough mixing, an ethanol solution was added to obtain a DMEPA ligand solution. The molar concentration of DMEPA in this ligand solution was 0.6 mol / L, the concentration of lactic acid was 20%, and the concentration of ethanol was 10%.

[0142] S2: Add samarium chloride and cobalt chloride to a lactic acid solution. After complete dissolution, add an ethanol solution and mix thoroughly to obtain a precursor solution of mixed coordination metals. The concentration of lactic acid in this precursor solution is 20%, the concentration of ethanol is 10%, the total molar concentration of coordination metals (samarium and cobalt) is 0.15 mol / L, and the molar ratio of cobalt chloride to samarium chloride is 1:8.

[0143] S3: Add samarium chloride to a lactic acid solution. After it is completely dissolved, add an ethanol solution and mix thoroughly to obtain a rare earth metal precursor solution. The concentration of lactic acid in this precursor solution is 20%, the concentration of ethanol is 10%, and the molar concentration of samarium is 0.15 mol / L.

[0144] S4: After exchanging ZSM-5 molecular sieve with Y-type molecular sieve using ammonium chloride, the molar content of Na2O in the mixed molecular sieve is reduced to below 0.1wt%.

[0145] S5: A mixture of ZSM-5 molecular sieve and Y-type molecular sieve is mixed with deionized water to obtain a molecular sieve slurry. A mixture of dilute hydrochloric acid and oxalic acid (molar ratio of hydrochloric acid to oxalic acid 3:1) is then added to the slurry. After adding the acid, the pH of the system is 1.0. The temperature is raised to 80℃, and the reaction is carried out in a reactor equipped with a reflux device for 2 hours. After the reaction is complete, the diethylenetriamine pentamethylphosphonic acid ligand solution prepared in S1 is added, and the mixture is stirred evenly. Then, an equal volume of the rare earth metal precursor solution prepared in S3 is added, and the mixture is stirred at the same temperature for another 0.5 hours. The resulting material is dried at 120℃ for 12 hours, and then calcined at 600℃ for 3 hours (100% steam is introduced for the first 120 minutes of calcination, and air is introduced for the next 60 minutes) to obtain the acid-treated molecular sieve.

[0146] The molar ratio of diethylenetriaminepentimidephosphonic acid to samarium chloride is 4:1.

[0147] S6: The hexamethylenediaminetetramethylenephosphonic acid ligand solution obtained in S1 is added to a high-shear dispersing emulsifier, and the temperature is maintained at 40℃. An equal volume of the mixed coordination metal precursor solution obtained in S2 is added, and the pH of the system is adjusted to 7 to obtain the binder modifier solution. A mixed aqueous solution of aluminum isopropoxide and phosphoric acid (P / Al molar ratio = 6:1) is added to the high-shear dispersing emulsifier, heated to 70℃, and the pH is adjusted to 3.0 to carry out the reaction. After the reaction is completed, the modified aluminum phosphate binder colloid is obtained. Then, the acid-treated molecular sieve obtained in S5 is mixed with deionized water and added to the high-shear emulsifier. After mixing evenly, a mixed slurry is obtained.

[0148] S7: Mix boehmite (colloidal index of 25%), kaolin, and deionized water to prepare a matrix slurry.

[0149] S8: Add the mixed slurry obtained in S6 to the matrix slurry obtained in S7, and continue mixing in a high-shear emulsifier for 1 minute. Then, perform spray molding. The spray molding conditions are that the furnace temperature of the spray tower is controlled at 580℃ and the temperature of the spray exhaust gas is controlled at 160℃. After the obtained material is calcined at 600℃ for 2 hours, it becomes the catalytic cracking co-catalyst.

[0150] The physicochemical properties and catalytic performance of the catalytic cracking co-catalyst are shown in Table 1.

[0151] Example 6

[0152] The catalytic cracking co-catalyst provided in this embodiment, based on the total dry weight of the catalytic cracking co-catalyst as 100%, contains 45wt% ZSM-5 molecular sieve, 11wt% Y-type molecular sieve, 3.0wt% binder modifier (based on the total mass of multi-gnawing chelate ligands and coordination metal oxides), 4wt% pseudoboehmite (colloidal index of 25%), 27wt% kaolin, and 10wt% binder (P / Al molar ratio of 6:1).

[0153] The specific preparation method is as follows:

[0154] S1: The octetral chelating ligand diethylenetriaminepentamethylphosphonic acid (DMEPA) was mixed with a lactic acid solution to prepare a lactic acid solution containing DMEPA as a multi-chelating ligand. After thorough mixing, an ethanol solution was added to obtain a DMEPA ligand solution. The molar concentration of DMEPA in this ligand solution was 0.6 mol / L, the concentration of lactic acid was 20%, and the concentration of ethanol was 10%.

[0155] S2: Add samarium chloride and cobalt chloride to a lactic acid solution. After complete dissolution, add an ethanol solution and mix thoroughly to obtain a precursor solution of mixed coordination metals. The concentration of lactic acid in this precursor solution is 20%, the concentration of ethanol is 10%, the total molar concentration of coordination metals (samarium and cobalt) is 0.15 mol / L, and the molar ratio of cobalt chloride to samarium chloride is 1:8.

[0156] S3: After exchanging ZSM-5 molecular sieve with Y-type molecular sieve using ammonium chloride, the molar content of Na2O in the mixed molecular sieve is reduced to below 0.1wt%.

[0157] S4: A mixture of ZSM-5 molecular sieve and Y-type molecular sieve was mixed with deionized water to obtain a molecular sieve slurry. Then, a mixture of dilute hydrochloric acid and oxalic acid (molar ratio of hydrochloric acid to oxalic acid 3:1) was added to the slurry. After adding the acid, the pH of the system was 1.0. The temperature was raised to 80℃, and the reaction was carried out in a reactor equipped with a reflux device for 2 hours until the reaction was complete. The resulting material was dried at 120℃ for 12 hours, and then calcined at 600℃ for 3 hours (100% steam was introduced for the first 120 minutes of calcination, and air was introduced for the next 60 minutes) to obtain the acid-treated molecular sieve.

[0158] S5: The hexamethylenediaminetetramethylenephosphonic acid ligand solution obtained in S1 is added to a high-shear dispersing emulsifier, and the temperature is maintained at 40℃. An equal volume of the mixed coordination metal precursor solution obtained in S2 is added, and the pH of the system is adjusted to 7 to obtain the binder modifier solution. A mixed aqueous solution of aluminum isopropoxide and phosphoric acid (P / Al molar ratio = 6:1) is added to the high-shear dispersing emulsifier, heated to 70℃, and the pH is adjusted to 3.0 to carry out the reaction. After the reaction is completed, the modified aluminum phosphate binder colloid is obtained. Then, the acid-treated molecular sieve obtained in S5 is mixed with deionized water and added to the high-shear emulsifier. After mixing evenly, a mixed slurry is obtained.

[0159] S6: Mix boehmite (colloidal index of 25%), kaolin, and deionized water to prepare a matrix slurry.

[0160] S7: Add the mixed slurry obtained in S5 to the matrix slurry obtained in S, and continue mixing in a high-shear emulsifier for 1 minute. Then, perform spray molding. The spray molding conditions are that the furnace temperature of the spray tower is controlled at 580℃ and the temperature of the spray exhaust gas is controlled at 160℃. After the obtained material is calcined at 600℃ for 2 hours, it becomes the catalytic cracking co-catalyst.

[0161] The physicochemical properties and catalytic performance of the catalytic cracking co-catalyst are shown in Table 1.

[0162] Comparative Example 1

[0163] The catalytic cracking co-catalyst provided in this comparative example contains 70 wt% molecular sieves, based on 100% of the total dry weight of the co-catalyst. Among them, ZSM-5 zeolite (Si / Al (mol) ratio of 50) content is 49 wt%, Beta molecular sieve content is 21 wt%, kaolinite content is 10 wt%, boehmite content is 4 wt% (colloidal solubility index 99%), co-catalyst (based on P2O5) content is 15 wt%, and La2O3 content is 1.0 wt%.

[0164] Preparation of phosphorus aluminum sol binder: 4 wt% of boehmite (dry basis) and a certain amount of deionized water were mixed and stirred. Then, 15 wt% (calculated as P2O5) and 85 wt% concentrated phosphoric acid were added to the slurry. A certain amount of hydrochloric acid was then added to control the pH of the system to 1.5, thus obtaining a colorless and transparent phosphorus aluminum sol.

[0165] Preparation of mixed molecular sieve slurry: 70 wt% of molecular sieve by dry weight is mixed with a certain amount of deionized water, stirred evenly, and then 1 wt% of La(NO3)3 solution (calculated as La2O3) by dry weight is added to prepare mixed molecular sieve slurry.

[0166] Preparation of the co-catalyst: Under stirring, 10 wt% kaolin (dry weight) and a certain amount of water were mixed and slurried. Phosphorus aluminum sol was added, and stirring was continued for 0.5 h. Then, the above-mentioned mixed molecular sieve slurry was added, and stirring was continued for 0.5 h. The solid content of the resulting slurry was 38 wt%. After homogenization, the slurry was spray-molded and calcined at 600℃ for 2 h to obtain the co-catalyst.

[0167] Comparative Example 2

[0168] 80g of NH4Cl was dissolved in 1000g of water. 100g (dry basis) of crystallized ZSM-5 molecular sieve (synthesized via amine method, SiO2 / Al2O3 = 170) was added to this solution. After exchange at 85℃ for 0.5h, the mixture was filtered to obtain a filter cake. 8.9g of NH4H2PO4 was dissolved in 60g of water and mixed with the filter cake for impregnation and drying. 31.9g of FeSO4·6H2O was dissolved in 90g of water and mixed with the above sample for impregnation and drying. The mixture was then calcined at 600℃ for 2 hours to obtain the molecular sieve. Elemental analysis showed the chemical composition to be 0.1Na2O·0.94Al2O3·5.1P2O5·10.1Fe2O3·84SiO2.

[0169] 0.37 kg of aluminum hydroxide powder (containing 0.28 kg of Al2O3), 0.52 kg of rettore (0.40 kg dry basis) and 4.31 kg of decationized water were mixed into a slurry for 30 minutes. While stirring, 2.14 kg of phosphoric acid (containing 1.32 kg of phosphorus pentoxide) was added to the slurry at a rate of 0.07 kg phosphoric acid / min / kg alumina source. The temperature was raised to 70°C and then reacted at this temperature for 45 minutes to obtain a clay-containing phosphorus aluminum inorganic binder.

[0170] The above-mentioned molecular sieve, kaolin (78 wt% solid content), diatomaceous earth and pseudoboehmite (60% solid content, industrial product produced by Shandong Aluminum Plant) were added, along with decationized water and water glass (industrial product produced by Qilu Petrochemical Catalyst Plant, with 28.9 wt% SiO2 content and 8.9 wt% Na2O content). The mixture was slurried for 120 minutes, and hydrochloric acid was added to adjust the pH of the slurry to 3.0. The mixture was slurried for 45 minutes, and diammonium hydrogen phosphate solid was added. Then, a phosphorus aluminum inorganic binder containing clay was added to the slurry, and the mixture was stirred for 30 minutes to obtain a slurry with a solid content of 38 wt%. The obtained slurry was then spray-dried to obtain microspheres with an average particle diameter of 65 micrometers. The microspheres were calcined at 500℃ for 1 hour, then mixed with a 1.5 wt% FeCl3·6H2O aqueous solution, and reacted at 60℃ for 20 minutes. The mixture was filtered, dried, and then calcined at 500℃ for 2 hours to obtain a catalytic cracking co-catalyst.

[0171] In the above-mentioned collodion soil, the content of quartz sand is <3.5wt%, Al2O3 is 39.0wt%, Fe2O3 is 2.0wt%, Na2O is 0.03wt%, and the solid content is 77wt%.

[0172] Comparative Example 3

[0173] In this comparative example, the content of each component in the catalytic cracking co-catalyst is the same as in Example 5, and the preparation method is similar to that in Example 5, except that the acid treatment step of the molecular sieve is omitted. The specific preparation process is as follows:

[0174] S1: The octetral chelating ligand diethylenetriaminepentamethylphosphonic acid (DMEPA) was mixed with a lactic acid solution to prepare a lactic acid solution containing DMEPA as a multi-chelating ligand. After thorough mixing, an ethanol solution was added to obtain a DMEPA ligand solution. The molar concentration of DMEPA in this ligand solution was 0.6 mol / L, the concentration of lactic acid was 20%, and the concentration of ethanol was 10%.

[0175] S2: Add samarium chloride and cobalt chloride to a lactic acid solution. After complete dissolution, add an ethanol solution and mix thoroughly to obtain a precursor solution of mixed coordination metals. The concentration of lactic acid in this precursor solution is 20%, the concentration of ethanol is 10%, the total molar concentration of coordination metals (samarium and cobalt) is 0.15 mol / L, and the molar ratio of cobalt chloride to samarium chloride is 1:8.

[0176] S3: Add samarium chloride to a lactic acid solution. After it is completely dissolved, add an ethanol solution and mix thoroughly to obtain a rare earth metal precursor solution. The concentration of lactic acid in this precursor solution is 20%, the concentration of ethanol is 10%, and the molar concentration of samarium is 0.15 mol / L.

[0177] S4: After exchanging ZSM-5 molecular sieve with Y-type molecular sieve using ammonium chloride, the molar content of Na2O in the mixed molecular sieve is reduced to below 0.1wt%.

[0178] S5: A mixture of ZSM-5 molecular sieve and Y-type molecular sieve was mixed with deionized water to obtain a molecular sieve slurry. The slurry was heated to 80℃, and then the diethylenetriamine pentamethylphosphonic acid ligand solution prepared in S1 was added. After stirring until homogeneous, an equal volume of the rare earth metal precursor solution prepared in S3 was added, and stirring continued at this temperature for 0.5 hours. The resulting material was dried at 120℃ for 12 hours, and then calcined at 600℃ for 3 hours (100% steam was introduced for the first 120 minutes of calcination, and air was introduced for the next 60 minutes) to obtain the modified molecular sieve.

[0179] The molar ratio of diethylenetriaminepentimidephosphonic acid to samarium chloride is 4:1.

[0180] S6: The hexamethylenediaminetetramethylenephosphonic acid ligand solution obtained in S1 is added to a high-shear dispersing emulsifier, and the temperature is maintained at 40℃. An equal volume of the mixed coordination metal precursor solution obtained in S2 is added, and the pH of the system is adjusted to 7 to obtain the binder modifier solution. A mixed aqueous solution of aluminum isopropoxide and phosphoric acid (P / Al molar ratio = 6:1) is added to the high-shear dispersing emulsifier, heated to 70℃, and the pH is adjusted to 3.0 to carry out the reaction. After the reaction is completed, the modified aluminum phosphate binder colloid is obtained. Then, the modified molecular sieve obtained in S5 is mixed with deionized water and added to a high-shear emulsifier. After mixing evenly, a mixed slurry is obtained.

[0181] S7: Mix boehmite (colloidal index of 25%), kaolin, and deionized water to prepare a matrix slurry.

[0182] S8: Add the mixed slurry obtained in S6 to the matrix slurry obtained in S7, and continue mixing in a high-shear emulsifier for 1 minute. Then, perform spray molding. The spray molding conditions are that the furnace temperature of the spray tower is controlled at 580℃ and the temperature of the spray exhaust gas is controlled at 160℃. After the obtained material is calcined at 600℃ for 2 hours, it becomes the catalytic cracking co-catalyst.

[0183] The physicochemical properties and catalytic performance of the co-catalyst are shown in Table 1.

[0184] Comparative Example 4

[0185] This comparative example is similar to Example 5, except that no multi-chelating ligand was added, and the precursors of the coordination metal and rare earth metal were dissolved in water instead of acid and alcohol. The specific preparation process is as follows:

[0186] S1: Add samarium chloride and cobalt chloride to water until completely dissolved to obtain a precursor solution of mixed coordination metals. The total molar concentration of coordination metals (samarium and cobalt) in the precursor solution is 0.15 mol / L, and the molar ratio of cobalt chloride to samarium chloride is 1:8.

[0187] S2: Add samarium chloride to water and allow it to dissolve completely to obtain a rare earth metal precursor solution. The molar concentration of samarium in this precursor solution is 0.15 mol / L.

[0188] S3: After exchanging ZSM-5 molecular sieve with Y-type molecular sieve using ammonium chloride, the molar content of Na2O in the mixed molecular sieve is reduced to below 0.1wt%.

[0189] S4: A mixture of ZSM-5 molecular sieve and Y-type molecular sieve was mixed with deionized water to obtain a molecular sieve slurry. A mixture of dilute hydrochloric acid and oxalic acid (molar ratio of hydrochloric acid to oxalic acid 3:1) was then added to the slurry. After adding the acid, the pH of the system was 1.0. The temperature was raised to 80°C, and the mixture was reacted in a reactor equipped with a reflux device for 2 hours. After the reaction was completed, the rare earth metal precursor solution obtained in S2 was added (the amount of samarium chloride added was the same as the amount added in step S5 of Example 5). After stirring evenly, the mixture was stirred at the same temperature for another 0.5 hours. The resulting material was dried at 120°C for 12 hours, and then calcined at 600°C for 3 hours (100% steam was introduced for the first 120 minutes of calcination, and air was introduced for the next 60 minutes) to obtain the acid-treated molecular sieve.

[0190] S5: The precursor solution of the mixed coordination metals obtained in S1 (the amount of samarium chloride and cobalt chloride added is the same as that added in step S6 of Example 5), the mixed aqueous solution of aluminum isopropoxide and phosphoric acid (P / Al molar ratio = 6:1) are added to a high-shear dispersing emulsifier, heated to 70°C, and the pH is adjusted to 3.0 to carry out the reaction. After the reaction is completed, the modified aluminum phosphate binder colloid is obtained. Then, the acid-treated molecular sieve obtained in S4 is mixed with deionized water and added to a high-shear emulsifier. After mixing evenly, the mixed slurry is obtained.

[0191] S6: Mix boehmite (colloidal index of 25%), kaolin, and deionized water to prepare a matrix slurry.

[0192] S7: Add the mixed slurry obtained in S5 to the matrix slurry obtained in S6, and continue mixing in a high-shear emulsifier for 1 minute. Then, perform spray molding. The spray molding conditions are that the furnace temperature of the spray tower is controlled at 580℃ and the temperature of the spray exhaust gas is controlled at 160℃. After the obtained material is calcined at 600℃ for 2 hours, it becomes the catalytic cracking co-catalyst.

[0193] The physicochemical properties and catalytic performance of the catalytic cracking co-catalysts prepared in this comparative example are shown in Table 1.

[0194] Comparative Example 5

[0195] This comparative example is similar to Example 5, except that the gel solubility index of the pseudoboehmite used is different. The gel solubility index of the pseudoboehmite used in this comparative example is 99%.

[0196] The physicochemical properties and catalytic performance of the catalytic cracking co-catalysts prepared in this comparative example are shown in Table 1.

[0197] Comparative Example 6

[0198] This comparative example is similar to Example 5, except that the apparatus used in the mixing slurry and calcination molding steps is different. In this comparative example, a stirred reactor is used instead of a high-shear emulsifier, and the working time is extended accordingly until the mixture is uniform.

[0199] Comparative Example 7

[0200] This comparative example is similar to Example 6, except that the binder modifier is a mixture of equal amounts of ethylenediaminetetraacetic acid chelated copper and hydroxyethyl ethylenediaminetriacetic acid chelated lanthanum (based on metal oxides, the amount of binder modifier added in this comparative example is equal to that in Example 6). The specific preparation method is as follows:

[0201] The catalytic cracking co-catalyst provided in this comparative example, based on the total dry weight of the catalytic cracking co-catalyst as 100%, contains 45wt% ZSM-5 molecular sieve, 11wt% Y-type molecular sieve, 3.0wt% binder modifier, 4wt% boehmite (colloidal index of 25%), 27wt% kaolin, and 10wt% binder (P / Al molar ratio of 6:1).

[0202] The specific preparation method is as follows:

[0203] Ammonium exchange: After exchanging ZSM-5 molecular sieve with Y-type molecular sieve using ammonium chloride, the molar content of Na2O in the mixed molecular sieve is reduced to below 0.1 wt%.

[0204] Acid treatment: The ammonium-exchanged mixed molecular sieve was mixed with deionized water to obtain a molecular sieve slurry. Then, a mixture of dilute hydrochloric acid and oxalic acid (molar ratio of hydrochloric acid to oxalic acid 3:1) was added to the molecular sieve slurry. After the acid was added, the pH of the system was 1.0. The temperature was raised to 80°C, and the reaction was carried out in a reactor equipped with a reflux device for 2 hours until the reaction was completed. The material obtained after the reaction was dried at 120°C for 12 hours, and then calcined at 600°C for 3 hours (100% steam was introduced for the first 120 minutes of calcination, and air was introduced for the last 60 minutes of calcination) to obtain the acid-treated molecular sieve.

[0205] Mixed slurry: The calcined molecular sieve obtained from the acid treatment step is mixed with deionized water, and dilute hydrochloric acid is added to stabilize the pH of the system at 1.0. The mixture is then added to a high-shear emulsifier, followed by the addition of aluminum hydroxide and heating to 60°C. After uniform dispersion, aluminum dihydrogen phosphate is added in proportion, and the mixture is kept at 60°C for a rapid reaction of 10 min. Then, a mixed solution of copper chelated with ethylenediaminetetraacetic acid and lanthanum chelated with hydroxyethylethylenediaminetriacetic acid is added (the ratio of the total molar amount of copper and lanthanum to the molar amount of phosphorus is 5:1, and the molar ratio of copper to lanthanum is 5:1). The mixture is then reacted at 60°C for another 5 min to obtain a mixed slurry of aluminum phosphate binder and molecular sieve.

[0206] Calcination and molding: Add matrix slurry (obtained by uniformly mixing boehmite, kaolin, and deionized water with a gel solubility index of 25%) to the above-mentioned aluminum phosphate binder and molecular sieve mixture slurry, and continue high-speed emulsification in a high-shear emulsifier for 2 minutes. Then, immediately export it for spray molding and drying. The spray molding conditions are that the furnace temperature of the spray tower is controlled at 580℃ and the temperature of the spray tail gas is controlled at 160℃. After calcining at 600℃ for 2 hours, the resulting material is a catalytic cracking aid.

[0207] The physicochemical properties and catalytic performance of the catalytic cracking co-catalyst are shown in Table 1.

[0208] The physicochemical properties and catalytic performance of the catalytic cracking co-catalysts prepared in this comparative example are shown in Table 1.

[0209] Table 1. Physicochemical and reactivity properties of co-catalysts

[0210]

[0211] As can be seen from the data in the table above, compared with the comparative example, the catalytic cracking co-catalyst provided by the present invention has higher wear resistance, larger pore volume and higher molecular sieve content, and the target product yield of catalytic cracking is higher.

[0212] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the claims of the present invention.

Claims

1. A catalytic cracking co-catalyst with high resistance to thermal abrasion, characterized in that, Includes molecular sieves, matrix, binder, and binder modifier; The molecular sieves having an MFI structure and a pore diameter of less than 0.7 nm account for 50 wt% to 100 wt% of the total molecular sieves. The matrix consists of γ-alumina precursors with a colloidal index ≤50% and clay; The binder is made from phosphorus-containing compounds and aluminum-containing compounds; The raw materials for the binder modifier include multi-chelating ligands, precursors of at least two coordination metals, alcohols, and organic acids; The adhesive, the adhesive modifier, and the matrix are all mixed in a high-shear emulsifier; In the binder modifier, the precursor of the coordination metal is selected from the chloride, sulfate or nitrate of rare earth metals and transition metals; In the binder modifier, the molar ratio of the transition metal to the rare earth metal is 1:5~10; the molar ratio of the multi-chelating ligand to the coordinating metal is 2~5:

1. Based on the total dry weight of the catalytic cracking co-catalyst (100%), the content of the molecular sieve is 20wt%~70wt%, the content of the matrix is ​​10wt%~40wt%, the content of the binder is 10wt%~30wt%, and the content of the binder modifier is 1.5wt%~10wt%. The preparation method of the catalytic cracking co-catalyst with high resistance to thermal abrasion includes the following steps: Acid treatment: Molecular sieves with Na2O content ≤0.1wt% are mixed with deionized water to form a molecular sieve slurry. A mixture of organic and inorganic acids is added until the pH of the molecular sieve slurry is ≤2.0 and the reaction is carried out. After the reaction is completed, the slurry is dried and calcined to obtain the acid-treated molecular sieve. Mixed slurry: The binder modifier and binder are mixed evenly in a high-shear emulsifier, and then the mixture of the acid-treated molecular sieve and deionized water is added and mixed evenly to obtain the mixed slurry; Calcination and molding: Add matrix slurry to the mixed slurry and continue to mix in a high-shear emulsifier for 5 minutes, then perform spray molding and drying, and calcination to obtain the catalytic cracking co-catalyst with high thermal abrasion resistance.

2. The catalytic cracking co-catalyst with high resistance to thermal abrasion as described in claim 1, characterized in that, The catalytic cracking co-catalyst also includes a molecular sieve modifier, which may be the same as or different from the binder modifier.

3. The catalytic cracking co-catalyst with high resistance to thermal abrasion as described in claim 1 or 2, characterized in that, The multi-gnawing chelate is a bi-gnawing chelate with at least two coordinating atoms, and the coordinating atoms are P, O, or N and O.

4. The catalytic cracking co-catalyst with high resistance to thermal abrasion as described in claim 1, wherein the rare earth metal is selected from light rare earth metals.

5. The catalytic cracking co-catalyst with high resistance to thermal abrasion as described in claim 2, characterized in that, The raw materials for the molecular sieve modifier include multi-chelating ligands, rare earth coordination metal precursors, alcohols, and organic acids.

6. The catalytic cracking co-catalyst with high resistance to thermal abrasion as described in claim 5, characterized in that, In the molecular sieve modifier, the molar ratio of the multi-chelating ligand to the rare earth coordination metal is 2~5:

1.

7. The catalytic cracking co-catalyst with high resistance to thermal abrasion as described in claim 1 or 2, characterized in that, The organic acid is one or more of benzoic acid, lactic acid, propionic acid, formic acid, acetic acid, sorbic acid and malic acid; The alcohol is selected from C1 to C3 monohydric alcohols.

8. The catalytic cracking co-catalyst with high resistance to thermal abrasion as described in claim 1, characterized in that, The molar ratio of phosphorus in the phosphorus-containing compound to aluminum in the aluminum-containing compound is 2~10:1; and / or The colloidal index of the γ-alumina precursor is 20%~30%; and / or The mass ratio of the γ-alumina precursor to the clay is 1:0.5~15.

9. The catalytic cracking co-catalyst with high resistance to thermal abrasion as described in claim 2, characterized in that, Based on the dry total weight of the catalytic cracking co-catalyst as 100%, the content of the molecular sieve modifier is 0wt%~2wt%.

10. The catalytic cracking co-catalyst with high resistance to thermal abrasion as described in claim 3, characterized in that, The multi-chelating ligand is selected from any one of aminotrimethylphosphonic acid, hydroxyethylidene diphosphonic acid, ethylenediaminetetramethylidene phosphonic acid, diethylenetriaminepentamethylidene phosphonic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, 2-hydroxyphosphonoacetic acid, bis(1,6-hexylenetriaminepentamethylidene phosphonic acid), hexamethylenediaminetetramethylidene phosphonic acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, and 1,2-ethylenediamine.

11. The catalytic cracking co-catalyst with high resistance to thermal abrasion as described in claim 3, characterized in that, The coordinating atoms in the multi-cheating ligand are P and O.

12. The catalytic cracking co-catalyst with high resistance to thermal abrasion as described in claim 7, characterized in that, The alcohol is selected from one or more of methanol, ethanol and propanol.

13. The catalytic cracking co-catalyst with high resistance to thermal abrasion as described in claim 8, characterized in that, The molar ratio of phosphorus in the phosphorus-containing compound to aluminum in the aluminum-containing compound is 4~8:

1.

14. The catalytic cracking co-catalyst with high resistance to thermal abrasion as described in claim 8, characterized in that, The XRD patterns of the γ-alumina precursor show characteristic peaks around 2θ of 14°, 28°, 38°, and 49°.

15. The catalytic cracking co-catalyst with high resistance to thermal abrasion as described in claim 8, characterized in that, The mass ratio of the γ-alumina precursor to the clay is 1:2~9.

16. The catalytic cracking co-catalyst with high resistance to thermal abrasion as described in claim 1, characterized in that, The preparation of the adhesive modifier includes the following steps: Add alcohol to the organic acid solution of the multi-chelating ligand, mix well, and a multi-chelating ligand solution is obtained; An alcohol is added to an organic acid solution containing precursors of at least two coordination metals, and the mixture is stirred to obtain a precursor solution of coordination metals. The multi-chelating ligand solution and the precursor solution of the coordinating metal were added to a high-shear dispersing emulsifier, and the pH of the system was adjusted to 5-8; thus, a binder modifier was obtained.

17. The catalytic cracking co-catalyst with high resistance to thermal abrasion as described in claim 1, characterized in that, The acid treatment step further includes adding a molecular sieve modifier after the reaction is completed.

18. The catalytic cracking co-catalyst with high resistance to thermal abrasion as described in claim 1, characterized in that, In the acid treatment step, 100% steam is introduced during the first two-thirds of the roasting time, and air is introduced during the last one-third of the time.

19. The catalytic cracking co-catalyst with high resistance to thermal abrasion as described in claim 1, characterized in that, The preparation of the adhesive includes the following steps: A mixed aqueous solution of phosphorus-containing and aluminum-containing compounds is added to a high-shear emulsifier, heated to 60-80°C, and the pH is adjusted to ≤4.0 to carry out the reaction, thereby obtaining the binder.

20. The catalytic cracking co-catalyst with high resistance to thermal abrasion as described in claim 17, characterized in that, The preparation of the molecular sieve modifier includes the following steps: Add alcohol to the organic acid solution of the multi-chelating ligand, mix well, and a multi-chelating ligand solution is obtained; An alcohol is added to an organic acid solution of a rare earth coordination metal precursor, and the mixture is stirred to obtain a rare earth metal precursor solution. The multi-chelate ligand solution and the rare earth metal precursor solution were added to a high-shear dispersing emulsifier, and the pH of the system was adjusted to 5-8 to obtain a molecular sieve modifier.

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