CN-121972212-A - Catalytic cracking catalyst and preparation method and application thereof

CN121972212ACN 121972212 ACN121972212 ACN 121972212ACN-121972212-A

Abstract

The invention relates to the field of preparation of catalytic cracking catalysts, and discloses a catalytic cracking catalyst, a preparation method and application thereof. The catalyst comprises a binder, clay and a molecular sieve-metal oxide composite material, wherein the molecular sieve-metal oxide composite material is of a core-shell structure, a molecular sieve is used as a core phase, a composite metal oxide is used as a shell phase, metals in the composite metal oxide comprise a first metal and a second metal, the first metal is aluminum, and the second metal is selected from at least one of iron, manganese and cobalt, and the molar ratio of the first metal to the second metal is 1:0.5-10 based on elements. The catalytic cracking catalyst provided by the invention is applied to the heavy oil catalytic cracking reaction, and has higher low-carbon olefin yield and lower coke yield.

Inventors

SONG HAITAO
SHA YUCHEN
WANG PENG
HAN LEI
GAO DI
ZHOU XIANG

Assignees

中国石油化工股份有限公司
中石化石油化工科学研究院有限公司

Dates

Publication Date: 20260505
Application Date: 20241031

Claims (13)

1. A catalytic cracking catalyst, wherein the catalyst comprises a binder, clay, and a molecular sieve-metal oxide composite; The molecular sieve-metal oxide composite material is in a core-shell structure, a molecular sieve is taken as a core phase, a composite metal oxide is taken as a shell phase, metals in the composite metal oxide comprise a first metal and a second metal, the first metal is aluminum, and the second metal is selected from at least one of iron, manganese and cobalt; wherein the molar ratio of the first metal to the second metal is 1:0.5-10 in terms of elements.
2. The catalyst according to claim 1, wherein, The molar ratio of the first metal to the second metal is 1:1-7 in terms of elements; Preferably, the molecular sieve is present in an amount of 50 to 85wt%, preferably 60 to 75wt%, and the composite metal oxide is present in an amount of 15 to 50wt%, preferably 25 to 40wt%, based on the total mass of the composite material.
3. The catalyst according to claim 1 or 2, wherein, The SiO 2 /Al 2 O 3 molar ratio of the molecular sieve is not more than 100, preferably 20-60; Preferably, the molecular sieve has a D 90 of no more than 10 μm, preferably 0.5-3 μm; Preferably, the molecular sieve is selected from at least one of MFI-type molecular sieves, preferably ZSM-5 molecular sieves; preferably, the composite material also contains phosphorus element; Preferably, the composite material contains 50-84wt%, preferably 60-75wt%, 15-40wt%, preferably 23-35wt% of composite metal oxide and 1-10wt%, preferably 2-8wt% of phosphorus based on P 2 O 5 , based on the total mass of the composite material.
4. A catalyst according to any one of claim 1 to 3, wherein, The clay content is 10-50wt%, preferably 15-30wt%, the binder content is 20-40wt%, preferably 25-40wt%, and the molecular sieve-metal oxide composite material content is 10-70wt%, preferably 30-60wt%, based on the dry weight of the catalyst; preferably, the clay is selected from at least one of kaolin, halloysite, rectorite, and montmorillonite; preferably, the binder is alumina.
5. A method for preparing a catalytic cracking catalyst, the method comprising the steps of: (1) Carrying out first mixing on the slurry containing the molecular sieve and an inorganic alkali source to obtain first mixed slurry; (2) Adding a solution containing a first metal compound and a second metal compound into the first mixed slurry to obtain a second mixed slurry, wherein the first metal is aluminum, and the second metal is at least one of manganese, iron and cobalt; (3) Carrying out precipitation reaction on the second mixed slurry to obtain a solid product; performing first roasting on the solid product to obtain a molecular sieve-metal oxide composite material; (4) Pulping the molecular sieve-metal oxide composite material obtained in the step (3), the binder precursor and clay in the presence of a solvent, and then spray-drying and second roasting; wherein, the mol ratio of the first metal compound to the second metal compound is 1:0.5-10 based on metal elements.
6. The method of claim 5, wherein, The SiO 2 /Al 2 O 3 molar ratio of the molecular sieve is not more than 100, preferably 20-60; Preferably, the molecular sieve has a D 90 of no more than 10 μm, preferably 0.5-3 μm; Preferably, the molecular sieve is selected from at least one of MFI-type molecular sieves, preferably ZSM-5 molecular sieves.
7. The method according to claim 5 or 6, wherein, The mass ratio of the molecular sieve to the inorganic alkali source is 1:0.8-2, preferably 1:1.1-1.5; Preferably, the concentration of molecular sieve in the slurry containing molecular sieve is 0.2-1wt%; Preferably, the inorganic alkali source is a carbonate and/or hydroxide, preferably at least one selected from NaOH, KOH, na 2 CO 3 、K 2 CO 3 and (NH 4 ) 2 CO 3 ).
8. The method according to any one of claims 5-7, wherein, The molar ratio of the first metal compound to the second metal compound is 1:1-7 based on metal elements; Preferably, the molecular sieve, the first metal compound and the second metal compound are used in such an amount that the composite material is produced, the molecular sieve content is 50 to 85wt%, preferably 60 to 75wt%, and the composite metal oxide content is 15 to 50wt%, preferably 25 to 40wt%, based on the total mass of the composite material.
9. The method according to any one of claims 5-8, wherein, The preparation process of the second mixed slurry in the step (2) comprises the steps of adding a solution containing a first metal compound and a second metal compound to the stirred first mixed slurry; Preferably, the pH of the first mixed slurry is controlled to be 8-13, preferably 9-10, all the time in the preparation process of the second mixed slurry; preferably, the rate of addition is no greater than 60mL/h, preferably 40-60mL/h; Preferably, the stirring rate is not less than 700rpm, preferably 700-1500rpm.
10. The method according to any one of claims 5-9, wherein, The conditions of the precipitation reaction in the step (3) comprise the temperature of 25-50 ℃ and the time of 0.5-1.5h; Preferably, the conditions of the first roasting in the step (3) comprise the temperature of 450-600 ℃ and the time of 2-8h.
11. The method according to any one of claims 5-10, wherein, The molecular sieve-metal oxide composite material, the binder precursor and the clay are used in amounts such that the catalyst is prepared with a clay content of 10-50wt%, preferably 15-30wt%, a binder content of 20-40wt%, preferably 25-40wt%, and a molecular sieve-metal oxide composite material content of 10-70wt%, preferably 30-60wt%, based on the dry weight of the catalyst; preferably, the clay is selected from at least one of kaolin, halloysite, rectorite, and montmorillonite; Preferably, the binder precursor is selected from at least one of pseudo-boehmite, hydrated alumina having a boehmite structure, hydrated alumina having a gibbsite structure, hydrated alumina having a bayerite structure, gamma-alumina, eta-alumina, theta-alumina, and x-alumina.
12. The method according to any one of claims 5-11, wherein, The method further comprises the steps of carrying out phosphorus modification on the molecular sieve-metal oxide composite material to obtain a phosphorus-containing molecular sieve-metal oxide composite material; preferably, the phosphorus modification comprises contacting the molecular sieve-metal oxide composite material with an impregnating solution containing a phosphorus-containing compound, and then drying and third roasting; Preferably, the phosphorus-containing compound is used in an amount such that the resulting composite material has a molecular sieve content of 50 to 84wt%, preferably 60 to 75wt%, a composite metal oxide content of 15 to 40wt%, preferably 23 to 35wt%, and a phosphorus content of 1 to 10wt%, preferably 2 to 8wt%, calculated as P 2 O 5 , based on the total mass of the composite material; Preferably, the phosphorus-containing compound is selected from at least one of ammonium hydrogen phosphate, diammonium hydrogen phosphate, monoammonium phosphate, and ammonium phosphate.
13. Use of the catalytic cracking catalyst according to any one of claims 1 to 4 or the catalytic cracking catalyst prepared by the preparation method according to any one of claims 5 to 12 in a catalytic cracking reaction of heavy oil.

Description

Catalytic cracking catalyst and preparation method and application thereof Technical Field The invention relates to the field of preparation of catalytic cracking catalysts, in particular to a catalytic cracking catalyst, a preparation method and application thereof. Background Ethylene and propylene are important chemical raw materials, with the development of society, the market demand of ethylene and propylene in China is rapidly increased, the import amount of ethylene and propylene and downstream products thereof is increased year by year, and the oil refining industry is promoted to develop towards the advanced processing direction. In recent years, the problems of climate warming and the like become more serious with environmental changes, and further reduction of coke selectivity is required in the petroleum refining process. The trend of crude oil in the world is increasing, so that the desire of refineries to convert heavy residual oil into light and high-cost products is increasing, and therefore, how to develop an efficient novel heavy oil cracking catalyst is the key of the heavy oil conversion problem. Zeolite molecular sieves are a class of crystalline aluminosilicates having a particular pore structure, suitable adjustable acidity, large specific surface area and excellent hydrothermal stability, and therefore find important applications in the petrochemical field. In general, however, zeolite molecular sieve surfaces have rich acid centers, which can lead to the formation of large amounts of coke on the surface during hydrocarbon cracking, thereby reducing the molecular sieve material activity. The surface properties, acidity, pore structure and the like of the molecular sieve material are modulated by modifying the molecular sieve material to obtain more excellent catalytic performance, and generally, conventional treatment modes comprise element modification, construction of a hierarchical pore structure and the like. CN114425418a proposes an application of a core-shell molecular sieve in a heavy oil catalytic cracking catalyst, wherein the core phase of the core-shell molecular sieve is a ZSM-5 molecular sieve, and the shell layer is a beta molecular sieve. The catalyst prepared by combining the molecular sieve with a carrier and a binder is used for heavy oil catalytic cracking, has higher conversion rate and low-carbon olefin yield, but has more complicated synthesis steps. Therefore, there is a need to develop a catalytic cracking catalyst having a simple preparation method and excellent catalytic performance. Disclosure of Invention The invention aims to overcome the problems in the prior art and provides a catalytic cracking catalyst, and a preparation method and application thereof. The catalytic cracking catalyst provided by the invention is applied to the heavy oil catalytic cracking reaction, and has higher low-carbon olefin yield and lower coke yield. In order to achieve the above object, a first aspect of the present invention provides a catalytic cracking catalyst comprising a binder, clay, and a molecular sieve-metal oxide composite material; The molecular sieve-metal oxide composite material is in a core-shell structure, a molecular sieve is taken as a core phase, a composite metal oxide is taken as a shell phase, metals in the composite metal oxide comprise a first metal and a second metal, the first metal is aluminum, and the second metal is selected from at least one of iron, manganese and cobalt; wherein the molar ratio of the first metal to the second metal is 1:0.5-10 in terms of elements. In a second aspect, the present invention provides a method for preparing a catalytic cracking catalyst, the method comprising the steps of: (1) Carrying out first mixing on the slurry containing the molecular sieve and an inorganic alkali source to obtain first mixed slurry; (2) Adding a solution containing a first metal compound and a second metal compound into the first mixed slurry to obtain a second mixed slurry, wherein the first metal is aluminum, and the second metal is at least one of manganese, iron and cobalt; (3) Carrying out precipitation reaction on the second mixed slurry to obtain a solid product; performing first roasting on the solid product to obtain a molecular sieve-metal oxide composite material; (4) Pulping the molecular sieve-metal oxide composite material obtained in the step (3), the binder precursor and clay in the presence of a solvent, and then spray-drying and second roasting; wherein, the mol ratio of the first metal compound to the second metal compound is 1:0.5-10 based on metal elements. The third aspect of the invention provides an application of the catalytic cracking catalyst of the first aspect or the catalytic cracking catalyst prepared by the preparation method of the second aspect in the catalytic cracking reaction of heavy oil. Through the technical scheme, the beneficial effects of the invention include: The molecular sieve-metal oxide comp