Catalytic cracking aid as well as preparation method and application thereof

Abstract

The invention provides a catalytic cracking aid as well as a preparation method and application thereof. The catalytic cracking aid comprises the following components in percentage by weight: 5 to 15 percent of clay, 5 to 30 percent of aluminum oxide, 40 to 70 percent of magnesium oxide, 5 to 15 percent of rare earth oxide and 5 to 15 percent of calcium oxide, wherein the total weight of the catalytic cracking aid is 100 percent. Compared with the prior art, the preparation method provided by the invention has the advantages that good strength can be ensured without adding an additional binder, the difunctional additive is prepared from common pseudo-boehmite, clay, metal salt and the like on a pilot plant, the process is mature and simple, the cost is relatively low, and industrial production is easy.

Description

Technical Field

[0001] The present invention relates to the field of chemical industry, in particular to a catalytic cracking aid and a preparation method and application thereof. Background Art

[0002] Cracking aids are chemical additives used to improve the efficiency of the cracking reaction during the petroleum refining process. Their primary functions include: 1. Improving cracking efficiency: promoting the breakdown of heavy oil molecules into lighter oils, increasing the yield of lighter products such as gasoline and diesel. 2. Improving product distribution: optimizing cracking products and increasing the proportion of high-value-added products. 3. Enhancing catalyst performance: increasing catalyst activity and selectivity.

[0003] When conventional sulfur transfer additives or anti-vanadium additives are prepared using methods, increasing the magnesium oxide content in the additive will enhance the additive's SOx capture and adsorption capacity and vanadium resistance. However, at the same time, the additive strength decreases with increasing magnesium content, and the wear index increases, making it unable to meet the use requirements of industrial equipment.

[0004] Patent CN111420687B discloses a dual-functional additive for NOx reduction and sulfur transfer in FCC regeneration flue gas, and its preparation method. The additive utilizes a MgF-2-modified catalytic cracking balancer as a carrier, and is loaded with lead, strontium, and a Group VIII metal by an in-situ isomeric impregnation method. Applied to an FCC industrial simulation unit, it can achieve NOx removal of over 85% and SOx removal of over 75%. However, the additive prepared by the impregnation method in CN111420687B suffers from uneven loading of the metals. Furthermore, the additive primarily serves as a dual-functional additive for NOx reduction and sulfur transfer in regeneration flue gas during catalytic cracking, and does not enhance the catalyst's vanadium resistance.

[0005] Patent CN108906135B, technical description: Discloses a dual-function catalytic cracking metal passivator and its preparation method. It is prepared by mixing passivator A and passivator B. Passivator A comprises, by mass percentage, 20-40 wt% antimony trioxide, 40-60 wt% water, 1-10 wt% organic acid, and 2-20 wt% organic amine; passivator B comprises 2-15 wt% lanthanum carbonate, 20-40 wt% water, 5-30 wt% organic acid, and 20-60 wt% organic amine. Passivator A also includes hydrogen peroxide. CN108906135B contains toxic antimony. While it can achieve both nickel passivation and vanadium protection, antimony itself is toxic and poses a serious health hazard if retained in the device or catalyst. Furthermore, the preparation process requires the use of multiple organic compounds and antimony, resulting in high costs. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a dual-functional additive that can reduce SOx emissions from FCC regeneration flue gas and improve the vanadium resistance of the catalyst during the catalytic cracking process. When the functional component content is high, MgO, the strength does not decrease, and the additive has a low wear index, which can meet the use requirements of industrial equipment.

[0007] The bifunctional additive prepared by this method has a low wear index, and the compounding of the additive during the catalytic cracking reaction can not only capture heavy metal vanadium, improve the conversion rate, reduce coke formation, and increase the yield of high value-added products, but also reduce the sulfur content in the flue gas, thereby improving quality and efficiency while protecting the environment.

[0008] Another object of the present invention is to provide a method for preparing the catalytic cracking aid.

[0009] Another object of the present invention is to provide a use of the catalytic cracking aid.

[0010] To achieve the above-mentioned object, in one aspect, the present invention provides a catalytic cracking aid, wherein, based on the total weight of the catalytic cracking aid being 100%, the catalytic cracking aid comprises the following components in weight percentage: 5-15% clay, 5-30% aluminum oxide, 40-70% magnesium oxide, 5-15% rare earth oxide, and 5-15% calcium oxide.

[0011] According to some specific embodiments of the present invention, the catalytic cracking aid contains the following components in weight percentage: 13-15% clay, 10% aluminum oxide, 50-60% magnesium oxide, 5-10% rare earth oxide and 12-15% calcium oxide.

[0012] The present invention provides a bifunctional additive for catalytic cracking and its preparation method. This additive utilizes a combination of rare earth and alkaline earth metals to achieve significant vanadium resistance. The alkaline earth metals are introduced in a unique manner, effectively enhancing the additive's strength and significantly improving its physical and chemical properties and evaluation results. The resulting additive significantly enhances the vanadium resistance of the system's catalyst, increasing conversion rates and optimizing product distribution.

[0013] According to some specific embodiments of the present invention, the rare earth is selected from one or a mixture of La and Ce.

[0014] According to some specific embodiments of the present invention, the clay is selected from a mixture of one or more of kaolin, halloysite, and montmorillonite.

[0015] On the other hand, the present invention also provides a method for preparing the catalytic cracking aid, wherein the method comprises the following steps:

[0016] (a) mixing water, pseudo-boehmite and acid to obtain a slurry;

[0017] (b) mixing slurry a with a magnesium compound, a rare earth component, and clay to obtain slurry b;

[0018] (c) mixing melamine, formaldehyde and a calcium-containing component, and then adding a sulfonating agent for sulfonation to obtain a calcium-containing gel complex c;

[0019] (d) adding the calcium-containing gel complex c to the slurry b to obtain slurry d;

[0020] (e) preparing microsphere solids from the slurry in step (d), and then calcining the microsphere solids to obtain the catalytic cracking aid.

[0021] According to some specific embodiments of the present invention, the mass amount of the acid in step (a) is 15-25% of the weight of the pseudo-boehmite dry basis (Al2O3).

[0022] According to some specific embodiments of the present invention, the acid in step (a) is hydrochloric acid and / or nitric acid.

[0023] According to some specific embodiments of the present invention, the solid content of the slurry a obtained in step (a) is 20%-25% by weight.

[0024] According to some specific embodiments of the present invention, step (a) comprises mixing water, pseudo-boehmite and acid and aging the mixture at 40-80° C. to obtain a slurry.

[0025] According to some specific embodiments of the present invention, step (a) comprises mixing water, pseudo-boehmite and acid and aging the mixture at 50-70° C. to obtain a slurry.

[0026] According to some specific embodiments of the present invention, step (a) comprises mixing water, pseudo-boehmite and acid and aging the mixture at 60-70° C. to obtain a slurry.

[0027] According to some specific embodiments of the present invention, the aging time in step (a) is 15-60 min.

[0028] According to some specific embodiments of the present invention, the aging time in step (a) is 20-50 min.

[0029] According to some specific embodiments of the present invention, the aging time in step (a) is 30-40 minutes.

[0030] According to some specific embodiments of the present invention, the magnesium compound in step (b) is a mixture of one or more of magnesium chloride, magnesium nitrate, magnesium oxide and magnesium hydroxide.

[0031] According to some specific embodiments of the present invention, the rare earth component in step (b) is selected from a mixture of one or more rare earth metal salts and rare earth oxides.

[0032] According to some specific embodiments of the present invention, the metal salt of rare earth in step (b) is selected from a mixture of one or more of rare earth chlorides, rare earth nitrates and rare earth carbonates.

[0033] According to some specific embodiments of the present invention, the rare earth metal salt in step (b) is selected from a mixture of one or more of lanthanum chloride, lanthanum carbonate, lanthanum nitrate, cerium nitrate, cerium chloride and cerium carbonate.

[0034] According to some specific embodiments of the present invention, in step (c), the weight ratio of formaldehyde to melamine is (0.6-1.0):1.

[0035] According to some specific embodiments of the present invention, in step (c), the weight ratio of formaldehyde to melamine is (0.8-1.0):1.

[0036] According to some specific embodiments of the present invention, in step (c), the weight ratio of the sulfonating agent to melamine is (0.7-1.5):1.

[0037] According to some specific embodiments of the present invention, in step (c), the weight ratio of the sulfonating agent to melamine is (0.9-1.4):1.

[0038] According to some specific embodiments of the present invention, in step (c), the weight ratio of the sulfonating agent to melamine is (0.9-1.5):1.

[0039] According to some specific embodiments of the present invention, the sulfonating agent in step (c) is sodium bisulfite and / or sodium sulfite.

[0040] According to some specific embodiments of the present invention, in step (c), the calcium-containing component is calculated as calcium oxide, and the mass ratio of calcium oxide to melamine is (0.5-1.7):1.

[0041] According to some specific embodiments of the present invention, the reaction time in step (c) is 1-2 h.

[0042] According to some specific embodiments of the present invention, the calcium-containing component in step (c) is selected from a mixture of one or more of calcium salts, calcium oxide and calcium hydroxide.

[0043] According to some specific embodiments of the present invention, in step (c), the calcium salt is selected from calcium chloride and / or calcium nitrate.

[0044] According to some specific embodiments of the present invention, the calcination temperature in step (e) is 500-700°C.

[0045] According to some specific embodiments of the present invention, the calcination time in step (e) is 1-2 hours.

[0046] According to some specific embodiments of the present invention, step (e) comprises spray-drying the slurry d to obtain solid microspheres.

[0047] When using a conventional additive preparation method, an increase in the magnesium content in the additive will enhance the additive's ability to capture and adsorb SOx, but at the same time, the additive's strength will decrease with the increase in magnesium content, and the wear index will increase, making it unable to meet the use requirements of industrial equipment. The present invention provides a bifunctional additive and preparation method for catalytic cracking, in which alkaline earth metal calcium is introduced in a special gel manner, which can not only effectively enhance the strength of the additive, but also the additive adopts a combination of alkaline earth metal and rare earth, so that the surplus alkaline earth metal and rare earth have excellent vanadium capture effects at the same time. Its high magnesium content will form magnesium-rich magnesium-aluminum spinel with active aluminum, giving the additive an SOx removal effect. Compounding the additive of the present invention can not only significantly enhance the vanadium resistance of the system catalyst, but also reduce coke formation and reduce the SOx content in the flue gas while increasing the conversion rate and total liquid yield.

[0048] In another aspect, the present invention also provides the use of the catalytic cracking aid in a catalytic cracking reaction.

[0049] In the present invention, the weight on a dry basis refers to the weight after calcination at 800° C. for 2 hours.

[0050] In the present invention, the solid content of a substance refers to the ratio of the weight after high-temperature calcination to the weight before calcination, that is, the solid content of the substance = 100% - the water content of the substance.

[0051] In the present invention, the catalyst-oil ratio refers to the mass ratio of the catalyst to the feedstock oil.

[0052] In the present invention, unless otherwise specified, ppm means ppm by weight.

[0053] In summary, the present invention provides a catalytic cracking aid, its preparation method, and application. The catalytic cracking aid of the present invention has the following advantages:

[0054] The bifunctional additive of the present invention combines rare earth and alkaline earth metals and exhibits excellent vanadium capture. The resulting compound not only significantly enhances the vanadium resistance of the system catalyst, but also reduces coke formation and SOx levels in flue gas while increasing conversion and total liquid yield. Compared to existing technologies, the preparation method of the bifunctional additive provided by the present invention ensures excellent strength without the addition of an additional binder. The additive is prepared in a pilot plant using common pseudo-boehmite, clay, and metal salts, resulting in a mature, simple process with low cost and amenable to industrial production.

[0055] In the preparation method of the dual-functional additive, alkaline earth metals are introduced in a unique manner, effectively enhancing the additive's strength and significantly improving its physical and chemical properties and evaluation results. This not only improves the additive's sulfur transfer performance, but also achieves a wear index that meets the requirements of industrial equipment. DETAILED DESCRIPTION

[0056] The following describes in detail the implementation process of the present invention and the beneficial effects produced by specific embodiments, which is intended to help readers better understand the essence and characteristics of the present invention and is not intended to limit the scope of implementation of this case.

[0057] In the following examples, the analysis and evaluation methods of the embodiments and comparative examples of the present invention are as follows:

[0058] 1. The specific surface area and pore volume of the bifunctional additive were determined according to the standard method (GB / T5816-1995); the crystallinity retention and wear index were determined according to the standard method RIPP146-90 (see Petrochemical Analytical Methods (RIPP Test Method)), edited by Yang Cuiding, Science Press, 1990 edition).

[0059] 2. The contents of RE2O3, Al2O3, MgO, CaO and V in the bifunctional additive / catalyst mixture were determined by X-ray fluorescence.

[0060] 3. The heavy metal vanadium-contaminated catalyst was contaminated according to the following steps: Appropriate amounts of oxalic acid, ammonium metavanadate, and deionized water were placed on a hot plate and heated to 300°C with stirring for 30 minutes. After the ammonium metavanadate was completely dissolved, the heat was turned off to obtain a vanadium-contaminated solution. The catalyst was then impregnated with different concentrations of the vanadium-contaminated solution using an equal volume impregnation method. After uniform stirring, the catalyst was heated to 70°C and dried for 4 hours, followed by drying at 100°C for 12 hours. The dried sample was calcined in a muffle furnace at 550°C for 2 hours to obtain the vanadium-contaminated catalyst.

[0061] 4. All catalysts used for evaluation must be aged at 800°C and 100% steam for 4 hours.

[0062] 5. Advanced Catalytic Cracking Evaluation Unit (ACE): The catalytic cracking evaluation conditions are to place the pretreated catalyst sample in the ACE experimental reactor, the reaction temperature is 530 ° C, the catalyst dosage is 9g, the reaction raw material is 3 million tons / year of heavy catalyst raw material of Lanzhou Petrochemical Company, and the catalyst-to-oil ratio is 5.0.

[0063] 2. Source of raw materials or equipment:

[0064] 1. Kaolin, China Kaolin Company, kaolinite content 86% by weight, loss on ignition 27.91% by weight, particle size D(V, 0.5), um = 2.131; pseudo-boehmite, loss on ignition 34.15% by weight; hydrochloric acid, analytical grade (concentration 37%), Sichuan Xilong Chemical Co., Ltd.

[0065] 2. Melamine, formaldehyde, lanthanum carbonate, lanthanum chloride heptahydrate, cerium nitrate hexahydrate, magnesium oxide, sodium bisulfite, calcium chloride, and calcium oxide were of analytical grade and obtained from Sinopharm Chemical Reagent Co., Ltd.

[0066] Example 1

[0067] (a) 8 g of pseudo-boehmite was added to 270 g of deionized water, stirred for 10 minutes, and then 1.1 mL of hydrochloric acid was added dropwise. After further stirring for 30 minutes, the mixture was heated in a water bath to 60° C. and aged for 30 minutes to obtain slurry a; (b) 70 g of magnesium oxide, 21 g of lanthanum carbonate, 13 g of cerium nitrate hexahydrate, and 7 g of kaolin were weighed and stirred for 30 minutes to obtain slurry b; (c) 10 g of melamine, 8 g of formaldehyde, and 10 g of calcium chloride were added to 100 g of water, stirred and heated to 70° C., and then 9 g of sodium bisulfite was added and stirred for 1.5 hours to obtain a calcium gel complex c; (d) the prepared complex c was added to slurry b and stirred for 30 minutes to obtain slurry d; (e) the slurry d was then spray-dried to obtain microsphere solids, and the microspheres were then calcined at 650° C. for 2 hours to obtain a bifunctional additive for catalytic cracking, and the obtained sample was recorded as Z1.

[0068] Examples 2-5

[0069] The bifunctional additives Z2 to Z5 were prepared according to the method of Example 1, wherein the preparation process, product composition and wear index are listed in Table 1.

[0070] Table 1 Preparation process of Examples 1 to 5, proportion of components in the products and wear index

[0071]

[0072]

[0073] Comparative Example 1

[0074] This comparative example is used to illustrate the preparation process of the comparative bifunctional additive D1. (1) 45 g of pseudo-boehmite was weighed and added to 200 g of deionized water. After stirring for 10 minutes, 9.6 mL of hydrochloric acid was added dropwise and continued to stir for 30 minutes. The mixture was heated in a water bath to 60°C and aged for 30 minutes to obtain slurry a; (2) 60 g of magnesium oxide, 21 g of lanthanum carbonate and 13 g of cerium nitrate hexahydrate were weighed and added to the solution a. After stirring for 30 minutes, slurry b was obtained; (3) 7 g of kaolin and 10 g of calcium chloride were weighed and added to 50 g of deionized water and stirred for 10 minutes to obtain slurry c; (4) slurry c was added to slurry b to obtain slurry d, and slurry d was then spray-dried to obtain microsphere solids; the microsphere solids were calcined at 650°C for 2 hours to obtain an additive. The obtained sample was recorded as D1, and its wear index was measured to be 5.8%.

[0075] Comparative Example 2

[0076] This comparative example is used to illustrate the preparation process of the comparative bifunctional additive D2. (1) 46 g of pseudo-boehmite was added to 385 g of deionized water, stirred for 3 minutes, and then 6.1 mL of hydrochloric acid was added dropwise for 30 seconds. After further stirring for 30 minutes, the mixture was heated in a water bath to 60° C. and aged for 1 hour to obtain slurry a; (2) 40 g of magnesium oxide was weighed and added to the slurry a, and stirred for 30 minutes to obtain slurry b; (3) 7 g of kaolin and 63 g of cerium nitrate hexahydrate were weighed and added to the slurry b, and stirred for 30 minutes to obtain slurry c, which was then spray-dried to obtain microsphere solids; the microsphere solids were calcined at 700° C. for 2 hours to obtain the additive. The obtained sample was recorded as D2, and its wear index was 6.1%.

[0077] Comparative Example 3

[0078] This comparative example is used to illustrate the preparation process of the comparative bifunctional additive D3. According to the conventional method disclosed in CN103785428A, a compound containing magnesium oxide, aluminum oxide and a phosphate aluminum compound was prepared: (1) 54.3 g of pseudo-boehmite was weighed and added to 400 g of deionized water, stirred for 3 minutes, and then 7.5 mL of hydrochloric acid was added dropwise and stirred for 30 minutes. The mixture was heated in a water bath to 60°C and aged for 1 hour to obtain slurry a; (2) 50 g of magnesium oxide was weighed and added to the slurry a, stirred for 30 minutes to obtain slurry b; (3) 15 g of kaolin and 14.98 g of a phosphate aluminum compound with a mass ratio of phosphorus to aluminum of 1:3 were weighed and added to the slurry b, stirred for 30 minutes; slurry c was spray-dried to obtain microsphere solids; the microsphere solids were calcined at 700°C for 2 hours to obtain the additive. The obtained sample was recorded as D3, and its wear index was 5.3%.

[0079] The parameters of the comparative example are shown in Table 2 below:

[0080] Table 2 Preparation process, product composition and wear index of Comparative Examples 1 to 3

[0081]

[0082]

[0083] Test example

[0084] Evaluation conditions and methods: A catalytic cracking catalyst currently in industrial use was selected as the main catalyst (blank agent, industrial agent LDC-200 of Lanzhou Petrochemical Catalyst Plant), denoted as B, and the auxiliary agent and the main catalyst were mixed according to the ratio of bifunctional auxiliary agent: main catalyst = 1:9. The mixed catalyst was subjected to vanadium contamination of 6000 ppm by the above-mentioned pollution method, and the catalytic cracking performance was evaluated on the ACE evaluation device. The evaluation results of its vanadium resistance performance are shown in Tables 3-1 and 3-2, and the sulfur transfer performance is shown in Tables 4-1 and 4-2.

[0085] Table 3-1 Evaluation results of vanadium resistance performance of compound dual-functional additives

[0086]

[0087]

[0088] Table 3-2 Evaluation results of vanadium resistance performance of compound dual-functional additives

[0089]

[0090] Table 4-1 Evaluation results of sulfur transfer performance of compound dual-functional additives

[0091] serial number Blank Example 1 Example 2 Example 3 catalyst 100B 90B+10Z1 90B+10Z2 90B+10Z3 <![CDATA[H2S,ppm]]> 3500 5100 4600 4800

[0092] Table 4-2 Evaluation results of sulfur transfer performance of compound dual-functional additives

[0093] serial number Example 4 Example 5 Comparative Example 1 Comparative Example 2 Comparative Example 3 catalyst 90B+10Z4 90B+10Z5 90B+10D1 90B+10D2 90B+10D3 <![CDATA[H2S,ppm]]> 4900 4700 4100 3800 4000

[0094] In the present invention, conversion rate = gasoline yield + liquefied gas yield + dry gas yield + coke yield, light oil yield = gasoline yield + diesel yield, total liquid yield = gasoline yield + diesel yield + liquefied gas yield, and coking factor = ((100-conversion rate) × coke yield) / conversion rate.

[0095] The bifunctional additives prepared according to the present invention in the examples shown in Table 1 exhibit good strength despite containing high MgO content, with a wear index ranging from 0.7 to 1.1%. In contrast, the additives prepared in the comparative examples have a wear index ranging from 5.3 to 6.1%. This demonstrates that the introduction of calcium in the form of a calcium gel complex significantly enhances the additive's strength.

[0096] It can be seen from the data in Table 3-1 and Table 3-2 that the addition of the bifunctional additive of the present invention to the main catalyst of catalytic cracking can effectively slow down the damage of heavy metal vanadium to the catalytic cracking catalyst, significantly improve the conversion rate, increase the light oil yield and total liquid yield, and at the same time reduce coke formation.

[0097] Combining the data in Tables 3-1 and 3-2 with Tables 4-1 and 4-2, it can be seen that compounding the bifunctional additive provided by the present invention for catalytic cracking significantly improves the catalyst's vanadium resistance and exhibits excellent sulfur transfer performance. After compounding the additive, the H2S content in the product gas significantly increased, indicating that compounding the bifunctional additive can effectively reduce SO2 emissions in flue gas and achieve sulfur transfer. While ensuring the additive has a low wear index and strength that meets the requirements of catalytic cracking units, it also has a high magnesium oxide content, which is key to the additive's sulfur transfer performance.

[0098] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art may make various corresponding changes and modifications based on the present invention, but these corresponding changes and modifications should all fall within the scope of protection of the claims of the present invention.

Claims

1. A catalytic cracking aid, wherein: Taking the total weight of the catalytic cracking aid as 100%, the catalytic cracking aid contains the following components in weight percentage: 5-15% clay, 5-30% aluminum oxide, 40-70% magnesium oxide, 5-15% rare earth oxide and 5-15% calcium oxide.

2. The catalytic cracking aid according to claim 1, wherein The rare earth is selected from one or a mixture of La and Ce; the clay is selected from one or a mixture of one or more of kaolin, halloysite, and montmorillonite.

3. The method for preparing the catalytic cracking aid according to claim 1 or 2, wherein: The method comprises the following steps: (a) mixing water, pseudo-boehmite and acid (preferably hydrochloric acid) to obtain a slurry (preferably the slurry has a solid content of 20% to 25% by weight); (b) mixing the slurry a with a magnesium compound (preferably a mixture of one or more of magnesium chloride, magnesium nitrate, magnesium oxide and magnesium hydroxide), a rare earth component (preferably a mixture of one or more selected from rare earth metal salts and rare earth oxides), and clay to obtain slurry b; (c) mixing melamine, formaldehyde and a calcium-containing component (preferably a mixture of one or more of a calcium salt (preferably calcium chloride and / or calcium nitrate), calcium oxide and calcium hydroxide), and then adding a sulfonating agent for sulfonation to obtain a calcium-containing gel complex c; (d) adding the calcium-containing gel complex c to the slurry b to obtain slurry d; (e) preparing microsphere solids from the slurry in step (d), and then calcining the microsphere solids to obtain the catalytic cracking aid.

4. The preparation method according to claim 3, wherein The mass amount of the acid used in step (a) is 15-25% of the dry weight of the pseudo-boehmite.

5. The preparation method according to claim 3 or 4, wherein In step (c), the weight ratio of formaldehyde to melamine is (0.6-1.0):1; the weight ratio of the sulfonating agent to melamine is (0.7-1.5):1; and the mass ratio of the calcium-containing component, calculated as calcium oxide, to melamine is (0.5-1.7):

1.

6. The preparation method according to any one of claims 3 to 5, wherein In step (b), after melamine, formaldehyde and calcium-containing components are mixed, the mixed solution is heated to 60-90° C., and then a sulfonating agent is added to carry out sulfonation.

7. The preparation method according to any one of claims 3 to 6, wherein The reaction time in step (c) is 1-2 h.

8. The preparation method according to any one of claims 3 to 7, wherein The calcination temperature in step (e) is 500-700° C. (preferably the calcination time is 1-2 h).

9. The preparation method according to any one of claims 3 to 8, wherein Step (e) comprises spray drying the slurry d to obtain microsphere solids.

10. Use of the catalytic cracking aid according to claim 1 or 2 in a catalytic cracking reaction.

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