A cracking catalyst, its preparation method and use

Abstract

The application provides a cracking catalyst and a preparation method and application thereof, and the preparation method comprises the following steps: preparing seeds by controlling pH value and a two-stage crystallization process, taking a molecular sieve material as raw material, and preparing a mother liquor by dissolving aluminum and silicon treatment and mixing of the two by adjusting the proportion of each raw material, then through aging treatment and hydrothermal crystallization treatment, a 13X molecular sieve with a high silicon to aluminum ratio, a high specific surface area and a high pore volume and a multi-level pore structure is prepared; the 13X molecular sieve is immersed in a carbon precursor solution for carbon modification treatment, immersed in a platinum precursor solution for treatment, pre-baked in an inert gas atmosphere, and calcined in an air atmosphere, so that platinum is combined with the framework of the 13X molecular sieve in the form of highly dispersed platinum metal oxide and platinum metal, forming a platinum-containing 13X molecular sieve cracking catalyst with stable structure and high catalytic activity, and the problems of low stability of the cracking catalyst in the prior art and lack of resource utilization of molecular sieve waste in the preparation process are solved.

Description

Technical Field

[0001] This invention relates to the field of catalytic materials technology, and more specifically, to a cracking catalyst, its preparation method, and its application. Background Technology

[0002] In the oil refining and petrochemical industries, cracking is a crucial process for converting heavier hydrocarbon feedstocks into more economically valuable lighter compounds, such as petroleum fuels, olefins, and aromatics. The core of cracking lies in using highly efficient catalysts to facilitate the reaction. Traditional cracking catalysts typically include acidic materials, such as zeolite molecular sieves. However, over time, these catalysts deactivate due to factors such as carbon buildup and metal deposition, requiring replacement, leading to production interruptions and the generation of molecular sieve waste. Furthermore, given the finite nature of resources and increasing environmental pressures, developing more economical, environmentally friendly, efficient, and stable cracking catalyst preparation processes is of great significance. Summary of the Invention

[0003] The main objective of this invention is to provide a cracking catalyst, its preparation method, and its application, in order to solve the problems of low stability of existing cracking catalysts and the lack of resource utilization of molecular sieve waste in the preparation process.

[0004] To achieve the above objectives, according to one aspect of the present invention, a method for preparing a cracking catalyst is provided, comprising the following steps:

[0005] Step S1: A silicon source and water are mixed to obtain a silicon-containing material, and an aluminum source and water are mixed to obtain an aluminum-containing material. The aluminum-containing material and the silicon-containing material are stirred and mixed to obtain a first gel-like mother liquor. The pH value of the first gel-like mother liquor is adjusted to 8.5-12.5 using sodium hydroxide. Then, a two-stage hydrothermal crystallization treatment is performed to obtain a solution containing 13X molecular sieve seed crystals. The crystallization temperature of the first stage hydrothermal crystallization treatment is 20-60℃, and the crystallization temperature of the second stage hydrothermal crystallization treatment is 80-120℃.

[0006] Step S2: Mix the molecular sieve material with sodium carbonate at a mass ratio of 1:0.5 to 1:5, calcine at 550 to 800°C for 60 to 120 minutes, dissolve the calcined product with a monobasic acid of 10% to 35% by mass, filter to obtain aluminum-rich liquid and residue, stir and mix the residue with sodium hydroxide and water at a mass ratio of 5 to 100:40 to 60:50 to 400 to dissolve the residue, filter to obtain silicon-rich liquid, mix the aluminum-rich liquid and silicon-rich liquid to obtain the second gel-like mother liquor;

[0007] Step S3: The solution containing 13X molecular sieve seed crystals is mixed with the second gel-like mother liquor and then aged. Then, hydrothermal crystallization is carried out at 60-105℃ to obtain 13X molecular sieve.

[0008] Step S4: The 13X molecular sieve is soaked in a carbon precursor solution to obtain a 13X molecular sieve impregnated with the carbon precursor solution. The 13X molecular sieve impregnated with the carbon precursor solution is then heat-treated at 600-900℃ under an inert gas atmosphere to obtain a carbon-modified 13X molecular sieve.

[0009] Step S5: The carbon-modified 13X molecular sieve is mixed with the platinum precursor solution, stirred and filtered to obtain the carbon-modified 13X molecular sieve impregnated with the platinum precursor solution. The carbon-modified 13X molecular sieve impregnated with the platinum precursor solution is pre-calcined in an inert gas atmosphere at 450-550℃ and then calcined in an air atmosphere at 700-900℃ to obtain the cracking catalyst.

[0010] Furthermore, the silicon source is selected from one or more of silica sol, tetraethyl orthosilicate, coarse-porous silica gel, silica powder, fly ash, and silica; the aluminum source is selected from one or more of sodium aluminate, boehmite, aluminum sulfate, and aluminum nitrate; the weight ratio of silicon source to aluminum source is (0.01 to 1.25):1.

[0011] Preferably, the mass fraction of silicon source in the silicon-containing material is 2% to 50%.

[0012] Preferably, the silicon source and water are stirred at 20–60°C for 0.1–12 hours to obtain a silicon-containing material.

[0013] Preferably, the mass fraction of aluminum source in the aluminum-containing material is 15% to 60%.

[0014] Preferably, aluminum source and water are stirred at 20–60°C for 0.1–12 hours to obtain aluminum-containing material.

[0015] Preferably, the mixture is stirred and mixed at 20–100°C for 0.1–24 h to obtain the first gel-like mother liquor.

[0016] Furthermore, the pH value of the first gel-like mother liquor is 11.8–12.5.

[0017] Preferably, the pH value of the first gel-like mother liquor is adjusted by adding solid sodium hydroxide or by adding an aqueous solution of sodium hydroxide.

[0018] Preferably, the crystallization temperature in the second crystallization process is 40°C or more higher than the crystallization temperature in the first crystallization process; more preferably, it is 50-60°C higher.

[0019] More preferably, in the first stage of hydrothermal crystallization treatment, the crystallization temperature is 40-60°C and the crystallization time is 4-24 hours, more preferably 11-24 hours.

[0020] More preferably, in the second stage of hydrothermal crystallization treatment, the crystallization temperature is 90-100°C and the crystallization time is 6-48 hours, more preferably 18-48 hours.

[0021] Preferably, the molar ratio of each component in the solution containing 13X molecular sieve seed crystals is: SiO2 / Al2O3 = (0.01~6):1, Na2O / SiO2 = (0.01~4.0):1, H2O / SiO2 = (1.0~50.0):1.

[0022] Furthermore, the molecular sieve-containing material is selected from one or more of the following: waste Z-5 molecular sieve catalyst, waste MTO catalyst, waste molecular sieve adsorbent, fly ash, waste FCC catalyst, and waste VOC adsorbent.

[0023] Preferably, the material containing molecular sieves is ground to below 200 mesh and then mixed with sodium carbonate.

[0024] Preferably, the monocarboxylic acid is selected from at least one of hydrochloric acid, acetic acid, and nitric acid.

[0025] Preferably, the molar ratio of each component in the second gel-like mother liquor is: SiO2 / Al2O3 = 0.5~6.0:1, Na2O / SiO2 = 0.5~6.0:1, H2O / SiO2 = 10~100:1.

[0026] Furthermore, based on the mass of the second gel-like mother liquor being 100%, the mass of the added solution containing 13X molecular sieve seeds is 5% to 20%.

[0027] Preferably, in step S3, the aging process is carried out under stirring conditions, the aging temperature is 20-100℃, and the aging time is 0.1-24h.

[0028] Preferably, in step S3, the hydrothermal crystallization treatment time is 0.1 to 36 hours.

[0029] Preferably, in step S3, the hydrothermal crystallization product is filtered, washed until neutral, and then dried at 80–120°C to constant weight to obtain 13X molecular sieve.

[0030] Furthermore, the carbon source in the carbon precursor solution is selected from one of benzene, furan, or furfural; the solvent in the carbon precursor solution is selected from one of N,N-dimethylformamide, acetone, ethanol, or tetrahydrofuran.

[0031] Preferably, the concentration of the carbon source is 5-25% by mass percentage of the carbon precursor solution.

[0032] Preferably, the stirring time in step S4 is 6 to 48 hours.

[0033] Preferably, the heat treatment time in step S4 is 2 to 4 hours.

[0034] Furthermore, the platinum source is selected from one or more of hexachloroplatinic acid dihydrate, potassium chloroplatinate, and platinum acetylacetonate.

[0035] Preferably, the platinum precursor solution is prepared by dispersing a platinum source in water.

[0036] More preferably, the concentration of the platinum source in the precursor solution is 1–3 g / L.

[0037] More preferably, the mass of the platinum source in the platinum precursor solution is 0.5% to 1.5%, based on the mass of the carbon-modified 13X molecular sieve as 100%.

[0038] More preferably, the carbon-modified 13X molecular sieve is dried and dehydrated before being placed in the platinum precursor solution. The drying and dehydration treatment temperature is 90–110°C, and the drying and dehydration treatment time is 2–12 h.

[0039] Further, in step S5, the carbon-modified 13X molecular sieve is mixed with the platinum precursor solution and stirred for 12 to 36 hours, and then filtered to obtain the carbon-modified 13X molecular sieve impregnated with the platinum precursor solution.

[0040] Preferably, the pre-calcination time is 1-3 hours, and the calcination time is 3-5 hours.

[0041] Preferably, the carbon-modified 13X molecular sieve impregnated with platinum precursor solution is dried and then pre-calcined at a temperature of 90–130°C for 8–16 hours.

[0042] According to another aspect of the present invention, a cracking catalyst prepared by the method described above is provided.

[0043] According to another aspect of the present invention, the application of the cracking catalyst prepared by the above-described method in petroleum cracking is provided.

[0044] Applying the technical solution of this invention, seed crystals are prepared by controlling pH value and a two-stage crystallization process. Using molecular sieve-containing materials as raw materials, aluminum and silicon dissolution treatments are performed through controlled ratios of each raw material, followed by mixing of the two materials to prepare mother liquor. Then, through aging and hydrothermal crystallization, a multi-level porous structure of 13X molecular sieve with a high silicon-to-aluminum ratio, high specific surface area, and high pore capacity is obtained. The silicon source utilization rate is high, and the prepared 13X molecular sieve possesses a high content of mesoporous (and macroporous) structures. Further modification of the surface and structure of the 13X molecular sieve yields… A cracking catalyst with good catalytic activity and stability is obtained by modifying its surface and structure. This includes impregnating 13X molecular sieves with a carbon precursor solution and then performing carbon modification treatment to form a carbon layer, thereby increasing its specific surface area and pore volume. Platinum has excellent catalytic activity. Through impregnation treatment with platinum precursor solution, pre-calcination in an inert gas atmosphere, and calcination treatment in an air atmosphere, platinum is combined with the 13X molecular sieve framework in the form of highly dispersed platinum oxide and platinum metal, forming a structurally stable and highly catalytically active platinum-containing 13X molecular sieve cracking catalyst.

[0045] Using the method of this invention, a cracking catalyst with a high silicon-to-aluminum ratio, high specific surface area, high pore capacity, and high content of mesoporous and macroporous structures was prepared. This cracking catalyst has good catalytic activity and stability, which improves the economic benefits of oil refining. Moreover, using molecular sieve waste as the main raw material, the recycling of molecular sieve waste can be realized, which helps to reduce the production cost of the catalyst and improve the green sustainability of the cracking process. Detailed Implementation

[0046] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the embodiments.

[0047] As described in the background section, the existing technology of this invention suffers from problems such as low stability of cracking catalysts and lack of resource utilization of molecular sieve waste in the preparation process. In order to solve the above problems, according to one aspect of the present invention, a method for preparing a cracking catalyst is provided, comprising the following steps:

[0048] Step S1: A silicon source and water are mixed to obtain a silicon-containing material, and an aluminum source and water are mixed to obtain an aluminum-containing material. The aluminum-containing material and the silicon-containing material are stirred and mixed to obtain a first gel-like mother liquor. The pH value of the first gel-like mother liquor is adjusted to 8.5-12.5 using sodium hydroxide. Then, a two-stage hydrothermal crystallization treatment is performed to obtain a solution containing 13X molecular sieve seed crystals. The crystallization temperature of the first stage hydrothermal crystallization treatment is 20-60℃, and the crystallization temperature of the second stage hydrothermal crystallization treatment is 80-120℃.

[0049] Step S2: Mix the molecular sieve material with sodium carbonate at a mass ratio of 1:0.5 to 1:5, calcine at 550 to 800°C for 60 to 120 minutes, dissolve the calcined product with a monobasic acid of 10% to 35% by mass, filter to obtain aluminum-rich liquid and residue, stir and mix the residue with sodium hydroxide and water at a mass ratio of 5 to 100:40 to 60:50 to 400 to dissolve the residue, filter to obtain silicon-rich liquid, mix the aluminum-rich liquid and silicon-rich liquid to obtain the second gel-like mother liquor;

[0050] Step S3: The solution containing 13X molecular sieve seed crystals is mixed with the second gel-like mother liquor and then aged. Then, hydrothermal crystallization is carried out at 60-105℃ to obtain 13X molecular sieve.

[0051] Step S4: The 13X molecular sieve is soaked in a carbon precursor solution to obtain a 13X molecular sieve impregnated with the carbon precursor solution. The 13X molecular sieve impregnated with the carbon precursor solution is then heat-treated at 600-900℃ under an inert gas atmosphere to obtain a carbon-modified 13X molecular sieve.

[0052] Step S5: The carbon-modified 13X molecular sieve is mixed with the platinum precursor solution, stirred and filtered to obtain the carbon-modified 13X molecular sieve impregnated with the platinum precursor solution. The carbon-modified 13X molecular sieve impregnated with the platinum precursor solution is pre-calcined in an inert gas atmosphere at 450-550℃ and then calcined in an air atmosphere at 700-900℃ to obtain the cracking catalyst.

[0053] To obtain a high-performance cracking catalyst, this invention provides a method for preparing a cracking catalyst. The method involves controlling the pH value and using a two-stage crystallization process to prepare seed crystals. Using molecular sieve-containing materials as raw materials, the method involves aluminum and silicon dissolution treatments, followed by mixing the two materials to prepare a mother liquor. Then, through aging and hydrothermal crystallization, a 13X molecular sieve with a high silicon-to-aluminum ratio, high specific surface area, and high pore capacity with a hierarchical porous structure is obtained. The silicon source utilization rate is high, and the prepared 13X molecular sieve possesses a high content of mesoporous (and macroporous) structures. Further surface treatment and... By modifying the structure, a cracking catalyst with good catalytic activity and stability was obtained. Surface and structural modification included impregnating 13X molecular sieves with a carbon precursor solution followed by carbon modification treatment to form a carbon layer, increasing its specific surface area and pore volume. Platinum, possessing excellent catalytic activity, was composited with the 13X molecular sieve framework in the form of highly dispersed platinum oxide and platinum metal through platinum precursor solution impregnation, pre-calcination under an inert gas atmosphere, and calcination under an air atmosphere, forming a structurally stable and highly catalytically active platinum-containing 13X molecular sieve cracking catalyst. Using the method of this invention, a cracking catalyst with a high silica-to-alumina ratio, excellent specific surface area, pore volume, and a high content of mesoporous and macroporous structures was prepared. This cracking catalyst exhibits good catalytic activity and stability, improving the economic efficiency of oil refining; and by using molecular sieve-containing waste as the main raw material, it can achieve the recycling of molecular sieve-containing waste, helping to reduce the production cost of the catalyst and improve the green sustainability of the cracking process.

[0054] To obtain a cracking catalyst with a high silicon-to-aluminum ratio and specific surface area, the silicon source is selected from one or more of silica sol, tetraethyl orthosilicate, coarse-porous silica gel, silica powder, fly ash, and silica; the aluminum source is selected from one or more of sodium aluminate, boehmite, aluminum sulfate, and aluminum nitrate; the weight ratio of silicon source to aluminum source is (0.01–1.25):1; to ensure sufficient reaction between the two and generate a cracking catalyst with a high silicon-to-aluminum ratio and specific surface area, the mass fraction of silicon source in the silicon-containing material is preferably 2%–50%; preferably, the silicon source and water are stirred at 20–60°C for 0.1–12 h to obtain the silicon-containing material; preferably, the mass fraction of aluminum source in the aluminum-containing material is 15%–60%; preferably, the aluminum source and water are stirred at 20–60°C for 0.1–12 h to obtain the aluminum-containing material; preferably, the mixture is stirred and mixed at 20–100°C for 0.1–24 h to obtain the first gel-like mother liquor.

[0055] In a preferred embodiment, the pH value of the first gel-like mother liquor is 11.8–12.5. Further precise control of the pH value to 11.8–12.5 facilitates the reaction between the silicon and aluminum sources and promotes the further generation of highly crystalline seed crystals with stable crystal forms and structures during the two-stage thermal crystallization process. This facilitates the further generation of 13X molecular sieves with high silicon-to-aluminum ratio, high specific surface area, high pore capacity, and a hierarchical pore structure. Preferably, the pH value of the first gel-like mother liquor is adjusted by adding solid sodium hydroxide or by adding an aqueous solution of sodium hydroxide. Preferably, the crystallization temperature in the second-stage crystallization process is at least 40°C higher than that in the first-stage crystallization process, more preferably 50–60°C higher. A two-stage hydrothermal crystallization process is employed, wherein the high silicon-to-aluminum ratio 13X molecular sieve seed crystals generated in the first-stage crystallization process are further grown and optimized to form a more desirable structure. A solution of complete, homogeneous 13X molecular sieve seed crystals with a high specific surface area, using the aforementioned higher temperature difference, is beneficial for optimizing the formation of cracking catalysts with higher specific surface areas. More preferably, in the first stage of hydrothermal crystallization treatment, the crystallization temperature is 40–60°C and the crystallization time is 4–24 h, more preferably 11–24 h; more preferably, in the second stage of hydrothermal crystallization treatment, the crystallization temperature is 90–100°C and the crystallization time is 6–48 h, more preferably 18–48 h; preferably, the molar ratio of each component in the solution containing 13X molecular sieve seed crystals is: SiO2 / Al2O3 = (0.01–6):1, Na2O / SiO2 = (0.01–4.0):1, H2O / SiO2 = (1.0–50.0):1, which is more conducive to the subsequent growth of 13X molecular sieves with specific pore structures; preferably, both stages of hydrothermal crystallization treatment are carried out in a hydrothermal reactor.

[0056] In a preferred embodiment, the molecular sieve-containing material is selected from one or more of the following: waste Z-5 molecular sieve catalyst, waste MTO catalyst, waste molecular sieve adsorbent, fly ash, waste FCC catalyst, and waste VOC adsorbent; preferably, the molecular sieve-containing material is ground to below 200 mesh and then mixed with sodium carbonate; preferably, the monobasic acid is selected from at least one of hydrochloric acid, acetic acid, and nitric acid; preferably, the molar ratio of each component in the second gel-like mother liquor is: SiO2 / Al2O3 = 0.5~6.0:1, Na2O / SiO2 = 0.5~6.0:1, H2O / SiO2 = 10~100:1. By adjusting the distribution ratio of each component in the mother liquor, it is beneficial to optimize and control the production of 13X molecular sieves with higher specific surface area and pore volume.

[0057] In a preferred embodiment, to obtain a more regular and uniform 13X molecular sieve, the mass of the solution containing 13X molecular sieve seed crystals added is 5% to 20% based on the mass of the second gel-like mother liquor as 100%; in preferred step S3, the aging treatment is carried out under stirring conditions, the aging treatment temperature is 20 to 100°C, and the aging treatment time is 0.1 to 24 hours; in preferred step S3, the hydrothermal crystallization treatment time is 0.1 to 36 hours; in preferred step S3, the hydrothermal crystallization product is filtered, washed until neutral, and then dried at 80 to 120°C to constant weight to obtain 13X molecular sieve.

[0058] In a preferred embodiment, the carbon source in the carbon precursor solution is selected from benzene, furan, or furfural; the solvent in the carbon precursor solution is selected from N,N-dimethylformamide, acetone, ethanol, or tetrahydrofuran; the above-mentioned organic solvent and carbon source form a stable and homogeneous carbon precursor solution, which can fully contact and wet the 13X molecular sieve, which is beneficial to the formation of carbon layer and increases the surface area and pore volume of the 13X molecular sieve; preferably, the concentration of carbon source in the carbon precursor solution is 5-25% by mass percentage of the carbon precursor solution; preferably, the soaking treatment in step S4 is carried out under stirring conditions for a stirring time of 6-48 hours; preferably, the heat treatment time in step S4 is 2-4 hours.

[0059] In a preferred embodiment, the platinum source is selected from one or more of hexachloroplatinic acid dihydrate, potassium chloroplatinate, and platinum acetylacetonate; preferably, the platinum precursor solution is prepared by dispersing the platinum source in water, using water as a dispersion solvent, which is environmentally friendly; preferably, the concentration of the platinum source in the precursor solution is 1-3 g / L, which obtains a platinum-containing 13X molecular sieve cracking catalyst with high catalytic activity and stable structure, while improving the utilization of platinum raw materials; more preferably, the mass of the platinum source in the platinum precursor solution is 0.5%-1.5% based on 100% of the mass of carbon-modified 13X molecular sieve; even more preferably, the carbon-modified 13X molecular sieve is dried before being placed in the platinum precursor solution, and the drying temperature is 90-110°C for 2-12 h, so as to remove the adsorbed water of the 13X molecular sieve and improve the platinum impregnation loading efficiency.

[0060] In a preferred embodiment, carbon-modified 13X molecular sieve is mixed with a platinum precursor solution and stirred for 12–36 h, then filtered to obtain carbon-modified 13X molecular sieve impregnated with the platinum precursor solution; preferably, the pre-calcination time is 1–3 h and the calcination time is 3–5 h; preferably, the carbon-modified 13X molecular sieve impregnated with the platinum precursor solution is dried before pre-calcination, the drying temperature is 90–130 °C and the drying time is 8–16 h.

[0061] According to another aspect of the present invention, a cracking catalyst prepared by the above-described method is provided. The prepared cracking catalyst possesses excellent specific surface area and pore capacity, and exhibits structural stability and high catalytic activity, showing promising application prospects in the field of cracking catalysis.

[0062] According to another aspect of the present invention, the cracking catalyst prepared by the above-mentioned method is provided for application in petroleum cracking. In the petroleum refining and petrochemical industries, cracking reaction is a key process. The obtained cracking catalyst has excellent specific surface area and pore capacity, stable structure and high catalytic activity. It can be used for cracking catalysis of heavy hydrocarbons, etc. Its high proportion of mesopores and macropores also makes it suitable for the entry of feedstock oils with larger diameters, such as heavy oil, into the cracking process, thereby improving cracking efficiency.

[0063] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0064] Example 1

[0065] A method for preparing a cracking catalyst, the specific steps of which are as follows:

[0066] Step 1: Dissolve 21.0g of silica sol (30% by mass of silica) in 36.0g of deionized water, and pretreat it in a sealed reactor at 25°C and 500rpm for 1 hour to obtain a silicon-containing material.

[0067] 24g of aluminum sulfate was dissolved in 18.0g of deionized water and stirred at 25℃ and 500rpm for 1h to obtain aluminum-containing source material;

[0068] Aluminum-containing material was added dropwise to silicon-containing material, and stirring was continued at 60°C for 8 hours to obtain a gel solution.

[0069] Dissolve 6.74g of sodium hydroxide in 36g of an aqueous solution of deionized sodium hydroxide, and add the solution to the gel solution until the pH value is 12 to obtain the gel solution.

[0070] The gel solution was placed in a hydrothermal reactor and subjected to two-stage hydrothermal crystallization treatment. In the first stage of hydrothermal crystallization treatment, the crystallization temperature was 40℃ and the crystallization time was 12 hours. In the second stage of hydrothermal crystallization treatment, the crystallization temperature was 95℃ and the crystallization time was 24 hours, resulting in a solution containing 13X molecular sieve seeds. The molar ratios of the components in the solution containing 13X molecular sieve seeds were: SiO2 / Al2O3 = 1.5:1, Na2O / SiO2 = 1.6:1, and H2O / SiO2 = 32:1.

[0071] Step 2: Grind the fly ash to below 200 mesh, mix the ground fly ash with NaCO3 at a mass ratio of 1:2.5, calcine at 700℃ for 90 min, dissolve the calcined product with 25% hydrochloric acid, and filter to obtain aluminum-rich liquid and residue.

[0072] The residue was mixed with NaOH and H2O at a mass ratio of 50:50:200 and then filtered to obtain a silicon-rich liquid.

[0073] Weigh out the silicon-rich liquid and aluminum-rich liquid and mix them to obtain a gel-like mother liquor. The molar ratio of each component in the gel-like mother liquor is: SiO2 / Al2O3 = 3.5:1, Na2O / SiO2 = 2.8:1, H2O / SiO2 = 80:1.

[0074] Step 3: Taking the mass of the gel-like mother liquor as 100%, add 15% by mass of the prepared solution containing 13X molecular sieve seed crystals to the prepared gel-like mother liquor, stir and age at 60℃ for 12h, and then perform hydrothermal crystallization treatment at 80℃ for 12h. Filter and wash the hydrothermal crystallization product until neutral, and dry it at 100℃ to constant weight to obtain 13X molecular sieve.

[0075] Step 4: Impregnate 13X molecular sieve in carbon precursor solution and stir for 24 hours. Under an inert gas atmosphere, heat the 13X molecular sieve impregnated with carbon precursor solution to 750°C and treat for 3 hours to obtain carbon-modified 13X molecular sieve. In the carbon precursor solution, the carbon source is benzene and the solvent is ethanol. The concentration of carbon source is 15% by mass percentage of carbon precursor solution.

[0076] Step 5,

[0077] (5) Take 100g of carbon-modified 13X molecular sieve and dry it at 110℃ for 4 hours to remove the adsorbed moisture. After completion, cool it to room temperature.

[0078] Dissolve 1g of hexachloroplatinic acid dihydrate (H2PtCl6·2H2O) in 500mL of deionized water to form a platinum precursor solution;

[0079] The dried 13X molecular sieve was added to the prepared platinum precursor solution and stirred thoroughly with a magnetic stirrer for 24 hours, and then filtered.

[0080] The filtered solid was placed in a drying oven and dried further at 110°C for 12 hours. The dried material was then placed in a molybdenum cloth furnace and pre-calcined at 500°C in a nitrogen atmosphere for 2 hours, and then calcined at 800°C in an air atmosphere for 4 hours to obtain the cracking catalyst.

[0081] Example 2

[0082] A method for preparing a cracking catalyst, the specific steps of which are as follows:

[0083] Step 1: Dissolve 1g of silicon powder in 18g of deionized water and pretreat in a sealed reactor at 25°C and 500rpm for 1 hour to obtain silicon-containing material.

[0084] 12g of aluminum nitrate was dissolved in 18.0g of deionized water and stirred at 35℃ and 500rpm for 1 hour to prepare aluminum-containing material;

[0085] Aluminum-containing material is added dropwise to silicon-containing material, and the mixture is stirred at 50°C for 6 hours to obtain a gel solution.

[0086] An aqueous solution of sodium hydroxide was prepared by dissolving 2g of sodium hydroxide in 36g of deionized water and added to the gel solution until the pH value reached 11.8, thus obtaining the gel solution.

[0087] The gel solution was transferred to a hydrothermal reactor for two-stage hydrothermal crystallization. In the first stage, the crystallization temperature was 50℃ and the crystallization time was 14 hours. In the second stage, the crystallization temperature was 100℃ and the crystallization time was 18 hours, resulting in a solution containing 13X molecular sieve seeds. The molar ratios of the components in the solution containing 13X molecular sieve seeds were: SiO2 / Al2O3 = 0.6:1, Na2O / SiO2 = 3:1, and H2O / SiO2 = 20:1.

[0088] Step 2: Grind the Z-5 molecular sieve catalyst to below 200 mesh, mix the ground Z-5 molecular sieve catalyst with NaCO3 at a mass ratio of 1:0.5, calcine at 550℃ for 60 min, dissolve the calcined product with acetic acid of 35% by mass, and filter to obtain aluminum-rich liquid and residue.

[0089] The residue was mixed with NaOH and H2O in a mass ratio of 5:40:50 and then filtered to obtain a silicon-rich liquid.

[0090] Weigh out the silicon-rich liquid and aluminum-rich liquid and mix them to obtain a gel-like mother liquor. The molar ratio of each component in the gel-like mother liquor is: SiO2 / Al2O3 = 6:1, Na2O / SiO2 = 0.5:1, H2O / SiO2 = 100:1.

[0091] Step 3: Taking the mass of the gel-like mother liquor as 100%, add 5% by mass of the prepared solution containing 13X molecular sieve seed crystals to the prepared gel-like mother liquor, stir and age at 20°C for 0.1 h, then perform hydrothermal crystallization treatment at 60°C for 0.1 h, filter and wash the hydrothermal crystallization product until neutral, and dry it at 80°C to constant weight to obtain 13X molecular sieve.

[0092] Step 4: Impregnate 13X molecular sieve in carbon precursor solution and stir for 6 hours. Under an inert gas atmosphere, heat the impregnated 13X molecular sieve to 600℃ and treat for 2 hours to obtain carbon-modified 13X molecular sieve. The carbon source in the carbon precursor solution is furan and the solvent is acetone. The concentration of the carbon source is 5% by mass percentage of the carbon precursor solution.

[0093] Step 5: Take 100 grams of carbon-modified 13X molecular sieve and dry it at 110°C for 4 hours to remove the adsorbed moisture. After completion, cool it to room temperature.

[0094] Dissolve 0.5 g of hexachloroplatinic acid dihydrate (H2PtCl6·2H2O) in 500 mL of deionized water to form a platinum precursor solution;

[0095] The dried 13X molecular sieve was added to the prepared platinum precursor solution, and the mixture was stirred thoroughly with a magnetic stirrer for 6 hours, and then filtered.

[0096] The filtered solid was placed in a drying oven and dried further at 90°C for 8 hours. The dried material was then placed in a molybdenum cloth furnace and pre-calcined at 450°C in a nitrogen atmosphere for 1 hour, and then calcined at 700°C in an air atmosphere for 3 hours to obtain the cracking catalyst.

[0097] Example 3

[0098] A method for preparing a cracking catalyst, the specific steps of which are as follows:

[0099] Step 1: Dissolve 0.17g of silicon powder in 6g of deionized water and pretreat it in a sealed reactor at 25°C and 200rpm for 1 hour to obtain silicon-containing material;

[0100] 12g of aluminum nitrate was dissolved in 18.0g of deionized water and stirred at 35℃ and 200rpm for 1 hour to prepare aluminum-containing material;

[0101] An aluminum source solution was added to a silicon-containing material and stirred at 100°C for 24 hours to obtain a gel solution.

[0102] An aqueous solution of sodium hydroxide was prepared by dissolving 0.9g of sodium hydroxide in 6g of deionized water and added to the gel solution until the pH value reached 12.5. The prepared gel was then poured into a hydrothermal reactor for two-stage crystallization. First, crystallization was carried out at 60℃ for 24 hours, and then the temperature was increased to 120℃ for 48 hours to obtain a solution containing 13X molecular sieve seeds. The molar ratio of each component in the solution containing 13X molecular sieve seeds was: SiO2 / Al2O3 = 0.1:1, Na2O / SiO2 = 4:1, and H2O / SiO2 = 1:1.

[0103] Step 2: Grind the waste MTO catalyst to below 200 mesh, mix the ground waste MTO catalyst with NaCO3 at a mass ratio of 1:5, calcine at 800℃ for 120 min, dissolve the calcined product with 10% nitric acid, and filter to obtain aluminum-rich liquid and residue.

[0104] The residue was mixed with NaOH and H2O at a mass ratio of 100:60:400 and then filtered to obtain a silicon-rich liquid.

[0105] Weigh out silicon-rich liquid and aluminum-rich liquid and mix them to obtain a gel-like mother liquor. The molar ratio of each component in the gel-like mother liquor is SiO2 / Al2O3 = 0.5:1, Na2O / SiO2 = 6.0:1, and H2O / SiO2 = 10:1.

[0106] Step 3: Taking the mass of the gel-like mother liquor as 100%, add 20% by mass of the prepared solution containing 13X molecular sieve seed crystals to the prepared gel-like mother liquor, stir and age at 100℃ for 24h, and then perform hydrothermal crystallization treatment at 105℃ for 36h. Filter and wash the hydrothermal crystallization product until neutral, and dry it at 120℃ to constant weight to obtain 13X molecular sieve.

[0107] Step 4: Impregnate 13X molecular sieve in carbon precursor solution and stir for 48 h. Under an inert gas atmosphere, heat the impregnated 13X molecular sieve to 900 °C and treat for 4 h to obtain carbon-modified 13X molecular sieve. The carbon source in the carbon precursor solution is furfural, the solvent is tetrahydrofuran, and the concentration of the carbon source is 25% by mass percentage of the carbon precursor solution.

[0108] Step 5: Take 100 grams of carbon-modified 13X molecular sieve and dry it at 110°C for 4 hours to remove the adsorbed moisture. After completion, cool it to room temperature.

[0109] Dissolve 1.5g of hexachloroplatinic acid dihydrate (H2PtCl6·2H2O) in 500mL of deionized water to form a platinum precursor solution;

[0110] The dried 13X molecular sieve was added to the prepared platinum precursor solution and stirred thoroughly with a magnetic stirrer for 48 hours, and then filtered.

[0111] The filtered solid was placed in a drying oven and dried further at 130°C for 16 hours. The dried material was then placed in a molybdenum cloth furnace and pre-calcined at 550°C in a nitrogen atmosphere for 3 hours, and then calcined at 900°C in an air atmosphere for 5 hours to obtain the cracking catalyst.

[0112] Example 4

[0113] The only difference between it and Example 1 is that step one is different. Specifically, step one is as follows:

[0114] Take 14.65g of tetraethyl orthosilicate and 36g of deionized water, mix them, and pretreat them in a closed reactor at 25°C and 800rpm for 1 hour to obtain silicon-containing material;

[0115] 12g of aluminum nitrate was dissolved in 18.0g of deionized water and stirred at 35℃ and 800rpm for 1 hour to obtain aluminum-containing material;

[0116] Aluminum-containing material was gradually added dropwise to silicon-containing material, and the mixture was stirred at 20°C for 0.1 hours to prepare a gel solution.

[0117] Dissolve 0.56g of sodium hydroxide in 6g of deionized water to prepare an aqueous sodium hydroxide solution. Pour the solution into the gel solution until the pH value is 8.5. Then, introduce the prepared gel into a hydrothermal reactor and perform a segmented crystallization reaction: first, set the crystallization temperature to 20℃ and hold for 4 hours, then increase it to 80℃ and maintain crystallization for 6 hours to obtain a solution containing 13X molecular sieve seeds. The molar ratio of each component in the solution containing 13X molecular sieve seeds is: SiO2 / Al2O3 = 2.5:1, Na2O / SiO2 = 0.1:1, H2O / SiO2 = 40:1.

[0118] Example 5

[0119] The only difference between it and Example 1 is that the crystallization temperature in the second hydrothermal crystallization process is 70°C.

[0120] Example 6

[0121] The only difference between it and Example 1 is that the crystallization temperature in the second hydrothermal crystallization process is 120°C.

[0122] Example 7

[0123] The only difference between it and Example 1 is that the pH of the gel solution is adjusted to 8.5 in step (1).

[0124] Comparative Example 1

[0125] The only difference between this and Example 1 is that step one involves a first stage of hydrothermal crystallization treatment. Specifically, step one is as follows:

[0126] Step 1: Dissolve 21.0g of silica sol (30% by mass of silica) in 36.0g of deionized water, and pretreat it in a sealed reactor at 25°C and 500rpm for 1 hour to obtain a silicon-containing material.

[0127] 24g of aluminum sulfate was dissolved in 18.0g of deionized water and stirred at 25℃ and 500rpm for 1h to obtain aluminum-containing source material;

[0128] Aluminum-containing material was added dropwise to silicon-containing material, and stirring was continued at 60°C for 8 hours to obtain a gel solution.

[0129] Dissolve 6.74g of sodium hydroxide in 36g of an aqueous solution of deionized sodium hydroxide, and add the solution to the gel solution until the pH value is 12 to obtain the gel solution.

[0130] The gel solution was placed in a hydrothermal reactor for hydrothermal crystallization at a temperature of 40°C for 12 hours to obtain a solution containing 13X molecular sieve seeds.

[0131] Comparative Example 2

[0132] The only difference between this and Example 1 is that step one involves a second stage of hydrothermal crystallization treatment. Specifically, step one is as follows:

[0133] Step 1: Dissolve 21.0g of silica sol (30% by mass of silica) in 36.0g of deionized water, and pretreat it in a sealed reactor at 25°C and 500rpm for 1 hour to obtain a silicon-containing material.

[0134] 24g of aluminum sulfate was dissolved in 18.0g of deionized water and stirred at 25℃ and 500rpm for 1h to obtain aluminum-containing source material;

[0135] Aluminum-containing material was added dropwise to silicon-containing material, and stirring was continued at 60°C for 8 hours to obtain a gel solution.

[0136] Dissolve 6.74g of sodium hydroxide in 36g of an aqueous solution of deionized sodium hydroxide, and add the solution to the gel solution until the pH value is 12 to obtain the gel solution.

[0137] The gel solution was placed in a hydrothermal reactor for hydrothermal crystallization at a temperature of 95°C for 24 hours to obtain a solution containing 13X molecular sieve seeds.

[0138] Comparative Example 3

[0139] The only difference between this and Example 1 is that step four is omitted. The specific steps are as follows:

[0140] Step 1: Dissolve 21.0g of silica sol (30% by mass of silica) in 36.0g of deionized water, and pretreat it in a sealed reactor at 25°C and 500rpm for 1 hour to obtain a silicon-containing material.

[0141] 24g of aluminum sulfate was dissolved in 18.0g of deionized water and stirred at 25℃ and 500rpm for 1h to obtain aluminum-containing source material;

[0142] Aluminum-containing material was added dropwise to silicon-containing material, and stirring was continued at 60°C for 8 hours to obtain a gel solution.

[0143] Dissolve 6.74g of sodium hydroxide in 36g of an aqueous solution of deionized sodium hydroxide, and add the solution to the gel solution until the pH value is 12 to obtain the gel solution.

[0144] The gel solution was placed in a hydrothermal reactor and subjected to two-stage hydrothermal crystallization treatment. In the first stage of hydrothermal crystallization treatment, the crystallization temperature was 40℃ and the crystallization time was 12 hours. In the second stage of hydrothermal crystallization treatment, the crystallization temperature was 95℃ and the crystallization time was 24 hours, resulting in a solution containing 13X molecular sieve seeds. The molar ratios of the components in the solution containing 13X molecular sieve seeds were: SiO2 / Al2O3 = 1.5:1, Na2O / SiO2 = 1.6:1, and H2O / SiO2 = 32:1.

[0145] Step 2: Grind the fly ash to below 200 mesh, mix the ground fly ash with NaCO3 at a mass ratio of 1:2.5, calcine at 700℃ for 90 min, dissolve the calcined product with 25% hydrochloric acid, and filter to obtain aluminum-rich liquid and residue.

[0146] The residue was mixed with NaOH and H2O at a mass ratio of 50:50:200 and then filtered to obtain a silicon-rich liquid.

[0147] Weigh out the silicon-rich liquid and aluminum-rich liquid and mix them to obtain a gel-like mother liquor. The molar ratio of each component in the gel-like mother liquor is: SiO2 / Al2O3 = 3.5:1, Na2O / SiO2 = 2.8:1, H2O / SiO2 = 80:1.

[0148] Step 3: Taking the mass of the gel-like mother liquor as 100%, add 15% by mass of the prepared solution containing 13X molecular sieve seed crystals to the prepared gel-like mother liquor, stir and age at 60℃ for 12h, and then perform hydrothermal crystallization treatment at 80℃ for 12h. Filter and wash the hydrothermal crystallization product until neutral, and dry it at 100℃ to constant weight to obtain 13X molecular sieve.

[0149] Step 4: Add 50g of 13X molecular sieve and 0.5g of methyltriethoxysilane to 49.5g of anhydrous ethanol, stir and react at room temperature for 4 hours, then filter, and calcine the filtered molecular sieve at 450℃ for 2 hours.

[0150] The calcined 13X molecular sieve was immersed in a 1 mol / L copper nitrate aqueous solution at room temperature for 24 hours.

[0151] 10g of tetrabutyl titanate was added dropwise to a mixed solvent of 50g ethanol and 10g distilled water, and stirred at 60℃ for 3 hours to obtain titanium precursor sol.

[0152] The 13X molecular sieve soaked in copper salt solution was added to the titanium precursor sol, stirred evenly, and then dried at 100°C for 12 hours. Subsequently, it was heated to 500°C in a kiln at a heating rate of 5°C / min and calcined for 2 hours.

[0153] The calcined product was dried in a vacuum drying device for 12 hours to obtain a molecular sieve organic oxide adsorbent.

[0154] Comparative Example 4

[0155] The only difference between it and Example 1 is that no pre-calcination treatment was performed in step five.

[0156] Comparative Example 5

[0157] The only difference between it and Example 1 is that calcination in air atmosphere is not performed in step five.

[0158] I. The specific surface area, pore volume, proportion of mesopores and macropores (volume ratio), and silicon-aluminum ratio of the cracking catalysts prepared in the examples and comparative examples were tested respectively. The results are shown in Table 1. Mesopores refer to pores with a diameter of 2 to 50 nm, and macropores refer to pores with a diameter greater than 50 nm.

[0159] II. Stability Test: The cracking catalysts prepared in the examples and comparative examples were subjected to aging treatment at 800°C and 100% steam for 20 hours in a fixed bed aging device. After hydrothermal aging treatment, the specific surface area, pore volume, and proportion of mesopores and macropores of the cracking catalysts are shown in Table 1. As can be seen from Table 1, after aging treatment, the pore structure of the samples remained almost unchanged, and they could still maintain a large specific surface area and proportion of mesopores and macropores, thus exhibiting good hydrothermal stability and being suitable for catalytic cracking.

[0160] Table 1

[0161]

[0162] III. Catalytic treatment of cracking reaction: The cracking reaction catalysts obtained in the above examples and comparative examples were used for naphtha steam cracking reaction. The specific reaction conditions were: reaction temperature of 550℃, reaction pressure of 80KPa, reaction time of 2 hours, and water-oil mass ratio of 0.6. The yield of the obtained trienes (ethylene, propylene, butadiene) and the selectivity of triene conversion are shown in Table 2.

[0163] Table 2

[0164] Total yield of trienes (%) Selectivity of coal-based naphtha products (%) Example 1 26.8 97.5 Example 2 26.4 96.8 Example 3 25.7 95.9 Example 4 25.9 96.3 Example 5 25.6 95.5 Example 6 25.3 95.1 Example 7 25.0 94.8 Comparative Example 1 20.0 87.9 Comparative Example 2 20.2 88.2 Comparative Example 3 18.7 87.0 Comparative Example 4 18.9 87.2 Comparative Example 5 19.5 87.5

[0165] As can be seen from the above, the embodiments of the present invention have prepared a cracking catalyst with a high silicon-to-aluminum ratio, high specific surface area, high pore capacity, and high content of mesoporous and macroporous structures. Specifically, the silicon-to-aluminum ratio is 2.2–2.9, and the pore volume is 0.39 cm³. 3 / g~0.5cm 3 The specific surface area is between / g and 800m². 2 / g~900m 2 The cracking catalyst exhibits good catalytic activity and hydrothermal stability within the range of / g. Furthermore, the method based on this invention can use molecular sieve waste as the main raw material, realizing the recycling of molecular sieve waste, which helps to reduce the production cost of the catalyst and improve the green sustainability of the cracking process.

[0166] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a cracking catalyst, characterized in that, Includes the following steps: Step S1: A silicon source and water are mixed to obtain a silicon-containing material, and an aluminum source and water are mixed to obtain an aluminum-containing material. The aluminum-containing material and the silicon-containing material are stirred and mixed to obtain a first gel-like mother liquor. The pH value of the first gel-like mother liquor is adjusted to 8.5-12.5 using sodium hydroxide. Then, a two-stage hydrothermal crystallization treatment is performed to obtain a solution containing 13X molecular sieve seed crystals. The crystallization temperature of the first stage hydrothermal crystallization treatment is 20-60℃, and the crystallization temperature of the second stage hydrothermal crystallization treatment is 80-120℃. Step S2: The molecular sieve-containing material is mixed with sodium carbonate at a mass ratio of 1:0.5 to 1:5, and then calcined at 550 to 800°C for 60 to 120 minutes. The calcined product is dissolved with a monobasic acid at a mass fraction of 10% to 35%, and filtered to obtain an aluminum-rich liquid and residue. The residue is then mixed with sodium hydroxide and water at a mass ratio of 5 to 100:40 to 60:50 to 400 to dissolve the residue. The mixture is then filtered to obtain a silicon-rich liquid. The aluminum-rich liquid and the silicon-rich liquid are mixed to obtain a second gel-like mother liquor. The molecular sieve-containing material is selected from one or more of the following: waste MTO catalyst, waste molecular sieve adsorbent, waste FCC catalyst, and waste VOC adsorbent. Step S3: The solution containing 13X molecular sieve seed crystals is mixed with the second gel-like mother liquor and then aged. Then, hydrothermal crystallization is performed at 60-105°C to obtain 13X molecular sieve. Step S4: The 13X molecular sieve is immersed in a carbon precursor solution to obtain a 13X molecular sieve impregnated with the carbon precursor solution. Under an inert gas atmosphere, the 13X molecular sieve impregnated with the carbon precursor solution is heat-treated at 600-900℃ to obtain a carbon-modified 13X molecular sieve. The carbon source in the carbon precursor solution is selected from benzene, furan, or furfural; the solvent in the carbon precursor solution is selected from N,N-dimethylformamide, acetone, ethanol, or tetrahydrofuran. Step S5: The carbon-modified 13X molecular sieve is mixed with a platinum precursor solution, stirred, and then filtered to obtain a carbon-modified 13X molecular sieve impregnated with the platinum precursor solution. The carbon-modified 13X molecular sieve impregnated with the platinum precursor solution is pre-calcined in an inert gas atmosphere at 450–550°C, and then calcined in an air atmosphere at 700–900°C to obtain a cracking catalyst.

2. The method for preparing the cracking catalyst according to claim 1, characterized in that, The silicon source is selected from one or more of silica sol, tetraethyl orthosilicate, coarse-porous silica gel, silica powder, fly ash, and silica fume; the aluminum source is selected from one or more of sodium aluminate, boehmite, aluminum sulfate, and aluminum nitrate; and the weight ratio of the silicon source to the aluminum source is (0.01~1.25):

1.

3. The method for preparing the cracking catalyst according to claim 1, characterized in that, The mass fraction of the silicon source in the silicon-containing material is 2% to 50%.

4. The method for preparing the cracking catalyst according to claim 1, characterized in that, The silicon source and the water are stirred at 20–60°C for 0.1–12 hours to obtain the silicon-containing material.

5. The method for preparing the cracking catalyst according to claim 1, characterized in that, The mass fraction of the aluminum source in the aluminum-containing material is 15% to 60%.

6. The method for preparing the cracking catalyst according to claim 1, characterized in that, The aluminum source and the water are stirred at 20–60°C for 0.1–12 hours to obtain the aluminum-containing material.

7. The method for preparing the cracking catalyst according to claim 1, characterized in that, The mixture was stirred and mixed at 20–100°C for 0.1–24 h to obtain the first gel-like mother liquor.

8. The method for preparing the cracking catalyst according to claim 1, characterized in that, The pH value of the first gel-like mother liquor is 11.8 to 12.

5.

9. The method for preparing the cracking catalyst according to claim 1, characterized in that, The pH value of the first gel-like mother liquor is adjusted by adding solid sodium hydroxide or by adding an aqueous solution of sodium hydroxide.

10. The method for preparing the cracking catalyst according to claim 1, characterized in that, The crystallization temperature in the second stage of hydrothermal crystallization treatment is more than 40°C higher than the crystallization temperature in the first stage of hydrothermal crystallization treatment.

11. The method for preparing the cracking catalyst according to claim 1, characterized in that, The crystallization temperature in the second stage of hydrothermal crystallization treatment is 50-60°C higher than that in the first stage of hydrothermal crystallization treatment.

12. The method for preparing the cracking catalyst according to claim 1, characterized in that, In the first stage of hydrothermal crystallization treatment, the crystallization temperature is 40-60℃ and the crystallization time is 4-24h.

13. The method for preparing the cracking catalyst according to claim 1, characterized in that, In the first stage of hydrothermal crystallization treatment, the crystallization time is 11 to 24 hours.

14. The method for preparing the cracking catalyst according to claim 1, characterized in that, In the second stage of hydrothermal crystallization treatment, the crystallization temperature is 90-100℃ and the crystallization time is 6-48h.

15. The method for preparing the cracking catalyst according to claim 1, characterized in that, In the second stage of hydrothermal crystallization treatment, the crystallization time is 18 to 48 hours.

16. The method for preparing the cracking catalyst according to claim 1, characterized in that, The molar ratios of the components in the solution containing 13X molecular sieve seeds are: SiO2 / Al2O3 = (0.01~6):1, Na2O / SiO2 = (0.01~4.0):1, H2O / SiO2 = (1.0~50.0):

1.

17. The method for preparing the cracking catalyst according to claim 1, characterized in that, The molecular sieve-containing material is ground to below 200 mesh and then mixed with the sodium carbonate.

18. The method for preparing the cracking catalyst according to claim 1, characterized in that, The monocarboxylic acid is selected from at least one of hydrochloric acid, acetic acid, and nitric acid.

19. The method for preparing the cracking catalyst according to claim 1, characterized in that, The molar ratios of the components in the second gel-like mother liquor are: SiO2 / Al2O3 = 0.5–6.0:1, Na2O / SiO2 = 0.5–6.0:1, and H2O / SiO2 = 10–100:

1.

20. The method for preparing the cracking catalyst according to claim 1, characterized in that, Based on the second gel-like mother liquor being 100% by mass, the mass of the solution containing 13X molecular sieve seeds added is 5% to 20%.

21. The method for preparing the cracking catalyst according to claim 1, characterized in that, In step S3, the aging process is carried out under stirring conditions, the aging temperature is 20-100℃, and the aging time is 0.1-24h.

22. The method for preparing the cracking catalyst according to claim 1, characterized in that, In step S3, the hydrothermal crystallization treatment takes 0.1 to 36 hours.

23. The method for preparing the cracking catalyst according to claim 1, characterized in that, In step S3, the product after hydrothermal crystallization is filtered, washed until neutral, and then dried at 80-120°C to constant weight to obtain the 13X molecular sieve.

24. The method for preparing the cracking catalyst according to claim 1, characterized in that, The concentration of the carbon source is 5-25% by mass percentage of the carbon precursor solution.

25. The method for preparing the cracking catalyst according to claim 1, characterized in that, The heat treatment time in step S4 is 2 to 4 hours.

26. The method for preparing the cracking catalyst according to claim 1, characterized in that, The platinum precursor is selected from one or more of hexachloroplatinic acid dihydrate, potassium chloroplatinate, and platinum acetylacetonate.

27. The method for preparing the cracking catalyst according to claim 1, characterized in that, The platinum precursor solution was prepared by dispersing platinum precursors in water.

28. The method for preparing the cracking catalyst according to claim 27, characterized in that, The concentration of the platinum precursor in the platinum precursor solution is 1–3 g / L.

29. The method for preparing the cracking catalyst according to claim 27, characterized in that, Based on the mass of the carbon-modified 13X molecular sieve being 100%, the mass of the platinum precursor in the platinum precursor solution is 0.5% to 1.5%.

30. The method for preparing the cracking catalyst according to claim 1, characterized in that, The carbon-modified 13X molecular sieve is dried and dehydrated before being placed in the platinum precursor solution. The drying and dehydration treatment is carried out at a temperature of 90-110°C for 2-12 hours.

31. The method for preparing the cracking catalyst according to claim 1, characterized in that, In step S5, the carbon-modified 13X molecular sieve is mixed with the platinum precursor solution and stirred for 12-36 hours, and then filtered to obtain the carbon-modified 13X molecular sieve impregnated with the platinum precursor solution.

32. The method for preparing the cracking catalyst according to claim 1, characterized in that, The pre-calcination time is 1 to 3 hours, and the calcination time is 3 to 5 hours.

33. The method for preparing the cracking catalyst according to claim 1, characterized in that, The carbon-modified 13X molecular sieve impregnated with the platinum precursor solution is dried and then pre-calcined. The drying temperature is 90-130°C and the drying time is 8-16 hours.

34. The cracking catalyst prepared by the method according to any one of claims 1 to 33.

35. The application of the cracking catalyst prepared by the method of any one of claims 1 to 33 in petroleum cracking.

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