A catalytic cracking process and a cracking catalyst comprising a phosphorus-modified ZSM-5 molecular sieve

Abstract

A catalytic cracking catalyst characterized in that it contains 2-20 wt% of Y-type molecular sieve on a dry basis, 3-80 wt% of phosphorus-modified ZSM-5 molecular sieve on a dry basis, 1-70 wt% of inorganic binder on a dry basis, and 2-60 wt% of clay on a dry basis, based on the dry weight of the catalytic cracking catalyst, wherein the phosphorus-modified ZSM-5 molecular sieve has an electron binding energy of phosphorus element in surface phosphorus species of the molecular sieve of 135.2 eV after hydrothermal aging at 800 DEG C under 100% water vapor for 17 h, and a crystallinity retention degree of 70-110% in XRD analysis, and the inorganic binder comprises a phosphorus-aluminum inorganic binder and / or other inorganic binder.

Description

Technical Field

[0001] This invention relates to a cracking method and a cracking catalyst, and more specifically to a catalytic cracking method and a cracking catalyst containing Y-type molecular sieve and phosphorus-modified ZSM-5 molecular sieve. Background Technology

[0002] Hydrocarbon cracking at high temperatures converts long-chain hydrocarbons into high-value-added low-carbon olefins such as ethylene and propylene. ZSM-5 molecular sieve (USP3702886), developed by Mobil Petroleum Corporation in the United States, is a high-silica, three-dimensional, straight-channel mesoporous molecular sieve with an MFI structure. Its unique pore structure gives it excellent shape-selective catalysis and isomerization performance. It also features high thermal and hydrothermal stability, high specific surface area, a wide range of silica-to-alumina ratios, unique surface acidity, and low carbon deposition. ZSM-5 molecular sieve is widely used as a catalyst and catalyst support, and has been successfully applied in alkylation, isomerization, disproportionation, catalytic cracking, methanol-to-gasoline, and methanol-to-olefins production processes.

[0003] Since 1983, ZSM-5 molecular sieves have been used as octane enhancers in catalytic cracking processes to improve the octane number and selectivity of low-carbon olefins in catalytic cracked gasoline. US3758403 first reported the use of ZSM-5 as an active component to enhance propylene production, specifically preparing an FCC catalyst using ZSM-5 and REY together as active components. US5997728 disclosed the use of ZSM-5 molecular sieves as an additive to enhance propylene production without any modification to the sieve. Both of these techniques resulted in low propylene yields. While HZSM-5 molecular sieves possess good shape selectivity and isomerization properties, their drawback is poor hydrothermal stability; they are prone to deactivation under harsh high-temperature hydrothermal conditions, leading to reduced catalytic performance.

[0004] In the 1980s, Mobil discovered that phosphorus could improve the hydrothermal stability of ZSM-5 molecular sieves. Furthermore, phosphorus modification of ZSM-5 molecular sieves could selectively convert primary cracking products (such as gasoline olefins) into C3 and C4 olefins, thereby increasing the yield of low-carbon olefins.

[0005] CN 1211469A discloses a five-membered ring molecular sieve composition that produces high yields of propylene and ethylene, comprising 85-95 wt% of a five-membered ring molecular sieve, 2-10 wt% of phosphorus (based on oxides), 0.3-5 wt% of alkaline earth metals (based on oxides), and 0.3-5 wt% of transition metal elements (based on oxides). This composition yields high ethylene yields when used in catalytic thermal cracking reactions.

[0006] US5171921 discloses a phosphorus-modified ZSM-5 molecular sieve with a silicon-to-aluminum ratio of 20-60. After being impregnated with a phosphorus-containing compound and treated with steam at 500-700°C, it exhibits higher activity than untreated HZSM-5 when used in the reaction of converting C3-C20 hydrocarbons into C2-C5 olefins.

[0007] CN102166533A discloses a method for preparing phosphorus-modified ZSM-5 molecular sieves. The method involves adding the molecular sieve to a phosphorus-containing aqueous solution and reacting it for a period of time under specific pH, temperature, and pressure conditions. The resulting product is then filtered, dried, and calcined to obtain the phosphorus-modified molecular sieve. Subsequently, the phosphorus-modified molecular sieve is added to an aqueous solution containing rare earth ions and reacted for a period of time under specific temperature and pressure conditions. This reaction is then followed by filtration, washing, drying, and calcination to obtain a composite modified molecular sieve. Model catalysts prepared using this composite modified molecular sieve exhibit higher hydrothermal stability and micro-activity compared to model catalysts containing unmodified molecular sieves or those modified by other methods.

[0008] CN106994364A discloses a method for preparing phosphorus-modified ZSM-5 molecular sieves. The method involves first mixing one or more phosphorus-containing compounds selected from phosphoric acid, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, and ammonium phosphate with a ZSM-5 molecular sieve containing high alkali metal ions to obtain a mixture with a phosphorus loading of at least 0.1 wt% (based on P2O5). The mixture is then dried, calcined, and subjected to ammonium ion exchange and water washing steps to reduce the alkali metal ion content to below 0.10 wt%. Finally, it undergoes drying and hydrothermal aging at 400-1000℃ under 100% steam conditions. The phosphorus-containing ZSM-5 molecular sieve obtained by this method has a high total acid content, excellent cracking conversion rate and propylene selectivity, and a high liquefied gas yield.

[0009] Although modifying ZSM-5 molecular sieves with organic / inorganic phosphorus compounds can inhibit framework dealuminization and thus improve hydrothermal stability, the introduction of phosphorus species can also regulate the acid center properties of ZSM-5 molecular sieves, thereby improving the cracking conversion rate of long-chain alkanes and the selectivity of low-carbon olefins. However, phosphoric acid or ammonium phosphate salts will generate large molecular phosphoric acid species such as polyphosphoric acid due to dehydration and self-polymerization. These species are prone to accumulate on the outer surface of the molecular sieve, blocking the pores, reducing the pore volume and specific surface area, resulting in low phosphorus-aluminum activation efficiency. Therefore, phosphorus modification cannot achieve the ideal effect of improving hydrothermal stability. Summary of the Invention

[0010] Based on extensive experiments, the inventors discovered that phosphorus-modified ZSM-5 molecular sieves prepared using solid phosphorus compounds with a +3 valence of phosphorus as precursors have different physicochemical characteristics from those of molecular sieves prepared by the conventional +5 valence phosphorus source aqueous solution impregnation method. This method can improve the phosphorus-aluminum stabilization efficiency. The hydrothermal stability, pyrolysis activity, and low-carbon olefin selectivity of the modified ZSM-5 molecular sieve are all improved.

[0011] One objective of this invention is to provide a catalytic cracking method in which one of the active components of the catalyst is a phosphorus-modified ZSM-5 molecular sieve with different physicochemical characteristics from conventional phosphorus-containing ZSM-5 molecular sieves and improved phosphorus-aluminum stabilization efficiency. This method has high cracking conversion rate and high yield of low-carbon olefins and liquefied gas in hydrocarbon catalytic cracking reactions. The second objective is to provide a cracking catalyst used in this cracking method.

[0012] To achieve one of the above objectives, the first aspect of the present invention provides a catalytic cracking method, which involves contacting hydrocarbon oil with a cracking catalyst under catalytic cracking reaction conditions. The cracking catalyst, based on its dry weight, contains 2-20% Y-type molecular sieve, 3-80% phosphorus-modified ZSM-5 molecular sieve, 1-70% inorganic binder, and 2-60% clay, on a dry basis. The phosphorus-modified ZSM-5 molecular sieve is characterized by being obtained by modifying phosphorus with a phosphorus-containing compound having a +3 valence state. After hydrothermal aging at 800°C and 100% steam for 17 hours, the phosphorus-modified ZSM-5 molecular sieve exhibits an electron binding energy of 135.2 eV for phosphorus in the phosphorus species on its surface and a crystallinity retention of 70%–110% in XRD analysis.

[0013] To achieve the second objective mentioned above, a second aspect of the present invention provides a pyrolysis catalyst, wherein, based on the dry weight of the pyrolysis catalyst, the pyrolysis catalyst contains, on a dry basis, 2-20% Y-type molecular sieve, 3-80% phosphorus-modified ZSM-5 molecular sieve, on a dry basis, 1-70% inorganic binder, and 2-60% clay, wherein the phosphorus-modified ZSM-5 molecular sieve is obtained by modification with a phosphorus-containing compound having a phosphorus oxidation state of +3, and the phosphorus-modified ZSM-5 molecular sieve, after hydrothermal aging at 800°C and 100% steam for 17 hours, has an electron binding energy of 135.2 eV for phosphorus in the phosphorus species on the molecular sieve surface and a crystallinity retention of 70% to 110% in XRD analysis.

[0014] The catalytic cracking method provided by this invention uses a catalyst containing a phosphorus-modified ZSM-5 molecular sieve with special physicochemical parameters. This phosphorus-modified ZSM-5 molecular sieve is obtained by modifying it with a +3 valent phosphorus source. After hydrothermal aging at 800℃ and 100% steam for 17 hours, it exhibits higher crystallinity retention, i.e., excellent hydrothermal stability. This method features high cracking conversion rate, high yield of low-carbon olefins, and high yield of liquefied petroleum gas. Attached Figure Description

[0015] Figure 1 This is the XPS (P2p Scan) spectrum of the phosphorus-modified ZSM-5 molecular sieve sample in this invention. Detailed Implementation

[0016] The catalytic cracking method provided by this invention involves contacting hydrocarbon oil with a cracking catalyst under catalytic cracking reaction conditions. Based on the dry weight of the cracking catalyst, the catalyst contains 2-20% Y-type molecular sieve (dry weight), 3-80% phosphorus-modified ZSM-5 molecular sieve (dry weight), 1-70% inorganic binder (dry weight), and 2-60% clay (dry weight). The phosphorus-modified ZSM-5 molecular sieve is characterized by being obtained by modifying phosphorus with a phosphorus-containing compound having a +3 valence state. After hydrothermal aging at 800°C and 100% steam for 17 hours, the phosphorus-modified ZSM-5 molecular sieve exhibits an electron binding energy of 135.2 eV for phosphorus species on its surface and a crystallinity retention of 70%–110% in XRD analysis.

[0017] In the method of the present invention, the pyrolysis catalyst is used alone, or the pyrolysis catalyst is used in a mixture with a conventional pyrolysis catalyst, wherein the pyrolysis catalyst accounts for no more than 30% by weight of the total mixture, preferably 1-25% by weight, more preferably 3-15% by weight. The conventional pyrolysis catalyst is well known to those skilled in the art, mainly a pyrolysis catalyst with Y-type molecular sieve as the main active component, and will not be described in detail here.

[0018] In the cracking catalyst used in the method of the present invention, the Y-type molecular sieve is selected from at least one of PSRY molecular sieve, PSRY-S molecular sieve, rare earth-containing PSRY molecular sieve, rare earth-containing PSRY-S molecular sieve, USY molecular sieve, rare earth-containing USY molecular sieve, REY molecular sieve, REHY molecular sieve and HY molecular sieve.

[0019] In the cracking catalyst used in this invention, the phosphorus-modified ZSM-5 molecular sieve, after drying in an air atmosphere at 100–120°C, exhibits a phosphorus binding energy of 134.5 eV as characterized by XPS; after hydrothermal aging at 800°C under 100% water vapor conditions, the phosphorus binding energy is 135.2 eV. In contrast, existing phosphoric acid-modified molecular sieves, lacking valence state transitions, exhibit almost unchanged binding energies during drying and aging, remaining at 134.8–134.9 eV. The phosphorus binding energy characterized by XPS represents its chemical environment and valence state, illustrating the degree of phosphorus species condensation and valence state transitions during drying and hydrothermal aging.

[0020] Furthermore, in the cracking catalyst used in the method of the present invention, the phosphorus-modified ZSM-5 molecular sieve exhibits a higher crystallinity retention (70% to 110%) after hydrothermal aging at 800°C and 100% steam for 17 hours. This also indicates that the coordination effect between phosphorus species and framework aluminum is significant, thus fully protecting the framework aluminum and demonstrating excellent hydrothermal stability of the molecular sieve.

[0021] In the cracking catalyst used in the method of the present invention, the phosphorus-modified ZSM-5 molecular sieve has a ratio of 0.01 to 5 when both phosphorus and aluminum are measured in molar amounts, with a preferred ratio of 0.1 to 3.

[0022] In the cracking catalyst used in this invention, the phosphorus-modified ZSM-5 molecular sieve is obtained by mixing and grinding a solid phosphorus-containing compound precursor with phosphorus in the +3 valence state and HZSM-5 molecular sieve to obtain a solid mixture; the solid mixture is then heated and melted; the heated and melted solid mixture is cooled to room temperature, such as 20-25°C, and then calcined to obtain the phosphorus-modified ZSM-5 molecular sieve; or, the HZSM-5 molecular sieve is impregnated with an aqueous solution of a phosphorus-containing compound with phosphorus in the +3 valence state, followed by drying and calcination. The impregnation is carried out at a water-to-sieve weight ratio of 0.5-2 for 0.5-10 hours at room temperature; the drying is carried out in an air atmosphere at 100-120°C for 2-24 hours; the calcination is carried out in an air atmosphere at 200-800°C for 0.5-12 hours. The heating and melting treatment is performed at a temperature higher than the melting point of the solid phosphorus-containing compound but lower than the temperature at which the solid phosphorus-containing compound decomposes or dehydrates, for a treatment time of 2–72 hours. The solid phosphorus-containing compound precursor with a phosphorus oxidation state of +3 is selected from phosphorous acid and / or ammonium phosphite. The molar ratio of the phosphorus-containing compound precursor with a phosphorus oxidation state of +3 to the HZSM-5 molecular sieve is (0.1–5):1, preferably (0.5–2.5):1, wherein the HZSM-5 molecular sieve is calculated as aluminum and the phosphorus-containing compound as phosphorus. The HZSM-5 molecular sieve is obtained by ammonium exchange of ZSM-5 molecular sieve to reduce sodium to Na₂O < 0.1 wt%, with a silicon-to-aluminum ratio (molar ratio of silicon oxide to aluminum oxide, the same below) ≥ 10, typically between 10 and 200.

[0023] Regarding the phosphorus-modified ZSM-5 molecular sieve in the catalyst of this application, this application also incorporates the contents of Chinese Invention Application No. 202210899906.6, filed on July 28, 2022, for reference.

[0024] In the cracking catalyst used in the method of the present invention, preferably, the Y-type molecular sieve and the phosphorus-modified ZSM-5 molecular sieve account for 6-85% by weight of the catalyst on a dry basis. Further, the Y-type molecular sieve accounts for 3-15% by weight of the catalyst on a dry basis, and the phosphorus-modified molecular sieve accounts for 5-75% by weight of the catalyst on a dry basis. More preferably, the weight ratio of the Y-type molecular sieve to the phosphorus-modified ZSM-5 molecular sieve is 1:(0.25-40).

[0025] In the cracking catalyst used in the method of the present invention, the inorganic binder includes a phosphorus-aluminum inorganic binder, which comprises 5-40% by weight on a dry basis of the catalyst. Based on the dry weight of the phosphorus-aluminum inorganic binder, the phosphorus-aluminum inorganic binder comprises 15-40% by weight of aluminum component based on Al2O3 and 45-80% by weight of phosphorus component based on P2O5, and its P / Al weight ratio is 1.0-6.0, pH value is 1-3.5, and solid content is 15-60% by weight; for example, it comprises 15-40% by weight of aluminum component based on Al2O3 and 45-80% by weight of phosphorus component based on P2O5; preferably, it contains 15-35% by weight of aluminum component based on Al2O3 and 50-75% by weight of phosphorus component based on P2O5, and its P / Al weight ratio is preferably 1.2-6.0, more preferably 2.0-5.0, and pH value is preferably 1.5-3.0. Preferably, the phosphorus-aluminum inorganic binder is based on its dry weight and comprises 20-40% by weight of aluminum component (calculated as Al2O3) and 60-80% by weight of phosphorus component (calculated as P2O5).

[0026] The phosphorus-aluminum inorganic binder can be prepared by the following steps: dispersing an alumina source, clay (e.g., tartar, kaolin) and water into a slurry with a solid content of 5-50% by weight; wherein the alumina source is aluminum hydroxide and / or alumina (e.g., boehmite, SB powder, γ-alumina) that can be dissolved by acid, relative to 15-50 parts by weight of the alumina source calculated as Al2O3; adding concentrated phosphoric acid to the slurry under stirring at a weight ratio of P / Al = 1-6, and reacting the resulting mixed slurry at 50-99°C for 15-90 minutes; wherein in the P / Al ratio, P is the weight of phosphorus in the phosphoric acid as elemental, and Al is the weight of aluminum in the alumina source as elemental.

[0027] The inorganic binder may also contain at least one selected from boehmite, aluminum sol, silica-alumina sol, and water glass.

[0028] In the pyrolysis catalyst used in the method of the present invention, the clay is well known to those skilled in the art. The clay can be at least one selected from kaolin, sepiolite, attapulgite, palygorskite, montmorillonite, and diatomaceous earth, preferably kaolin, metakaolin, or palygorskite. Based on the dry weight of the catalytic pyrolysis catalyst, it contains 2-60% by weight of clay, preferably 5-55% by weight, and more preferably 15-40% by weight of clay.

[0029] Catalyst Preparation Process. In one specific embodiment of the catalyst preparation of the present invention, an inorganic binder (e.g., boehmite, alumina sol, silica sol, aluminosilicate gel, or a mixture of two or more thereof) is mixed with clay (e.g., kaolin) and water (e.g., deoxygenated water and / or deionized water) to prepare a slurry with a solid content of 10-50% by weight. The mixture is stirred evenly, and the pH of the slurry is adjusted to 1-4 with an inorganic acid such as hydrochloric acid, nitric acid, phosphoric acid, or sulfuric acid. This pH value is maintained, and the mixture is allowed to age at 20-80°C for 0-2 hours, for example, 0.3-2 hours. Then, alumina sol and / or silica sol are added, and the mixture is stirred for 0.5-1.5 hours to form a colloid. Then, molecular sieves, including the phosphorus-modified ZSM-5 molecular sieve and Y-type molecular sieve, are added to form a catalyst slurry with a solid content of, for example, 20-45% by weight. After continued stirring, the mixture is spray-dried to prepare microsphere catalysts. The microsphere catalyst is then calcined, for example at 350–650°C or 400–600°C, preferably 450–550°C, for 0.5–6 hours or 0.5–2 hours. It is then washed with ammonium sulfate (the washing temperature can be 40–70°C, and the weight ratio of ammonium sulfate:microsphere catalyst:water is 0.2–0.8:1:5–15) until the sodium oxide content is less than 0.25% by weight. After washing with water and filtering, it is then dried.

[0030] In another specific embodiment of the preparation of the catalyst of the present invention, Y-type molecular sieve and phosphorus-modified ZSM-5 molecular sieve, phosphorus aluminum inorganic binder and other inorganic binders can be mixed, clay can be added, pulping can be carried out, and spray drying can be performed.

[0031] The present invention also provides a cracking catalyst used in the above-mentioned catalytic cracking of hydrocarbon oils. Based on the dry weight of the cracking catalyst, the cracking catalyst contains 2-20% Y-type molecular sieve, 3-80% phosphorus-modified ZSM-5 molecular sieve, 1-70% inorganic binder, and 2-60% clay, on a dry basis. The phosphorus-modified ZSM-5 molecular sieve is characterized by being obtained by modification with a phosphorus-containing compound in which phosphorus has a +3 valence state. After hydrothermal aging at 800°C and 100% steam for 17 hours, the phosphorus-modified ZSM-5 molecular sieve exhibits an electron binding energy of 135.2 eV for phosphorus species on its surface and a crystallinity retention of 70%–110% in XRD analysis.

[0032] When the described cracking catalyst is used in a catalytic cracking process, the catalyst can be added alone to the catalytic cracking reactor, for example, under catalytic cracking conditions, to allow the hydrocarbon oil to contact and react with the catalytic cracking catalyst of the present invention; or, the cracking catalyst can be used in a mixture with other cracking catalysts, wherein the catalytic cracking catalyst of the present invention accounts for no more than 30% by weight of the total amount of the mixture, preferably 1-25% by weight, more preferably 3-15% by weight. The cracking method provided by the present invention can use various hydrocarbon oils as feedstock. The hydrocarbon oil can be selected from various petroleum fractions, such as crude oil, naphtha, catalytic gasoline, atmospheric residue, vacuum residue, atmospheric wax oil, vacuum wax oil, straight-run wax oil, propane light / heavy deoiling, coking wax oil, and one or more of coal liquefaction products. The hydrocarbon oil may contain heavy metal impurities such as nickel and vanadium, as well as sulfur and nitrogen impurities; for example, the sulfur content in the hydrocarbon oil can be as high as 3.0% by weight, the nitrogen content can be as high as 2.0% by weight, and the content of metal impurities such as vanadium and nickel can be as high as 3000 ppm.

[0033] In the hydrocarbon oil catalytic cracking method of the present invention, the catalytic cracking conditions can be those conventional in the art, preferably including: a reaction temperature of 500-800°C, for example 550-680°C.

[0034] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0035] X-ray diffraction (XRD) patterns were determined using a Rigaku TTR-3 powder X-ray diffractometer. Instrument parameters: copper target (tube voltage 40 kV, tube current 250 mA), scintillation counter, step width 0.02°, scan rate 0.4 (°) / min. ZSM-5 molecular sieve synthesized using the method in Example 1 of CN1056818C was used as a standard, and its crystallinity was defined as 100%. Relative crystallinity was expressed as a percentage, representing the sum of the peak areas of the five characteristic diffraction peaks between 2θ and 25.0° in the X-ray diffraction patterns of the obtained product and the standard.

[0036] X-ray photoelectron spectroscopy (XPS) was used to analyze the surface of molecular sieves and examine the migration of phosphorus compounds. A Thermo Fisher-VG ESCALAB 250 X-ray photoelectron spectrometer was used. Instrument parameters: the excitation source was monochromatic AlKα X-rays with a power of 150 W, and the charge shift was corrected using the C1s peak (284.8 eV) from contaminating carbon.

[0037] Unless otherwise specified, the instruments and reagents used in the embodiments of the present invention are instruments and reagents commonly used by those skilled in the art.

[0038] The properties of some of the raw materials used in the examples are as follows:

[0039] Boehmite is an industrial product manufactured by Shandong Aluminum Company, with a solid content of 60% by weight.

[0040] The aluminum sol is an industrial product manufactured by Sinopec Catalysts Qilu Branch, with an Al2O3 content of 21.5% by weight.

[0041] The silica sol is an industrial product manufactured by Sinopec Catalysts Qilu Branch, with a SiO2 content of 28.9% by weight and a Na2O content of 8.9%.

[0042] The kaolin is a special kaolin for catalytic cracking catalysts produced by Suzhou Kaolin Company, with a solid content of 78% by weight. The rettosite is produced by Hubei Zhongxiang Mingliu Rettosite Development Co., Ltd., with a quartz sand content of <3.5% by weight, an Al2O3 content of 39.0% by weight, a Na2O content of 0.03% by weight, and a solid content of 77% by weight.

[0043] SB aluminum hydroxide powder, manufactured by Condex GmbH, Germany, has an Al2O3 content of 75% by weight.

[0044] HRY molecular sieve is an industrial product manufactured by Sinopec Catalyst Changling Branch, with a rare earth content of 10% by weight.

[0045] PSRY molecular sieve is an industrial product manufactured by Sinopec Catalyst Changling Branch. It has a Na2O content of <1.5 wt%, a P2O5 content of 0.8-1.2 wt%, a cell constant of <2.456 nm, and a crystallinity of ≥64%.

[0046] Unless otherwise specified, the instruments and reagents used in the embodiments of the present invention are instruments and reagents commonly used by those skilled in the art.

[0047] Examples 1-6 illustrate the phosphorus-modified ZSM-5 molecular sieve used in the catalyst of the present invention and its preparation.

[0048] Example 1

[0049] 10.8g of solid phosphorous acid was added to 100g of HZSM-5 molecular sieve (nSiO2 / nAl2O3=30), and the mixture was ground and mixed for 0.5h. The mixture was then transferred to a Teflon-lined stainless steel high-pressure reactor for a melting process at 100℃ for 10h. After the process, the sample was allowed to cool to room temperature naturally before being removed. The sample was then calcined at 550℃ for 2h to obtain a phosphorus-modified ZSM-5 molecular sieve sample, denoted as RYB-1.

[0050] Example 1-1

[0051] 10.8g of solid phosphorous acid was dissolved in 145g of deionized water at 25℃ and stirred for 0.5h to obtain a phosphorus-containing aqueous solution. 100g of HZSM-5 molecular sieve (nSiO2 / nAl2O3=30) was added, and the solution was modified by impregnation. After impregnation at 25℃ for 0.5h, the solution was transferred to an oven and dried at 120℃ for 12h. The solution was then calcined in an air atmosphere in a muffle furnace at 550℃ for 2h. The resulting phosphorus-modified ZSM-5 molecular sieve control sample was designated as RYB-1s.

[0052] Example 2

[0053] 15.4g of solid diammonium hydrogen phosphite was added to 100g of HZSM-5 molecular sieve (nSiO2 / nAl2O3=30). After grinding and mixing for 0.5h, the mixture was transferred to a Teflon-lined stainless steel high-pressure reactor for melting at 100℃ for 10h. After the melting process, the sample was taken out after naturally cooling to room temperature. The sample was then calcined at 550℃ for 2h to obtain a phosphorus-modified ZSM-5 molecular sieve sample, denoted as RYB-2.

[0054] Comparative Example 1

[0055] 17.4 g of diammonium hydrogen phosphate was dissolved in 145 g of deionized water at 25 °C and stirred for 0.5 h to obtain a phosphorus-containing aqueous solution. 100 g of HZSM-5 molecular sieve (nSiO2 / nAl2O3 = 30) was added, and the solution was modified by impregnation. After impregnation at 25 °C for 0.5 h, the solution was transferred to an oven and dried at 120 °C for 12 h. The solution was then calcined in an air atmosphere in a muffle furnace at 550 °C for 2 h. The resulting phosphorus-modified ZSM-5 molecular sieve control sample was designated as D-1.

[0056] Comparative Example 2

[0057] 15.1 g of phosphoric acid solution (85 wt%) was dissolved in 145 g of deionized water at 25 °C and stirred for 0.5 h to obtain a phosphorus-containing aqueous solution. 100 g of HZSM-5 molecular sieve (nSiO2 / nAl2O3 = 30) was added, and the solution was modified by impregnation. After impregnation at 25 °C for 0.5 h, the solution was transferred to an oven and dried at 120 °C for 12 h. The solution was then calcined in an air atmosphere in a muffle furnace at 550 °C for 2 h. The resulting phosphorus-modified ZSM-5 molecular sieve control sample was designated as D-2.

[0058] In Examples 1, 1-1, 2 and Comparative Examples 1, 2, the phosphorus-aluminum ratio of the phosphorus-containing compound to the molecular sieve was 1.25.

[0059] The XPS (P2p Scan) spectrum of sample RYB-1 is shown below. Figure 1 . Figure 1In the image, peaks of 134.5 eV and 135.2 eV represent the electron binding energies of phosphorus in the phosphorus species on the surface of sample RYB-1 after drying and calcination, respectively. The XPS (P2pScan) spectra of RYB-1s and RYB-2 both exhibit... Figure 1 Its characteristics.

[0060] The relative crystallinity and crystallinity retention of XRD values ​​for RYB-1, RYB-1s, RYB-2, D-1, and D-2 before and after hydrothermal aging treatment at 800℃ and 100% steam for 17 hours are shown in Table 1.

[0061] Table 1

[0062]

[0063] Example 3

[0064] 6.5g of solid phosphorous acid was added to 100g of HZSM-5 molecular sieve (nSiO2 / nAl2O3=30), and the mixture was ground and mixed for 0.5h. The mixture was then transferred to a Teflon-lined stainless steel high-pressure reactor for a melting process at 100℃ for 10h. After the melting process, the sample was allowed to cool to room temperature naturally before being removed. The sample was then calcined at 550℃ for 2h to obtain a phosphorus-modified ZSM-5 molecular sieve sample, denoted as RYB-3.

[0065] Example 3-1

[0066] 6.5g of solid phosphorous acid was dissolved in 145g of deionized water at 25℃ and stirred for 0.5h to obtain a phosphorus-containing aqueous solution. 100g of HZSM-5 molecular sieve (nSiO2 / nAl2O3=30) was added, and the solution was modified by impregnation. After impregnation at 25℃ for 0.5h, the solution was transferred to an oven and dried at 120℃ for 12h. The solution was then calcined in an air atmosphere in a muffle furnace at 550℃ for 2h. The resulting phosphorus-modified ZSM-5 molecular sieve control sample was designated as RYB-3s.

[0067] Example 4

[0068] Take 9.3g of solid diammonium hydrogen phosphite and add it to 100g of HZSM-5 molecular sieve (nSiO2 / nAl2O3=30). Grind and mix it for 0.5h and then transfer it to a Teflon-lined stainless steel high-pressure reactor for a melting process at 100℃ for 10h. After the process, let the sample cool to room temperature naturally and then take it out. After calcining the above sample at 550℃ for 2h, a phosphorus-modified ZSM-5 molecular sieve sample is obtained, which is denoted as RYB-4.

[0069] Comparative Example 3

[0070] 10.5g of diammonium hydrogen phosphate was dissolved in 145g of deionized water at 25℃ and stirred for 0.5h to obtain a phosphorus-containing aqueous solution. 100g of HZSM-5 molecular sieve (nSiO2 / nAl2O3=30) was added, and the solution was modified by impregnation. After impregnation at 25℃ for 0.5h, the solution was transferred to an oven and dried at 120℃ for 12h. The solution was then calcined in an air atmosphere in a muffle furnace at 550℃ for 2h. The resulting phosphorus-modified ZSM-5 molecular sieve control sample was designated as D-3.

[0071] Comparative Example 4

[0072] 9.2 g of phosphoric acid solution (85 wt%) was dissolved in 145 g of deionized water at 25 °C and stirred for 0.5 h to obtain a phosphorus-containing aqueous solution. 100 g of HZSM-5 molecular sieve (nSiO2 / nAl2O3 = 30) was added, and the solution was modified by impregnation. After impregnation at 25 °C for 0.5 h, the solution was transferred to an oven and dried at 120 °C for 12 h. The solution was then calcined in an air atmosphere in a muffle furnace at 550 °C for 2 h. The resulting phosphorus-modified ZSM-5 molecular sieve control sample was designated as D-4.

[0073] In Examples 3, 3-1, 4 and Comparative Examples 3, 4, the phosphorus-aluminum ratio of the phosphorus-containing compound to the molecular sieve was 0.75.

[0074] XPS (P2p Scan) spectra of samples RYB-3, RYB-3s, and RYB-4 all have Figure 1 Its characteristics.

[0075] The relative crystallinity and crystallinity retention of XRD values ​​for RYB-3, RYB-3s, RYB-4, D-3, and D-4 before and after hydrothermal aging treatment at 800℃ and 100% steam for 17 hours are shown in Table 3.

[0076] Table 3

[0077]

[0078] Example 5

[0079] 15.0g of solid phosphorous acid was added to 100g of HZSM-5 molecular sieve (nSiO2 / nAl2O3=30), and the mixture was ground and mixed for 0.5h. The mixture was then transferred to a Teflon-lined stainless steel high-pressure reactor for a melting process at 100℃ for 10h. After the melting process, the sample was allowed to cool to room temperature naturally before being removed. The sample was then calcined at 550℃ for 2h to obtain a phosphorus-modified ZSM-5 molecular sieve sample, denoted as RYB-5.

[0080] Example 5-1

[0081] 15.0g of solid phosphorous acid was dissolved in 145g of deionized water at 25℃ and stirred for 0.5h to obtain a phosphorus-containing aqueous solution. 100g of HZSM-5 molecular sieve (nSiO2 / nAl2O3=30) was added, and the solution was modified by impregnation. After impregnation at 25℃ for 0.5h, the solution was transferred to an oven and dried at 120℃ for 12h. The solution was then calcined in an air atmosphere in a muffle furnace at 550℃ for 2h. The resulting phosphorus-modified ZSM-5 molecular sieve control sample was designated as RYB-5s.

[0082] Example 6

[0083] 21.7g of solid diammonium hydrogen phosphite was added to 100g of HZSM-5 molecular sieve (nSiO2 / nAl2O3=30). After grinding and mixing for 0.5h, the mixture was transferred to a Teflon-lined stainless steel high-pressure reactor for melting at 100℃ for 10h. After the melting process, the sample was taken out after naturally cooling to room temperature. The sample was then calcined at 550℃ for 2h to obtain a phosphorus-modified ZSM-5 molecular sieve sample, denoted as RYB-6.

[0084] Comparative Example 5

[0085] 24.5g of diammonium hydrogen phosphate was dissolved in 145g of deionized water at 25℃ and stirred for 0.5h to obtain a phosphorus-containing aqueous solution. 100g of HZSM-5 molecular sieve (nSiO2 / nAl2O3=30) was added, and the solution was modified by impregnation. After impregnation at 25℃ for 0.5h, the solution was transferred to an oven and dried at 120℃ for 12h. The solution was then calcined in an air atmosphere in a muffle furnace at 550℃ for 2h. The resulting phosphorus-modified ZSM-5 molecular sieve control sample was designated as D-5.

[0086] Comparative Example 6

[0087] 21.4 g of phosphoric acid solution (85 wt%) was dissolved in 145 g of deionized water at 25 °C and stirred for 0.5 h to obtain a phosphorus-containing aqueous solution. 100 g of HZSM-5 molecular sieve (nSiO2 / nAl2O3 = 30) was added, and the solution was modified by impregnation. After impregnation at 25 °C for 0.5 h, the solution was transferred to an oven and dried at 120 °C for 12 h. The solution was then calcined in an air atmosphere in a muffle furnace at 550 °C for 2 h. The resulting phosphorus-modified ZSM-5 molecular sieve control sample was designated as D-6.

[0088] In Examples 5, 5-1, 6 and Comparative Examples 5, 6, the phosphorus-aluminum ratio of the phosphorus-containing compound to the molecular sieve was 1.75.

[0089] XPS (P2p Scan) spectra of samples RYB-5, RYB-5s, and RYB-6 all have Figure 1 Its characteristics.

[0090] The relative crystallinity and crystallinity retention of XRD values ​​for RYB-5, RYB-5s, RYB-6, D-5, and D-6 before and after hydrothermal aging treatment at 800℃ and 100% steam for 17 hours are shown in Table 5.

[0091] Table 5

[0092]

[0093]

[0094] Examples 7-26 illustrate the cracking catalyst provided by the present invention.

[0095] The phosphorus-aluminum inorganic binder used in the examples was prepared using the following process:

[0096] 1. NJ1: 1.91 kg of boehmite (containing 1.19 kg of Al2O3), 0.56 kg of kaolin (0.5 kg on a dry basis), and 3.27 kg of decationized water were mixed into a slurry for 30 minutes. While stirring, 5.37 kg of concentrated phosphoric acid (85% by mass) was added to the slurry at a rate of 0.04 kg phosphoric acid / min / kg alumina source. The temperature was raised to 70°C, and the mixture was reacted at this temperature for 45 minutes to obtain the phosphorus-aluminum inorganic binder. The material ratio is shown in Table 6, and the sample number is NJ1.

[0097] 2. NJ2: Following the preparation process of NJ1, the material ratio is shown in Table 9, and the sample number is NJ2.

[0098] Table 6

[0099]

[0100]

[0101] Examples 7-9

[0102] Take the phosphorus-modified molecular sieve RYB-1, Y-type molecular sieve (PSRY molecular sieve), kaolin and pseudoboehmite from Example 1, add decationized water and slurry for 120 minutes to obtain a slurry with a solid content of 30% by weight. Add hydrochloric acid to adjust the pH of the slurry to 3.0, and then continue slurrying for 45 minutes. Then add phosphorus-aluminum inorganic binder NJ1, stir for 30 minutes, and spray dry the obtained slurry to obtain microspheres. Calcine the microspheres at 500°C for 1 hour to obtain the catalyst, designated Cat1.

[0103] The molecular sieve RYB-1 was replaced by samples RYB-1s and RYB-2 from Examples 1-1 and 2, respectively, and catalysts were prepared using the same preparation process as described above. These catalysts were numbered Cat2 and Cat3.

[0104] In the material proportions of Cat1, Cat2, and Cat3, on a dry basis, phosphorus-modified molecular sieve accounts for 60%, PSRY accounts for 5%, kaolin accounts for 20%, phosphorus-aluminum binder NJ1 accounts for 10%, and pseudoboehmite accounts for 5%.

[0105] Comparative Examples 7 and 8

[0106] The preparation process and material ratio were the same as in Example 7, except that the phosphorus-modified molecular sieves D-1 and D-2 of Comparative Examples 1 and 2 were used to replace molecular sieve RYB-1 to prepare comparative catalysts, which were numbered DCat1 and DCat2 respectively.

[0107] Examples 10-12

[0108] Take the phosphorus-modified molecular sieve RYB-3, Y-type molecular sieve (HRY molecular sieve), and kaolin from Example 3, add decationized water and aluminum sol, and slurry for 120 minutes to obtain a slurry with a solid content of 30% by weight. Add hydrochloric acid to adjust the pH of the slurry to 3.0, and then continue slurrying for 45 minutes. Then add phosphorus-aluminum inorganic binder NJ2, stir for 30 minutes, and spray dry the obtained slurry to obtain microspheres. Calcine the microspheres at 500°C for 1 hour to obtain the catalyst, designated Cat4.

[0109] Catalysts were prepared by replacing molecular sieve RYB-3 with phosphorus-modified molecular sieves RYB-3s and RYB-4 from Examples 3-1 and 4, respectively, using the same preparation process as described above. The catalysts were numbered Cat5 and Cat6.

[0110] In the material proportions of Cat4, Cat5, and Cat6, on a dry basis by weight, phosphorus-modified ZSM-5 molecular sieve accounts for 60%, HRY accounts for 5%, kaolin accounts for 20%, phosphorus-aluminum binder NJ2 accounts for 10%, and alumina sol accounts for 5%.

[0111] Comparative Examples 9 and 10

[0112] The preparation process and material ratio were the same as in Example 10, except that phosphorus-modified molecular sieves D-3 and D-4 of Comparative Examples 3 and 4 were used to replace molecular sieve RYB-3 to prepare comparative catalysts, which were numbered DCat3 and DCat4 respectively.

[0113] Examples 13-15

[0114] Take the phosphorus-modified molecular sieve RYB-5, Y-type molecular sieve (PSRY molecular sieve), and kaolin from Example 5, add decationized water and alumina sol, and slurry for 120 minutes to obtain a slurry with a solid content of 30% by weight. Add hydrochloric acid to adjust the pH of the slurry to 3.0, and then continue slurrying for 45 minutes. Then add phosphorus-aluminum inorganic binder NJ1, stir for 30 minutes, and spray dry the obtained slurry to obtain microspheres. Calcine the microspheres at 500°C for 1 hour to obtain the catalyst, designated Cat7.

[0115] Catalysts were prepared by replacing molecular sieve RYB-5 with phosphorus-modified molecular sieves RYB-5s and RYB-6 from Examples 5-1 and 6, respectively, using the same preparation process as described above. The catalysts were numbered Cat8 and Cat9.

[0116] In the material composition of Cat7, Cat8, and Cat9, on a dry basis, phosphorus-modified ZSM-5 molecular sieve accounts for 50%, PSRY accounts for 20%, kaolin accounts for 15%, phosphorus-aluminum binder NJ1 accounts for 10%, and alumina sol accounts for 5%.

[0117] Comparative Examples 11 and 12

[0118] The preparation process and material ratio were the same as in Example 13, except that the phosphorus-modified molecular sieves D-5 and D-6 of Comparative Examples 5 and 6 were used to replace molecular sieve RYB-5 to prepare comparative catalysts, which were numbered DCat5 and DCat6 respectively.

[0119] The following examples illustrate the catalytic cracking method provided by the present invention.

[0120] Examples 16-18

[0121] Catalysts Cat1-Cat3 were aged at 800℃ under a 100% steam atmosphere for 17 hours. The aged catalysts were then loaded into a fixed-bed microreactor to evaluate their catalytic cracking ability for light hydrocarbons. The evaluation conditions were: reaction temperature 650℃, regeneration temperature 620℃, and catalyst-to-oil ratio 3.2.

[0122] The properties of the feedstock oil are shown in Table 7. The reaction results are shown in Table 8.

[0123] Table 7

[0124] project Light hydrocarbons <![CDATA[Density (20 °C) / (kg·m -3 )]]> 670.7 Elemental mass composition / % C 83.81 H 16.19 <![CDATA[S / mg.L -1 ]]> 2.6 <![CDATA[N / mg.L -1 ]]> <0.3 Distillation range / ℃ Initial boiling point 33.7 10％ 56.3 30％ 69.1 50％ 86.6 70％ 107.2 90％ 130.5 95％ 137.5 Final boiling point 155.7 Hydrocarbon mass composition / % n-Alkanes 72.69 Isoalkanes 25.48 Olefins 0.13 Cycloalkanes 1.56 Aromatics 0.17 total 100.03

[0125] Comparative Examples 13 and 14

[0126] Same as Example 16, except that comparative catalysts DCat1 and DCat2 are used instead of Cat1.

[0127] The reaction results are shown in Table 8.

[0128] Table 8

[0129]

[0130]

[0131] Examples 19-21

[0132] Catalyst C at 4-C at 6. The catalyst was aged at 800℃ for 17 hours under a 100% water vapor atmosphere. The aged catalyst was then loaded into a fixed-bed microreactor to evaluate its catalytic cracking ability for light hydrocarbons. The evaluation conditions were: reaction temperature 650℃, regeneration temperature 620℃, and catalyst-to-oil ratio 3.2.

[0133] The reaction results are shown in Table 9.

[0134] Comparative Examples 15 and 16

[0135] Same as Example 19, except that the comparative catalysts DCat3 and DCat4 are used instead of Cat4, respectively.

[0136] The reaction results are shown in Table 9.

[0137] Table 9

[0138] project Example 19 Example 20 Example 21 Comparative Example 15 Comparative Example 16 Catalyst name Cat4 Cat5 Cat6 DCat3 DCat4 Conversion rate 69.63 67.01 68.76 62.80 61.49 Coke quantity 10.44 11.02 10.89 12.71 12.97 Liquid product yield / wt% 28.12 30.53 29.31 31.25 31.29 Gas product yield / wt% 61.44 58.45 59.80 56.04 55.74 Cracking gas product yield (wt%) C2＝ 16.13 15.23 15.81 11.27 11.01 C3＝ 21.17 18.01 19.37 16.03 15.73

[0139] Examples 22-24

[0140] Catalysts Cat7-Cat9 were aged at 800℃ under a 100% steam atmosphere for 17 hours. The aged catalysts were then loaded into a fixed-bed microreactor to evaluate their catalytic cracking capacity for light hydrocarbons. The evaluation conditions were: reaction temperature 650℃, regeneration temperature 620℃, and catalyst-to-oil ratio 3.2.

[0141] The reaction results are shown in Table 10.

[0142] Comparative Examples 17 and 18

[0143] Same as Example 22, except that comparative catalysts DCat5 and DCat6 are used instead of Cat7.

[0144] The reaction results are shown in Table 10.

[0145] Table 10

[0146] project Example 22 Example 23 Example 24 Comparative Example 17 Comparative Example 18 Catalyst name Cat7 Cat8 Cat9 DCat5 DCat6 Conversion rate 54.15 51.81 54.03 45.72 43.84 Coke quantity 4.29 4.47 4.16 4.71 4.53 Liquid product yield / wt% 50.05 53.11 51.16 57.56 59.09 Gas product yield / wt% 45.66 42.42 44.68 37.73 36.38 Cracking gas product yield (wt%) C2＝ 7.44 6.99 7.29 4.58 4.18 C3＝ 12.32 11.61 11.90 8.77 8.01

[0147] Examples 25-27

[0148] Catalysts Cat1-Cat3 were aged at 800℃ under a 100% steam atmosphere for 17 hours. The aged catalysts were then loaded into a fixed-bed microreactor to evaluate their catalytic cracking capacity for light hydrocarbons. The evaluation conditions were: reaction temperature 660℃, regeneration temperature 600℃, and catalyst-to-oil ratio 15.

[0149] The reaction results are shown in Table 11.

[0150] Comparative Examples 19 and 20

[0151] Same as Example 25, except that comparative catalysts DCat1 and DCat2 are used instead of Cat1.

[0152] The reaction results are shown in Table 11.

[0153] Table 11

[0154] project Example 25 Example 26 Example 27 Comparative Example 19 Comparative Example 20 Catalyst name Cat1 Cat2 Cat3 DCat1 DCat2 Conversion rate 78.42 75.81 77.67 72.18 71.00 Coke quantity 10.55 11.23 10.79 12.47 12.15 Liquid product yield / wt% 22.69 24.11 23.52 26.76 27.42 Gas product yield / wt% 66.76 64.66 65.69 60.77 60.43 Cracking gas product yield (wt%) C2＝ 18.07 17.48 17.93 16.71 16.07 C3＝ 23.80 21.92 23.27 19.83 19.26

[0155] As shown in Tables 8, 9, 10, and 11, the catalytic cracking catalysts prepared by modifying ZSM-5 molecular sieves with phosphorus-containing compounds in the +3 oxidation state have higher hydrocarbon conversion rates, lower coke production, and higher ethylene and propylene yields compared to the catalytic cracking catalysts prepared by modifying ZSM-5 molecular sieves with phosphorus-containing compounds in the +5 oxidation state.

Claims

1. A catalytic cracking method, which is a method of bringing a hydrocarbon oil into contact with a cracking catalyst under catalytic cracking reaction conditions, the cracking catalyst containing, on a dry basis, 2 to 20% of a Y-type molecular sieve, 3 to 80% of a phosphorus-modified ZSM-5 molecular sieve, 1 to 70% of an inorganic binder, and 2 to 60% of clay, based on the dry weight of the cracking catalyst, characterized in that, The phosphorus-modified ZSM-5 molecular sieve is obtained by mixing and grinding a solid phosphorus-containing compound with valence +3 and HZSM-5 molecular sieve to obtain a solid mixture, heating and melting the solid mixture, and then obtaining the phosphorus-modified ZSM-5 molecular sieve by calcination after the heated and melted solid mixture is cooled to room temperature; or the phosphorus-modified ZSM-5 molecular sieve is obtained by contacting and impregnating HZSM-5 molecular sieve with an aqueous solution of a solid phosphorus-containing compound with valence +3, and then drying and calcining; the solid phosphorus-containing compound with valence +3 is selected from phosphorous acid and / or ammonium phosphite; the phosphorus-modified ZSM-5 molecular sieve has an electron binding energy of phosphorus element in phosphorus species on the molecular sieve surface of 135.2 eV after hydrothermal aging at 800 ℃ under 100% steam for 17 h, and a crystalline retention degree of 70% to 110% in XRD analysis.

2. The method according to claim 1, characterized in that The cracking catalyst is used alone or in a mixture with a conventional cracking catalyst, and the cracking catalyst accounts for not more than 30% by weight of the total amount of the mixture.

3. The method of claim 2, wherein, In the mixture, the cracking catalyst accounts for 1 to 25% by weight of the total amount of the mixture.

4. The method of claim 3, wherein, In the mixture, the cracking catalyst accounts for 3 to 15% by weight of the total amount of the mixture.

5. The method of claim 1, wherein, The catalytic cracking reaction conditions include a reaction temperature of 500 to 800 ℃.

6. The method of claim 1, wherein, The hydrocarbon oil is selected from one or more of crude oil, naphtha, gasoline, atmospheric residue, vacuum residue, atmospheric wax oil, vacuum wax oil, straight-run wax oil, propane light / heavy deoiled, coking wax oil, and coal liquefaction products.

7. The method of claim 1, wherein, The Y-type molecular sieve is at least one selected from PSRY molecular sieve, PSRY-S molecular sieve, rare earth-containing PSRY molecular sieve, rare earth-containing PSRY-S molecular sieve, USY molecular sieve, rare earth-containing USY molecular sieve, REY molecular sieve, REHY molecular sieve, and HY molecular sieve.

8. The method of claim 1, wherein, The phosphorus-modified ZSM-5 molecular sieve has a crystalline retention degree of 95% to 110% in XRD analysis after hydrothermal aging at 800 ℃ under 100% steam for 17 h.

9. The method of claim 1, wherein, The phosphorus-modified ZSM-5 molecular sieve has a ratio of phosphorus to aluminum of 0.01 to 5.

10. The method of claim 1, wherein, The phosphorus-modified ZSM-5 molecular sieve has a ratio of phosphorus to aluminum of 0.1 to 3.

11. The method of claim 1, wherein, The heating and melting treatment has a temperature higher than the melting point of the solid phosphorus-containing compound with valence +3 and lower than the temperature at which the solid phosphorus-containing compound with valence +3 decomposes or dehydrates, and a treatment time of 2 to 72 hours.

12. The method of claim 1, wherein, The molar ratio of the solid phosphorus-containing compound with valence +3 to HZSM-5 molecular sieve is 0.1 to 5.

13. The method of claim 12, wherein, The molar ratio of the solid phosphorus-containing compound with valence +3 to HZSM-5 molecular sieve is 0.5 to 2.

5.

14. The method of claim 1, wherein, The inorganic binder includes a phosphorus-aluminum inorganic binder, and the phosphorus-aluminum inorganic binder accounts for 5 to 40% by weight of the dry catalyst.

15. The method of claim 1 or 14, wherein, The inorganic binder further contains at least one selected from pseudo-boehmite, aluminum sol, silica-alumina sol and water glass.

16. The method of claim 1, wherein, The clay is at least one selected from kaolin, sepiolite, attapulgite, rectorite, montmorillonite and diatomite.

17. A cracking catalyst comprising, on a dry basis, 2 to 20% of a Y-type molecular sieve, 3 to 80% of a phosphorus-modified ZSM-5 molecular sieve, 1 to 70% of an inorganic binder, and 2 to 60% of clay, based on the dry basis weight of the cracking catalyst, characterized in that, The phosphorus-modified ZSM-5 molecular sieve is obtained by mixing and grinding a solid phosphorus compound with valence state of +3 and HZSM-5 molecular sieve to obtain a solid mixture, heating and melting the solid mixture, cooling the heated and melted solid mixture to room temperature, and then performing calcination treatment; or, the phosphorus-modified ZSM-5 molecular sieve is obtained by contacting and impregnating HZSM-5 molecular sieve with an aqueous solution of a solid phosphorus compound with valence state of +3, and then drying and calcining; the solid phosphorus compound with valence state of +3 is selected from phosphorous acid and / or ammonium phosphite; the phosphorus-modified ZSM-5 molecular sieve has an electron binding energy of phosphorus element in phosphorus species on the surface of the molecular sieve of 135.2 eV after hydrothermal aging at 800 DEG C and 100% steam for 17 h, and a crystallinity retention of 70% to 110% in XRD analysis.

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