Catalytic cracking assistant and catalytic cracking reaction method

Abstract

The invention relates to a cracking auxiliary agent, which comprises, by dry base weight, 20-80% of a phosphorus-modified ZSM-5 molecular sieve, 1-70% of an inorganic binder and 2-60% of clay, and is characterized in that the chemical shift range of a resonance signal peak of the phosphorus-modified ZSM-5 molecular sieve in a 31PMAS-NMR spectrogram is 5-20 ppm, and after the molecular sieve is subjected to hydrothermal aging for 17 h at a temperature of 800 DEG C under a 100% water vapor condition, the chemical shift range of the resonance signal peak of the phosphorus-modified ZSM-5 molecular sieve is 5-20 ppm. And the ratio of the resonance signal peak area with the chemical shift of-30 + / -3ppm to the resonance signal peak area with the chemical shift of-40 + / -3ppm is greater than 1.

Description

TECHNICAL FIELD

[0001] The present invention relates to a catalytic cracking reaction method and an additive used for this method. More specifically, the present invention relates to a catalytic cracking reaction method and a cracking additive containing phosphorus-modified ZSM-5 molecular sieve. BACKGROUND ART

[0002] The cracking reaction of hydrocarbons at high temperature is to convert long-chain hydrocarbons into high-value-added light olefins such as ethylene and propylene. ZSM-5 molecular sieve is a mesoporous molecular sieve with a high-silica three-dimensional straight channel of MFI structure developed by Mobil Oil Company in the United States (USP3702886). Its unique pore structure enables it to have good shape-selective catalysis and isomerization performance. ZSM-5 molecular sieve also has characteristics such as high thermal and hydrothermal stability, high specific surface area, wide range of silicon-aluminum ratio changes, unique surface acidity, and low carbon deposition amount. ZSM-5 molecular sieve is widely used as a catalyst and catalyst carrier and has been successfully used in production processes such as alkylation, isomerization, disproportionation, catalytic cracking, methanol-to-gasoline, and methanol-to-olefins.

[0003] Since 1983, ZSM-5 molecular sieve has been applied to the catalytic cracking process as a catalytic cracking octane number additive, aiming to improve the octane number of catalytic cracking gasoline and the selectivity of light olefins. In the technology first reported in US3758403, ZSM-5 is used as an active component for increasing propylene production and is prepared into an FCC catalyst together with REY. US5997728 discloses a technology using ZSM-5 molecular sieve as an additive for increasing propylene production, and the molecular sieve is not modified in any way. The propylene yields in the above two technologies are not high. Although HZSM-5 molecular sieve has good shape-selective performance and isomerization performance, its disadvantage is poor hydrothermal stability and it is easily deactivated under harsh high-temperature hydrothermal conditions, resulting in a reduction in catalytic performance.

[0004] Mobil Company found that phosphorus can improve the hydrothermal stability of ZSM-5 molecular sieve. At the same time, after modifying ZSM-5 molecular sieve with phosphorus, the primary cracking products (such as gasoline olefins) can be selectively converted into C3 and C4 olefins, increasing the light olefin yield. Introducing an appropriate amount of inorganic phosphorus compound for modification after the synthesis of ZSM-5 molecular sieve can stabilize the framework aluminum under harsh hydrothermal conditions.

[0005] CN1211469A discloses a pentacyclic molecular sieve composition for producing more propylene and ethylene, which is composed of 85-95 wt% of pentacyclic molecular sieve, 2-10 wt% of phosphorus in terms of oxide, 0.3-5 wt% of alkaline earth metal in terms of oxide, and 0.3-5 wt% of transition metal element in terms of oxide. When this composition is used for catalytic thermal cracking reaction, a higher ethylene yield is obtained.

[0006] A ZSM-5 molecular sieve modified with phosphorus disclosed in US5171921 has a silica-alumina ratio of 20-60. When the HZSM-5 molecular sieve is impregnated with a phosphorus-containing compound and treated with steam at 500-700 °C, it has higher activity when used in the reaction of converting C3-C20 hydrocarbons into C2-C5 olefins compared to the untreated HZSM-5.

[0007] A preparation method of a phosphorus-modified ZSM-5 molecular sieve disclosed in CN102166533A is to add the molecular sieve into an aqueous solution containing phosphorus, react for a period of time under certain pH value, temperature and pressure, and then obtain the phosphorus-modified molecular sieve through filtration, drying and calcination. Subsequently, the phosphorus-modified molecular sieve is added into an aqueous solution containing rare earth ions, reacted for a period of time under certain temperature and pressure, and then obtained the composite-modified molecular sieve through filtration, washing, drying and calcination. Using this composite-modified molecular sieve to prepare a model catalyst has higher hydrothermal stability and microactivity performance compared to the model catalysts containing unmodified and other modified molecular sieves.

[0008] A preparation method of a phosphorus-modified ZSM-5 molecular sieve disclosed in CN106994364A is to first mix a ZSM-5 molecular sieve with a high alkali metal ion content with a phosphorus-containing compound selected from one or more of phosphoric acid, diammonium hydrogen phosphate, ammonium dihydrogen phosphate and ammonium phosphate to obtain a mixture with a phosphorus loading of at least 0.1 wt% calculated as P2O5. The mixture is dried, calcined, then subjected to an ammonium exchange step and a water washing step to reduce the alkali metal ion content to less than 0.10 wt%, and then undergoes drying and hydrothermal aging at 400-1000 °C and 100% steam conditions. The phosphorus-containing ZSM-5 molecular sieve obtained by this preparation method has a high total acid amount, excellent cracking conversion rate and propylene selectivity, and at the same time has a high liquefied gas yield.

[0009] Although modifying the ZSM-5 molecular sieve with organic / inorganic phosphorus-containing compounds can inhibit framework dealumination and thus improve hydrothermal stability, the introduction of phosphorus species also has the effect of regulating the acid center properties of the ZSM-5 molecular sieve, improving the cracking conversion rate of long-chain alkanes and the selectivity of light olefins. However, during the calcination process of the prior art, phosphoric acid or ammonium phosphate salts will dehydrate and self-polymerize to form macromolecular phosphorus species such as polyphosphoric acid, which are easily enriched 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 and unable to achieve the ideal effect of improving hydrothermal stability after phosphorus modification. Summary of the Invention

[0010] Based on a large number of experiments, the inventors found that the phosphorus-modified ZSM-5 zeolite prepared using solid phosphorus-containing compounds with a valence of +1, such as hypophosphorous acid and hypophosphites, as precursors and calcined at a low temperature of 300-400 °C has physicochemical characteristics different from those of zeolites prepared by impregnating with an aqueous solution of a conventional +5-valent phosphorus source, and can improve the phosphorus-aluminum stabilization efficiency. The hydrothermal stability, cracking activity, and light olefin selectivity of the ZSM-5 zeolite modified in this way are all improved.

[0011] Therefore, one of the objectives of the present invention is to provide a cracking aid with a phosphorus-modified ZSM-5 zeolite having physicochemical characteristics different from those of conventional phosphorus-containing ZSM-5 zeolites and an improved phosphorus-aluminum stabilization efficiency of the zeolite as the active component; the second objective is to provide a catalytic cracking reaction method in which the cracking aid participates.

[0012] To achieve the above objective one, a cracking aid provided in the first aspect of the present invention, based on the dry basis weight of the catalytic cracking aid, is composed of 20-80% of phosphorus-modified ZSM-5 zeolite based on the dry basis, 1-70% of an inorganic binder based on the dry basis, and 2-60% of clay based on the dry basis. It is characterized in that the phosphorus-modified ZSM-5 zeolite is modified with a phosphorus-containing compound with a valence of +1 for phosphorus, and the phosphorus-modified ZSM-5 zeolite, its 31 In the P MAS-NMR spectrum, the chemical shift range where resonance signal peaks appear is 5 to -20 ppm.

[0013] To achieve the above objective two, a catalytic cracking reaction method provided in the second aspect of the present invention is to contact hydrocarbon oil with a mixture of a cracking catalyst and an aid under catalytic cracking reaction conditions. The aid is composed of a phosphorus-modified ZSM-5 zeolite, an inorganic binder, and clay. It is characterized in that the phosphorus-modified ZSM-5 zeolite is modified with a phosphorus-containing compound with a valence of +1 for phosphorus, and the phosphorus-modified ZSM-5 zeolite, its 31 In the P MAS-NMR spectrum, the chemical shift range where resonance signal peaks appear is 5 to -20 ppm.

[0014] The cracking aid provided by the present invention contains a phosphorus-modified ZSM-5 zeolite with a special physicochemical parameter. The phosphorus-modified ZSM-5 zeolite is obtained by selecting a +1-valent phosphorus source for modification; its 31 In the P MAS-NMR spectrum, the chemical shift range where resonance signal peaks appear is 5 to -20 ppm. Using the phosphorus-modified ZSM-5 zeolite as the active component in the cracking aid in the catalytic cracking reaction can improve the selectivity of ethylene and propylene. Description of the Drawings

[0015] Figure 1For the phosphorus-modified ZSM-5 zeolite sample 31 P MAS-NMR spectrum.

[0016] Figure 2 For the phosphorus-modified ZSM-5 zeolite sample after hydrothermal aging treatment at 800 °C, 100% water vapor, and 17 h 31 PMAS-NMR spectrum.

[0017] Figure 3 For the phosphorus-modified ZSM-5 zeolite sample 27 Al MAS-NMR spectrum.

[0018] Figure 4 For the phosphorus-modified ZSM-5 zeolite sample 31 P MAS-NMR spectrum.

[0019] Figure 5 For the phosphorus-modified ZSM-5 zeolite sample after hydrothermal aging treatment at 800 °C, 100% water vapor, and 17 h 31 PMAS-NMR spectrum.

[0020] Figure 6 For the phosphorus-modified ZSM-5 zeolite sample 27 Al MAS-NMR spectrum.

[0021] Figure 7 For the phosphorus-modified ZSM-5 zeolite sample 31 P MAS-NMR spectrum.

[0022] Figure 8 For the phosphorus-modified ZSM-5 zeolite sample after hydrothermal aging treatment at 800 °C, 100% water vapor, and 17 h 31 PMAS-NMR spectrum.

[0023] Figure 9 For the phosphorus-modified ZSM-5 zeolite sample 27 Al MAS-NMR spectrum.

[0024] Figure 10 For the phosphorus-modified ZSM-5 zeolite sample 31 P MAS-NMR spectrum.

[0025] Figure 11 For the phosphorus-modified ZSM-5 zeolite sample after hydrothermal aging treatment at 800 °C, 100% water vapor, and 17 h 31 PMAS-NMR spectrum.

[0026] Figure 12 For the phosphorus-modified ZSM-5 zeolite sample 27Al MAS-NMR spectrum. Detailed implementation mode

[0027] The cracking aid provided by the first aspect of the present invention is composed of phosphorus-modified ZSM-5 molecular sieve, inorganic binder and clay. It is characterized in that the phosphorus-modified ZSM-5 molecular sieve is modified with a phosphorus-containing compound with a phosphorus valence state of +1. The phosphorus-modified ZSM-5 molecular sieve, its 31 In the P MAS-NMR spectrum, the chemical shift range where resonance signal peaks appear is 5 to -20 ppm.

[0028] Of the phosphorus-modified ZSM-5 molecular sieve 31 In the P MAS-NMR spectrum of the phosphorus-modified ZSM-5 molecular sieve, due to the diversity of phosphorus species, the chemical shift of the resonance signal peaks generated has a certain range, representing the degree of condensation of the overall phosphorus species. Among them, the resonance signal peaks in the low-field range such as 0 ppm, -6 ppm and -15 ppm represent phosphorus species with a relatively small degree of condensation such as monomeric phosphoric acid and pyrophosphoric acid, while the resonance signal peaks in the range of -20 to -40 ppm represent polyphosphoric acid species with a relatively high degree of condensation. The inventors of the present invention unexpectedly found that in the preparation process of the phosphorus-modified ZSM-5 molecular sieve, instead of the conventional calcination method at 550 °C in the prior art, after low-temperature calcination at 300 to 400 °C in an air atmosphere environment, the chemical shift range of the resonance signal peaks is 5 to -20 ppm, indicating that the degree of condensation of its phosphorus species is relatively low; while for the molecular sieve modified with phosphoric acid in the prior art, after calcination at 550 °C conventionally, the degree of condensation of the phosphorus species is relatively high, and the chemical shift range of the resonance signal peaks is 5 to -50 ppm.

[0029] Furthermore, in the present invention, after the phosphorus-modified ZSM-5 molecular sieve is hydrothermally aged for 17 h under the conditions of 800 °C and 100% water vapor, 31 In the P MAS-NMR spectrum, the ratio of the peak areas of the resonance signals with chemical shifts of -30 ± 3 ppm and -40 ± 3 ppm > 1. Preferably, the area ratio is 1.05 to 1.4, and more preferably the area ratio is 1.1 to 1.3. The resonance signal with a chemical shift of -30 ± 3 ppm represents the tetracoordinated phosphorus species formed after stabilizing the framework aluminum species, and the resonance signal with a chemical shift of -40 ± 3 ppm represents the condensed pentacoordinated phosphorus species. The larger the ratio of the peak areas of the resonance signals of -30 ± 3 ppm and -40 ± 3 ppm, the more phosphorus species that can stabilize the framework aluminum. In the prior art, the ratio of the peak areas of the resonance signals of -30 ± 3 ppm and -40 ± 3 ppm of the ZSM-5 molecular sieve modified with phosphorus-containing precursors with a phosphorus valence of +5 such as diammonium hydrogen phosphate or phosphoric acid < 1.

[0030] Further, in the present invention, after the phosphorus-modified ZSM-5 zeolite is hydrothermally aged for 17 h under the conditions of 800 °C and 100% water vapor, its 27 In the Al MAS-NMR spectrum, resonance signal peaks with chemical shifts of 39 ± 3 ppm and -12 ± 3 ppm appear simultaneously. The resonance signal with a chemical shift of 39 ± 3 ppm represents the framework aluminum species stabilized after coordination with phosphorus species, that is, distorted tetracoordinated framework aluminum; the resonance signal with a chemical shift of -12 ± 3 ppm represents the extra-framework aluminum species combined with phosphorus species.

[0031] In the present invention, the phosphorus-modified ZSM-5 zeolite has a higher phosphorus retention rate after being washed with water. For example, after being washed with hot water at 70 °C for 2 h, the phosphorus content retention rate is higher than 50%, about 51-75%, while the phosphorus content retention rate in the prior art is less than 50%. The definition of the phosphorus content retention rate is P2O5 before water washing / P2O5 after water washing, calculated as a mass percentage.

[0032] In the present invention, when both phosphorus and aluminum are measured in moles, the ratio of the two is 0.01-5, and the preferred ratio is 0.1-3.

[0033] In one embodiment of the phosphorus-modified ZSM-5 zeolite of the present invention, it is modified with a phosphorus-containing compound with a phosphorus valence state of +1 and obtained through a step including air calcination at 300-400 °C.

[0034] More specifically, in the preparation method of the phosphorus-modified ZSM-5 zeolite of the present invention, the preparation method of the phosphorus-modified ZSM-5 zeolite includes two methods: impregnation with an aqueous solution of a phosphorus precursor with a +1 valence phosphorus and heat melting treatment. One is to contact and impregnate the HZSM-5 zeolite with an aqueous solution of a phosphorus-containing compound with a phosphorus valence state of +1, dry it, and calcine it in air at 300-400 °C to obtain the phosphorus-modified ZSM-5 zeolite; the other is to perform heat melting treatment on the mixture obtained by mixing and grinding the HZSM-5 zeolite with a solid phosphorus-containing compound with a phosphorus valence state of +1, cool it to 20-25 °C, and then calcine it at 300-400 °C.

[0035] In the embodiment of aqueous solution impregnation, the weight ratio of water to zeolite is 0.5-2, and it is carried out for 0.5-10 hours; for the drying, the atmosphere is air, carried out at 100-120 °C for 2-24 hours; for the calcination, the atmosphere is air, carried out at 300-400 °C, preferably 330-370 °C, more preferably 350 °C for 0.5-12 hours.

[0036] In the embodiment of the heat melting treatment, the temperature is higher than the melting point of the solid phosphorus-containing compound and lower than the temperature at which the solid phosphorus-containing compound decomposes or dehydrates (for example, the melting point of hypophosphorous acid is 26.5 °C and the decomposition temperature is 130 °C), and the treatment time is 2 to 72 hours.

[0037] In the present invention, the phosphorus-modified ZSM-5 molecular sieve is obtained by treating the HZSM-5 molecular sieve with a phosphorus-containing compound in which the valence state of phosphorus is +1. By selecting a +1-valent phosphorus source with a relatively small molecule, the migration process of phosphorus species into the pores of the ZSM-5 molecular sieve is accelerated, and the activation efficiency of phosphorus-aluminum species is increased. The phosphorus-containing compound in which the valence state of phosphorus is +1 is one or more of hypophosphorous acid, ammonium hypophosphite, and hypophosphite; or, the aqueous solution of the phosphorus-containing compound in which the valence state of phosphorus is +1 is obtained by adjusting the pH value of the aqueous solution of hypophosphorous acid to 5-9 with ammonia water. They are used as precursors of the phosphorus-containing compound. After air calcination at 300-400 °C, especially 350 °C, phosphorus is converted from +1 valence to a higher oxidation state and has the condition to stabilize framework aluminum during the aging process.

[0038] Regarding the phosphorus-modified ZSM-5 molecular sieve involved in the present application, the content of the Chinese invention application with the application number 202310788556.0 and the application date of June 30, 2023 is incorporated by reference.

[0039] The cracking aid of the present invention, based on the dry basis weight of the cracking aid, is composed of 20-80% of the phosphorus-modified ZSM-5 molecular sieve, 1-70% of the inorganic binder, and 2-60% of the clay.

[0040] The inorganic binder may include a phosphorus-aluminum inorganic binder and / or other inorganic binders. Preferably, the inorganic binder may include 2-45% by weight of the phosphorus-aluminum inorganic binder based on the dry basis and 5-30% by weight of the other inorganic binder based on the dry basis.

[0041] Based on the dry basis weight of the phosphoaluminum inorganic binder, the phosphoaluminum inorganic binder comprises 15-40 wt% of an aluminum component calculated as Al2O3, 45-80 wt% of a phosphorus component calculated as P2O5, with a P / Al weight ratio of 1.0-6.0, a pH value of 1-3.5, and a solid content of 15-60 wt%; for example, it comprises 15-40 wt% of an aluminum component calculated as Al2O3 and 45-80 wt% of a phosphorus component calculated as P2O5; preferably, it contains 15-35 wt% of an aluminum component calculated as Al2O3 and 50-75 wt% of a phosphorus component calculated as P2O5, and its P / Al weight ratio is preferably 1.2-6.0, more preferably 2.0-5.0, and the pH value is preferably 1.5-3.0. Preferably, based on the dry basis weight of the phosphoaluminum inorganic binder, the phosphoaluminum inorganic binder comprises 20-40 wt% of an aluminum component calculated as Al2O3 and 60-80 wt% of a phosphorus component calculated as P2O5. The phosphoaluminum inorganic binder can be prepared by the following steps: slurrying an alumina source, clay (such as rectorite, kaolin) with water to form a slurry with a solid content of 5-50 wt%; wherein the alumina source is aluminum hydroxide and / or alumina that can be acid peptized (such as pseudo-boehmite, SB powder, γ-alumina), relative to 15-50 parts by weight of the alumina source calculated as Al2O3; adding concentrated phosphoric acid to the slurry at a weight ratio of P / Al = 1-6 under stirring, and reacting the resulting mixed slurry at 50-99 °C for 15-90 minutes; wherein P in P / Al is the weight of phosphorus in the phosphoric acid calculated as the element, and Al is the weight of aluminum in the alumina source calculated as the element.

[0042] The other inorganic binder is selected from at least one of pseudo-boehmite, aluminum sol, silica-alumina sol, and water glass.

[0043] The clay is well-known to those skilled in the art. The clay can be selected from at least one of kaolin, metakaolin, diatomite, sepiolite, attapulgite, montmorillonite, and rectorite, preferably kaolin, metakaolin, rectorite. Based on the dry basis weight of the auxiliary agent, it contains 2-60 wt% of clay calculated on a dry basis, preferably contains 5-55 wt% of clay, and more preferably 15-40 wt% of clay.

[0044] In a specific preparation embodiment of the cracking promoter provided by the present invention, an inorganic binder (such as pseudoboehmite, aluminum sol, silica sol, silica-alumina gel or a mixture of two or more thereof) can be mixed with clay (such as kaolin) and water (such as deoxygenated ion water and / or deionized water) to prepare a slurry with a solid content of 10-50% by weight, 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. After maintaining this pH value and aging at 20-80 °C for 0-2 hours, for example, after 0.3-2 hours, aluminum sol and / or silica sol is added, stirred for 0.5-1.5 hours to form a colloid, and then phosphorus-modified ZSM-5 molecular sieve is added to form a catalyst slurry. The solid content of the catalyst slurry is, for example, 20-45% by weight. After continuous stirring, it is spray-dried to form microspheres. Then the microspheres are calcined, for example, calcined at 350-650 °C or 400-600 °C, preferably 450-550 °C for 0.5-6 hours or 0.5-2 hours, and then washed with ammonium sulfate (wherein the washing temperature can be 40-70 °C, ammonium sulfate: microspheres: water = 0.2-0.8:1:5-15 by weight ratio) until the sodium oxide content is less than 0.25% by weight, washed with water and filtered, and then dried.

[0045] In another specific preparation embodiment of the promoter of the present invention, phosphorus-modified ZSM-5 molecular sieve, phosphorus-aluminum inorganic binder and other inorganic binders can be mixed, clay is added, slurried, and spray-dried.

[0046] In the catalytic cracking reaction method provided by the second aspect of the present invention, under catalytic cracking reaction conditions, hydrocarbon oil is contacted with a mixture of a cracking catalyst and a promoter, and the promoter is the cracking promoter provided by the present invention. It is characterized in that in the cracking promoter, the phosphorus-modified ZSM-5 molecular sieve is modified with a phosphorus-containing compound with a phosphorus valence state of +1, and the phosphorus-modified ZSM-5 molecular sieve, its 31 In the P MAS-NMR spectrum, the chemical shift range where resonance signal peaks appear is 5--20 ppm.

[0047] In the catalytic cracking reaction method provided by the present invention, the content of the promoter in the mixture of the cracking catalyst and a promoter is preferably 0.1-30% by weight.

[0048] The cracking catalyst can be a commonly used catalytic cracking catalyst in the art, and its composition includes common molecular sieve active components, inorganic binders, clay, etc. of the cracking catalyst. The molecular sieve active component of the cracking catalyst includes Y-type molecular sieve. 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.

[0049] In the present invention, the hydrocarbon oil is selected from one or more of crude oil, naphtha, gasoline, atmospheric residue, vacuum residue, atmospheric gas oil, vacuum gas oil, straight-run wax oil, propane light / heavy deoiled wax, coker gas oil, and 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 wt%, the nitrogen content can be as high as 2.0 wt%, and the content of metal impurities such as vanadium and nickel can be as high as 3000 ppm.

[0050] In the present invention, the catalytic cracking reaction conditions can be conventional in the art, and preferably include: a reaction temperature of 500 to 800 °C, for example, 550 to 680 °C.

[0051] The following provides a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only for explaining and illustrating the present invention, and are not used to limit the present invention.

[0052] The X-ray diffraction (XRD) pattern was measured on 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°, scanning rate 0.4 (°) / min. The ZSM-5 molecular sieve synthesized by the method of Example 1 in CN1056818C was used as a standard sample, and its crystallinity was set at 100%. The relative crystallinity is expressed as a percentage of the ratio of the sum of the peak areas of five characteristic diffraction peaks with 2θ between 22.5 and 25.0° in the X-ray diffraction patterns of the obtained product and the standard sample.

[0053] 31 The P MAS-NMR spectrum analysis was performed on a Bruker AVANCE III 600WB spectrometer. Instrument parameters: rotor diameter 4 mm, resonance frequency 202.4 MHz, pulse width 0.4 μs (corresponding to a 15° flip angle), magic angle spinning speed 10 kHz. 31 For the characteristics of the P MAS-NMR spectrum, the peak areas of the resonance signal peaks with chemical shifts of -30 ± 3 ppm and -40 ± 3 ppm were calculated by deconvolution fitting.

[0054] 27 The Al MAS-NMR spectrum analysis was performed on a Bruker AVANCE III 600WB spectrometer. Instrument parameters: rotor diameter 4 mm, resonance frequency 156.4 MHz, pulse width 0.4 μs (corresponding to a 15° flip angle), magic angle spinning speed 12 kHz, delay time 1 s. 27The characteristics of the Al MAS-NMR spectrum, the characteristic peak at 39 ± 3 ppm is attributed to phosphorus-stabilized framework aluminum (distorted tetrahedral coordinated framework aluminum), and the full width at half maximum of this characteristic peak is calculated by deconvolution fitting.

[0055] X-ray photoelectron spectroscopy (XPS) was used for the analysis of phosphorus species on the surface of molecular sieves to investigate the valence state changes of phosphorus compounds loaded on phosphorus-modified molecular sieves after drying and calcination. An ESCALAB 250 X-ray photoelectron spectrometer from Thermo Fisher-VG was used. Instrument parameters: The excitation source was monochromatized AlKα X-ray with a power of 150 W, and the charge shift was corrected using the C1s peak (284.8 eV) from contaminated carbon.

[0056] The instruments and reagents used in the examples of the present invention are, unless otherwise specified, commonly used instruments and reagents by those skilled in the art.

[0057] The properties of some raw materials used in the examples are as follows:

[0058] Pseudoboehmite is an industrial product produced by Shandong Aluminum Company, with a solid content of 60 wt%.

[0059] Aluminum sol is an industrial product produced by Qilu Branch of Sinopec Catalyst Co., Ltd., with an Al2O3 content of 21.5 wt%.

[0060] Silica sol is an industrial product produced by Qilu Branch of Sinopec Catalyst Co., Ltd., with an SiO2 content of 28.9 wt% and an Na2O content of 8.9%.

[0061] Kaolin is a special kaolin for fluid catalytic cracking catalysts produced by Suzhou Kaolin Company, with a solid content of 78 wt%.

[0062] Rectorite is produced by Hubei Zhongxiang Mingliu Rectorite Development Co., Ltd., with a quartz sand content of < 3.5 wt%, an Al2O3 content of 39.0 wt%, an Na2O content of 0.03 wt%, and a solid content of 77 wt%.

[0063] SB aluminum hydroxide powder is produced by German Condex Company, with an Al2O3 content of 75 wt%.

[0064] HRY molecular sieve is an industrial product produced by Changling Branch of Sinopec Catalyst Co., Ltd., with a rare earth content of 10 wt%.

[0065] PSRY molecular sieve is an industrial product produced by Changling Branch of Sinopec Catalyst Co., Ltd., with an Na2O content of < 1.5 wt%, a P2O5 content of 0.8 - 1.2 wt%, a unit cell constant of < 2.456 nm, and a crystallinity of ≥ 64%.

[0066] The instruments and reagents used in the embodiments of the present invention are, unless otherwise specified, commonly used instruments and reagents by those skilled in the art.

[0067] Examples 1-8 illustrate the phosphorus-modified ZSM-5 molecular sieve and its preparation used in the cracking aid of the present invention.

[0068] Example 1

[0069] Take 6.9 g of hypophosphorous acid and dissolve it in 145 g of deionized water at 25 °C, stir for 0.5 h to obtain an aqueous solution containing phosphorus, add 100 g of HZSM-5 molecular sieve (nSiO2 / nAl2O3 = 30), modify it by the impregnation method, impregnate for 0.5 h at 25 °C and then transfer it to an oven for drying at 120 °C for 12 h, and conduct a calcination treatment at 350 °C for 2 h in an air atmosphere in a muffle furnace to obtain a phosphorus-modified ZSM-5 molecular sieve sample, denoted as TCB-1.

[0070] Example 2

[0071] Take 6.9 g of solid hypophosphorous acid and add it to 100 g of HZSM-5 molecular sieve (nSiO2 / nAl2O3 = 30), grind and mix them for 0.5 h and then transfer them to a stainless-steel autoclave with a Teflon liner for a melting process at a heating temperature of 40 °C for 10 h. After the end, take out the sample after it naturally cools to room temperature; the above sample is subjected to a calcination treatment at 350 °C for 2 h to obtain a phosphorus-containing ZSM-5 molecular sieve sample, denoted as TRCB-1.

[0072] Comparative Example 1

[0073] Take 13.9 g of diammonium hydrogen phosphate and dissolve it in 145 g of deionized water at 25 °C, stir for 0.5 h to obtain an aqueous solution containing phosphorus, add 100 g of HZSM-5 molecular sieve (nSiO2 / nAl2O3 = 30), modify it by the impregnation method, impregnate for 0.5 h at 25 °C and then transfer it to an oven for drying at 120 °C for 12 h, and conduct a calcination treatment at 550 °C for 2 h in an air atmosphere in a muffle furnace to obtain a phosphorus-containing ZSM-5 molecular sieve comparative sample, denoted as DPB-1.

[0074] Comparative Example 2

[0075] Take 12.1 g of phosphoric acid solution (mass fraction 85 wt%) and dissolve it in 145 g of deionized water at 25 °C, stir for 0.5 h to obtain an aqueous solution containing phosphorus, add 100 g of HZSM-5 molecular sieve (nSiO2 / nAl2O3 = 30), modify it by the impregnation method, impregnate for 0.5 h at 25 °C and then transfer it to an oven for drying at 120 °C for 12 h, and conduct a calcination treatment at 550 °C for 2 h in an air atmosphere in a muffle furnace to obtain a phosphorus-containing ZSM-5 molecular sieve comparative sample, denoted as DPB-2.

[0076] Comparative Example 3

[0077] 6.9 g of hypophosphorous acid was dissolved in 145 g of deionized water at 25 °C, and stirred for 0.5 h to obtain an aqueous solution containing phosphorus. 100 g of HZSM-5 molecular sieve (nSiO2 / nAl2O3 = 30) was added and modified by the impregnation method. After impregnation at 25 °C for 0.5 h, it was transferred to an oven and dried at 120 °C for 12 h, and then calcined in a muffle furnace under air atmosphere at 550 °C for 2 h to obtain a phosphorus-modified ZSM-5 molecular sieve sample, denoted as JCB-1.

[0078] The 31 P MAS-NMR spectra of the phosphorus-modified ZSM-5 molecular sieve samples TCB-1, TRCB-1, the comparative samples DPB-1, DPB-2, and JCB-1 are shown in Figure 1 。 Figure 1 Among them, the characteristic peaks at chemical shifts of 0 ppm, -6 ppm, and -15 ppm belong to oligophosphorus species such as monomeric phosphoric acid and pyrophosphoric acid; the characteristic peaks in the range of -20 to -50 ppm belong to high-polymeric phosphorus species.

[0079] The 31 P MAS-NMR spectra of the phosphorus-modified ZSM-5 molecular sieve samples TCB-1, TRCB-1, the comparative samples DPB-1, DPB-2, and JCB-1 after hydrothermal aging treatment at 800 °C, 100% water vapor, and 17 h are shown in Figure 2 。 Figure 2 Among them, the resonance signal at a chemical shift of -30 ± 3 ppm represents the tetracoordinated phosphorus species formed after the stable framework aluminum species, and the resonance signal at -40 ± 3 ppm represents the condensed pentacoordinated phosphorus species. The ratio of the signal peak area at -30 ± 3 ppm to the signal peak area at -40 ± 3 ppm is shown in Table 1.

[0080] Figure 3 The 27 AlMAS-NMR spectra of the phosphorus-modified ZSM-5 molecular sieve samples TCB-1, TRCB-1, the comparative samples DPB-1, DPB-2, and JCB-1.

[0081] The relative crystallinity and crystallinity retention of the phosphorus-modified ZSM-5 molecular sieve samples TCB-1, TRCB-1, the comparative samples DPB-1, DPB-2, and JCB-1 before and after hydrothermal aging treatment at 800 °C, 100% water vapor, and 17 h are shown in Table 2.

[0082] The phosphorus content retention rates of the phosphorus-modified ZSM-5 molecular sieve samples TCB-1, TRCB-1, the comparative samples DPB-1, DPB-2, and JCB-1 after washing with water are shown in Table 3.

[0083] Table 1

[0084] Sample Signal peak area ratio of -30±3 ppm / -40±3 ppm TCB-1 1.2 TRCB-1 1.1 DPB-1 0.6 DPB-2 0.7 JCB-1 0.7

[0085] Table 2

[0086]

[0087] Table 3

[0088] Sample Retention rate of phosphorus content / % TCB-1 62 TRCB-1 61 DPB-1 45 DPB-2 48 JCB-1 49

[0089] Example 3

[0090] Take 3.45 g of hypophosphorous acid and dissolve it in 145 g of deionized water at 25 °C. Stir for 0.5 h to obtain an aqueous solution containing phosphorus. Add 100 g of HZSM-5 molecular sieve (nSiO2 / nAl2O3 = 30), and modify it by the impregnation method. After impregnating for 0.5 h at 25 °C, transfer it to an oven and dry it at 120 °C for 12 h. Then, calcine it in a muffle furnace under an air atmosphere at 350 °C for 2 h to obtain a phosphorus-modified ZSM-5 molecular sieve sample, denoted as TCB-2.

[0091] Example 4

[0092] Take 3.45 g of solid hypophosphorous acid and add it to 100 g of HZSM-5 molecular sieve (nSiO2 / nAl2O3 = 30). Grind and mix them for 0.5 h, then transfer them to a Teflon-lined stainless steel autoclave and carry out a melting process at a heating temperature of 40 °C for 10 h. After completion, wait for the sample to cool to room temperature naturally and then take it out. The above sample is calcined at 350 °C for 2 h to obtain a phosphorus-modified ZSM-5 molecular sieve sample, denoted as TRCB-2.

[0093] Comparative Example 4

[0094] Take 6.95 g of diammonium hydrogen phosphate and dissolve it in 145 g of deionized water at 25 °C. Stir for 0.5 h to obtain an aqueous solution containing phosphorus. Add 100 g of HZSM-5 molecular sieve (nSiO2 / nAl2O3 = 30), and modify it by the impregnation method. After impregnating for 0.5 h at 25 °C, transfer it to an oven and dry it at 120 °C for 12 h. Then, calcine it in a muffle furnace under an air atmosphere at 550 °C for 2 h to obtain a comparative sample of phosphorus-modified ZSM-5 molecular sieve, denoted as DPB-3.

[0095] Comparative Example 5

[0096] Take 6.05 g of phosphoric acid solution (mass fraction 85 wt%) and dissolve it in 145 g of deionized water at 25 °C. Stir for 0.5 h to obtain an aqueous solution containing phosphorus. Add 100 g of HZSM-5 molecular sieve (nSiO2 / nAl2O3 = 30), and modify it by the impregnation method. After impregnating at 25 °C for 0.5 h, transfer it to an oven and dry at 120 °C for 12 h. Then, calcine it in a muffle furnace under an air atmosphere at 550 °C for 2 h to obtain a phosphorus-modified ZSM-5 molecular sieve comparative sample, denoted as DPB-4.

[0097] Comparative Example 6

[0098] Take 3.45 g of hypophosphorous acid and dissolve it in 145 g of deionized water at 25 °C. Stir for 0.5 h to obtain an aqueous solution containing phosphorus. Add 100 g of HZSM-5 molecular sieve (nSiO2 / nAl2O3 = 30), and modify it by the impregnation method. After impregnating at 25 °C for 0.5 h, transfer it to an oven and dry at 120 °C for 12 h. Then, calcine it in a muffle furnace under an air atmosphere at 550 °C for 2 h to obtain a phosphorus-modified ZSM-5 molecular sieve sample, denoted as JCB-2.

[0099] The P MAS-NMR spectra of the phosphorus-modified ZSM-5 molecular sieve samples TCB-2, TRCB-2, comparative samples DPB-3, DPB-4, JCB-2 31 are shown in Figure 4 . Figure 4 Among them, the characteristic peaks at chemical shifts of 0 ppm, -6 ppm, and -15 ppm belong to low-polymer phosphorus species such as monomeric phosphoric acid and pyrophosphoric acid; the characteristic peaks in the range of -20 to -50 ppm belong to high-polymer phosphorus species.

[0100] The P MAS-NMR spectra of the phosphorus-modified ZSM-5 molecular sieve samples TCB-2, TRCB-2, comparative samples DPB-3, DPB-4, JCB-2 after being hydrothermally aged at 800 °C, 100% steam, and 17 h 31 are shown in Figure 5 . Figure 5 Among them, the resonance signal at a chemical shift of -30 ± 3 ppm represents the tetracoordinated phosphorus species formed after stabilizing the framework aluminum species, and the resonance signal at -40 ± 3 ppm represents the condensed pentacoordinated phosphorus species. The signal peak area ratio of -30 ± 3 ppm / -40 ± 3 ppm is shown in Table 4.

[0101] Figure 6 is 27 the spectrum of Al MAS-NMR.

[0102] The relative crystallinity and crystallization retention of the phosphorus-modified ZSM-5 zeolite samples TCB-2, TRCB-2, and the comparative samples DPB-3, DPB-4, JCB-2 before and after hydrothermal aging treatment at 800 °C, 100% water vapor, and for 17 h are shown in Table 5.

[0103] The phosphorus-modified ZSM-5 zeolite samples TCB-2, TRCB-2, and the comparative samples DPB-3, DPB-4, JCB-2 were washed with water, and the phosphorus content retention rate is shown in Table 6.

[0104] Table 4

[0105] Sample Signal peak area ratio of -30±3 ppm / -40±3 ppm TCB-2 1.3 TRCB-2 1.2 DPB-3 0.7 DPB-4 0.7 JCB-2 0.8

[0106] Table 5

[0107]

[0108] Table 6

[0109] Sample Retention rate of phosphorus content / % TCB-2 70 TRCB-2 71 DPB-3 48 DPB-4 46 JCB-2 47

[0110] Example 5

[0111] 10.35 g of hypophosphorous acid was dissolved in 145 g of deionized water at 25 °C. Ammonia water was added to adjust the pH value of the solution within the range of 5 - 9, and it was stirred for 0.5 h to obtain an aqueous solution containing phosphorus. 100 g of HZSM-5 zeolite (nSiO2 / nAl2O3 = 30) was added, and it was modified by the impregnation method. After impregnation at 25 °C for 0.5 h, it was transferred to an oven and dried at 120 °C for 12 h, and then calcined in a muffle furnace under an air atmosphere at 350 °C for 2 h to obtain a phosphorus-modified ZSM-5 zeolite sample, denoted as TCB-3.

[0112] Example 6

[0113] 13.02 g of ammonium hypophosphite was added to 100 g of HZSM-5 zeolite (nSiO2 / nAl2O3 = 30), and they were ground and mixed for 0.5 h and then transferred to a stainless steel autoclave with a Teflon liner for a melting process at a heating temperature of 40 °C for 10 h. After completion, the sample was taken out after naturally cooling to room temperature; the above sample was calcined at 350 °C for 2 h to obtain a phosphorus-modified ZSM-5 zeolite sample, denoted as TRCB-3.

[0114] Comparative Example 7

[0115] Take 20.85 g of diammonium hydrogen phosphate and dissolve it in 145 g of deionized water at 25 °C. Stir for 0.5 h to obtain an aqueous solution containing phosphorus. Add 100 g of HZSM-5 molecular sieve (nSiO2 / nAl2O3 = 30), and modify it by the impregnation method. After impregnating for 0.5 h at 25 °C, transfer it to an oven and dry at 120 °C for 12 h. Then, perform calcination treatment at 550 °C for 2 h in an air atmosphere in a muffle furnace to obtain a phosphorus-modified ZSM-5 molecular sieve comparative sample, denoted as DPB-5.

[0116] Comparative Example 8

[0117] Take 18.15 g of phosphoric acid solution (mass fraction 85 wt%) and dissolve it in 145 g of deionized water at 25 °C. Stir for 0.5 h to obtain an aqueous solution containing phosphorus. Add 100 g of HZSM-5 molecular sieve (nSiO2 / nAl2O3 = 30), and modify it by the impregnation method. After impregnating for 0.5 h at 25 °C, transfer it to an oven and dry at 120 °C for 12 h. Then, perform calcination treatment at 550 °C for 2 h in an air atmosphere in a muffle furnace to obtain a phosphorus-modified ZSM-5 molecular sieve comparative sample, denoted as DPB-6.

[0118] Comparative Example 9

[0119] Take 10.35 g of hypophosphorous acid and dissolve it in 145 g of deionized water at 25 °C. Add ammonia water to adjust the pH value of the solution within the range of 5 - 9. Stir for 0.5 h to obtain an aqueous solution containing phosphorus. Add 100 g of HZSM-5 molecular sieve (nSiO2 / nAl2O3 = 30), and modify it by the impregnation method. After impregnating for 0.5 h at 25 °C, transfer it to an oven and dry at 120 °C for 12 h. Then, perform calcination treatment at 550 °C for 2 h in an air atmosphere in a muffle furnace to obtain a phosphorus-modified ZSM-5 molecular sieve sample, denoted as JCB-4.

[0120] The P MAS-NMR spectra of the phosphorus-modified ZSM-5 molecular sieve samples TCB-3, TRCB-3, and the comparative samples DPB-5, DPB-6, JCB-4 31 are shown in Figure 7 . Figure 7 Among them, the characteristic peaks at chemical shifts of 0 ppm, -6 ppm, and -15 ppm belong to low-polymer phosphorus species such as monomeric phosphoric acid and pyrophosphoric acid; the characteristic peaks in the range of -20 to -50 ppm belong to high-polymer phosphorus species.

[0121] The P MAS-NMR spectra of the phosphorus-modified ZSM-5 molecular sieve samples TCB-3, TRCB-3, and the comparative samples DPB-5, DPB-6, JCB-4 after being hydrothermally aged at 800 °C, 100% steam, and for 17 h 31 are shown in Figure 8 . Figure 8Among them, the resonance signal with a chemical shift of -30 ± 3 ppm represents the tetracoordinate phosphorus species formed after the stable framework aluminum species, and the resonance signal of -40 ± 3 ppm represents the condensed pentacoordinate phosphorus species. The signal peak area ratio of -30 ± 3 ppm / -40 ± 3 ppm is shown in Table 7.

[0122] Figure 9 is 27 the spectrum of Al MAS-NMR.

[0123] The relative crystallinity and crystallization retention of the phosphorus-modified ZSM-5 molecular sieve samples TCB-3, TRCB-3, the comparative samples DPB-5, DPB-6, and JCB-4 before and after hydrothermal aging treatment at 800 °C, 100% water vapor, and 17 h are shown in Table 8.

[0124] The phosphorus content retention rates of the phosphorus-modified ZSM-5 molecular sieve samples TCB-3, TRCB-3, the comparative samples DPB-5, DPB-6, and JCB-4 after being washed with water are shown in Table 9.

[0125] Table 7

[0126] Sample Signal peak area ratio of -30±3 ppm / -40±3 ppm TCB-3 1.2 TRCB-3 1.2 DPB-5 0.7 DPB-6 0.8 JCB-4 0.8

[0127] Table 8

[0128]

[0129] Table 9

[0130] Sample Retention rate of phosphorus content / % TCB-3 58 TRCB-3 55 DPB-5 42 DPB-6 41 JCB-4 45

[0131] Example 7

[0132] 1.36 g of ammonium hypophosphite was dissolved in 145 g of deionized water at 25 °C, stirred for 0.5 h to obtain an aqueous solution containing phosphorus, 100 g of HZSM-5 molecular sieve (nSiO2 / nAl2O3 = 100) was added, and it was modified by the impregnation method. After impregnation at 25 °C for 0.5 h, it was transferred to an oven and dried at 120 °C for 12 h, and then calcined in a muffle furnace under an air atmosphere at 350 °C for 2 h to obtain the phosphorus-modified ZSM-5 molecular sieve sample, denoted as TCB-4.

[0133] Comparative Example 10

[0134] Take 2.16 g of diammonium hydrogen phosphate and dissolve it in 145 g of deionized water at 25°C. Stir for 0.5 h to obtain an aqueous solution containing phosphorus. Add 100 g of HZSM-5 molecular sieve (nSiO2 / nAl2O3 = 100), and modify it by the impregnation method. After impregnating at 25°C for 0.5 h, transfer it to an oven and dry it at 120°C for 12 h. Then, perform a calcination treatment at 550°C for 2 h in an air atmosphere in a muffle furnace to obtain a phosphorus-modified ZSM-5 molecular sieve comparative sample, denoted as DPB-7.

[0135] Comparative Example 11

[0136] Take 1.36 g of ammonium hypophosphite and dissolve it in 145 g of deionized water at 25°C. Stir for 0.5 h to obtain an aqueous solution containing phosphorus. Add 100 g of HZSM-5 molecular sieve (nSiO2 / nAl2O3 = 100), and modify it by the impregnation method. After impregnating at 25°C for 0.5 h, transfer it to an oven and dry it at 120°C for 12 h. Then, perform a calcination treatment at 550°C for 2 h in an air atmosphere in a muffle furnace to obtain a phosphorus-modified ZSM-5 molecular sieve comparative sample, denoted as JCB-5.

[0137] Example 8

[0138] Take 0.91 g of ammonium hypophosphite and dissolve it in 145 g of deionized water at 25°C. Stir for 0.5 h to obtain an aqueous solution containing phosphorus. Add 100 g of HZSM-5 molecular sieve (nSiO2 / nAl2O3 = 150), and modify it by the impregnation method. After impregnating at 25°C for 0.5 h, transfer it to an oven and dry it at 120°C for 12 h. Then, perform a calcination treatment at 350°C for 2 h in an air atmosphere in a muffle furnace to obtain a phosphorus-modified ZSM-5 molecular sieve sample, denoted as TCB-5.

[0139] Comparative Example 12

[0140] Take 1.45 g of diammonium hydrogen phosphate and dissolve it in 145 g of deionized water at 25°C. Stir for 0.5 h to obtain an aqueous solution containing phosphorus. Add 100 g of HZSM-5 molecular sieve (nSiO2 / nAl2O3 = 150), and modify it by the impregnation method. After impregnating at 25°C for 0.5 h, transfer it to an oven and dry it at 120°C for 12 h. Then, perform a calcination treatment at 550°C for 2 h in an air atmosphere in a muffle furnace to obtain a phosphorus-modified ZSM-5 molecular sieve comparative sample, denoted as DPB-8.

[0141] Comparative Example 13

[0142] Take 0.91 g of ammonium hypophosphite and dissolve it in 145 g of deionized water at 25 °C. Stir for 0.5 h to obtain an aqueous solution containing phosphorus. Add 100 g of HZSM-5 zeolite (nSiO2 / nAl2O3 = 150), and modify it by the impregnation method. After impregnating for 0.5 h at 25 °C, transfer it to an oven and dry it at 120 °C for 12 h. Then, calcine it in a muffle furnace under an air atmosphere at 550 °C for 2 h to obtain a phosphorus-modified ZSM-5 zeolite sample, denoted as JCB-6.

[0143] The phosphorus-modified ZSM-5 zeolite samples TCB-4, the comparative sample DPB-7, the comparative sample JCB-5, the sample TCB-5, the comparative sample DPB-8, and the comparative sample JCB-6 31 The P MAS-NMR spectra are shown in Figure 10 . Figure 10 Among them, the characteristic peaks at chemical shifts of 0 ppm, -6 ppm, and -15 ppm are attributed to oligophosphorus species such as monomeric phosphoric acid and pyrophosphoric acid; the characteristic peaks in the range of -20 to -50 ppm are attributed to high-polymeric phosphorus species.

[0144] The phosphorus-modified ZSM-5 zeolite samples TCB-4, the comparative sample DPB-7, the comparative sample JCB-5, the sample TCB-5, the comparative sample DPB-8, and the comparative sample JCB-6 are respectively hydrothermally aged at 800 °C, 100% water vapor, and for 17 h. The 31 P MAS-NMR spectra are shown in Figure 11 . Figure 11 Among them, the resonance signal at a chemical shift of -30 ± 3 ppm represents the tetracoordinated phosphorus species formed after the stable framework aluminum species, and the resonance signal at -40 ± 3 ppm represents the condensed pentacoordinated phosphorus species. The area ratio of the -30 ± 3 ppm / -40 ± 3 ppm signal peaks is shown in Table 13.

[0145] Figure 12 is 27 the spectrum of Al MAS-NMR.

[0146] The relative crystallinity and crystallinity retention of the phosphorus-modified ZSM-5 zeolite samples TCB-4, the comparative sample DPB-7, the comparative sample JCB-5, the sample TCB-5, the comparative sample DPB-8, and the comparative sample JCB-6 before and after hydrothermal aging at 800 °C, 100% water vapor, and for 17 h are shown in Table 14.

[0147] The phosphorus-modified ZSM-5 zeolite samples TCB-4, the comparative sample DPB-7, the comparative sample JCB-5, the sample TCB-5, the comparative sample DPB-8, and the comparative sample JCB-6 are washed with water, and the phosphorus content retention rate is shown in Table 15.

[0148] Table 10

[0149] Sample Signal peak area ratio of -30±3 ppm / -40±3 ppm TCB-4 1.2 DPB-7 0.7 JCB-5 0.8 TCB-5 1.1 DPB-8 0.7 JCB-6 0.7

[0150] Table 11

[0151]

[0152] Table 12

[0153] Sample Retention rate of phosphorus content / % TCB-4 73 DPB-7 45 JCB-5 47 TCB-5 72 DPB-8 44 JCB-6 43

[0154] Examples 9-16 illustrate the FCC promoter of the present invention.

[0155] The phosphorus-aluminum inorganic binders NJ1 and NJ2 used in the examples were prepared by the following process:

[0156] 1. NJ1: 1.91 kg of pseudo-boehmite (containing 1.19 kg of Al2O3), 0.56 kg of kaolin (dry basis 0.5 kg) and 3.27 kg of deionized water were slurried for 30 minutes. While stirring, 5.37 kg of concentrated phosphoric acid (mass concentration 85%) was added to the slurry at a rate of 0.04 kg of phosphoric acid per minute per kg of alumina source. The temperature was raised to 70 °C and then reacted at this temperature for 45 minutes to obtain the phosphorus-aluminum inorganic binder. The material ratio is shown in Table 13, and the sample number is NJ1.

[0157] 2. NJ2: According to the preparation process of NJ1, the material ratio is shown in Table 13, and the sample number is NJ2.

[0158] Table 13

[0159] Phosphorus-aluminum binder number NJ1 NJ2 Pseudoboehmite, kg 1.91 <![CDATA[Al2O3, kg]]> 1.19 SB, kg 0.94 <![CDATA[Al2O3, kg]]> 0.70 Rectorite, kg 1.28 Dry basis, kg 1.00 Kaolin, kg 0.56 Dry basis, kg 0.50 Phosphoric acid, kg 5.37 5.36 <![CDATA[P2O5, kg]]> 3.31 3.30 Decationized water, kg 3.27 6.71 Total amount, kg 11.11 14.29 Total dry basis, kg 5.00 5.00 Binder solid content, kg / kg 0.45 0.35 P / Al 2.29 3.89 <![CDATA[Al2O3, wt%]]> 23.82 14.00 <![CDATA[P2O5, wt%]]> 66.18 66.00 Clay, wt% 10.00 20.00 pH 2.20 2.37

[0160] Examples 9-10

[0161] Take the phosphorus-modified ZSM-5 zeolite TCB-1, kaolin and pseudo-boehmite of Example 1, add deionized 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 value of the slurry to 3.0, then continue to slurry for 45 minutes, then add the phosphorus-aluminum inorganic binder NJ1. After stirring for 30 minutes, the obtained slurry was spray-dried to obtain microspheres, and the microspheres were calcined at 500 °C for 1 hour to obtain the promoter, numbered Zcat1.

[0162] Using the phosphorus-modified ZSM-5 zeolite TRCB-1 of Example 2 to replace the zeolite TCB-1, with the same above preparation process, the promoters were respectively prepared, numbered Zcat2.

[0163] In the material ratio of Zcat1 and Zcat2, based on the dry basis weight, the phosphorus-modified zeolite accounts for 65%, kaolin accounts for 20%, the phosphorus-aluminum binder NJ1 accounts for 10%, and pseudo-boehmite accounts for 5%.

[0164] Comparative Examples 14, 15, and 16

[0165] The preparation process and material ratio are the same as those in Example 9, except that the phosphorus-modified ZSM-5 molecular sieve samples DPB-1, DPB-2, and JCB-1 of Comparative Examples 1, 2, and 3 are used to replace TCB-1 respectively to prepare comparative additives numbered DZCat1, DZCat2, and DZCat3.

[0166] Examples 11 - 12

[0167] Take the phosphorus-modified ZSM-5 molecular sieve TCB-2 and kaolin of Example 3, add deionized water and aluminum sol and beat for 120 minutes to obtain a slurry with a solid content of 30% by weight. Add hydrochloric acid to adjust the pH value of the slurry to 3.0, then continue to beat for 45 minutes, then add the phosphorus-aluminum inorganic binder NJ2, stir for 30 minutes, and then spray-dry the obtained slurry to obtain microspheres. Bake the microspheres at 500 °C for 1 hour to prepare a catalyst numbered Zcat3.

[0168] Replace the molecular sieve TCB-2 with the phosphorus-modified molecular sieve TRCB-2 of Example 4, and follow the above preparation process to prepare catalysts numbered Zcat4 respectively.

[0169] In the material ratio of Zcat3 and Zcat4, based on the dry weight, the phosphorus-modified ZSM-5 molecular sieve accounts for 55%, kaolin accounts for 30%, the phosphorus-aluminum binder NJ2 accounts for 10%, and aluminum sol accounts for 5%.

[0170] Comparative Examples 17, 18, and 19

[0171] The preparation process and material ratio are the same as those in Example 11, except that the phosphorus-modified ZSM-5 molecular sieve samples DPB-3, DPB-4, and JCB-2 of Comparative Examples 4, 5, and 6 are used to replace TCB-2 respectively to prepare comparative additives numbered DZcat4, DZcat5, and DZcat6.

[0172] Examples 13 - 14

[0173] Take the phosphorus-modified ZSM-5 molecular sieve TCB-3 and kaolin of Example 5, add deionized water and aluminum sol and beat for 120 minutes to obtain a slurry with a solid content of 30% by weight. Add hydrochloric acid to adjust the pH value of the slurry to 3.0, then continue to beat for 45 minutes, then add the phosphorus-aluminum inorganic binder NJ1, stir for 30 minutes, and then spray-dry the obtained slurry to obtain microspheres. Bake the microspheres at 500 °C for 1 hour to prepare a catalyst numbered Zcat5.

[0174] Replace the molecular sieve TCB-3 with the phosphorus-modified molecular sieve TRCB-3 of Example 6, and prepare the catalyst respectively according to the above preparation process, numbered Zcat6.

[0175] In the material ratios of Zcat5 and Zcat6, based on the dry weight, the phosphorus-modified ZSM-5 molecular sieve accounts for 65%, kaolin accounts for 20%, phosphorus-aluminum binder NJ2 accounts for 10%, and aluminum sol accounts for 5%.

[0176] Comparative Examples 20, 21, 22

[0177] Same as the preparation process and material ratio of Example 13, the difference is that the phosphorus-modified ZSM-5 molecular sieve samples DPB-5, DPB-6 and JCB-4 of Comparative Examples 7, 8 and 9 are used to replace TCB-3 respectively to prepare the comparative additives, numbered DZcat7, DZcat8, DZat9.

[0178] Example 15

[0179] Take the phosphorus-modified molecular sieve TCB-4 and kaolin of Example 7, add deionized water and aluminum sol and beat for 120 minutes to obtain a slurry with a solid content of 30% by weight. Add hydrochloric acid to adjust the pH value of the slurry to 3.0, then continue to beat for 45 minutes, then add the phosphorus-aluminum inorganic binder NJ1, stir for 30 minutes, and then spray-dry the obtained slurry to obtain microspheres. Bake the microspheres at 500 °C for 1 hour to prepare the additive, numbered ZCat7.

[0180] In the material ratio of ZCat7, based on the dry weight, the phosphorus-modified ZSM-5 molecular sieve accounts for 65%, kaolin accounts for 20%, phosphorus-aluminum binder NJ1 accounts for 10%, and aluminum sol accounts for 5%.

[0181] Comparative Examples 23, 24

[0182] Same as the preparation process and material ratio of Example 15, the difference is that the phosphorus-modified ZSM-5 molecular sieves DPB-7 and JCB-5 of Comparative Examples 10 and 11 are used to replace TCB-4 respectively to prepare the comparative additives, numbered DZCat10 and DZCat11.

[0183] Example 16

[0184] Take the phosphorus-modified molecular sieve TCB-5 and kaolin of Example 8, add deionized water and aluminum sol and beat for 120 minutes to obtain a slurry with a solid content of 30% by weight. Add hydrochloric acid to adjust the pH value of the slurry to 3.0, then continue to beat for 45 minutes, then add the phosphorus-aluminum inorganic binder NJ1, stir for 30 minutes, and then spray-dry the obtained slurry to obtain microspheres. Bake the microspheres at 500 °C for 1 hour to prepare the catalyst, numbered ZCat8.

[0185] In the material ratio of ZCat8, based on the dry basis weight, the phosphorus-modified ZSM-5 molecular sieve accounts for 60%, kaolin accounts for 20%, the phosphorus-aluminum binder NJ1 accounts for 15%, and the aluminum sol accounts for 5%.

[0186] Comparative Examples 25 and 26

[0187] Same as the preparation process and material ratio of Example 16, the difference is that the phosphorus-modified molecular sieves DPB-8 and JCB-6 of Comparative Examples 12 and 13 are used to replace the molecular sieve TCB-5 respectively, and the comparative catalysts numbered DZCat12 and DZCat13 are prepared respectively.

[0188] The following examples illustrate the catalytic cracking method provided by the present invention.

[0189] Examples 17 - 18

[0190] The additives Zcat1 - Zcat2 are respectively aged at 800°C for 17 hours under the condition of 100% water vapor atmosphere.

[0191] The aged additives are respectively mixed with the industrial FCC equilibrium catalyst (the equilibrium catalyst of industrial grade MMC, the light oil microactivity is 63). The additives account for 10% by weight in the mixture. The mixture is loaded into a fixed-bed microreactor to evaluate the catalytic cracking ability of the additives for light hydrocarbons. The evaluation conditions are reaction temperature 650°C, regeneration temperature 620°C, and catalyst-oil ratio 3.2.

[0192] The properties table of the feedstock oil is shown in Table 14. The reaction results are shown in Table 15.

[0193] Comparative Examples 13 and 14

[0194] Same as Example 17, the difference is that the comparative additives DZcat1, DZcat2, and DZcat3 are used to replace Zcat1 respectively. The reaction results are shown in Table 15.

[0195] Table 14

[0196] Item Light hydrocarbon <![CDATA[Density (20 °C) / (kg·m -3 )]]> 670.7 Element mass composition / % C 83.81 H 16.19 <![CDATA[S / mg.L -1 > 2.6 <![CDATA[N / mg.L -1 > <0.3 Distillation range / °C 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-alkane 72.69 iso-alkane 25.48 Olefin 0.13 Naphthene 1.56 Aromatic hydrocarbon 0.17 Total 100.03

[0197] Table 15

[0198]

[0199]

[0200] Examples 19 - 20

[0201] The promoters Zcat3-Zcat4 were respectively subjected to an aging treatment at 800 °C under a 100% steam atmosphere for 17 hours. The aged promoters were respectively mixed with an industrial FCC equilibrium catalyst (the equilibrium catalyst of industrial grade MMC, with a light oil microactivity of 63), and loaded into a fixed-bed microreactor to evaluate the catalytic cracking ability of the promoters for light hydrocarbons. The evaluation conditions were a reaction temperature of 650 °C, a regeneration temperature of 620 °C, and a catalyst-oil ratio of 3.2. The reaction results are shown in Table 16.

[0202] Comparative Examples 30, 31, and 32

[0203] Same as Example 19, except that the comparative catalysts DZcat4, DZcat5, and DZcat5 were used to replace Zcat3 respectively. The reaction results are shown in Table 16.

[0204] Table 16

[0205]

[0206] Examples 21-22

[0207] The catalysts Zcat5-Zcat6 were respectively subjected to an aging treatment at 800 °C under a 100% steam atmosphere for 17 hours. The aged promoters were respectively mixed with an industrial FCC equilibrium catalyst (the equilibrium catalyst of industrial grade MMC, with a light oil microactivity of 63), and loaded into a fixed-bed microreactor to evaluate the catalytic cracking ability of the promoters for light hydrocarbons. The evaluation conditions were a reaction temperature of 650 °C, a regeneration temperature of 620 °C, and a catalyst-oil ratio of 3.2. The reaction results are shown in Table 17.

[0208] Comparative Examples 33, 34, and 35

[0209] Same as Example 21, except that the comparative catalysts DZcat7, DZcat8, and DZcat9 were used to replace Zcat5 respectively. The reaction results are shown in Table 17.

[0210] Table 17

[0211]

[0212] Examples 23-24

[0213] The catalysts Zcat7-Zcat8 were respectively subjected to an aging treatment at 800 °C under a 100% steam atmosphere for 17 hours. The aged promoters were respectively mixed with an industrial FCC equilibrium catalyst (the equilibrium catalyst of industrial grade MMC, with a light oil microactivity of 63), and the aged catalysts were loaded into a fixed-bed microreactor to evaluate the catalytic cracking ability of the promoters for light hydrocarbons. The evaluation conditions were a reaction temperature of 650 °C, a regeneration temperature of 620 °C, and a catalyst-oil ratio of 3.2. The reaction results are shown in Table 18.

[0214] Comparative Examples 33, 34, 35, 36

[0215] Same as Example 23, except that Comparative Catalysts DZcat10, DZcat11, DZcat12, and DZcat13 were used to replace Zcat7, respectively. The reaction results are shown in Table 18.

[0216] Table 18

[0217]

[0218] From the above reaction results, it can be seen that the FCC catalytic additives prepared by modifying ZSM-5 molecular sieve with phosphorus-containing compounds with a phosphorus valence state of +1 after low-temperature calcination have higher hydrocarbon conversion and ethylene and propylene yields than those prepared by modifying ZSM-5 molecular sieve with phosphorus-containing compounds with a phosphorus valence state of +5 and phosphorus-containing compounds with a phosphorus valence state of +1 after high-temperature calcination.

Claims

1. A cracking aid, which is composed of phosphorus-modified ZSM-5 molecular sieve, inorganic binder and clay, and is characterized in that, In the 31 P MAS-NMR spectrum of the phosphorus-modified ZSM-5 molecular sieve, the chemical shift range where resonance signal peaks appear is 5 to -20 ppm.

2. The cracking aid according to claim 1, wherein After the phosphorus-modified ZSM-5 molecular sieve is hydrothermally aged for 17 h under the conditions of 800 °C and 100% water vapor, 31 In the P MAS-NMR spectrum, the ratio of the peak area of the resonance signal with a chemical shift of -30 ± 3 ppm to the peak area of the resonance signal with a chemical shift of -40 ± 3 ppm > 1, preferably 1.05 - 1.4, more preferably 1.1 - 1.

3.

3. The cracking aid according to claim 1, characterized in that, After the phosphorus-modified ZSM-5 molecular sieve is hydrothermally aged for 17 h under the conditions of 800 °C and 100% water vapor, 27 In the Al MAS-NMR spectrum, resonance signal peaks with chemical shifts of 39 ± 3 ppm and -12 ± 3 ppm appear simultaneously.

4. The cracking aid according to claim 1, characterized in that, After the phosphorus-modified ZSM-5 molecular sieve is washed with hot water at 70 °C for 2 h, the retention rate of phosphorus content is higher than 50%, about 51-75%. The definition of the retention rate of phosphorus content is P2O5 before washing / P2O5 after washing, calculated as a mass percentage.

5. The cracking aid according to claim 1, characterized in that, When phosphorus and aluminum in the phosphorus-modified ZSM-5 molecular sieve are both in terms of moles, the ratio of the two is 0.01-5, and the preferred ratio is 0.1-3.

6. The cracking aid according to any one of claims 1 to 5, characterized in that, The phosphorus-modified ZSM-5 molecular sieve is obtained by contacting and impregnating the HZSM-5 molecular sieve with an aqueous solution of a phosphorus-containing compound with a phosphorus valence state of +1, followed by drying and air calcination at 300-400 °C; or, the phosphorus-modified ZSM-5 molecular sieve is obtained by heating and melting a mixture obtained by mixing and grinding the HZSM-5 molecular sieve with a solid phosphorus-containing compound with a phosphorus valence state of +1, cooling to 20-25 °C, and then performing air calcination at 300-400 °C.

7. The cracking aid according to claim 6, characterized in that In the impregnation, the weight ratio of water to sieve is 0.5-2, and it is carried out at room temperature for 0.5-10 hours; for the drying, the atmosphere is air, carried out at 100-120 °C for 2-24 hours; for the calcination, it is carried out at 330-370 °C, such as 350 °C, for 0.5-12 hours.

8. The cracking aid according to claim 6, characterized in that, For the heating and melting treatment, the temperature is higher than the melting point of the solid phosphorus-containing compound and lower than the temperature at which the solid phosphorus-containing compound decomposes or dehydrates, and the treatment time is 2-72 hours.

9. The cracking aid according to claim 1, characterized in that, The phosphorus-containing compound with a phosphorus valence state of +1 is selected from one or more of hypophosphorous acid, ammonium hypophosphite, and hypophosphite; or, the aqueous solution of the phosphorus-containing compound with a phosphorus valence state of +1 is an aqueous solution of hypophosphorous acid adjusted to a pH value of 5-9 with ammonia water.

10. The cracking aid according to claim 6, characterized in that, The molar ratio of the HZSM-5 molecular sieve to the phosphorus-containing compound with a phosphorus valence state of +1 is (0.1-2.5):1, preferably (0.5-1.5):1, where the HZSM-5 molecular sieve is calculated based on aluminum and the phosphorus-containing compound is calculated based on phosphorus.

11. The cracking aid according to claim 1, wherein The inorganic binder includes a phosphorus-aluminum inorganic binder, and the phosphorus-aluminum inorganic binder accounts for 5-40% by weight based on the dry basis of the additives.

12. The cracking aid according to claim 1, characterized in that, The inorganic binder also contains at least one selected from pseudoboehmite, aluminum sol, silica-alumina sol, and water glass.

13. The cracking aid according to claim 1, characterized in that, The clay is selected from at least one of kaolin, sepiolite, attapulgite, rectorite, montmorillonite, and diatomite.

14. A catalytic cracking reaction method is to contact hydrocarbon oil with a mixture of a cracking catalyst and a cracking aid under catalytic cracking reaction conditions, and the cracking aid is the cracking aid according to any one of claims 1-13.

15. The catalytic cracking reaction method according to claim 1, wherein, In the mixture of the cracking catalyst and a cracking aid, the content of the cracking aid is 0.1-30% by weight.

16. The catalytic cracking reaction method according to claim 14 or 15, wherein, The cracking catalyst has an active component including Y-type molecular sieve.

17. The catalytic cracking reaction method according to claim 16, wherein, 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.

18. The catalytic cracking reaction method according to claim 14, wherein The catalytic cracking reaction conditions include: the reaction temperature is 500 - 800 °C.

19. The catalytic cracking reaction method according to claim 14, wherein The hydrocarbon oil is selected from one or more of crude oil, naphtha, gasoline, atmospheric residue, vacuum residue, atmospheric gas oil, vacuum gas oil, straight-run wax oil, propane light / heavy deoiled oil, coker gas oil, and coal liquefaction products.

Images