CN111617798A - Preparation method of rare earth modified composite material - Google Patents

Preparation method of rare earth modified composite material Download PDF

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CN111617798A
CN111617798A CN201910149968.3A CN201910149968A CN111617798A CN 111617798 A CN111617798 A CN 111617798A CN 201910149968 A CN201910149968 A CN 201910149968A CN 111617798 A CN111617798 A CN 111617798A
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rare earth
degrees
molecular sieve
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hours
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郑金玉
王成强
罗一斌
满征
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Sinopec Research Institute of Petroleum Processing
China Petroleum and Chemical Corp
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Sinopec Research Institute of Petroleum Processing
China Petroleum and Chemical Corp
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
    • B01J35/61—Surface area
    • B01J35/615—100-500 m2/g
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J29/08—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the faujasite type, e.g. type X or Y
    • B01J29/085—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the faujasite type, e.g. type X or Y containing rare earth elements, titanium, zirconium, hafnium, zinc, cadmium, mercury, gallium, indium, thallium, tin or lead
    • B01J29/088—Y-type faujasite
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/40—Catalysts, in general, characterised by their form or physical properties characterised by dimensions, e.g. grain size
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
    • B01J35/61—Surface area
    • B01J35/617—500-1000 m2/g
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
    • B01J35/63—Pore volume
    • B01J35/635—0.5-1.0 ml/g
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
    • B01J35/64—Pore diameter
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/30—Ion-exchange
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G11/00—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils
    • C10G11/02—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils characterised by the catalyst used
    • C10G11/04—Oxides
    • C10G11/05—Crystalline alumino-silicates, e.g. molecular sieves
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2229/00—Aspects of molecular sieve catalysts not covered by B01J29/00
    • B01J2229/10—After treatment, characterised by the effect to be obtained
    • B01J2229/20—After treatment, characterised by the effect to be obtained to introduce other elements in the catalyst composition comprising the molecular sieve, but not specially in or on the molecular sieve itself

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  • Silicates, Zeolites, And Molecular Sieves (AREA)

Abstract

A preparation method of a rare earth modified composite material comprises the step of carrying out double-cross double-baking treatment on a porous material, wherein a mesoporous structure of the porous material grows on the surface of a Y-shaped molecular sieve crystal grain and coats the molecular sieve crystal grain, the grain size is 1-2 mu m, and the total specific surface area is 300-650 m2(ii) a total pore volume of 0.4 to 1.0cm3The a/b of the porous material is 1.2-9.5, wherein a represents the shift of 500cm in Raman spectrum‑1B represents a Raman shift of 350cm‑1Spectral peak intensity of (a). The composite material prepared by the method is prepared by rare earthThe moderate modification of the catalyst can modulate the pore structure and the acid property, improve the hydrothermal stability and the accessibility of an active center, and obviously improve the reaction activity.

Description

Preparation method of rare earth modified composite material
Technical Field
The invention relates to a preparation method of a composite material, and further relates to a preparation method of a composite material subjected to rare earth modification treatment.
Background
Catalytic cracking is an important process in petroleum refining, is widely applied to the petroleum processing industry, and plays a significant role in oil refineries. In the catalytic cracking process, heavy fractions such as vacuum distillates or residues of heavier components are reacted in the presence of a catalyst to convert into gasoline, distillates and other liquid cracked products and lighter gaseous cracked products of four carbons or less. The catalytic cracking reaction process follows a carbonium ion reaction mechanism, and therefore, an acidic catalytic material, particularly a catalytic material having a strong B acid center, needs to be used. Amorphous alumino-silicate material is an acidic catalytic material, which has both B and L acid centers, is the main active component in early catalytic cracking catalysts, but is gradually replaced by crystalline molecular sieves due to its lower cracking activity and higher required reaction temperature. Crystalline molecular sieves are porous materials with a pore size of less than 2nm and a special crystalline phase structure, and materials with a pore size of less than 2nm are named as microporous materials according to the definition of IUPAC, so that crystalline molecular sieves or zeolites generally belong to microporous materials, and the microporous molecular sieve materials have stronger acidity and higher structural stability due to complete crystal structures and special framework structures, show higher catalytic activity in catalytic reactions, and are widely applied to petroleum processing and other catalytic industries.
The Y-type molecular sieve is used as a typical microporous molecular sieve material, and is applied in the fields of catalytic cracking, hydrocracking and the like on a large scale due to the regular pore channel structure, good stability and strong acidity. When the modified Y-type molecular sieve is used in a catalytic cracking catalyst, certain modification treatment is usually required to be carried out on the Y-type molecular sieve, such as skeleton dealumination inhibition through rare earth modification, the structural stability of the molecular sieve is improved, the retention degree of acid centers is increased, and the cracking activity is further improved; or the framework silicon-aluminum ratio is improved through ultra-stabilization treatment, so that the stability of the molecular sieve is improved. CN1436727A discloses a modified faujasite and a hydrocarbon cracking catalyst containing the zeolite, which adopts a one-exchange one-baking process, namely NaY firstly carries out a one-exchange reaction with a phosphorus compound and an ammonium compound, then a rare earth solution is added for continuous reaction, and the catalyst is obtained by filtering, washing and hydrothermal roasting.
CN1382631A discloses a high-silicon rare earth Y-type zeolite, which is prepared by gas phase reaction of rare earth Y-type zeolite and silicon tetrachloride, wherein the content of rare earth in crystal is 4-15 wt%, the cell constant is 2.450-2.458 nm, the collapse temperature is 1000-1056 ℃, the silica-alumina ratio is 8.3-8.8, and the content of sodium oxide is less than 1.0 wt%.
CN101823726A discloses a modified Y molecular sieve, which is prepared by a one-exchange one-baking process, namely NaY is firstly subjected to a one-exchange reaction with a rare earth solution, then a phosphorus compound is added for continuous reaction, and the modified Y molecular sieve is obtained by filtering, washing and hydrothermal roasting, wherein the content of rare earth is about 11-23 wt%, most of rare earth is positioned in a sodalite cage, the stability of the molecular sieve is improved, meanwhile, the acidity of the molecular sieve can be adjusted, and a catalyst containing the molecular sieve has the characteristics of strong heavy oil conversion capability and good coke selectivity.
CN100344374C discloses a rare earth Y molecular sieve and a preparation method thereof, the content of rare earth is 12-22 wt% calculated by rare earth oxide, and rare earth ions are all positioned in a molecular sieve small cage which is a small cage27In the Al MASNMR spectrum, no peak appears at a chemical shift of 0 ppm. The preparation method comprises the steps of adopting a one-way and one-way roasting process, adjusting the pH value of a solution to 8-11 by using an alkaline solution after one-way exchange, then filtering, washing, drying and roasting, or separating a molecular sieve filter cake after one-way exchange, collecting filtrate, adding the alkaline solution into the filtrate to adjust the pH value of the solution to 8-11, adding water into the obtained rare earth hydroxide filter cake and the molecular sieve filter cake, pulping, filtering, washing, drying and roasting. The process can prevent the loss of rare earth and protect the rare earth from being precipitated by excessive rare earth ions in the solutionThe rare earth ions are all positioned in the molecular sieve small cage.
CN1317547A discloses an olefin reduction catalyst and a preparation method thereof, the catalyst mainly comprises REY molecular sieve with the rare earth content of 12-20 wt% and the crystallinity of more than 50% and a phosphorus and rare earth compound modified PREY molecular sieve with the rare earth content of 2-12 wt%, the phosphorus content of 0.2-3 wt% and the unit cell constant of 2.445-2.465 nm.
CN1506161A discloses a rare earth ultrastable Y molecular sieve, which adopts a double-cross double-baking process, namely, after a first-cross single-baking rare earth sodium Y is obtained, the first-cross single-baking rare earth sodium Y reacts with rare earth and phosphorus-containing substances step by step and is roasted for the second time to obtain a composite modified Y molecular sieve with the rare earth content of 8-25 wt%, the phosphorus content of 0.1-3.0 wt%, the crystallinity of 30-55% and the unit cell constant of 2.455-2.477 nm.
The molecular sieve prepared by adopting the double cross double roasting process also has other characteristics, for example, the molecular sieve which is disclosed in CN101537366A and can improve the coking performance and the preparation method thereof still adopt the double cross double roasting process, the phosphorus content of the molecular sieve is 0.05-5.0%, the rare earth content is less, only 0.05-4.0%, the unit cell constant is 2.430-2.440 nm, and the crystallinity is 35-55%.
Along with the increasing exhaustion of petroleum resources, the trend of crude oil heaving and deterioration is obvious, the slag blending proportion is continuously improved, and the requirement of the market for light oil products is not reduced, so that in recent years, the deep processing of heavy oil and residual oil is more and more emphasized in the petroleum processing industry, a plurality of refineries begin to blend vacuum residual oil, even normal pressure residual oil is directly used as a cracking raw material, the catalytic cracking of heavy oil gradually becomes a key technology for improving economic benefits of oil refining enterprises, and the macromolecular cracking capability of a catalyst therein is a focus of attention. The Y-type molecular sieve is the most main cracking active component in the conventional cracking catalyst, but due to the smaller pore channel structure, the Y-type molecular sieve shows a relatively obvious pore channel limiting effect in macromolecular reaction, and also shows a certain inhibiting effect on the cracking reaction of macromolecules such as heavy oil or residual oil and the like. Therefore, for catalytic cracking of heavy oil, it is necessary to use a material having a large pore size, no diffusion limitation to reactant molecules, and a high cracking activity.
According to the IUPAC definition, a material with a pore size of 2-50 nm is a mesoporous (mesoporous) material, and the size range of macromolecules such as heavy oil or residual oil is in the pore size range, so that the research of mesoporous materials, particularly mesoporous silicon-aluminum materials, has attracted great interest to researchers in the catalysis field. Mesoporous materials are firstly developed and succeeded by Mobil Corporation in 1992 (Beck J S, Vartuli J Z, Roth W J et al, J.Am.Chem.Comm.Soc., 1992, 114, 10834-containing 10843) and named as M41S series mesoporous molecular sieves, including MCM-41(Mobil Corporation Material-41) and MCM-48, etc., wherein the pore diameter of the molecular sieves can reach 1.6-10 nm, and the mesoporous materials are uniform and adjustable, have concentrated pore diameter distribution, large specific surface area and pore volume and strong adsorption capacity; however, the pore wall structure of the molecular sieve is an amorphous structure, so that the molecular sieve has poor hydrothermal stability and weak acidity, cannot meet the operation conditions of catalytic cracking, and is greatly limited in industrial application.
In order to solve the problem of poor hydrothermal stability of mesoporous molecular sieves, part of research work focuses on increasing the thickness of the pore walls of the molecular sieves, and if a neutral template agent is adopted, the molecular sieve with thicker pore walls can be obtained, but the defect of weaker acidity still exists. In CN1349929A, a novel mesoporous molecular sieve is disclosed, in which the primary and secondary structural units of zeolite are introduced into the pore walls of the molecular sieve, so that the molecular sieve has the basic structure of the conventional zeolite molecular sieve, and the mesoporous molecular sieve has strong acidity and ultrahigh hydrothermal stability. However, the molecular sieve has the defects that a template agent with high price is required to be used, the aperture is only about 2.7nm, the molecular sieve still has large steric hindrance effect on macromolecular cracking reaction, the structure is easy to collapse under the high-temperature hydrothermal condition, and the cracking activity is poor.
In the field of catalytic cracking, silicon-aluminum materials are widely used due to their strong acid centers and good cracking properties. The proposal of the mesoporous concept provides possibility for the preparation of novel catalysts, and the current research results mostly focus on the use of expensive organic templates and the preparation of the novel catalystsThe silicon source is used, and most of the silicon source is subjected to a high-temperature hydrothermal post-treatment process. In order to reduce the preparation cost and obtain a porous material in the mesoporous range, more research efforts have been focused on the development of disordered mesoporous materials. US5,051,385 discloses a monodisperse mesoporous silicon-aluminum composite material, which is prepared by mixing acidic inorganic aluminum salt and silica sol and then adding alkali for reaction, wherein the aluminum content is 5-40 wt%, the aperture is 20-50 nm, and the specific surface area is 50-100 m2(ii) in terms of/g. US4,708,945 discloses a catalyst prepared by loading silica particles or hydrated silica on porous boehmite and hydrothermally treating the obtained composite at a temperature of more than 600 ℃ for a certain time to obtain a catalyst prepared by loading silica on the surface of the boehmite, wherein the silica is combined with hydroxyl of the transition boehmite and the surface area reaches 100-200 m2(iv) g, average pore diameter of 7 to 7.5 nm. A series of acidic cracking catalysts are disclosed in US4,440,872, some of which are supported on gamma-Al2O3Impregnating silane, and then roasting at 500 ℃ or treating with water vapor. In CN1353008A, inorganic aluminum salt and water glass are used as raw materials, stable and clear silicon-aluminum sol is formed through the processes of precipitation, washing, dispergation and the like, white gel is obtained through drying, and then the silicon-aluminum catalytic material is obtained through roasting for 1-20 hours at 350-650 ℃. CN1565733A discloses a mesoporous silicon-aluminum material which has a pseudo-boehmite structure, concentrated pore size distribution and a specific surface area of about 200-400 m2The mesoporous silicon-aluminum material has the advantages that the pore volume is 0.5-2.0 ml/g, the average pore diameter is 8-20 nm, the most probable pore diameter is 5-15 nm, an organic template agent is not needed in the preparation of the mesoporous silicon-aluminum material, the synthesis cost is low, the obtained silicon-aluminum material has high cracking activity and hydrothermal stability, and the high macromolecular cracking performance is shown in a catalytic cracking reaction.
Disclosure of Invention
The invention aims to provide a preparation method of a rare earth modified composite material, which comprises the following steps: (1) carrying out first ion exchange treatment on a porous material and a rare earth solution and/or an ammonium salt solution, filtering, washing and drying; (2) carrying out primary roasting treatment on the obtained product in the step (1) under the condition of 0-100% of water vapor; (3) the product obtained in the step (2) is treated according to the following stepsMixing the solution with ammonium salt solution at a certain ratio for the second ion exchange treatment, filtering or not, or mixing the solution with acid solution for the second ion exchange treatment, filtering; (4) mixing the obtained slurry in the step (3) with a rare earth solution in proportion, adjusting the pH value of the slurry to 5-10 by using an alkaline solution, and filtering or not filtering; (5) and (4) carrying out secondary roasting treatment on the obtained product in the step (4) under the condition of 0-100% of water vapor. Wherein, the mesoporous structure of the porous material in the step (1) grows on the surface of a Y-shaped molecular sieve crystal grain and coats the molecular sieve crystal grain, the grain size is 1-2 mu m, and the total specific surface area is 300-650 m2(ii) a total pore volume of 0.4 to 1.0cm3(vii)/g, wherein the XRD spectrum has diffraction peaks at 6.2 °, 10.1 °, 11.9 °, 15.7 °, 18.7 °, 20.4 °, 23.7 °, 27.1 °, 28 °, 31.4 °, 38.5 °, 49 ° and 65 °, and the chemical composition of the mesoporous layer is determined by the XPS method as the surface chemical composition, in atomic mass: 7-20% of aluminum and 5-12% of silicon; the a/b of the porous material is 1.2-9.5, wherein a represents the shift of 500cm in Raman spectrum-1B represents a Raman shift of 350cm-1Spectral peak intensity of (a).
The porous material in the step (1) has XRD spectrum with characteristic diffraction peaks at 6.2 deg., 10.1 deg., 11.9 deg., 15.7 deg., 18.7 deg., 20.4 deg., 23.7 deg., 27.1 deg., 31.4 deg. and the like corresponding to FAU crystal phase structure of Y-type molecular sieve, and characteristic diffraction peaks at 28 deg., 38.5 deg., 49 deg. and 65 deg. corresponding to pseudo-boehmite structure of mesoporous layer. The porous material can be seen in a scanning electron microscope SEM picture that the wrinkled mesoporous structure is coated on the surface of the crystal grains of the Y-shaped molecular sieve, the granularity is uniform and is between 1 and 2 mu m, and the granularity is equivalent to the size of the crystal grains of the Y-shaped molecular sieve. The low-temperature nitrogen adsorption and desorption isotherm of the mesoporous silicon dioxide is in a type IV typical form and has mesoporous characteristics; the mesoporous layer is derived on the surface of the Y-type molecular sieve crystal grain in a crystal attachment growth mode.
The porous material in the step (1) simultaneously contains a microporous structure and a mesoporous structure, and the silicon-aluminum mesoporous layer is derived from the surface of the Y-shaped molecular sieve and coated on the surface of the molecular sieve, so that the granularity is more uniform, the mesoporous structure on the surface is smooth, a continuous gradient channel structure is formed with the internal molecular sieve, and the accessibility of macromolecules is enhanced.
The porous material in the step (1) has special physical and chemical properties, and can be obtained through the following preparation processes: (a) preparing raw materials capable of synthesizing a NaY molecular sieve, uniformly mixing, and then performing static crystallization at the temperature of 95-105 ℃; (b) filtering and washing the slurry after the static crystallization to obtain a NaY molecular sieve filter cake; (c) adding water into the NaY molecular sieve filter cake again for pulping, uniformly dispersing, adding an aluminum source and an alkali solution into the NaY molecular sieve filter cake at the temperature of between 30 and 70 ℃ under the condition of vigorous stirring for reaction, and controlling the pH value of a slurry system in the reaction process to be between 9 and 11; (d) in terms of SiO, based on the weight of alumina contained in the added aluminum source and alkali solution2:Al2O3Adding a silicon source according to the weight ratio of (1-6), continuously aging at 30-90 ℃ for 1-8 hours, and recovering the product, or aging at 30-90 ℃ for 1-4 hours, then placing in a closed reaction kettle, continuously crystallizing at 95-105 ℃ for 3-30 hours, and recovering the product.
The raw materials for synthesizing the NaY molecular sieve in step (a) of the process for preparing the porous material in step (1) are usually directing agent, water glass, sodium metaaluminate, aluminum sulfate and deionized water, and they may be added in the proportion of the conventional NaY molecular sieve, for example, Na2O：Al2O3：SiO2：H2O is 1.5-8: 1: 5-18: 100 to 500, the charge ratio of NaY molecular sieve for preparing special performance, for example, the charge ratio of NaY molecular sieve for preparing large or small crystal grains, is not particularly limited as long as NaY molecular sieve having FAU crystal phase structure can be obtained. The guiding agent can be prepared according to the prior art (US3639099 and US3671191), and the guiding agent is prepared by mixing a silicon source, an aluminum source, alkali liquor and deionized water according to (15-18) Na2O:Al2O3:(15～17)SiO2:(280～380)H2Mixing the components according to the molar ratio of O, uniformly stirring, and standing and aging for 0.5-48 h at room temperature to 70 ℃. In the feeding proportion of the NaY molecular sieve, Al in the guiding agent2O3The content of (A) is based on the total charge Al2O33 to 15%, preferably 5 to 10% of the total amount. The static crystallization in the step (a) is carried out for 8 to 50 hours, preferably 10 to 40 hours, and more preferably 15 to 35 hours.
In the preparation of the porous material in the step (1), the aluminum source in the step (c) is selected from one or more of aluminum nitrate, aluminum sulfate and aluminum chloride; the alkali solution is one or more selected from ammonia water, potassium hydroxide, sodium hydroxide and sodium metaaluminate. When sodium metaaluminate is used as the alkali solution, the alumina content is counted in the total alumina content. The reaction temperature in the step (c) is 30-70 ℃, preferably 35-65 ℃.
In the preparation process of the porous material in the step (1), the silicon source in the step (d) is one or more selected from water glass, sodium silicate, tetraethoxysilane, tetramethoxysilane and silicon oxide. The aging temperature is 30-90 ℃, preferably 40-80 ℃, and the aging time is 1-8 hours, preferably 2-7 hours.
In the preparation method, in the first ion exchange treatment process of the porous material and the rare earth solution and/or the ammonium salt solution in the step (1), the weight ratio of the rare earth solution to the porous material calculated by rare earth oxide is 0.02-0.14, preferably 0.03-0.13, the weight ratio of the ammonium salt to the porous material is 0.1-1.0, the exchange temperature is 40-90 ℃, preferably 50-80 ℃, and the exchange time is 0.5-3.0 hours, preferably 1-2 hours.
The first and second roasting treatments in the steps (2) and (5) are carried out at 500-700 ℃, preferably 530-680 ℃, and 0-100% of water vapor, preferably 20-100% of water vapor, for 0.5-4.0 hours, preferably 1-3 hours.
In the second ion exchange treatment process with ammonium salt in the step (3), the weight ratio of the ammonium salt to the ammonium salt obtained in the step (2) is 0.3-0.5, the exchange temperature is 40-90 ℃, preferably 50-80 ℃, and the exchange time is 0.5-3.0 hours, preferably 1-2 hours. In the ion exchange treatment process with the acid solution, the weight ratio of the acid solution to the acid solution obtained in the step (2) is 0.03-0.12, preferably 0.05-0.1, the exchange temperature is room temperature-60 ℃, and the exchange time is 0.5-3.0 hours, preferably 1-2 hours.
In the mixing process of the rare earth solution and the mixture obtained in the step (3) in the step (4), the weight ratio of the rare earth oxide is 0.01-0.10, preferably 0.02-0.08; and adjusting the pH value of the slurry to 5-10, preferably 6-9, wherein the alkaline solution is one or more selected from sodium hydroxide, water glass and ammonia water.
The rare earth solution is well known to those skilled in the art, and can be rare earth chloride or rare earth nitrate, or rare earth chloride or rare earth nitrate consisting of a single rare earth element, wherein the common rare earth solution comprises lanthanum chloride, lanthanum nitrate, cerium chloride or cerium nitrate, and the like, or mixed rare earth with different rare earth element proportions, such as cerium-rich or lanthanum-rich mixed rare earth, and the concentration of the mixed rare earth solution can be any concentration; the ammonium salt can be one or more of ammonium chloride, ammonium nitrate, ammonium carbonate and ammonium bicarbonate.
The filtration, water washing and drying processes are well known to those skilled in the art and will not be described herein.
The rare earth modified composite material prepared by the preparation method simultaneously contains a Y-type molecular sieve microporous structure and a layer of gamma-Al on the surface2O3The two structures are connected with each other, the XRD spectrogram has Y-type molecular sieve characteristic diffraction peaks at 6.2 degrees, 10.1 degrees, 11.9 degrees, 15.7 degrees, 18.7 degrees, 20.4 degrees, 23.7 degrees, 27.1 degrees, 31.4 degrees and the like, a wide peak between 20 degrees and 30 degrees and gamma-Al at about 66 degrees2O3A characteristic diffraction peak of the mesoporous structure; the rare earth content is 2-23 wt%, preferably 4-20 wt% calculated by rare earth oxide, the unit cell constant is 2.450-2.470 nm, preferably 2.452-2.466 nm, the relative crystallinity is 20-60%, preferably 23-58%, and the total specific surface area is 250-550 m2(g) total pore volume of 0.3-0.9 cm3A grain size of 1 to 2 μm.
The rare earth modified composite material prepared by the method of the invention, considering the organic combination of the micropore and the mesoporous and the moderate modification of the rare earth, promotes the modulation of the pore structure and the acid property of the material, is not only beneficial to improving the hydrothermal stability, but also beneficial to improving the accessibility of an active center, and obviously improves the reaction activity.
Drawings
FIG. 1 is a SEM photograph of the porous material SAYN-1 in example 1.
FIG. 2 is a SEM photograph of a typical NaY molecular sieve in example 1.
FIG. 3 is an X-ray diffraction pattern of the porous material SAYN-1 in example 1.
FIG. 4 is a low temperature nitrogen desorption isotherm of the porous material SAYN-1 of example 1.
FIG. 5 is an X-ray diffraction spectrum of the rare earth modified composite material RDL-1 prepared in example 1.
FIG. 6 is a SEM photograph of the porous material SAY-1 of example 4.
FIG. 7 is an X-ray diffraction pattern of the porous material SAY-1 of example 4.
FIG. 8 is a pore size distribution curve of the porous material SAY-1 of example 4.
Detailed Description
The invention is further illustrated by the following examples, which are not intended to limit the scope of the invention.
The preparation process of the directing agent used in the examples was: 5700g of water glass (available from Changling catalysts, Inc., SiO 2261 g/L, modulus 3.31, density 1259g/L) was placed in a beaker and 4451g of high-alkali sodium metaaluminate (available from Changling catalysts, Inc., Al) was added with vigorous stirring2O339.9g/L，Na2O279.4 g/L, density 1326g/L) and aging at 30 ℃ for 18 hours to obtain Na with the molar ratio of 16.12O:Al2O3:15SiO2:318.5H2A directing agent for O.
The chemical composition of the mesoporous layer of the porous material in the examples was determined by X-ray photoelectron spectroscopy. The phase, unit cell constant, crystallinity, and the like were measured by X-ray diffraction. Wherein, the crystallinity is measured according to the industry standards SH/T0340-92 and SH/T0339-92 of China general petrochemical company, and the NaY molecular sieve crystallinity standard sample is measured: NaY molecular sieve (GS BG 75004-. The rare earth content was measured by X-ray fluorescence (see "analytical methods in petrochemical industry (RIPP methods of experiments)", edited by yangcui et al, published by scientific publishers, 1990).
The porous material test in the examples, SEM test, was performed using a Hitachi S4800, Hitachi, Japan, field emission scanning electron microscope, acceleration voltage 5kV, and energy spectrum collected and processed by Horiba 350 software. The laser Raman spectrum adopts a LabRAM HR UV-NIR type laser confocal Raman spectrometer of HORIBA company of Japan, the wavelength of an excitation light source is 325nm, an ultraviolet 15-time objective lens, a confocal pinhole is 100 mu m, and the spectrum scanning time is 100 s.
Example 1
This example illustrates the rare earth-modified composite material prepared by the method of the present invention.
Under the condition of vigorous stirring, water glass, aluminum sulfate, sodium metaaluminate, guiding agent and deionized water are mixed according to 7.5SiO2：Al2O3：2.15Na2O：190H2Mixing the molar ratio of O to form NaY molecular sieve gel, wherein the mass ratio of the guiding agent is 5%, continuously stirring for 1 hour at room temperature, placing the gel in a crystallization kettle for static crystallization treatment for 40 hours at 100 ℃, quickly cooling after crystallization, and filtering and washing crystallized slurry to obtain a NaY molecular sieve filter cake; adding water again to the obtained NaY molecular sieve filter cake for pulping, dispersing uniformly, and then stirring Al vigorously at 30 DEG C2(SO4)3Solution (concentration 89 gAl)2O3/L) and NaAlO2Solution (concentration 156 gAl)2O3/L) is added into the reaction kettle simultaneously to react, the pH value of a slurry system in the reaction process is controlled to be 9.5, and after a certain time of adding, the total Al content is determined according to the Al2(SO4)3 solution and the NaAlO2 solution2O3By weight, in terms of SiO2:Al2O31:2.3 weight ratio, the desired water glass solution (concentration 100g SiO)2/L) is added into the reaction system, and then aging is continued for 6 hours at 70 ℃, after the aging is finished, filtration is carried out, washing is carried out, and drying is carried out at 120 ℃, so as to obtain the porous material SAYN-1.
A SEM photograph of SAYN-1 is shown in FIG. 1, a typical SEM of NaY molecular sieveThe photographs are shown in FIG. 2, the comparison of FIG. 1 and FIG. 2 shows that the SAYN-1 has uniform particle size distribution, 1-2 μm particle size and corrugated structure on the surface, which indicates that the SAYN-1 is a material with corrugated mesoporous structure growing on the surface of NaY molecular sieve grains, the XRD spectrum of the SAYN-1 is shown in FIG. 3, and diffraction peaks appear at 6.2 °, 10.1 °, 11.9 °, 15.7 °, 18.7 °, 20.4 °, 23.7 °, 27.1 °, 28 °, 31.4 °, 38.5 °, 49 ° and 65 °, wherein the characteristic diffraction peak labeled ★ corresponds to the FAU crystal phase structure of the Y-type molecular sieve, the characteristic diffraction peak labeled ▲ corresponds to the pseudo-boehmite structure of the mesoporous layer, the low-temperature nitrogen adsorption and desorption isotherm of the SAYN-1 is shown in FIG. 4, and is in typical type IV form with mesoporous characteristics, and the total specific surface area is 516m2(ii)/g, total pore volume 0.92cm3(ii) in terms of/g. The surface chemical composition measured by XPS method was 13.6% aluminum and 7.1% silicon by atomic mass. Raman (Raman) spectrometry with a/b of 2.1, wherein a represents a 500cm shift in the Raman (Raman) spectrum-1B represents a Raman shift of 350cm-1Spectral peak intensity of (a).
Carrying out first ion exchange treatment on the SAYN-1 and the rare earth solution at 80 ℃ according to the weight ratio of the rare earth oxide to the SAYN-1 of 0.10, wherein the exchange time is 1 hour, and filtering, washing and drying the solution; roasting for 2 hours at 550 ℃ under the condition of 100 percent of water vapor; mixing the obtained mixture with an ammonium salt solution according to the weight ratio of 1:0.35, carrying out secondary ion exchange treatment at 80 ℃ for 1 hour, filtering, adding a rare earth solution according to the weight ratio of rare earth oxide to a filtered sample dry basis of 0.04, uniformly stirring, adjusting the pH value of a system to 7.9 by using ammonia water, directly drying, and carrying out secondary roasting treatment at 550 ℃ under the condition of 100% water vapor to obtain the rare earth modified composite material RDL-1.
The XRD diffraction pattern of RDL-1 is shown in FIG. 5, while the FAU crystal phase structure and gamma-Al of Y-type molecular sieve can be seen2O3Structure, in the figure? Diffraction peaks at 6.2 °, 10.1 °, 11.9 °, 15.7 °, 18.7 °, 20.4 °, 23.7 °, 27.1 ° and 31.4 ° corresponding to the numbers are FAU crystal phase structure characteristic peaks, and diffraction peaks at 20 ° to 30 ° and about 66 ° corresponding to parenthesis in the figure are γ -Al2O3Structural characteristic peaks.
RDL-1 contains rare earth oxide 13.7 wt%, unit cell constant 2.461nm, relative crystallinity 31%, and total specific surface area 448m2G, total pore volume 0.85cm3A grain size of 1 to 2 μm.
Example 2
This example illustrates the rare earth-modified composite material prepared by the method of the present invention.
The preparation of the NaY molecular sieve is the same as that of the example 1, except that the crystallization treatment time is 24 hours; adding water again into the obtained NaY molecular sieve filter cake for pulping, dispersing uniformly, and then stirring Al (NO) vigorously at room temperature3)3Adding the solution and ammonia water simultaneously, controlling pH value of slurry system at 10.1, adding Al (NO) according to the amount of the solution3)3Al of solution2O3By weight, in terms of SiO2:Al2O3Adding the required tetraethoxysilane into the reaction system according to the weight ratio of 1:1.8, continuing to age at 65 ℃ for 6 hours, filtering after the aging is finished, washing and drying at 120 ℃ to obtain the porous material SAYN-6.
The scanning electron microscope photo of SAYN-6 has the characteristics shown in figure 1, the particle size distribution is uniform, the particle size is 1-2 mu m, and the surface of the NaY molecular sieve crystal grain is coated with a wrinkled mesoporous structure. The XRD spectrum has the characteristics shown in figure 3, and simultaneously contains an FAU crystal phase structure and a pseudo-boehmite structure. The low-temperature nitrogen adsorption and desorption isotherm of SAYN-6 has the characteristics shown in figure 4, is in the form of IV isotherms, has mesoporous characteristics and has the total specific surface area of 588m2In terms of/g, total pore volume of 0.78cm3(ii) in terms of/g. The surface chemical composition measured by the XPS method was 13.5% by atomic mass of aluminum and 9.5% by atomic mass of silicon. Raman (Raman) spectroscopy, which gave an a/b of 5.9.
Carrying out first ion exchange treatment on the SAYN-6 and the rare earth solution at 70 ℃ according to the weight ratio of the rare earth oxide to the SAYN-6 of 0.10, wherein the exchange time is 2 hours, and filtering, washing and drying the solution; roasting for 2 hours at 600 ℃ under the condition of 100 percent of water vapor; mixing the obtained mixture with an ammonium salt solution according to the weight ratio of 1:0.3, carrying out secondary ion exchange treatment at 70 ℃ for 1 hour, filtering, adding a rare earth solution according to the weight ratio of 0.06 of the rare earth oxide to the dry basis of a filtered sample, uniformly stirring, adjusting the pH value of a system to 6.0 by using ammonia water, filtering, drying, and carrying out secondary roasting treatment at 500 ℃ under the condition of 100% water vapor for 2 hours to obtain the rare earth modified composite material RDL-2.
The XRD diffraction pattern of RDL-2 has the characteristics shown in figure 5, and the FAU crystal phase structure and gamma-Al of the Y-type molecular sieve can be seen2O3And (5) structure.
RDL-2 contains rare earth oxide 15.7 wt%, unit cell constant 2.464nm, relative crystallinity 42%, and total specific surface area 485m2G, total pore volume 0.63cm3A grain size of about 1 to 2 μm.
Example 3
This example illustrates the rare earth-modified composite material prepared by the method of the present invention.
The preparation of NaY molecular sieve is the same as example 1 except that the crystallization treatment time is 45 hours; adding water again to the NaY molecular sieve filter cake, pulping, dispersing uniformly, and adding AlCl under vigorous stirring at 60 deg.C3Solution and NaAlO2Adding the solution into the reaction kettle simultaneously for reaction, controlling the pH value of a slurry system to be 10.8 in the reaction process, and adding AlCl according to the use after a certain time3Solution and NaAlO2Total Al of solution2O3By weight, in terms of SiO2:Al2O3Adding the required tetraethoxysilane into the reaction system according to the weight ratio of 1:4, continuing to age at 50 ℃ for 3 hours, filtering after the aging is finished, washing and drying at 120 ℃ to obtain the porous material SAYN-7.
The scanning electron microscope photo of SAYN-7 has the characteristics shown in figure 1, the particle size distribution is uniform, the particle size is 1-2 mu m, and the surface of the NaY molecular sieve crystal grain is coated with a wrinkled mesoporous structure. The XRD spectrum has the characteristics shown in figure 3, and simultaneously contains an FAU crystal phase structure and a pseudo-boehmite structure. The low-temperature nitrogen adsorption and desorption isotherm of SAYN-7 has the characteristics shown in figure 4, is in the form of IV isotherms, has mesoporous characteristics and has a total specific surface area of 474m2(ii)/g, total pore volume 0.81cm3(ii) in terms of/g. Tables measured by XPS methodThe surface chemical composition was 16.1% by atomic mass of aluminum and 7.7% by atomic mass of silicon. Raman (Raman) spectroscopy, which gave an a/b of 9.3.
Carrying out first ion exchange treatment on SAYN-7 and a rare earth solution at 60 ℃ according to the weight ratio of 0.04 of rare earth oxide to SAYN-7 and the ratio of 1:0.25 of ammonium salt, wherein the exchange time is 1 hour, and filtering, washing and drying are carried out; roasting at 580 deg.c for 2 hr; and mixing the obtained mixture with an ammonium salt solution according to the weight ratio of 1:0.35, carrying out secondary ion exchange treatment at 60 ℃ for 1 hour, adding a rare earth solution into the ion exchange solution according to the weight ratio of rare earth oxide of 0.03, adjusting the pH value of the system to 6.5 by using sodium hydroxide, filtering, drying, and carrying out secondary roasting treatment at 580 ℃ under the condition of 100% water vapor for 2 hours to obtain the rare earth modified composite material RDL-3.
The XRD diffraction spectrum of RDL-3 has the characteristics shown in figure 5, and the FAU crystal phase structure and gamma-Al of the Y-type molecular sieve can be seen2O3And (5) structure.
RDL-3 contains rare earth oxide 6.6 wt%, unit cell constant 2.456nm, relative crystallinity 23%, and total specific surface area 420m2In terms of/g, total pore volume 0.77cm3A grain size of about 1 to 2 μm.
Example 4
This example illustrates the rare earth-modified composite material prepared by the method of the present invention.
Under the condition of vigorous stirring, water glass, aluminum sulfate, sodium metaaluminate, guiding agent and deionized water are mixed according to 8.5SiO2：Al2O3：2.65Na2O：210H2Mixing the molar ratio of O to prepare NaY molecular sieve gel, wherein the mass ratio of the guiding agent is 5%, stirring for 1 hour at room temperature, placing the gel in a crystallization kettle for static crystallization treatment for 30 hours at 100 ℃, cooling after crystallization, and filtering and washing crystallized slurry to obtain a NaY molecular sieve filter cake; adding water again into the obtained NaY molecular sieve filter cake for pulping, homogenizing, and adding AlCl at 45 deg.C under vigorous stirring3Solution (concentration 60 gAl)2O3/L) and NaAlO2Solution (concentration 102 gAl)2O3/L) adding the components at the same time to carry out gellingReacting, controlling the pH value of the slurry to be 10.0 in the gelling process, adding the slurry for a certain time according to the AlCl used3Solution and NaAlO2Total Al in solution2O3By weight, in terms of SiO2:Al2O31:1.8 weight ratio, the desired water glass solution (concentration 125 gSiO)2/L) is added into the gel forming slurry, and then the gel forming slurry is aged for 3 hours at 55 ℃, after the aging, the slurry is placed into a stainless steel reaction kettle and crystallized for 20 hours at the temperature of 100 ℃, and then the filtration, the washing and the drying at the temperature of 120 ℃ are carried out, thus obtaining the porous material SAY-1.
SAY-1 SEM photograph is shown in FIG. 6, the particle size distribution is uniform, the particle size is 1-2 μm, the surface is wrinkled, it shows that the mesoporous structure grows on the NaY molecular sieve grain surface and covers it, the XRD spectrogram is shown in FIG. 7, diffraction peaks appear at 6.2 °, 10.1 °, 11.9 °, 15.7 °, 18.7 °, 20.4 °, 23.7 °, 27.1 °, 28 °, 31.4 °, 38.5 °, 49 ° and 65 °, wherein the characteristic diffraction peak marked as ★ corresponds to FAU crystal phase structure of Y-type molecular sieve, the characteristic diffraction peak marked as # corresponds to pseudo-boehmite structure, SAY-1 a/b is 6.6, wherein a is the shift of 500cm in Raman spectrum-1B is a shift of 350cm-1(ii) spectral peak intensity of; the surface silicon-aluminum atomic ratio measured by the XPS method was 0.74. SAY-1, as shown in FIG. 8, exhibits hierarchical pore distribution characteristics, and several pore distributions at 3.8nm, 11nm and 60nm, respectively, and a total specific surface area of 644m2(g) the mesoporous specific surface area is 65m2/g。
Carrying out first ion exchange treatment on SAY-1 and rare earth solution according to the weight ratio of 0.06 of rare earth oxide to SAY-1 and the ratio of 1:0.15 of ammonium salt at 65 ℃ for 1 hour, filtering, washing with water and drying; roasting for 2 hours at the temperature of 630 ℃ under the condition of 100 percent of water vapor; mixing the obtained mixture with an ammonium salt solution according to the weight ratio of 1:0.3, carrying out secondary ion exchange treatment at 65 ℃ for 1 hour, filtering, adding the rare earth solution, stirring uniformly, adjusting the pH value of a system to 7.8 by using ammonia water according to the weight ratio of 0.06 of rare earth oxide, filtering, drying, and carrying out secondary roasting treatment at 630 ℃ under the condition of 100% water vapor for 2 hours to obtain the rare earth modified composite material RDL-4.
The XRD diffraction pattern of RDL-4 has the characteristics shown in figure 5, and the FAU crystal phase structure and gamma-Al of the Y-type molecular sieve can be seen2O3And (5) structure.
RDL-4 contains rare earth oxide 11.9 wt%, unit cell constant 2.459nm, relative crystallinity 44%, total specific surface area 531m2G, total pore volume 0.48cm3A grain size of about 1 to 2 μm.
Example 5
This example illustrates the rare earth-modified composite material prepared by the method of the present invention.
The preparation of NaY molecular sieve is the same as that of example 4, except that the crystallization treatment time is 26 hours; adding water again into the obtained NaY molecular sieve filter cake for pulping, homogenizing, and stirring at 60 deg.C under vigorous stirring to obtain Al2(SO4)3Adding the solution and ammonia water simultaneously to carry out gelling reaction, controlling the pH value of the slurry to be 9.4 in the gelling process, and adding Al according to the used Al after a certain time2(SO4)3Al of solution2O3By weight, in terms of SiO2:Al2O3Adding the required water glass solution into the gel-forming slurry according to the weight ratio of 1:1.5, aging at 60 ℃ for 1.5 hours, placing the slurry into a stainless steel reaction kettle after aging, crystallizing at 100 ℃ for 25 hours, filtering, washing and drying at 120 ℃ to obtain the porous material SAY-5.
SAY-5 scanning electron microscope photo has the characteristics shown in figure 6, the particle size distribution is uniform, the particle size is 1-2 μm, and the mesoporous structure grows on the surface of NaY molecular sieve crystal grains and covers the NaY molecular sieve crystal grains. The XRD spectrum has the characteristics shown in figure 7, and simultaneously contains an FAU crystal phase structure and a pseudo-boehmite structure. SAY-5, has an a/b of 1.5, and has a surface silicon-aluminum atomic ratio of 0.88 as measured by XPS method. SAY-5 has the characteristics shown in FIG. 8, and shows a multi-level pore distribution with a total specific surface area of 398m2(g) the mesoporous specific surface area is 285m2/g。
Carrying out first ion exchange treatment on SAY-5 and rare earth solution according to the weight ratio of 0.08 of rare earth oxide to SAY-5 and the ratio of 1:0.1 of ammonium salt at 75 ℃ for 2 hours, filtering, washing with water and drying; roasting at 650 deg.C and 100% steam for 1 hr; and mixing the obtained mixture with an ammonium salt solution according to the weight ratio of 1:0.35, carrying out secondary ion exchange treatment at 75 ℃ for 1 hour, filtering, adding a rare earth solution, adjusting the pH value of a system to 7.0 by using ammonia water according to the weight ratio of 0.02 of rare earth oxide, drying, and carrying out secondary roasting treatment at 650 ℃ for 2 hours to obtain the rare earth modified composite material RDL-5.
The XRD diffraction spectrum of RDL-5 has the characteristics shown in figure 5, and the FAU crystal phase structure and gamma-Al of the Y-type molecular sieve can be seen2O3And (5) structure.
RDL-5 contains 9.8 wt% of rare earth oxide, unit cell constant is 2.457nm, relative crystallinity is 27%, and total specific surface area is 349m2G, total pore volume 0.83cm3A grain size of about 1 to 2 μm.
Example 6
This example illustrates the rare earth-modified composite material prepared by the method of the present invention.
Under the condition of vigorous stirring, water glass, aluminum sulfate, sodium metaaluminate, guiding agent and deionized water are mixed according to 7.5SiO2：Al2O3：2.15Na2O：190H2Mixing the molar ratio of O to prepare NaY molecular sieve gel, wherein the mass ratio of the directing agent is 5%, stirring for 1 hour at room temperature, and then placing the gel in a crystallization kettle for static crystallization treatment for 30 hours at 100 ℃; adding water again into the obtained NaY molecular sieve filter cake for pulping, homogenizing, and then stirring Al vigorously at 40 DEG C2(SO4)3Solution and NaAlO2Adding the solution at the same time to carry out gelling reaction, controlling the pH value of the slurry to be 10.2 in the gelling process, and adding Al according to the used Al after a certain time2(SO4)3Solution and NaAlO2Total Al of solution2O3By weight, in terms of SiO2:Al2O3Adding the required water glass solution into the gel-forming slurry according to the weight ratio of 1:2.6, aging at 75 ℃ for 3 hours, placing the slurry into a stainless steel reaction kettle after aging, and crystallizing at 100 ℃ for 4 hoursFiltered, washed and dried at 120 ℃ to give porous material SAY-6.
SAY-6 has the characteristics shown in figure 6, the particle size distribution is uniform, the particle size is 1-2 μm, and the mesoporous structure grows on the surface of NaY molecular sieve crystal grains and covers the NaY molecular sieve crystal grains. The XRD spectrum has the characteristics shown in figure 7, and simultaneously contains an FAU crystal phase structure and a pseudo-boehmite structure. SAY-6, has an a/b of 2.6, and has a surface silicon-aluminum atomic ratio of 0.50 as measured by XPS method. SAY-6 has the characteristics shown in FIG. 8, presents a multistage pore distribution, and has a total specific surface area of 532m2(iv)/g, mesoporous specific surface area is 209m2/g。
SAY-6 and ammonium salt are subjected to first ion exchange treatment at 70 ℃ according to the ratio of 1:1, the exchange time is 1 hour, and the solution is filtered, washed and dried; roasting at 550 deg.c for 4 hr; and mixing the obtained mixture with an ammonium salt solution according to the weight ratio of 1:0.3, carrying out secondary ion exchange treatment at 70 ℃ for 1 hour, adding a rare earth solution into the exchange slurry according to the weight ratio of 0.05 of rare earth oxide, adjusting the pH value of the system to 7.5 by using ammonia water, filtering, drying, and carrying out secondary roasting treatment at 550 ℃ under the condition of 100% water vapor for 2 hours to obtain the rare earth modified composite material RDL-6.
The XRD diffraction pattern of RDL-6 has the characteristics shown in figure 5, and the FAU crystal phase structure and gamma-Al of the Y-type molecular sieve can be seen2O3And (5) structure.
RDL-6 contains rare earth oxide 5 wt%, unit cell constant 2.454nm, relative crystallinity 36%, and total specific surface area 445m2In g, total pore volume 0.68cm3A grain size of about 1 to 2 μm.
Example 7
This example illustrates the rare earth-modified composite material prepared by the method of the present invention.
The preparation of NaY molecular sieve is the same as example 4, except that the crystallization treatment time is 40 hours; adding water again into the obtained NaY molecular sieve filter cake, pulping, homogenizing, and stirring vigorously at room temperature to obtain Al (NO)3)3Solution and NaAlO2Adding the solution at the same time to carry out gelling reaction, and controlling the pH value of the slurry to be 10 in the gelling process.5, after a certain time of addition, depending on the Al (NO) used3)3Solution and NaAlO2Total Al of solution2O3By weight, in terms of SiO2:Al2O3Adding the needed tetraethoxysilane into the gel-forming slurry according to the weight ratio of 1:5.2, aging at 65 ℃ for 4 hours, placing the slurry into a stainless steel reaction kettle after aging, crystallizing at 100 ℃ for 30 hours, filtering, washing and drying at 120 ℃ to obtain the porous material SAY-7.
SAY-7 scanning electron microscope photo has the characteristics shown in figure 6, the particle size distribution is uniform, the particle size is 1-2 μm, and the mesoporous structure grows on the surface of NaY molecular sieve crystal grains and covers the NaY molecular sieve crystal grains. The XRD spectrum has the characteristics shown in figure 7, and simultaneously contains an FAU crystal phase structure and a pseudo-boehmite structure. SAY-7, has an a/b of 1.4, and has a surface silicon-aluminum atomic ratio of 0.29 as measured by XPS method. SAY-7 has the characteristics shown in FIG. 8, presents a multistage pore distribution, and has a total specific surface area of 457m2Per g, the mesoporous specific surface area is 381m2/g。
Carrying out first ion exchange treatment on SAY-7 and rare earth solution according to the weight ratio of rare earth oxide to SAY-7 of 0.04 and the ratio of ammonium salt to 1:0.2 at 60 ℃ for 2 hours, filtering, washing with water and drying; roasting for 2 hours at 500 ℃ under the condition of 100 percent of water vapor; mixing the obtained mixture with an ammonium salt solution according to the weight ratio of 1:0.35, carrying out secondary ion exchange treatment for 1 hour at 60 ℃, adding a rare earth solution according to the weight ratio of 0.08 of rare earth oxide, uniformly stirring, adjusting the pH value of a system to 8.0 by using ammonia water, filtering, drying, and carrying out secondary roasting treatment for 2 hours at 500 ℃ under the condition of 100% water vapor to obtain the rare earth modified composite material RDL-7.
The XRD diffraction pattern of RDL-7 has the characteristics shown in figure 5, and the FAU crystal phase structure and gamma-Al of the Y-type molecular sieve can be seen2O3And (5) structure.
RDL-7 contains rare earth oxide 11.5 wt%, unit cell constant 2.456nm, relative crystallinity 24%, and total specific surface area 386m2In terms of/g, total pore volume 0.79cm3A grain size of about 1 to 2 μm.
Example 8
This example illustrates the rare earth-modified composite material prepared by the method of the present invention.
Under the condition of vigorous stirring, water glass, aluminum sulfate, sodium metaaluminate, guiding agent and deionized water are mixed according to 7.5SiO2：Al2O3：2.15Na2O：190H2Mixing the molar ratio of O to prepare NaY molecular sieve gel, wherein the mass ratio of the guiding agent is 5%, stirring for 1 hour at room temperature, placing the gel in a crystallization kettle for static crystallization treatment for 35 hours at 100 ℃, cooling after crystallization, and filtering and washing crystallized slurry to obtain a NaY molecular sieve filter cake; adding water again into the obtained NaY molecular sieve filter cake for pulping, homogenizing, and stirring at 55 deg.C under vigorous stirring to obtain Al2(SO4)3Solution (concentration 90 gAl)2O3/L) and ammonia water are added simultaneously to carry out gelling reaction, the pH value of slurry in the gelling process is controlled to be 9.0, and after a certain time, Al is added according to the use2(SO4)3Al of solution2O3By weight, in terms of SiO2:Al2O3Adding the required tetraethoxysilane into the gel-forming slurry according to the weight ratio of 1:2.2, aging at 80 ℃ for 2 hours, placing the slurry into a stainless steel reaction kettle after aging, crystallizing at 100 ℃ for 9 hours, filtering, washing and drying at 120 ℃ to obtain the porous material SAY-3.
SAY-3 scanning electron microscope photo has the characteristics shown in figure 6, the particle size distribution is uniform, the particle size is 1-2 μm, and the mesoporous structure grows on the surface of NaY molecular sieve crystal grains and covers the NaY molecular sieve crystal grains. The XRD spectrum has the characteristics shown in figure 7, and simultaneously contains an FAU crystal phase structure and a pseudo-boehmite structure. SAY-3, has an a/b of 3.4, and has a surface silicon to aluminum atomic ratio of 0.52 as measured by XPS. The BJH pore size distribution curve has the characteristics shown in FIG. 8, presents a multistage pore distribution characteristic, and has a total specific surface area of 542m2Per g, the mesoporous specific surface area is 154m2/g。
SAY-3 and rare earth solution are subjected to first ion exchange treatment at 75 ℃ according to the weight ratio of rare earth oxide to SAY-3 of 0.13, the exchange time is 1 hour, and the mixture is filtered, washed and dried; roasting for 2 hours at 600 ℃ under the condition of 100 percent of water vapor; mixing the obtained mixture with an ammonium salt solution according to the weight ratio of 1:0.3, carrying out secondary ion exchange treatment at 75 ℃ for 1 hour, filtering, adding the rare earth solution, stirring uniformly, adjusting the pH value of a system to 8.5 by using ammonia water according to the weight ratio of 0.05 of rare earth oxide, drying, and carrying out secondary roasting treatment at 600 ℃ under the condition of 100% water vapor for 2 hours to obtain the rare earth modified composite material RDL-8.
The XRD diffraction spectrum of RDL-8 has the characteristics shown in figure 5, and the FAU crystal phase structure and gamma-Al of the Y-type molecular sieve can be seen2O3And (5) structure.
RDL-8 contains rare earth oxide 18.1 wt%, unit cell constant 2.467nm, relative crystallinity 36%, total specific surface area 447m2In terms of/g, total pore volume 0.62cm3A grain size of about 1 to 2 μm.
Examples 9 to 16
Examples 9-16 illustrate the microreflective activity of the rare earth-modified composite material prepared by the method of the present invention after aging treatment at 800 ℃ and 100% steam for 17 hours.
The composite materials RDL-1 to RDL-8 in the embodiments 1 to 8 are mixed and exchanged with an ammonium chloride solution, the content of sodium oxide is washed to be below 0.3 weight percent, after filtering and drying, tabletting and screening are carried out to obtain particles of 20 to 40 meshes, the particles are aged for 17 hours under the conditions of 800 ℃ and 100 percent of water vapor, and then the micro-reaction activity index MA is tested on a light oil micro-reaction evaluation device.
Light oil micro-reverse evaluation conditions: the raw oil is Dagang straight run light diesel oil, the sample loading is 2g, the oil inlet is 1.56g, and the reaction temperature is 460 ℃.
The microreflective index is shown in Table 1.
TABLE 1
Sample (I) MA Sample (I) MA
RDL-1 59 RDL-5 55
RDL-2 62 RDL-6 54
RDL-3 53 RDL-7 57
RDL-4 59 RDL-8 60
As can be seen from the test results of the micro-inversion activity index MA shown in Table 1, the MA of the rare earth modified composite materials RDL-1 to RDL-8 obtained in examples 1 to 8 can still reach 53 to 62 after aging treatment for 17 hours at 800 ℃ by 100% steam, and the cracking activity is kept at a high level.
The rare earth modified composite material obtained by the method has a structure containing two pore channel structures of micropores and mesopores, so that better gradient pore channels and gradient acid distribution are formed, and after rare earth modification, the supporting effect of rare earth ions on the micropore channels and the adsorption effect in the mesopore channels play great promoting roles in the stability and cracking activity of the composite material, and the composite material shows better cracking activity.

Claims (12)

1. A preparation method of a rare earth modified composite material comprises the following steps: (1) carrying out first ion exchange treatment on a porous material and a rare earth solution and/or an ammonium salt solution, filtering, washing and drying; (2) carrying out primary roasting treatment on the obtained product in the step (1) under the condition of 0-100% of water vapor; (3) mixing the solution obtained in the step (2) with an ammonium salt solution for secondary ion exchange treatment, and filtering or not, or mixing the solution obtained in the step (2) with an acid solution for secondary ion exchange treatment and filtering; (4) mixing the slurry obtained in the step (3) with a rare earth solution, adjusting the pH value of the slurry to 5-10 by using an alkaline solution, and filtering or not filtering; (5) carrying out secondary roasting treatment on the obtained product in the step (4) under the condition of 0-100% of water vapor; wherein, the mesoporous structure of the porous material in the step (1) grows on the surface of a Y-shaped molecular sieve crystal grain and coats the molecular sieve crystal grain, the grain size is 1-2 μm, and the total specific surface area is 300-650 m2(ii) a total pore volume of 0.4 to 1.0cm3(g) in an XRD spectrum, diffraction peaks exist at 6.2 degrees, 10.1 degrees, 11.9 degrees, 15.7 degrees, 18.7 degrees, 20.4 degrees, 23.7 degrees, 27.1 degrees, 28 degrees, 31.4 degrees, 38.5 degrees, 49 degrees and 65 degrees, and the chemical composition of the mesoporous structure layer is determined by the surface chemical composition measured by an XPS method, and the chemical composition is calculated by atomic mass: 7-20% of aluminum and 5-12% of silicon; the a/b of the porous material is 1.2-9.5, wherein a represents the shift of 500cm in Raman spectrum-1B represents a Raman shift of 350cm-1Spectral peak intensity of (a).
2. The production method according to claim 1, wherein the porous material described in the step (1) is obtained by: (a) preparing raw materials capable of synthesizing a NaY molecular sieve, uniformly mixing, and then performing static crystallization at the temperature of 95-105 ℃; (b) filtering and washing the slurry after the static crystallization to obtain a NaY molecular sieve filter cake; (c) adding water into the NaY molecular sieve filter cake again for pulping, uniformly dispersing, adding an aluminum source and an alkali solution into the NaY molecular sieve filter cake at the temperature of between 30 and 70 ℃ under the condition of vigorous stirring for reaction, and controlling the pH value of a slurry system in the reaction process to be between 9 and 11; (d) with added aluminiumThe alumina content of the source and alkali solution is calculated as SiO2:Al2O3Adding a silicon source according to the weight ratio of (1-6), continuously aging at 30-90 ℃ for 1-8 hours and recovering the product, or aging at 30-90 ℃ for 1-4 hours, then placing in a closed reaction kettle, continuously crystallizing at 95-105 ℃ for 3-30 hours and recovering the product.
3. The method according to claim 2, wherein the raw materials for synthesizing NaY molecular sieve in step (a) are directing agent, water glass, sodium metaaluminate, aluminum sulfate and deionized water.
4. The method of claim 2 wherein the aluminum source in step (c) is selected from one or more of aluminum nitrate, aluminum sulfate and aluminum chloride.
5. The method according to claim 2, wherein the alkali solution in the step (c) is one or more selected from the group consisting of aqueous ammonia, potassium hydroxide, sodium hydroxide and sodium metaaluminate.
6. The process according to claim 2, wherein in the case of sodium metaaluminate as the alkali solution in the step (c), the alumina content is calculated from the alumina content in the step (d).
7. The method according to claim 2, wherein the silicon source in step (d) is one or more selected from the group consisting of water glass, sodium silicate, tetraethoxysilane, tetramethoxysilane, and silicon oxide.
8. The preparation method according to claim 1, wherein in the first ion exchange treatment of the porous material and the rare earth solution and/or the ammonium salt solution in the step (1), the weight ratio of the rare earth solution to the porous material calculated as rare earth oxide is 0.02 to 0.14, preferably 0.03 to 0.13, the weight ratio of the ammonium salt to the porous material is 0.1 to 1.0, the exchange temperature is 40 to 90 ℃, preferably 50 to 80 ℃, and the exchange time is 0.5 to 3.0 hours, preferably 1 to 2 hours.
9. The method according to claim 1, wherein the first calcination treatment in step (2) and the second calcination treatment in step (5) are conducted under conditions of 500 ℃ to 700 ℃, preferably 530 ℃ to 680 ℃, and 20% to 100% steam for 0.5 to 4.0 hours, preferably 1 to 3 hours.
10. The preparation method according to claim 1, wherein in the step (3), in the process of mixing the ammonium salt solution obtained in the step (2) and performing the second ion exchange treatment, the weight ratio of the ammonium salt to the ammonium salt solution obtained in the step (2) is 0.3-0.5, the exchange temperature is 40-90 ℃, preferably 50-80 ℃, and the exchange time is 0.5-3.0 hours, preferably 1-2 hours; in the ion exchange treatment process of the acid solution and the acid solution obtained in the step (2), the weight ratio of the acid solution to the acid solution obtained in the step (2) is 0.03-0.12, preferably 0.05-0.1, the exchange temperature is room temperature-60 ℃, and the exchange time is 0.5-3.0 hours, preferably 1-2 hours.
11. The process according to claim 1, wherein in the step (4), in the step of mixing the rare earth solution obtained in the step (3) with the rare earth solution, the weight ratio of the rare earth solution in terms of rare earth oxide to the rare earth solution obtained in the step (3) is 0.01 to 0.10, preferably 0.02 to 0.08; the pH value is 6-9, and the alkaline solution is selected from one or more of sodium hydroxide, water glass and ammonia water.
12. The method according to claim 1, wherein the rare earth modified composite material contains a Y-type molecular sieve microporous structure and a layer of gamma-Al on the surface2O3The two structures are connected with each other, the XRD spectrogram has Y-type molecular sieve characteristic diffraction peaks at 6.2 degrees, 10.1 degrees, 11.9 degrees, 15.7 degrees, 18.7 degrees, 20.4 degrees, 23.7 degrees, 27.1 degrees, 31.4 degrees and the like, a wide peak between 20 degrees and 30 degrees and gamma-Al at about 66 degrees2O3A characteristic diffraction peak of the mesoporous structure; the rare earth content is 2-23 wt%, preferably 4-20 wt% calculated by rare earth oxide, and the unit cell constant is 2.450-2.470nm, preferably 2.452-2.466 nm, relative crystallinity of 20-60%, preferably 23-58%, and total specific surface area of 250-550 m2(g) total pore volume of 0.3-0.9 cm3A grain size of 1 to 2 μm.
CN201910149968.3A 2019-02-28 2019-02-28 Preparation method of rare earth modified composite material Pending CN111617798A (en)

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