CN111744534A - Preparation method of hierarchical pore composite material - Google Patents

Preparation method of hierarchical pore composite material Download PDF

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CN111744534A
CN111744534A CN201910236272.4A CN201910236272A CN111744534A CN 111744534 A CN111744534 A CN 111744534A CN 201910236272 A CN201910236272 A CN 201910236272A CN 111744534 A CN111744534 A CN 111744534A
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degrees
silicon
hours
aluminum
rare earth
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郑金玉
王成强
满征
罗一斌
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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
    • 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
    • B01J35/60—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
    • 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
    • B01J35/633—Pore volume less than 0.5 ml/g
    • 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

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • General Chemical & Material Sciences (AREA)
  • Catalysts (AREA)
  • Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)

Abstract

A preparation method of a hierarchical pore composite material is characterized in that a silicon-aluminum material is modified in a phosphorus and rare earth sequence and is combined with a modification mode of double cross single baking or double cross double baking, wherein a pseudo-boehmite structure alumina mesoporous layer of the silicon-aluminum material is coated on the surface of an FAU crystal phase structure, the silicon-aluminum material has a gradient pore distribution characteristic formed by a microporous structure and a mesoporous structure, and a few pores with two characteristics can be distributed at 3-4 nm and 7-10 nm. The hierarchical porous composite material obtained by the method is characterized in that on the basis of the existence of a micro-mesoporous composite structure, the pore structure and acidity are optimized by further modifying phosphorus and rare earth, and the catalytic cracking reaction activity is improved.

Description

Preparation method of hierarchical pore composite material
Technical Field
The invention relates to a preparation method of a hierarchical porous composite material, in particular to a preparation method of a hierarchical porous composite material which contains a Y-type molecular sieve, is coated with a gamma-alumina mesoporous layer on the surface and contains phosphorus and rare earth.
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 makes the excessive rare earth ions in the solution precipitate to avoid the rare earth loss and ensure that the rare earth ions are completely 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 a novel catalyst, and the current research results mostly focus on the use of expensive organic template and organic silicon source, and mostly need to be 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 monodisperseThe mesoporous silicon-aluminum composite material 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 pore diameter is 20-50 nm, and the specific surface area is 50-100 m2(ii) in terms of/g. The method disclosed in US4,708,945 is that firstly silica particles or hydrated silica are loaded on porous boehmite, and then the obtained compound is subjected to hydrothermal treatment for a certain time at the temperature of more than 600 ℃ to prepare the catalyst with the silica loaded on the surface of the boehmite, wherein the silica is combined with hydroxyl of the transitional 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 hierarchical pore composite material with an FAU crystal phase structure and a pseudo-boehmite structure, which is different from the prior art.
The preparation method of the hierarchical pore composite material comprises the following preparation processes:
(1) carrying out first contact treatment on a silicon-aluminum material, an ammonium salt solution and a phosphorus source, filtering, washing and drying; (2) carrying out primary roasting treatment on the sample obtained in the step (1) under the condition of 0-100% of water vapor; (3) and (3) carrying out secondary contact treatment on the sample obtained in the step (2) and a rare earth solution and/or an ammonium salt solution, filtering, washing and drying, or carrying out secondary roasting treatment under the condition of 0-100% of water vapor.
Wherein, the XRD spectrogram of the silicon-aluminum material in the step (1) has characteristic diffraction peaks at 6.2 degrees, 10.1 degrees, 11.9 degrees, 14 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, which represent that the silicon-aluminum material simultaneously has an FAU crystal phase structure and a pseudo-boehmite structure; the alumina mesoporous layer with the wrinkled pseudo-boehmite structure is coated on the surface of the FAU crystal phase structure, and the two structures are communicated with each other and grow together; the oxide-containing silica-alumina composite material comprises, by weight, 4-12% of sodium oxide, 20-60% of silica and 30-75% of alumina.
Wherein, the silicon-aluminum material in the step (1) can be seen as a wrinkled structure and a faujasite structure in a scanning electron microscope SEM, and the wrinkled structure is wholly or partially coated on the surface of the zeolite. An ordered and regular diffraction stripe and an irregular disordered structure without fixed crystal face trend can be seen in a Transmission Electron Microscope (TEM), wherein the ordered stripe represents a FAU crystal structure, the disordered structure is a pseudo-boehmite structure, the disordered structure grows along the edge of the ordered diffraction stripe of a FAU crystal phase, the edge line of the crystal structure disappears, and the two structures are connected together to form a gradient pore channel distribution characteristic.
Wherein the silicon-aluminum material in the step (1) has a gradient pore distribution characteristic formed by a microporous structure and a mesoporous structure, can be distributed in several pores with two characteristics at 3-4 nm and 7-10 nm, and has a specific surface area of 420-720 m2(ii) a total pore volume of 0.35 to 0.50cm3Characteristic of/g.
Wherein, the silicon-aluminum material in the step (1) can be prepared by the following steps: adding water into molecular sieve dry powder with FAU crystal phase structure, pulping and homogenizing; adding an aluminum source and an alkali solution into the slurry at the room temperature to 85 ℃ in a parallel flow mode to perform a neutralization reaction, and controlling the pH value of the slurry system to be 8-10.5; after the neutralization reaction, continuously aging for 1-10 hours at the temperature of room temperature to 90 ℃ and recovering to obtain the material, or after aging for 1-4 hours, transferring to a closed crystallization kettle, continuously crystallizing for 3-30 hours at the temperature of 95-105 ℃ and recovering the product. In the process, a mesoporous alumina layer with typical mesoporous aperture and excellent diffusion property is grown on the surface of the crystal grain of the Y-type molecular sieve to form a composite structure in which a mesoporous pore passage and a microporous pore passage are connected with each other, so that not only can gradient pore passage distribution be formed, but also gradient acid center distribution can be formed.
In the preparation process of the silicon-aluminum material, the molecular sieve with the FAU crystal phase structure can be molecular sieve dry powder which is directly synthesized and then filtered and dried, or can be a commercial molecular sieve dry powder finished product, and can be NaY molecular sieves with different silicon-aluminum ratios, different crystallinities and different crystal grain sizes, wherein the crystallinity is preferably more than 70 percent, and more preferably more than 80 percent. For example, the NaY molecular sieve dry powder can be obtained by mixing and stirring water glass, sodium metaaluminate, aluminum sulfate, a directing agent and deionized water in a specific feeding sequence in proportion, crystallizing for a plurality of times at a temperature of 95-105 ℃, filtering, washing and drying. The adding proportion of the water glass, the sodium metaaluminate, the aluminum sulfate, the guiding agent and the deionized water can be the feeding proportion of a conventional NaY molecular sieve or the feeding proportion of a NaY molecular sieve for preparing special performance, such as the feeding proportion of a large-grain or small-grain NaY molecular sieve, and the feeding proportion and the concentration of each raw material are not specially limited as long as the NaY molecular sieve with an FAU crystal phase structure can be obtained. The order of addition may be various, and is not particularly limited. The directing agent can be prepared by various methods, for example, the directing agent can be prepared according to the methods disclosed in the prior art (US3639099 and US3671191), and the typical directing agent is prepared by mixing a silicon source, an aluminum source, an alkali solution and deionized water according to (15-18) Na2O:Al2O3:(15～17)SiO2:(280～380)H2And mixing the components according to the molar ratio of O, uniformly stirring, and standing and aging for 0.5-48 h at the temperature of room temperature to 70 ℃. The silicon source used for preparing the guiding agent is water glass, the aluminum source is sodium metaaluminate, and the alkali liquor is sodium hydroxide solution.
During the preparation process of the silicon-aluminum material, the aluminum source is selected from one or more of aluminum nitrate, aluminum sulfate or aluminum chloride; the alkali solution is selectedThe alumina content of one or more of ammonia water, potassium hydroxide, sodium hydroxide or sodium metaaluminate is counted in the total alumina content when the sodium metaaluminate is used as an alkali solution. The sodium metaaluminate can be sodium metaaluminate with different causticity ratios and different concentrations. The caustic ratio is preferably 1.5 to 11.5, more preferably 1.65 to 2.55, and the concentration is preferably 40 to 200gAl2O3a/L, more preferably 41 to 190gAl2O3/L。
In the preparation process of the silicon-aluminum material, the concept of the concurrent flow mode of simultaneously adding the aluminum source and the alkali solution refers to an operation mode of simultaneously adding n +1(n is more than or equal to 1) materials (such as the aluminum source and the alkali solution in the invention) into a container for mixing, so that each material is added at a constant speed, and the n +1 materials are added in the same time. For example, a peristaltic pump can be used in the specific operation, the flow parameters per unit time of the peristaltic pumps for respectively conveying the aluminum source and the alkali solution are controlled, and the process is performed at a constant speed so as to ensure that the aluminum source and the alkali solution are added in the same time.
In the preparation process of the silicon-aluminum material, the neutralization reaction is carried out at the temperature of between room temperature and 85 ℃, and preferably at the temperature of between 30 and 70 ℃. The aging temperature is between room temperature and 90 ℃, preferably 40-80 ℃, and the time is 1-10 hours, preferably 2-8 hours; the process for recovering the product generally comprises the steps of filtering, washing and drying the aged product.
In the invention, in the process of carrying out the first contact treatment on the silicon-aluminum material, the ammonium salt solution and the phosphorus source in the step (1), the weight ratio of the ammonium salt to the silicon-aluminum material is 0.4-0.6, the weight ratio of the phosphorus source to the silicon-aluminum material is 0.01-0.06, the contact temperature is 40-90 ℃, preferably 50-80 ℃, and the contact time is 0.5-3.0 hours, preferably 1-2 hours.
In the present invention, the first or second baking treatment in steps (2) and (3) is performed at 500 to 700 ℃, preferably 550 to 650 ℃, under the condition of 0 to 100% steam, preferably 20 to 100% steam, for 0.5 to 4.0 hours, preferably 1 to 3 hours.
In the invention, in the process of carrying out the second contact treatment with the rare earth solution and/or the ammonium salt solution in the step (3), the weight ratio of the rare earth solution calculated by rare earth oxide to the weight ratio obtained in the step (2) is 0.01-0.06, the weight ratio of the ammonium salt to the weight ratio obtained in the step (2) is 0-0.35, the contact temperature is room temperature-90 ℃, preferably 50-80 ℃, and the contact time is 0.5-3.0 hours, preferably 1-2 hours.
In the invention, the phosphorus source can be one or more of ammonium phosphate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate and phosphoric acid. The ammonium salt can be one or more of ammonium chloride, ammonium nitrate, ammonium carbonate and ammonium bicarbonate. The rare earth solution is well known to those skilled in the art, and may be rare earth chloride or rare earth nitrate, or rare earth chloride or rare earth nitrate composed of a single rare earth element, wherein the rare earth solution commonly includes lanthanum chloride, lanthanum nitrate, cerium chloride or cerium nitrate, or may be a mixed rare earth with different rare earth element ratios, such as cerium-rich or lanthanum-rich mixed rare earth, and may be in any concentration.
The hierarchical porous composite material prepared by the invention contains 1-6 wt% of phosphorus oxide and 1-6 wt% of rare earth oxide, and simultaneously contains FAU crystal phase structure and gamma-Al2O3The structure of the compound has an XRD spectrogram which has FAU structure 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 and 31.4 degrees and has gamma-Al at about 20 degrees to 30 degrees and 66 degrees2O3Structural characteristic diffraction peak, unit cell constant 2.455-2.463 nm, relative crystallinity 35-65%, total specific surface area 370-600 m2(ii) a total pore volume of 0.32 to 0.43cm3/g。
On the basis of a silicon-aluminum material containing a microporous structure and a mesoporous structure, the invention adopts a preparation method of firstly introducing phosphorus, roasting and then modifying rare earth, wherein the introduction of phosphorus can play a role in stabilizing the framework aluminum of the molecular sieve, but the roasting process still causes the unit cell shrinkage of the molecular sieve, so that the introduction amount of rare earth, particularly the amount of rare earth entering a small cage of the molecular sieve, can be influenced in the subsequent rare earth modification process. The hierarchical pore composite material prepared by the method has excellent reaction performance, and the pore property and the acidic characteristic of the material are improved and the reaction activity is improved by further modifying phosphorus and rare earth on the basis of the existence of a micro-mesoporous composite structure.
Drawings
FIG. 1 is an X-ray diffraction spectrum of a silicon-aluminum material YCA-1 in example 1.
FIG. 2 is a SEM scanning electron micrograph of the sialon material YCA-1 of example 1.
FIG. 3 is a TEM transmission electron micrograph of the sialon material YCA-1 of example 1.
FIG. 4 is a BJH pore size distribution curve of the silicoalumina material YCA-1 of example 1.
FIG. 5 is an X-ray diffraction pattern of a hierarchical pore composite PRAL-1 prepared in example 1.
FIG. 6 is an X-ray diffraction pattern of the sialon material MMC-3 of example 6.
FIG. 7 is an SEM scanning electron micrograph of the silicoalumina material MMC-3 of example 6.
FIG. 8 is a TEM transmission electron micrograph of the silicoalumina material MMC-3 in example 6.
FIG. 9 is the BJH pore size distribution curve of the silicoaluminophosphate MMC-3 of example 6.
Detailed Description
The following examples further illustrate the invention but are not intended to limit the invention thereto.
In each example, Na of the sample2O、Al2O3、SiO2、P2O5、RE2O3The content was measured by X-ray fluorescence (see "analytical methods in petrochemical industry (RIPP methods of experiments)", eds Yang Cui et al, published by scientific Press, 1990). 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 75004-1988).
The SEM test adopts a Hitachi S4800 type Japan field emission scanning electron microscope with an accelerating voltage of 5 kV.
Transmission Electron microscope TEM test was carried out using a transmission electron microscope model of FEI Tecnai F20G2S-TWIN, operating at a voltage of 200 kV.
The specific surface, pore volume and pore size distribution are measured by a low-temperature nitrogen adsorption-desorption volumetric method.
The preparation process of the directing agent used in the examples was: 5700g of water glass (available from Changling catalysts, Inc., SiO)2261g/L, modulus 3.31, density 1259g/L) was placed in a beaker and 4451g of high alkali sodium metaaluminate (provided by Changling catalysts, Inc., Al) was added with vigorous stirring2O339.9g/L，Na2O279.4g/L, density 1326g/L) and aging at 30 ℃ for 18 hours to obtain 16.1Na with molar ratio2O:Al2O3:15SiO2:318.5H2A directing agent for O.
Examples 1-8 illustrate the preparation of the hierarchical pore composite material of the present invention and the resulting hierarchical pore composite material.
Example 1
With 7.5SiO2：Al2O3：2.15Na2O：190H2And synthesizing the NaY molecular sieve by using the gel feeding molar ratio of O. Respectively mixing water glass, aluminum sulfate, sodium metaaluminate, a guiding agent and deionized water according to the above proportion, and vigorously stirring for 1 hour, wherein the adding proportion of the guiding agent is 5% by weight, crystallizing the mixed gel at 100 ℃ for 34 hours, filtering, washing and drying to obtain the NaY molecular sieve dry powder.
Mixing the NaY molecular sieve dry powder with a proper amount of deionized water, pulping, heating to 45 ℃, and simultaneously adding Al (NO) in a parallel flow mode at the temperature3)3Solution (concentration 60 gAl)2O3/L) and NaAlO2Solution (concentration 102 gAl)2O3L) adding the silicon-aluminum material into the solution to perform neutralization reaction, keeping the pH value of the slurry system at 10.0 by adjusting the flow rate of the two materials, continuing aging treatment at 55 ℃ for 8 hours after the neutralization reaction, and filtering, washing and drying to obtain the silicon-aluminum material YCA-1.
The X-ray diffraction pattern of YCA-1 is shown in FIG. 1, and characteristic diffraction peaks appear at 6.2 °, 10.1 °, 11.9 °, 14 °, 15.7 °, 18.7 °, 20.4 °, 23.7 °, 27.1 °, 28 °, 31.4 °, 38.5 °, 49 ° and 65 °, respectively, indicating that it is simultaneously observedContains FAU crystal phase structure and pseudo-boehmite structure. The SEM photograph is shown in FIG. 2, and the wrinkled structure can be seen, and the faujasite structure of the NaY molecular sieve can be seen occasionally, and the wrinkled structure is coated on the surface of the molecular sieve crystal grains. The TEM photograph of the transmission electron microscope is shown in FIG. 3, and it can be seen that two different structures are connected together, the structure with regular diffraction fringes is the FAU crystal phase structure, the disordered structure is the pseudo-boehmite structure of alumina, and the disordered structure grows along the edges of the regular diffraction fringes to form a composite structure. YCA-1 contains 10.6 percent of sodium oxide, 53.7 percent of silicon oxide and 35.1 percent of aluminum oxide by weight of oxides; the specific surface area thereof was 662m2(ii)/g, total pore volume 0.396cm3The BJH pore size distribution curve of YCA-1 is shown in FIG. 4, where the distribution of the viable number appears at 3.8nm and 8.1nm, respectively, indicating that the material has a graded pore distribution profile.
Mixing YCA-1 with ammonium chloride according to the ratio of 1: 0.5 by weight ratio to diammonium hydrogen phosphate in a ratio of 1: 0.03, performing first contact treatment at 65 ℃ for 1 hour, filtering, washing with water, and drying; then roasting for 2 hours at 600 ℃ under the condition of 100 percent of water vapor; mixing the obtained mixture with a rare earth solution according to the weight ratio of 1: 0.02, and ammonium salt in a weight ratio of 1: 0.15, carrying out secondary contact treatment at 75 ℃ for 1 hour, filtering, washing and drying; and then carrying out secondary roasting treatment at 600 ℃ under the condition of 100% water vapor for 2 hours to obtain the hierarchical pore composite material PRAL-1.
The XRD diffraction pattern of PRAL-1 is shown in FIG. 5, and contains both FAU crystal phase structure and gamma-Al2O3The structure shows FAU structure characteristic diffraction peaks (corresponding to # in the figure) 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, and gamma-Al appears at about 20 degrees to 30 degrees and 66 degrees2O3Structural feature diffraction peaks (peaks corresponding to parenthesis in the figure).
PRAL-1 contains 2.8 wt% of phosphorus oxide, 1.8 wt% of rare earth oxide, 2.458nm in unit cell constant, 58% in relative crystallinity and 580m in total specific surface area2Per g, total pore volume 0.356cm3/g。
Example 2
Preparing NaY molecular sieve gel according to the gel feeding molar ratio and the same feeding sequence in the example 1, violently stirring for 1 hour, crystallizing the gel at 100 ℃ for 25 hours, filtering, washing and drying to obtain NaY molecular sieve dry powder.
Mixing the NaY molecular sieve dry powder with a proper amount of deionized water, pulping, and simultaneously adding AlCl in a parallel flow mode at 30 DEG C3Solution (concentration 60 gAl)2O3L) and NaOH solution (concentration is 1M) are added into the solution to carry out neutralization reaction, the pH value of the slurry system is kept at 9.4 by adjusting the flow rate of the two materials, the aging treatment is continued for 2 hours at 60 ℃ after the neutralization reaction, and the silicon-aluminum material YCA-2 is obtained after filtration, washing and drying.
The X-ray diffraction spectrum of YCA-2 has the characteristics shown in figure 1, and characteristic diffraction peaks appear at 6.2 degrees, 10.1 degrees, 11.9 degrees, 14 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 respectively, which shows that the crystal structure of the FAU and the pseudo-boehmite structure are contained simultaneously. The SEM photograph has the characteristics shown in FIG. 2, and shows a wrinkled structure, and occasionally shows a faujasite structure of the NaY molecular sieve, and the wrinkled structure is coated on the surface of the molecular sieve crystal grains. The TEM photograph of the transmission electron microscope has the characteristics shown in FIG. 3, and shows that two different structures are connected together, the structure with regular diffraction fringes is an FAU crystal phase structure, the disordered structure is a pseudo-boehmite structure of alumina, and the disordered structure grows along the edges of the regular diffraction fringes to form a composite structure. YCA-2 contains 9.3 percent of sodium oxide, 43.6 percent of silicon oxide and 46.2 percent of aluminum oxide by weight of oxides; the specific surface area is 600m2In terms of/g, total pore volume of 0.428cm3The BJH pore size distribution curve has the characteristics shown in fig. 4, showing a variable distribution at about 4nm and 7nm, respectively, indicating that the material has a graded pore distribution characteristic.
Mixing YCA-2 with ammonium chloride according to the ratio of 1: 0.5, in a weight ratio to phosphoric acid of 1: 0.04, performing first contact treatment at 55 ℃ for 2 hours, filtering, washing with water, and drying; then roasting for 2 hours at 580 ℃ under the condition of 100 percent of water vapor; mixing the obtained mixture with a rare earth solution according to the weight ratio of 1: 0.04, and ammonium salt according to a weight ratio of 1: 0.1, carrying out secondary contact treatment at 65 ℃ for 1 hour, filtering, washing with water, and drying to obtain the hierarchical porous composite material PRAL-2.
The XRD diffraction pattern of PRAL-2 has the characteristics shown in figure 5, and simultaneously contains FAU crystal phase structure and gamma-Al2O3And (5) structure.
PRAL-2 contained phosphorus oxide 4.0 wt%, rare earth oxide 3.9 wt%, unit cell constant 2.463nm, relative crystallinity 56%, total specific surface area 543m2(ii)/g, total pore volume 0.387cm3/g。
Example 3
With 8.5SiO2：Al2O3：2.65Na2O：210H2And synthesizing the NaY molecular sieve by using the gel feeding molar ratio of O. Respectively mixing water glass, aluminum sulfate, sodium metaaluminate, a guiding agent and deionized water according to the above proportion, vigorously stirring for 1 hour, wherein the adding proportion of the guiding agent is 5% by weight, crystallizing the mixed gel at 100 ℃ for 42 hours, and filtering, washing and drying to obtain the NaY molecular sieve dry powder.
Mixing the NaY molecular sieve dry powder with a proper amount of deionized water, pulping, heating to 40 ℃, and simultaneously carrying out Al parallel flow at the temperature2(SO4)3Solution (concentration 90 gAl)2O3Adding 8% of ammonia water and/L) into the solution to perform neutralization reaction, adjusting the flow rates of the two materials to keep the pH value of the slurry system at 8.7, continuing aging treatment at 55 ℃ for 6 hours after the neutralization reaction, and filtering, washing and drying to obtain the silicon-aluminum material YCA-3.
The X-ray diffraction spectrum of YCA-3 has the characteristics shown in figure 1, and characteristic diffraction peaks appear at 6.2 degrees, 10.1 degrees, 11.9 degrees, 14 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 respectively, which shows that the crystal structure of the FAU and the pseudo-boehmite structure are contained simultaneously. The SEM photograph has the characteristics shown in FIG. 2, and shows a wrinkled structure, occasionally shows a faujasite structure of the NaY molecular sieve, and the wrinkled structure is coated on the molecular sieve crystalThe surface of the pellet. The TEM photograph of the transmission electron microscope has the characteristics shown in FIG. 3, and shows that two different structures are connected together, the structure with regular diffraction fringes is an FAU crystal phase structure, the disordered structure is a pseudo-boehmite structure of alumina, and the disordered structure grows along the edges of the regular diffraction fringes to form a composite structure. YCA-3 contains sodium oxide 5.9%, silicon oxide 31.3%, and aluminum oxide 62.2%; the specific surface area is 510m2(ii)/g, total pore volume 0.443cm3The BJH pore size distribution curve has the characteristics shown in fig. 4, showing a variable distribution at about 4nm and 9nm, respectively, indicating that the material has a graded pore distribution characteristic.
Mixing YCA-3 with ammonium chloride according to the ratio of 1: 0.6, in a weight ratio to phosphoric acid of 1: 0.02, carrying out first contact treatment at 70 ℃ for 1 hour, filtering, washing with water, and drying; then roasting for 2 hours at 550 ℃ under the condition of 100 percent of water vapor; mixing the obtained product with ammonium salt according to a weight ratio of 1: 0.35, the second contact treatment is carried out for 0.5 hour at 70 ℃, and the weight ratio of the filtered solution to the rare earth solution according to the rare earth oxide is 1: mechanically mixing according to the proportion of 0.05, grinding uniformly, drying, and then roasting for 2 hours at the temperature of 550 ℃ under the condition of 100% water vapor to obtain the hierarchical pore composite material PRAL-3.
The XRD diffraction pattern of PRAL-3 has the characteristics shown in figure 5, and simultaneously contains FAU crystal phase structure and gamma-Al2O3And (5) structure.
PRAL-3 contains phosphorus oxide 1.9 wt%, rare earth oxide 5.0 wt%, unit cell constant 2.460nm, relative crystallinity 46%, and total specific surface area 475m2In terms of/g, total pore volume 0.410cm3/g。
Example 4
Mixing commercial NaY molecular sieve dry powder (relative crystallinity 88%, silicon-aluminum ratio 5.0) with a proper amount of deionized water, pulping, heating to 50 ℃, and simultaneously carrying out AlCl in a parallel flow mode at the temperature3Solution (concentration 60 gAl)2O3L) and ammonia water (mass fraction 8%) are added to the mixture to carry out neutralization reaction, the pH value of the slurry system is kept at 10.5 by adjusting the flow rate of the two materials, and the neutralization reaction is continued at 50 DEG CAging for 3 hours, filtering, washing and drying to obtain the silicon-aluminum material YCA-5.
The X-ray diffraction spectrum of YCA-5 has the characteristics shown in figure 1, and characteristic diffraction peaks appear at 6.2 degrees, 10.1 degrees, 11.9 degrees, 14 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 respectively, which shows that the crystal structure of the FAU and the pseudo-boehmite structure are contained simultaneously. The SEM photograph has the characteristics shown in FIG. 2, and shows a wrinkled structure, and occasionally shows a faujasite structure of the NaY molecular sieve, and the wrinkled structure is coated on the surface of the molecular sieve crystal grains. The TEM photograph of the transmission electron microscope has the characteristics shown in FIG. 3, and shows that two different structures are connected together, the structure with regular diffraction fringes is an FAU crystal phase structure, the disordered structure is a pseudo-boehmite structure of alumina, and the disordered structure grows along the edges of the regular diffraction fringes to form a composite structure. YCA-5 contains 10.2% of sodium oxide, 59.5% of silicon oxide and 30.1% of aluminum oxide by weight of oxides; the specific surface area is 702m2In terms of/g, total pore volume of 0.362cm3The BJH pore size distribution curve has the characteristics shown in fig. 4, showing a variable distribution at about 4nm and 9nm, respectively, indicating that the material has a graded pore distribution characteristic.
Mixing YCA-5 and ammonium chloride according to the ratio of 1: 0.4, and diammonium hydrogen phosphate according to a weight ratio of 1: 0.06 weight ratio, carrying out first contact treatment at 50 ℃ for 3 hours, filtering, washing with water, and drying; then roasting for 2 hours at the temperature of 620 ℃ and under the condition of 100 percent of water vapor; mixing the obtained product with ammonium salt according to a weight ratio of 1: 0.35, the second contact treatment is carried out for 1 hour at 50 ℃, and the weight ratio of the filtered solution to the rare earth solution according to the rare earth oxide is 1: mechanically mixing at a ratio of 0.03, grinding uniformly, drying, and roasting at 500 deg.C under 100% water vapor for 1 hr to obtain hierarchical porous composite material PRAL-4.
The XRD diffraction pattern of PRAL-4 has the characteristics shown in figure 5, and simultaneously contains FAU crystal phase structure and gamma-Al2O3And (5) structure.
PRAL-4 contained 5.7% by weight of phosphorus oxide, 3.0% by weight of rare earth oxide, a unit cell constant of 2.459nm, a relative crystallinity of 63%, and a total specific surface area591m2In terms of/g, total pore volume 0.324cm3/g。
Example 5
Mixing commercial NaY molecular sieve dry powder (relative crystallinity 85%, Si/Al ratio 5.1) with appropriate amount of deionized water, pulping, heating to 55 deg.C and simultaneously adding Al in parallel flow mode at the temperature2(SO4)3Solution (concentration 60 gAl)2O3adding/L) and NaOH (concentration is 1M) into the solution to perform neutralization reaction, adjusting the flow rates of the two materials to keep the pH value of the slurry system at 10.2, continuing aging treatment at 75 ℃ for 2 hours after the neutralization reaction, and filtering, washing and drying to obtain the silicon-aluminum material YCA-8.
The X-ray diffraction spectrum of YCA-8 has the characteristics shown in figure 1, and characteristic diffraction peaks appear at 6.2 degrees, 10.1 degrees, 11.9 degrees, 14 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 respectively, which shows that the crystal structure of the FAU and the pseudo-boehmite structure are contained simultaneously. The SEM photograph has the characteristics shown in FIG. 2, and shows a wrinkled structure, and occasionally shows a faujasite structure of the NaY molecular sieve, and the wrinkled structure is coated on the surface of the molecular sieve crystal grains. The TEM photograph of the transmission electron microscope has the characteristics shown in FIG. 3, and shows that two different structures are connected together, the structure with regular diffraction fringes is an FAU crystal phase structure, the disordered structure is a pseudo-boehmite structure of alumina, and the disordered structure grows along the edges of the regular diffraction fringes to form a composite structure. YCA-8 contains 10.9% of sodium oxide, 55.6% of silicon oxide and 32.8% of aluminum oxide by weight of oxides; the specific surface area is 663m2(iv)/g, total pore volume of 0.386cm3The BJH pore size distribution curve has the characteristics shown in fig. 4, with a fractional distribution at about 4nm and 8nm, respectively, indicating that the material has a graded pore distribution.
Mixing YCA-8 and ammonium chloride according to the ratio of 1: 0.5, in a weight ratio to phosphoric acid of 1: 0.045, performing first contact treatment at 75 ℃ for 1 hour, filtering, washing with water, and drying; then roasting for 2 hours at 580 ℃ under the condition of 100 percent of water vapor; mixing the obtained mixture with a rare earth solution according to the weight ratio of 1: 0.015, and ammonium salt in a weight ratio of 1: 0.3, carrying out secondary contact treatment at 75 ℃ for 1 hour, filtering, washing with water, and drying to obtain the hierarchical porous composite material PRAL-5.
The XRD diffraction pattern of PRAL-5 has the characteristics shown in figure 5, and simultaneously contains FAU crystal phase structure and gamma-Al2O3And (5) structure.
PRAL-5 contains phosphorus oxide 4.4 wt%, rare earth oxide 1.4 wt%, unit cell constant 2.458nm, relative crystallinity 65%, and total specific surface area 578m2In terms of/g, total pore volume 0.336cm3/g。
Example 6
According to 7.5SiO2：Al2O3：2.15Na2O：190H2Preparing NaY molecular sieve gel according to the molar ratio of the fed materials of the NaY molecular sieve gel of O, violently stirring for 1 hour, crystallizing the gel for 48 hours at the temperature of 100 ℃, and filtering, washing and drying to obtain NaY molecular sieve dry powder. Mixing the obtained NaY molecular sieve dry powder with a proper amount of deionized water, pulping, and simultaneously adding Al in a parallel flow mode at 35 DEG C2(SO4)3Solution (concentration 90 gAl)2O3adding/L) and NaOH (with the concentration of 1M) into the solution to perform neutralization reaction, keeping the pH value of the slurry system at 8.5 by adjusting the flow rate of the two materials, continuing to age the slurry for 1 hour at 55 ℃, then transferring the slurry into a stainless steel crystallization kettle to seal the kettle, performing crystallization treatment at 100 ℃ for 28 hours, filtering, washing and drying to obtain the silicon-aluminum material MMC-3.
The X-ray diffraction spectrum of MMC-3 has the characteristics shown in figure 6, and characteristic diffraction peaks appear 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, 14 degrees, 28 degrees, 38.5 degrees, 49 degrees and 65 degrees respectively, which shows that the MMC-3 contains an FAU crystal phase structure and a pseudo-boehmite structure at the same time. The scanning electron micrograph has the characteristics shown in fig. 7, and it can be seen that the surface of the molecular sieve grains is coated with the wrinkled structure of the alumina layer. The TEM picture of the transmission electron microscope has the characteristics shown in figure 8, two structures coexist, the structure with regular ordered diffraction fringes is an FAU crystal phase structure, the disordered structure of the aluminum oxide layer extends and grows along the edges of the ordered diffraction fringes of the FAU crystal phase, and the two structures are connected to oneForming a composite structure of micropores and mesopores. The MMC-3 contains 7.2 percent of sodium oxide, 22.7 percent of silicon oxide and 69.4 percent of aluminum oxide by weight of oxides; the specific surface area is 435m2(ii)/g, total pore volume 0.489cm3The BJH pore size distribution curve has the characteristics shown in figure 9, two pore size distributions appear at 4nm and 7nm respectively, and the silicon-aluminum material has the characteristic of gradient pore distribution.
Mixing MMC-3 with ammonium chloride according to the proportion of 1: 0.6, in a weight ratio to ammonium dihydrogen phosphate of 1: 0.015 weight ratio, the first contact treatment is carried out at the temperature of 60 ℃, the contact time is 1 hour, and the filtration, the water washing and the drying are carried out; then roasting for 3 hours at 530 ℃ under the condition of 100 percent of water vapor; mixing the obtained mixture with a rare earth solution according to the weight ratio of 1: 0.06, carrying out secondary contact treatment at 75 ℃ for 1 hour, filtering, washing with water, drying, and roasting at 530 ℃ under the condition of 100% steam for 2 hours to obtain the hierarchical porous composite material PRAL-6.
The XRD diffraction pattern of PRAL-6 has the characteristics shown in figure 5, and simultaneously contains FAU crystal phase structure and gamma-Al2O3And (5) structure.
PRAL-6 contains phosphorus oxide 1.5 wt%, rare earth oxide 5.8 wt%, unit cell constant 2.460nm, relative crystallinity 35%, and total specific surface area 370m2In terms of/g, total pore volume 0.421cm3/g。
Example 7
According to 8.7SiO2：Al2O3：2.75Na2O：200H2Preparing NaY molecular sieve gel according to the molar ratio of the fed materials of the NaY molecular sieve gel of O, violently stirring for 1 hour, crystallizing the gel for 20 hours at the temperature of 100 ℃, and filtering, washing and drying to obtain NaY molecular sieve dry powder. Mixing the obtained NaY molecular sieve dry powder with a proper amount of deionized water, pulping, heating to 45 ℃, and simultaneously carrying out AlCl in a parallel flow mode at the temperature3Solution (concentration 60 gAl)2O3/L) and NaAlO2Solution (concentration 180 gAl)2O3/L) adding into the slurry, adjusting the flow rate of the two materials to keep the pH value of the slurry system at 9.4, continuing aging at 65 ℃ for 1 hour after the neutralization reaction, and then adding the slurryAnd (3) transferring the liquid to a stainless steel crystallization kettle, sealing, performing crystallization treatment at 100 ℃ for 16 hours, filtering, washing and drying to obtain the silicon-aluminum material MMC-5.
The X-ray diffraction spectrum of MMC-5 has the characteristics shown in figure 6, and characteristic diffraction peaks appear 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, 14 degrees, 28 degrees, 38.5 degrees, 49 degrees and 65 degrees respectively, which shows that the MMC-5 contains an FAU crystal phase structure and a pseudo-boehmite structure at the same time. The scanning electron micrograph has the characteristics shown in fig. 7, and it can be seen that the surface of the molecular sieve grains is coated with the wrinkled structure of the alumina layer. The TEM picture of the transmission electron microscope has the characteristics shown in figure 8, two structures coexist, the structure with regular ordered diffraction fringes is an FAU crystal phase structure, the disordered structure of the aluminum oxide layer extends and grows along the edges of the ordered diffraction fringes of the FAU crystal phase, and the two structures are connected together to form a composite structure of micropores and mesopores. The MMC-5 contains 11.5 percent of sodium oxide, 56.7 percent of silicon oxide and 31.3 percent of aluminum oxide by weight of oxides; the specific surface area is 711m2(ii)/g, total pore volume 0.382cm3The BJH pore size distribution curve has the characteristics shown in figure 9, two pore size distributions appear at 4nm and 9nm respectively, and the composite material has the characteristic of gradient pore distribution.
Mixing MMC-5 with ammonium chloride according to the proportion of 1: 0.5 by weight ratio to diammonium hydrogen phosphate in a ratio of 1: 0.035, performing a first contact treatment at 65 ℃ for 2 hours, filtering, washing and drying; then roasting for 2 hours at 600 ℃ under the condition of 100 percent of water vapor; mixing the obtained product with ammonium salt according to a weight ratio of 1: 0.3, the second contact treatment is carried out for 1 hour at 65 ℃, and the weight ratio of the filtered rare earth solution to the rare earth solution is 1: 0.025, grinding uniformly, drying, and roasting at 600 ℃ for 1 hour under the condition of 100% water vapor to obtain the hierarchical porous composite material PRAL-7.
The XRD diffraction pattern of PRAL-7 has the characteristics shown in figure 5, and simultaneously contains FAU crystal phase structure and gamma-Al2O3And (5) structure.
PRAL-7 contains phosphorus oxide 3.5 wt%, rare earth oxide 2.5 wt%, unit cell constant 2.456nm, and relative crystallinity 60% total specific surface area 588m2G, total pore volume 0.360cm3/g。
Example 8
Preparing NaY molecular sieve gel according to the feeding molar ratio of the NaY molecular sieve gel in the embodiment 7, violently stirring for 1 hour, crystallizing the gel at 100 ℃ for 49 hours, filtering, washing and drying to obtain NaY molecular sieve dry powder. Mixing the obtained NaY molecular sieve dry powder with a proper amount of deionized water, pulping, and simultaneously adding Al (NO) in a parallel flow mode at room temperature3)3Solution (concentration 60 gAl)2O3adding/L) and NaOH solution (with the concentration of 1M) into the solution to perform neutralization reaction, keeping the pH value of the slurry system at 10.3 by adjusting the flow rate of the two materials, continuing to age for 4 hours at 65 ℃ after the neutralization reaction, then transferring the slurry into a stainless steel crystallization kettle to seal, performing crystallization treatment for 20 hours at 100 ℃, filtering, washing and drying to obtain the silicon-aluminum material MMC-8.
The MMC-8 has the characteristics shown in figure 6, and characteristic diffraction peaks appear 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, 14 degrees, 28 degrees, 38.5 degrees, 49 degrees and 65 degrees respectively, which shows that the MMC-8 simultaneously contains an FAU crystal phase structure and a pseudo-boehmite structure. The scanning electron micrograph has the characteristics shown in fig. 7, and it can be seen that the surface of the molecular sieve grains is coated with the wrinkled structure of the alumina layer. The TEM picture of the transmission electron microscope has the characteristics shown in figure 8, two structures coexist, the structure with regular ordered diffraction fringes is an FAU crystal phase structure, the disordered structure of the aluminum oxide layer extends and grows along the edges of the ordered diffraction fringes of the FAU crystal phase, and the two structures are connected together to form a composite structure of micropores and mesopores. The MMC-8 contains 8.4 percent of sodium oxide, 28.9 percent of silicon oxide and 62.1 percent of aluminum oxide by weight of oxides; the specific surface area is 500m2(ii)/g, total pore volume 0.472cm3The BJH pore size distribution curve has the characteristics shown in figure 9, two pore size distributions appear at 4nm and 9nm respectively, and the silicon-aluminum material has the characteristic of gradient pore distribution.
Mixing MMC-8 with ammonium chloride according to the proportion of 1: 0.4, in a weight ratio to phosphoric acid of 1: 0.05, performing first contact treatment at 55 ℃ for 1 hour, filtering, washing with water, and drying; then roasting for 2 hours at 550 ℃ under the condition of 100 percent of water vapor; mixing the obtained mixture with a rare earth solution according to the weight ratio of 1: 0.05, carrying out secondary contact treatment at 70 ℃ for 1 hour, filtering, washing with water, drying, and roasting at 550 ℃ for 2 hours under the condition of 100% steam to obtain the hierarchical porous composite material PRAL-8.
The XRD diffraction pattern of PRAL-8 has the characteristics shown in figure 5, and simultaneously contains FAU crystal phase structure and gamma-Al2O3And (5) structure.
PRAL-8 contains phosphorus oxide 4.9 wt%, rare earth oxide 4.6 wt%, unit cell constant 2.459nm, relative crystallinity 46%, and total specific surface area 449m2In terms of/g, total pore volume 0.428cm3/g。
Examples 9 to 16
Examples 9-16 illustrate the cracking performance of the hierarchical pore composites prepared by the process of the present invention.
The hierarchical porous composite materials PRAL-1 to PRAL-8 described in the above examples 1 to 8 were washed until the sodium oxide content was less than 0.3 wt%, filtered, dried, tableted and sieved into 20 to 40 mesh particles, aged at 800 ℃ for 8 hours under 100% steam conditions, and subjected to cracking performance test on a light oil micro-reverse evaluation apparatus.
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
PRAL-1 58 PRAL-5 60
PRAL-2 63 PRAL-6 57
PRAL-3 61 PRAL-7 62
PRAL-4 61 PRAL-8 60
As can be seen from the micro-inverse activity index MA in Table 1, the MA of the hierarchical pore composite materials PRAL-1 to PRAL-8 in examples 1 to 8 can reach 57 to 63 after aging treatment with 100% water vapor at 800 ℃ for 8 hours, and the hierarchical pore composite materials show higher reactivity.
The hierarchical porous composite material has two structures of micropores and mesopores, and the porous composite material is modified by phosphorus and rare earth, so that the pore canal property and the acidic characteristic of the material are improved, and the reaction performance is improved.

Claims (12)

1. A preparation method of a hierarchical porous composite material comprises the following preparation steps:
(1) carrying out first contact treatment on a silicon-aluminum material, an ammonium salt solution and a phosphorus source, filtering, washing and drying; (2) carrying out primary roasting treatment on the sample obtained in the step (1) under the condition of 0-100% of water vapor; (3) will be described in detail(2) Carrying out secondary contact treatment on the obtained sample and a rare earth solution and/or an ammonium salt solution, filtering, washing and drying, or carrying out secondary roasting treatment under the condition of 0-100% of water vapor; wherein, the XRD spectrogram of the silicon-aluminum material in the step (1) has characteristic diffraction peaks at 6.2 degrees, 10.1 degrees, 11.9 degrees, 14 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, which represent that the silicon-aluminum material simultaneously has FAU crystal phase structure and pseudo-boehmite structure, the wrinkled pseudo-boehmite structure alumina mesoporous layer is coated on the surface of the FAU crystal phase structure, and the two structures are communicated with each other and grow together; the silicon-aluminum material contains 4-12% of sodium oxide, 20-60% of silicon oxide and 30-75% of aluminum oxide by weight of oxides; the silicon-aluminum material has the gradient pore distribution characteristic formed by a microporous structure and a mesoporous structure, and can be distributed in a few pores with two characteristics at 3-4 nm and 7-10 nm, and the specific surface area is 420-720 m2(ii) a total pore volume of 0.35 to 0.50cm3Characteristic of/g.
2. The method of claim 1, wherein the silica-alumina material of step (1) is prepared by the steps of: adding water into molecular sieve dry powder with FAU crystal phase structure, pulping and homogenizing; adding an aluminum source and an alkali solution into the slurry at the room temperature to 85 ℃ in a parallel flow mode to perform a neutralization reaction, and controlling the pH value of the slurry system to be 8-10.5; and after the neutralization reaction, continuously aging for 1-10 hours at the temperature of room temperature to 90 ℃ and recovering to obtain the silicon-aluminum material, or aging for 1-4 hours after the neutralization reaction, transferring to a closed crystallization kettle, continuously crystallizing for 3-30 hours at the temperature of 95-105 ℃, and recovering the product.
3. The method of claim 2 wherein the source of aluminum is selected from the group consisting of aluminum nitrate, aluminum sulfate and aluminum chloride.
4. The process according to claim 2, wherein the alkali solution is one or more selected from the group consisting of aqueous ammonia, potassium hydroxide, sodium hydroxide and sodium metaaluminate, and when sodium metaaluminate is used as the alkali solution, the alumina content is calculated as the total alumina content.
5. The process according to claim 2, wherein the neutralization reaction temperature is from 30 ℃ to 70 ℃.
6. The method according to claim 2, wherein the aging is carried out at a temperature of 40 ℃ to 80 ℃ for 2 to 8 hours.
7. The preparation method according to claim 1, wherein in the first contact treatment process of the silicon-aluminum material, the ammonium salt solution and the phosphorus source in the step (1), the weight ratio of the ammonium salt to the silicon-aluminum material is 0.4-0.6, the weight ratio of the phosphorus source to the silicon-aluminum material is 0.01-0.06, the contact temperature is 40-90 ℃, preferably 50-80 ℃, and the contact time is 0.5-3.0 hours, preferably 1-2 hours.
8. The process according to claim 1, wherein the first or second calcination treatment in steps (2) and (3) is carried out at 500 to 700 ℃, preferably 550 to 650 ℃, under the condition of 0 to 100% steam, preferably 20 to 100% steam, for 0.5 to 4.0 hours, preferably 1 to 3 hours.
9. The preparation method according to claim 1, wherein in the second contact treatment with the rare earth solution and/or the ammonium salt solution in the step (3), the weight ratio of the rare earth solution to the solution obtained in the step (2) is 0.01 to 0.06 in terms of rare earth oxide, the weight ratio of the ammonium salt to the solution obtained in the step (2) is 0 to 0.35, the contact temperature is room temperature to 90 ℃, preferably 50 to 80 ℃, and the contact time is 0.5 to 3.0 hours, preferably 1 to 2 hours.
10. The method according to claim 1, wherein the phosphorus source in step (1) is one or more selected from the group consisting of ammonium phosphate, diammonium phosphate, monoammonium phosphate, and phosphoric acid.
11. The method according to claim 1, wherein the ammonium salt in the steps (1) and (3) is one or more of ammonium chloride, ammonium nitrate, ammonium carbonate and ammonium bicarbonate.
12. The preparation method according to claim 1, characterized in that the prepared hierarchical porous composite material contains 1-6 wt% of phosphorus oxide and 1-6 wt% of rare earth oxide, and contains FAU crystal phase structure and gamma-Al2O3The structure of the compound has an XRD spectrogram which has FAU structure 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 and 31.4 degrees and has gamma-Al at about 20 degrees to 30 degrees and 66 degrees2O3Structural characteristic diffraction peak, unit cell constant 2.455-2.463 nm, relative crystallinity 35-65%, total specific surface area 370-600 m2(ii) a total pore volume of 0.32 to 0.43cm3/g。
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JPH07166173A (en) * 1993-12-16 1995-06-27 Sanwa Kako Co Ltd Production of fuel oil in steam atmosphere using thermal cracking oil of polyolefin resin
CN1353086A (en) * 2000-11-13 2002-06-12 中国石油化工股份有限公司 Process for preparing Y-type molecular sieve
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