Y-type molecular sieve with high silica-alumina ratio and preparation method thereof

Abstract

The invention provides a Y-type molecular sieve with a high silica-alumina ratio and a preparation method thereof. The preparation method comprises the following steps: carrying out an isomorphous substitution reaction on a NaY type molecular sieve containing a metal element Mn in a skeleton and gas-phase SiCl4 according to a mass ratio of (0.1-20): 1 at 200-600 DEG C, and roasting to obtain the Y type molecular sieve with the high silica-alumina ratio. According to the technical scheme provided by the invention, the NaY type molecular sieve containing the metal element Mn in the skeleton and the gas-phase SiCl4 are subjected to isomorphous substitution and then are roasted, so that the silica-alumina ratio of the skeleton of the Y type molecular sieve is greatly increased, and the prepared Y type molecular sieve also has relatively high crystallinity.

Description

Technical Field

[0001] The invention belongs to the technical field of molecular sieve preparation, and specifically relates to a high silicon-aluminum ratio Y-type molecular sieve and a preparation method thereof. Background Art

[0002] The process of producing low-carbon olefins by direct catalytic cracking of crude oil is one of the important processes in the petrochemical industry, and the catalyst is the core of the process. At present, the raw oil used in the process of producing low-carbon olefins by direct catalytic cracking of crude oil is becoming increasingly heavy, which puts higher requirements on the performance of the catalyst.

[0003] Y-type zeolite is the main active component of the catalyst used in the direct catalytic cracking of crude oil to produce light olefins. The framework atomic composition, silicon-aluminum ratio, acid properties and pore structure of Y-type molecular sieve all affect the catalytic performance of the catalyst.

[0004] In actual industrial applications, Y-type molecular sieves are usually required to have a higher silicon-aluminum ratio to improve their thermal stability and hydrothermal stability. At present, the hydrothermal method is usually used in the industry to synthesize Y-type molecular sieves. However, due to the constraints of the hydrothermal synthesis mechanism, the silicon-aluminum ratio of Y-type molecular sieves synthesized by conventional hydrothermal methods is difficult to be greater than 6. In order to improve the silicon-aluminum ratio of the Y-type molecular sieve framework, the hydrothermal ultra-stable method is usually used in the industry to treat Y-type molecular sieves. However, this method has limited ability to improve the silicon-aluminum ratio of Y-type molecular sieves; and it often requires two or even multiple ammonium ion exchange treatments and harsh hydrothermal conditions (600℃-700℃), resulting in a long production process, high water consumption, high energy consumption, and a large amount of ammonium salt (ammonia nitrogen wastewater treatment has great environmental pressure, and its cost accounts for more than half of the USY production cost), resulting in high production costs and difficulty in clean production; in addition, it also causes the collapse of part of the zeolite crystal structure, a large decrease in crystallinity (close to 40%), severe acidity loss, and reduced activity.

[0005] In order to improve the silicon-to-aluminum ratio of Y-type zeolites, industry researchers have also proposed some other treatment methods that are different from the hydrothermal ultrastabilization method. However, these treatment methods generally have problems such as limited ability to improve the silicon-to-aluminum ratio, complex treatment process, and greatly reduced crystallinity.

[0006] Based on this, at present, there is still a need to study simple and easy-to-implement technical solutions that can significantly increase the silicon-to-aluminum ratio of Y-type molecular sieves while ensuring crystallinity. Summary of the invention

[0007] The object of the present invention is to provide a technical solution that can significantly improve the silicon-to-aluminum ratio of a Y-type molecular sieve; the Y-type molecular sieve prepared by the technical solution has a high silicon-to-aluminum ratio and a high degree of crystallinity.

[0008] In order to achieve the above objectives, the present invention provides the following two technical solutions.

[0009] In a first aspect, the present invention provides a method for preparing a Y-type molecular sieve with a high silicon-aluminum ratio, wherein the method comprises:

[0010] A NaY type molecular sieve containing the metal element Mn in the framework is subjected to isomorphous substitution reaction with gas phase SiCl4 at a mass ratio of 0.1-20:1, and then calcined to obtain a high silicon-aluminum ratio Y type molecular sieve;

[0011] Wherein, the reaction temperature of the isomorphous substitution reaction is 200-600°C;

[0012] Among them, the molar ratio of MnO2 to Al2O3 in the NaY type molecular sieve containing the metal element Mn in the framework is 0.01-10.0.

[0013] The technical solution provided by the present invention is to first dope manganese into the NaY type molecular sieve framework, and then cooperate with gas phase SiCl4 to carry out isomorphous substitution reaction, so as to achieve a substantial improvement in the silicon-aluminum ratio of the Y type molecular sieve while still retaining a high degree of crystallinity. The high silicon-aluminum ratio Y type molecular sieve obtained by the technical solution provided by the present invention is a high silicon-aluminum ratio Y type molecular sieve containing heteroatoms Mn in the framework. In the technical solution provided by the present invention, manganese Mn atoms are first doped into the NaY type molecular sieve framework to enter the molecular sieve framework to replace the position of a small part of the Al atoms in the NaY molecular sieve framework, and then gas phase SiCl4 is carried out for isomorphous substitution reaction, gas phase SiCl4 and the NaY molecular sieve framework heteroatoms Mn further synergistically, and a large number of Al atoms are isomorphously replaced, thereby achieving a substantial improvement in the framework silicon-aluminum ratio without the need for hydrothermal dealumination, and the prepared Y molecular sieve has a high relative crystallinity.

[0014] According to a preferred embodiment of the first aspect, the method further comprises the step of preparing a NaY type molecular sieve containing the metal element Mn in the framework, specifically comprising:

[0015] Sodium hydroxide, an aluminum source, a silicon source and water are mixed in a molar ratio of (10-30)Na2O:Al2O3:(10-30)SiO2:(180-400)H2O, and aged at 0-80°C to obtain a directing agent;

[0016] A directing agent, sodium hydroxide, a silicon source, an aluminum source, a manganese source and water are mixed according to a molar ratio of (1-10) Na2O:Al2O3:(0.01-10.0)MnO2:(5-20)SiO2:(120-360)H2O to obtain a reaction system to be crystallized, and the reaction system to be crystallized at 60-120°C to obtain a NaY type molecular sieve containing the metal element Mn in the framework; wherein, based on the mass of Al2O3 in the reaction system to be crystallized as 100%, the mass of Al2O3 provided by the directing agent accounts for 3-25% of the mass of Al2O3 in the reaction system to be crystallized;

[0017] The preferred technical scheme is to introduce Mn heteroatoms into the framework of the molecular sieve by a direct synthesis method, and then the obtained NaY type molecular sieve containing Mn heteroatoms is subjected to isomorphous substitution reaction with gas phase SiCl4 at a certain temperature, and then roasted to obtain a high silicon-to-aluminum ratio Y type molecular sieve with Mn heteroatoms in the framework; the Y type molecular sieve prepared by this method not only has a high silicon-to-aluminum ratio but also has a high crystallinity, and does not require multiple ammonium ion exchange and hydrothermal treatment processes, so that the sodium oxide content of the molecular sieve can be reduced to below 1.0wt%; the Y type molecular sieve prepared by the preferred technical scheme has a higher silicon-to-aluminum ratio, higher crystallinity, and suitable acidity compared to the Y type molecular sieve prepared by traditional metal impregnation and hydrothermal ultra-stabilization technology, and shortens the production process, reduces production costs, and reduces ammonia nitrogen wastewater discharge;

[0018] The preferred technical solution is to introduce Mn heteroatoms into the framework of the molecular sieve by a direct synthesis method, which has significant advantages over the traditional impregnation method or ion exchange method: the impregnation method usually introduces metal heteroatoms into the molecular sieve surface, but it is difficult to introduce them into the molecular sieve framework, and the metal heteroatoms introduced by the impregnation method are easy to block the molecular sieve pores; the ion exchange method can only introduce a very small amount of metal heteroatoms into the molecular sieve, and the introduced metal heteroatoms are mostly present on the outer surface and pore surface of the molecular sieve, and it is difficult to enter the molecular sieve framework; and the introduction of metal heteroatoms by the direct synthesis method is that during the molecular sieve synthesis process, part of the metal source is directly added to the synthesis gel, and the crystal nucleus is gradually formed under the action of the directing agent, and then part of the metal is introduced into the molecular sieve framework by crystallization;

[0019] Further, in the process of preparing the directing agent, sodium hydroxide, an aluminum source, a silicon source and water are mixed in a molar ratio of (10-20)Na2O:Al2O3:(10-20)SiO2:(240-360)H2O;

[0020] Furthermore, in the process of preparing the reaction system to be crystallized, the directing agent, sodium hydroxide, silicon source, aluminum source, manganese source and water are mixed according to the molar ratio of (1-5) Na2O:Al2O3:(0.01-5.0)MnO2:(5-15)SiO2:(150-300)H2O to obtain the reaction system to be crystallized (gel mixture), and the reaction system to be crystallized is crystallized at 60-120°C.

[0021] Further, aging is carried out at 10-60°C;

[0022] Further, the aging time is 1-60h; further, the aging time is 2-50h;

[0023] Further, the crystallization is carried out at 70-110°C;

[0024] Further, the crystallization time is 0.5-72h; further, the crystallization time is 12-48h;

[0025] Further, the crystallized sample is filtered, washed, and dried; further, the drying is performed at 120° C. for 24 hours;

[0026] Furthermore, the silicon source includes but is not limited to at least one of ethyl silicate, water glass, silica gel, sodium silicate and silica gel.

[0027] Further, the aluminum source includes but is not limited to at least one of sodium metaaluminate, aluminum sulfate, aluminum isopropoxide, tert-butyl aluminum and aluminum oxide;

[0028] Further, the manganese source includes but is not limited to at least one of manganese chloride and manganese sulfate.

[0029] According to a preferred embodiment of the first aspect, when the isomorphous substitution reaction is carried out, the mass ratio of the NaY type molecular sieve containing the metal element Mn in the framework to the gas phase SiCl4 is 0.5-15:1.

[0030] According to a preferred embodiment of the first aspect, the molar ratio of MnO2 to Al2O3 in the NaY type molecular sieve containing the metal element Mn in the framework is 0.01-5.0.

[0031] According to a preferred embodiment of the first aspect, the reaction temperature of the isomorphous substitution reaction is 280-580°C; further, the reaction temperature of the isomorphous substitution reaction is 300-500°C.

[0032] According to a preferred embodiment of the first aspect, the reaction time of the isomorphous substitution reaction is 10 minutes to 5 hours.

[0033] According to a preferred embodiment of the first aspect, the method further comprises cooling, washing, filtering and drying the isomorphous substitution reaction product after the isomorphous substitution reaction and before calcination;

[0034] Furthermore, the cooling is carried out under N2 purge.

[0035] According to a preferred embodiment of the first aspect, the calcination temperature is 500-600°C.

[0036] According to a preferred embodiment of the first aspect, the calcination time is 2-6 hours.

[0037] In the second aspect, the present invention provides a high silicon-aluminum ratio Y-type molecular sieve prepared by the preparation method of the high silicon-aluminum ratio Y-type molecular sieve provided in the first aspect, wherein the high silicon-aluminum ratio Y-type molecular sieve contains heteroatom Mn in the skeleton, and the skeleton silicon-aluminum molar ratio n(SiO2) / n(Al2O3) is above 6.

[0038] According to a preferred embodiment of the second aspect, the framework silicon-aluminum molar ratio n(SiO2) / n(Al2O3) is greater than 9.

[0039] Since metal heteroatoms are different from Si and Al atoms in the molecular sieve framework in terms of ionic radius, electronegativity and complexing ability, the introduction of metal heteroatoms will regulate the acidity and surface properties of the molecular sieve catalyst. However, due to the diversity of heteroatom types and the diversity of molecular sieve channels, the effects of different heteroatoms on the performance of different molecular sieves are different. Therefore, what kind of heteroatom will be introduced into what kind of molecular sieve and what kind of performance impact has always been a research difficulty in the field of molecular sieves. The present invention achieves a substantial improvement in Y-type molecular sieves by introducing Mn atoms into the NaY-type molecular sieve framework and then performing an isomorphous substitution reaction with SiCl4. Compared with the prior art, it has the following beneficial effects:

[0040] 1. The technical solution provided by the present invention achieves an increase in the framework silicon-to-aluminum ratio of the Y-type molecular sieve by isomorphously replacing a NaY-type molecular sieve containing the metal element Mn in its framework with gas-phase SiCl4 and then calcining the NaY-type molecular sieve. The framework silicon-to-aluminum molar ratio n(SiO2) / n(Al2O3) of the prepared Y-type molecular sieve is above 9.

[0041] The technical solution provided by the present invention can obtain Y-type molecular sieves with different silicon-to-aluminum ratios by regulating the reaction conditions of NaY-type molecular sieves containing the metal element Mn in the framework and gas-phase SiCl4. In the preferred technical solution, the framework silicon-to-aluminum molar ratio n(SiO2) / n(Al2O3) of the Y-type molecular sieve can reach more than 18 or even more than 20.

[0042] In the technical solution provided by the present invention, the framework of the NaY molecular sieve contains the metal element Mn, and the aluminum element of the framework is replaced by the Mn element. The silicon-aluminum ratio of the framework is improved compared with the conventional NaY. When the framework of the NaY molecular sieve containing Mn undergoes an isomorphous substitution reaction with the gas phase SiCl4, the SiCl4 vapor contacts the NaY molecular sieve, and under the influence of the Mn element, the Na exchange reaction effectively occurs. + Produce NaCl and SiCl3 + ions and adsorbed on the molecular sieve surface, and then SiCl3 + The ions replace the framework aluminum at high temperature and produce AlCl3, so that the framework silicon-aluminum ratio is significantly improved.

[0043] 2. The Y-type molecular sieve prepared by the technical solution provided by the present invention has a high silicon-aluminum ratio and a high crystallinity, wherein the crystallinity is above 80%.

[0044] 3. The technical solution provided by the present invention is to obtain a Y-type molecular sieve with a high silicon-aluminum ratio by isomorphously replacing a NaY-type molecular sieve containing the metal element Mn in its framework with gas-phase SiCl4 and then calcining it. The sodium oxide content of the Y-type molecular sieve can be reduced to below 1.0wt% without the need for multiple ammonium ion exchanges and harsh hydrothermal treatments (600°C-700°C). The production process is simple, the production cost is low, and the discharge of ammonia nitrogen wastewater is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 XRD spectra of the Y-type molecular sieves provided for Example 1 to Example 5 and Comparative Example 2, Comparative Example 3, and Comparative Example 5. DETAILED DESCRIPTION

[0046] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0047] The relative crystallinity, unit cell parameters and framework silicon-aluminum ratio (SiO2 / Al2O3 molar ratio) of the Y-type molecular sieve in the present invention are determined by X-ray diffraction (XRD), and the spectrum with a 2θ angle of 5 to 40° is recorded. The metal element content and Na2O content of the Y-type molecular sieve are measured by X-ray fluorescence spectrometer, and the specific surface area and pore structure parameters are measured by low-temperature nitrogen adsorption and desorption.

[0048] Description of the raw materials used in the embodiments of the present invention:

[0049] Sodium hydroxide: produced by Beijing Chemical Plant, purity is 99%;

[0050] Sodium aluminate: produced by Tianjin Jinke Fine Chemical Research Institute, Al2O3 content is 45wt%, Na2O content is 41wt%, and the balance is water;

[0051] Water glass: produced by Beijing Red Star Soda Factory, with SiO2 content of 28.83wt%, Na2O content of 8.84wt%, and the balance being water;

[0052] Silica sol: produced by Tianjin Jinke Fine Chemical Research Institute, SiO2 content is 28.88wt%, the balance is water;

[0053] Aluminum sulfate: produced by Nanzhao Huaxin Chemical Co., Ltd., with a purity of 99%;

[0054] Manganese sulfate: produced by Tianjin Suzhuang Chemical Reagent Factory, purity 99%.

[0055] Manganese chloride: produced by Tianjin Suzhuang Chemical Reagent Factory, purity 99%.

[0056] Aluminum isopropoxide: Shanghai MacLean Biochemical Technology Co., Ltd., purity 99.8%;

[0057] Alumina: Shanghai McLean Biochemical Technology Co., Ltd., purity 99.99%.

[0058] Ethyl silicate: Shanghai MacLean Biochemical Technology Co., Ltd., SiO2 content is 28.83wt%, the balance is water.

[0059] Example 1

[0060] This embodiment provides a high silicon-aluminum ratio Y-type molecular sieve, which is prepared by the following preparation method:

[0061] 8.51 g of sodium hydroxide was added to 38.62 g of distilled water, and after stirring for 30 minutes, 2.25 g of sodium aluminate and 30.66 g of water glass were added, and after stirring evenly, the mixture was aged at 35° C. for 5 hours to obtain a directing agent;

[0062] Add 41.0g of directing agent to 225.6g of silica sol, stir for 1h, then add 13.78g of sodium hydroxide, 3.75g of sodium aluminate and 141.92g of distilled water and stir for 1h, then add 159.80g of aluminum sulfate solution (Al2O3 mass concentration is 7.6wt%), stir for 1h, then add 1.72g of manganese sulfate (MnSO4·H2O), continue stirring for 1h to obtain the reaction system to be crystallized (gel mixture). The reaction system to be crystallized is placed in a stainless steel crystallization kettle, sealed and dynamically crystallized in a rotary oven at 100°C for 28 hours, filtered, washed, and the filter cake is dried in an oven at 120°C for 24 hours; the dried product is transferred to a quartz tube reactor of a rotary tube furnace, purged with high-purity nitrogen, and programmed to heat (4° / min) to 550°C, and calcined at 550°C for 4 hours to obtain a NaY type molecular sieve containing the metal element Mn in the framework (the molar ratio of MnO2 to Al2O3 is 0.071).

[0063] Then, 7.64 g of gaseous SiCl4 was introduced into a rotary tube furnace quartz tube reactor containing 38.6 g of NaY type molecular sieve containing the metal element Mn in the framework to carry out isomorphous substitution reaction at 350°C for 1 hour, and then the product of the isomorphous substitution reaction was repeatedly washed with deionized water, filtered, dried, and calcined at 550°C for 4 hours to obtain a high silicon-aluminum ratio Y type molecular sieve containing heteroatom Mn, named Mn-DY1. The physicochemical properties data of the sample are shown in Table 1, and the XRD spectrum is shown in Figure 1 .

[0064] Example 2

[0065] This embodiment provides a high silicon-aluminum ratio Y-type molecular sieve, which is prepared by the following preparation method:

[0066] 9.02 g of sodium hydroxide was added to 40.52 g of distilled water, and after stirring for 30 minutes, 2.46 g of sodium aluminate and 45 g of water glass were added, and after stirring evenly, the mixture was aged at 30° C. for 6 hours to obtain a directing agent.

[0067] Add 97g of directing agent to 200g of water glass, stir for 1h, add 12.70g of sodium hydroxide, 3.46g of sodium aluminate and 140.09g of distilled water, stir for 1h, add 136.20g of aluminum sulfate solution (Al2O3 mass concentration is 7.6wt%), stir for 1h, add 4.16g of manganese sulfate (MnSO4·H2O), continue stirring for 1h, and obtain the reaction system to be crystallized (gel mixture). The reaction system to be crystallized is placed in a stainless steel crystallization kettle, sealed and placed in a rotary oven at 105°C for crystallization for 24 hours, filtered, washed, and the filter cake is dried in an oven at 120°C for 24 hours; the dried product is transferred to a quartz tube reactor of a rotary tube furnace, purged with high-purity nitrogen, and programmed to heat (4° / min) to 550°C, and calcined at 550°C for 4 hours to obtain a NaY type molecular sieve containing the metal element Mn in the framework (the molar ratio of MnO2 to Al2O3 is 0.192).

[0068] Then, 7.78 g of gaseous SiCl4 was introduced into a quartz tube reactor of a rotary tube furnace containing 26 g of NaY type molecular sieve containing the metal element Mn in the framework to carry out isomorphous substitution reaction at 450°C for 1 hour, and then the product of the isomorphous substitution reaction was repeatedly washed with deionized water, filtered, dried, and calcined at 550°C for 4 hours to obtain a high silicon-aluminum ratio Y type molecular sieve containing heteroatom Mn, named Mn-DY2. The physicochemical properties of the sample are shown in Table 1, and the XRD spectrum is shown in Figure 1 .

[0069] Comparative Example 1

[0070] This comparative example provides a Y-type molecular sieve, which is prepared by the following preparation method:

[0071] 9.02 g of sodium hydroxide was added to 40.52 g of distilled water, and after stirring for 30 minutes, 2.46 g of sodium aluminate and 45 g of water glass were added, and after stirring evenly, the mixture was aged at 30° C. for 6 hours to obtain a directing agent.

[0072] 97g of directing agent was added to 200g of water glass, stirred for 1h, 12.70g of sodium hydroxide, 3.46g of sodium aluminate and 140.09g of distilled water were added, and after stirring for 1h, 136.20g of aluminum sulfate solution (Al2O3 mass concentration was 7.6wt%) was added, and after stirring for 1h, a gel mixture was formed, and stirring was continued for 1 hour to obtain a reaction system to be crystallized; the reaction system to be crystallized was placed in a stainless steel crystallization kettle, sealed and dynamically crystallized in a rotary oven at 105°C for 24h, filtered, washed, and the filter cake was dried in an oven at 120°C for 24h; the dried product was transferred to a quartz tube reactor of a rotary tube furnace, purged with high-purity nitrogen, and programmed to heat (4° / min) to 550°C, and calcined at 550°C for 4h to obtain a NaY type molecular sieve, named NaY2. The physicochemical properties of the sample are shown in Table 1.

[0073] Comparative Example 2

[0074] This comparative example provides a Y-type molecular sieve, which is prepared by a conventional hydrothermal USY-type molecular sieve preparation method, specifically:

[0075] 9.02 g of sodium hydroxide was added to 40.52 g of distilled water, and after stirring for 30 minutes, 2.46 g of sodium aluminate and 45 g of water glass were added, and after stirring evenly, the mixture was aged at 30° C. for 6 hours to obtain a directing agent.

[0076] 97g of directing agent is added to 200g of water glass, stirred for 1h, 12.70g of sodium hydroxide, 3.46g of sodium aluminate and 140.09g of distilled water are added, and after stirring for 1h, 136.20g of aluminum sulfate solution (Al2O3 mass concentration is 7.6wt%) is added, and after stirring for 1h, a gel mixture is formed, and stirring is continued for 1 hour to obtain a reaction system to be crystallized; the reaction system to be crystallized is placed in a stainless steel crystallization kettle, sealed and dynamically crystallized in a rotary oven at 105°C for 24h, filtered, washed, and the filter cake is dried in an oven at 120°C for 24h; the dried product is transferred to a quartz tube reactor of a rotary tube furnace, purged with high-purity nitrogen, and programmed to heat (4° / min) to 550°C, and calcined at 550°C for 4h to obtain a NaY type molecular sieve.

[0077] The NaY molecular sieve was mixed with 1 mol / L ammonium chloride solution at a mass ratio of 1:10 and ion exchanged at 90°C for 1 hour, filtered, washed repeatedly, and the filter cake was dried in an oven at 120°C for 24 hours, and then treated with 100% water vapor at 600°C for 2 hours. The above steps were repeated for another ion exchange and water vapor treatment to obtain a hydrothermal USY molecular sieve named USY-2. The physicochemical properties of the sample are shown in Table 1, and the XRD spectrum is shown in Figure 1 .

[0078] Comparative Example 3

[0079] This comparative example provides a Y-type molecular sieve, which is prepared by the following preparation method:

[0080] 9.02 g of sodium hydroxide was added to 40.52 g of distilled water, and after stirring for 30 minutes, 2.46 g of sodium aluminate and 45 g of water glass were added, and after stirring evenly, the mixture was aged at 30° C. for 6 hours to obtain a directing agent.

[0081] 97g of directing agent is added to 200g of water glass, stirred for 1h, 12.70g of sodium hydroxide, 3.46g of sodium aluminate and 140.09g of distilled water are added, stirred for 1h, 136.20g of aluminum sulfate solution (Al2O3 mass concentration is 7.6wt%) is added, stirred for 1h, 4.16g of manganese sulfate (MnSO4·H2O) is added, and stirring is continued for 1h to obtain a reaction system to be crystallized (gel mixture); the reaction system to be crystallized is placed in a stainless steel crystallization kettle, sealed and dynamically crystallized in a rotary oven at 105°C for 24h, filtered, washed, and the filter cake is dried in an oven at 120°C for 24h; the dried product is transferred to a quartz tube reactor of a rotary tube furnace, purged with high-purity nitrogen, and programmed to heat (4° / min) to 550°C, and calcined at 550°C for 4h to obtain a NaY type molecular sieve containing the metal element Mn in the framework. The NaY molecular sieve containing the metal element Mn in the framework was mixed with an ammonium chloride solution with a concentration of 1 mol / L at a mass ratio of 1:10, and ion exchange was performed at 90°C for 1 hour, filtered, washed repeatedly, and the filter cake was dried in an oven at 120°C for 24 hours, and then treated with 100% water vapor at 600°C for 2 hours. The above steps were repeated for another ion exchange and a water vapor treatment to obtain a hydrothermal USY molecular sieve containing heteroatom Mn, named Mn-USY2. The physicochemical properties of the sample are shown in Table 1, and the XRD spectrum is shown in Figure 1 .

[0082] Comparative Example 4

[0083] This comparative example provides a Y-type molecular sieve, which is prepared by the following method:

[0084] 9.02 g of sodium hydroxide was added to 40.52 g of distilled water, and after stirring for 30 minutes, 2.46 g of sodium aluminate and 45 g of water glass were added, and after stirring evenly, the mixture was aged at 30° C. for 6 hours to obtain a directing agent.

[0085] 97g of directing agent was added to 200g of water glass, stirred for 1h, 12.70g of sodium hydroxide, 3.46g of sodium aluminate and 140.09g of distilled water were added, stirred for 1h, 136.20g of aluminum sulfate solution (Al2O3 mass concentration is 7.6wt%) was added, stirred for 1h, 4.16g of manganese sulfate (MnSO4·H2O) was added, and stirring was continued for 1h to obtain a reaction system to be crystallized (gel mixture); the reaction system to be crystallized was placed in a stainless steel crystal The product was placed in a rotary oven at 105°C for dynamic crystallization for 24 hours, filtered, washed, and dried in a 120°C oven for 24 hours. The dried product was transferred to a quartz tube reactor of a rotary tube furnace, purged with high-purity nitrogen, and programmed to rise in temperature (4° / min) to 550°C. The product was calcined at 550°C for 4 hours to obtain a NaY type molecular sieve containing the metal element Mn in the framework, named Mn-NaY2. The physicochemical properties of the sample are shown in Table 1.

[0086] Comparative Example 5

[0087] This comparative example provides a Y-type molecular sieve, which is prepared by the following method:

[0088] 9.02 g of sodium hydroxide was added to 40.52 g of distilled water, and after stirring for 30 minutes, 2.46 g of sodium aluminate and 45 g of water glass were added, and after stirring evenly, the mixture was aged at 30° C. for 6 hours to obtain a directing agent;

[0089] 97g of directing agent is added to 200g of water glass, stirred for 1h, 12.70g of sodium hydroxide, 3.46g of sodium aluminate and 140.09g of distilled water are added, stirred for 1h, 136.20g of aluminum sulfate solution (Al2O3 mass concentration is 7.6wt%) is added, and stirring is continued for 1h to obtain a reaction system to be crystallized (gel mixture). The reaction system to be crystallized is placed in a stainless steel crystallization kettle, sealed and dynamically crystallized in a rotary oven at 105°C for 24h, filtered, washed, and the filter cake is dried in a 120°C oven for 24h; the dried product is transferred to a quartz tube reactor of a rotary tube furnace, purged with high-purity nitrogen, and programmed to heat (4° / min) to 550°C, and calcined at 550°C for 4h to obtain a NaY type molecular sieve free of heteroatom Mn.

[0090] Then, 7.64 g of gaseous SiCl4 was introduced into a rotary tube furnace quartz tube reactor containing 38.6 g of NaY type molecular sieve without heteroatom Mn to carry out isomorphous substitution reaction at 350°C for 1 hour, and then the product of the isomorphous substitution reaction was repeatedly washed with deionized water, filtered, dried, and calcined at 550°C for 4 hours to obtain a high silicon-aluminum ratio Y type molecular sieve without heteroatom Mn, named DY2. The physicochemical properties of the sample are shown in Table 1, and the XRD spectrum is shown in Figure 1 .

[0091] Comparative Example 6

[0092] This comparative example provides a Y-type molecular sieve, which is prepared by the following method:

[0093] 2.22 g of sodium aluminate, 8.21 g of sodium hydroxide, 35.62 g of distilled water, and 30.61 g of water glass were mixed in order, stirred evenly, and aged at 25° C. for 24 hours to obtain a directing agent.

[0094] 188.7 g of water glass, 46.3 g of 30 wt% sodium aluminate solution, 42.8 g of 50 wt% aluminum sulfate solution, 1.30 g of manganese chloride (MnCl2·H2O), and 40.3 g of a directing agent were mixed and vigorously stirred until uniform to obtain a reaction system to be crystallized (gel mixture); the reaction system to be crystallized was placed in a stainless steel crystallization kettle, sealed and dynamically crystallized in a rotary oven at 100° C. for 28 h, filtered, washed, and the filter cake was dried in an oven at 120° C. for 24 h to obtain a NaY type molecular sieve containing the metal element Mn in the framework, named Mn-D1-NaY. The physicochemical property data of the sample are shown in Table 1.

[0095] Comparative Example 7

[0096] This comparative example provides a Y-type molecular sieve, which is prepared by the following method:

[0097] The Y-type molecular sieve provided in Comparative Example 6 was rinsed three times with a 1.5 mol / L ammonium sulfate solution at 85°C, and then calcined at 540°C for 2 hours. The calcined molecular sieve was rinsed three times with a 0.5 mol / L ammonium sulfate solution, and then a 0.5 mol / L manganese sulfate solution was added to the wet filter cake. After stirring evenly, it was transferred to a hydrothermal device and calcined at 600°C with water vapor for 4 hours to obtain an ultra-stable Y-type molecular sieve. The sample was named Mn-D1-USY. The physicochemical properties of the sample are listed in Table 1.

[0098] Example 3

[0099] This embodiment provides a high silicon-aluminum ratio Y-type molecular sieve, which is prepared by the following preparation method:

[0100] 8.51 g of sodium hydroxide was added to 38.62 g of distilled water, and after stirring for 30 minutes, 2.25 g of sodium aluminate and 37.09 g of silica sol were added, and after stirring evenly, the mixture was aged at 60° C. for 2 hours to obtain a directing agent.

[0101] 40.3 g of directing agent was added to 132.47 g of silica sol, and after stirring for 1 hour, 23.27 g of NaOH and 160 g of distilled water, 1.58 g of sodium aluminate were added, and after stirring for 1 hour, 98.72 g of aluminum sulfate solution (Al2O3 mass concentration is 7.6 wt%) was added, and after stirring for 1 hour, 6.08 g of manganese chloride (MnCl2·H2O) was added, and stirring was continued for 1 hour to obtain a reaction system to be crystallized (gel mixture); the reaction system to be crystallized was placed in a non- The product was placed in a stainless steel crystallization kettle, sealed, and subjected to dynamic crystallization in a rotary oven at 94°C for 28 hours, filtered, washed, and the filter cake was dried in an oven at 120°C for 24 hours; the dried product was transferred to a quartz tube reactor of a rotary tube furnace, purged with high-purity nitrogen, and programmed to heat (4° / min) to 550°C, and calcined at 550°C for 4 hours to obtain a NaY type molecular sieve containing the metal element Mn in the framework (the molar ratio of MnO2 to Al2O3 is 0.360).

[0102] Then, 8.61 g of gaseous SiCl4 was introduced into a quartz tube reactor of a rotary tube furnace containing 25 g of NaY type molecular sieve containing the metal element Mn in the framework to carry out isomorphous substitution reaction at 410°C for 1 hour, and then the product of the isomorphous substitution reaction was repeatedly washed with deionized water, filtered, dried, and calcined at 550°C for 4 hours to obtain a high silicon-aluminum ratio Y type molecular sieve containing heteroatom Mn, named Mn-DY3. The physicochemical properties of the sample are shown in Table 1, and the XRD spectrum is shown in Figure 1 .

[0103] Example 4

[0104] This embodiment provides a high silicon-aluminum ratio Y-type molecular sieve, which is prepared by the following preparation method:

[0105] 15.48 g of sodium hydroxide was added to 60 g of distilled water, and after stirring for 30 minutes, 3.06 g of sodium aluminate and 35.58 g of ethyl silicate were added, and after stirring evenly, the mixture was aged at 35° C. for 16 hours to obtain a directing agent.

[0106] 100g of directing agent was added to 137.79g of ethyl silicate, and after stirring for 1h, 23.27g of NaOH and 282.43g of distilled water were added, and after stirring for 1h, 1.58g of sodium aluminate was added, and after stirring for 1h, 12.81g of aluminum isopropoxide and 92g of water were added, and after stirring for 1h, 2.30g of manganese chloride (MnCl2·H2O) was added, and stirring was continued for 1h to obtain a reaction system to be crystallized (gel mixture); the reaction system to be crystallized was placed in a stainless steel crystal The product was placed in a sealed reactor and subjected to dynamic crystallization in a rotary oven at 100°C for 28 hours. The product was then filtered, washed, and the filter cake was dried in an oven at 120°C for 24 hours. The dried product was transferred to a quartz tube reactor of a rotary tube furnace, purged with high-purity nitrogen, and programmed to rise in temperature (4° / min) to 550°C. The product was calcined at 550°C for 4 hours to obtain a NaY type molecular sieve containing the metal element Mn in the framework (the molar ratio of MnO2 to Al2O3 is 0.234).

[0107] Then, 8.05 g of gaseous SiCl4 was introduced into a quartz tube reactor of a rotary tube furnace containing 26.8 g of NaY type molecular sieve containing the metal element Mn in the framework to carry out isomorphous substitution reaction at 380°C for 1 hour, and then the product of the isomorphous substitution reaction was repeatedly washed with deionized water, filtered, dried, and calcined at 550°C for 4 hours to obtain a high silicon-aluminum ratio Y type molecular sieve containing heteroatom Mn, named Mn-DY4. The physicochemical properties of the sample are shown in Table 1, and the XRD spectrum is shown in Figure 1 .

[0108] Example 5

[0109] This embodiment provides a high silicon-aluminum ratio Y-type molecular sieve, which is prepared by the following preparation method:

[0110] 10.7 g of sodium hydroxide was added to 38.62 g of distilled water, and 1.2 g of aluminum oxide and 30.66 g of water glass were added, stirred evenly, and then aged at 50° C. for 3 h to obtain a directing agent.

[0111] 41.0 g of the directing agent was added to 189.0 g of water glass, and after stirring for 1 hour, 12.65 g of sodium hydroxide, 1.20 g of aluminum oxide and 303.21 g of distilled water were added, and after stirring for 1 hour, 104 g of aluminum sulfate solution (the mass concentration of aluminum oxide was 7.6 wt%) was added, and after stirring for 1 hour, 15.31 g of manganese chloride (MnCl2·H2O) was added, and stirring was continued for 1 hour to obtain a reaction system to be crystallized (gel mixture); the reaction system to be crystallized was placed in a stainless steel The crystallization kettle was sealed and then dynamically crystallized in a rotary oven at 100°C for 28 hours, then filtered, washed, and the filter cake was dried in a 120°C oven for 24 hours; the dried product was transferred to a quartz tube reactor of a rotary tube furnace, purged with high-purity nitrogen, and programmed to rise in temperature (4° / min) to 550°C, and calcined at 550°C for 4 hours to obtain a NaY type molecular sieve containing the metal element Mn in the framework (the molar ratio of MnO2 to Al2O3 is 1.030).

[0112] Then, 8.55 g of gaseous SiCl4 was introduced into a quartz tube reactor of a rotary tube furnace containing 20 g of NaY type molecular sieve containing the metal element Mn in the framework to carry out isomorphous substitution reaction at 460°C for 1 hour, and then the product of the isomorphous substitution reaction was repeatedly washed with deionized water, filtered, dried, and calcined at 550°C for 4 hours to obtain a high silicon-aluminum ratio Y type molecular sieve containing heteroatom Mn, named Mn-DY5. The physicochemical properties of the sample are shown in Table 1, and the XRD spectrum is shown in Figure 1 .

[0113] Table 1

[0114]

[0115] It can be seen from Table 1 that in the process of improving the silicon-to-aluminum ratio of the Y molecular sieve framework, there is a synergistic effect between the framework doping with Mn and the gas-phase SiCl4 isomorphous substitution reaction. The cooperation of the framework doping with Mn and the gas-phase SiCl4 isomorphous substitution reaction can achieve a significant improvement in the silicon-to-aluminum ratio of the Y molecular sieve framework, which is an effect that cannot be achieved by only doping the framework with Mn, only performing the SiCl4 isomorphous substitution reaction, only performing the hydrothermal superstabilization, and performing both the framework doping with Mn and the SiCl4 isomorphous substitution reaction.

Claims

1. A method for preparing a Y-type molecular sieve with a high silicon-aluminum ratio, wherein: The method includes: A NaY type molecular sieve containing a metal element Mn in its framework is subjected to an isomorphous substitution reaction with gas phase SiCl4 at a mass ratio of 0.1-20:1, and then calcined to obtain a high silicon-aluminum ratio Y type molecular sieve; Wherein, the reaction temperature of the isomorphous substitution reaction is 200-600°C; Among them, the molar ratio of MnO2 to Al2O3 in the NaY type molecular sieve containing the metal element Mn in the framework is 0.01-10.

0.

2. The method according to claim 1, wherein: The method also includes the step of preparing a NaY type molecular sieve containing the metal element Mn in the framework, specifically comprising: Sodium hydroxide, an aluminum source, a silicon source and water are mixed in a molar ratio of (10-30)Na2O:Al2O3:(10-30)SiO2:(180-400)H2O, and aged at 0-80°C to obtain a directing agent; A directing agent, sodium hydroxide, a silicon source, an aluminum source, a manganese source and water are mixed according to a molar ratio of (1-10)Na2O:Al2O3:(0.01-10.0)MnO2:(5-20)SiO2:(120-360)H2O to obtain a reaction system to be crystallized. The reaction system to be crystallized is crystallized at 60-120°C to obtain a NaY type molecular sieve containing the metal element Mn in the framework; wherein the mass of Al2O3 provided by the directing agent accounts for 3-25% of the mass of Al2O3 in the reaction system to be crystallized.

3. The method according to claim 2, wherein: In the process of preparing the directing agent, sodium hydroxide, an aluminum source, a silicon source and water are mixed according to the molar ratio of (10-20)Na2O:Al2O3:(10-20)SiO2:(240-360)H2O.

4. The method according to claim 2, wherein: In the process of preparing the reaction system to be crystallized, the directing agent, sodium hydroxide, silicon source, aluminum source, manganese source and water are mixed according to the molar ratio of (1-5) Na2O:Al2O3:(0.01-5.0)MnO2:(5-15)SiO2:(150-300)H2O.

5. The method according to claim 2 or 3, wherein: Aging is carried out at 10-60°C.

6. The method according to claim 2 or 4, wherein: Crystallization is carried out at 70-110°C.

7. The method according to any one of claims 2, 3 and 4, wherein: The silicon source includes at least one of ethyl silicate, water glass and silica sol.

8. The method according to any one of claims 2, 3 and 4, wherein: The aluminum source includes at least one of sodium metaaluminate, aluminum sulfate, aluminum isopropoxide, tert-butyl aluminum, and aluminum oxide.

9. The method according to any one of claims 2, 3 and 4, wherein: The manganese source includes at least one of manganese chloride and manganese sulfate.

10. The method according to claim 1, wherein: When performing isomorphous substitution reaction, the mass ratio of the NaY type molecular sieve containing the metal element Mn in the framework to the gas phase SiCl4 is 0.5-15:1; and / or The molar ratio of MnO2 to Al2O3 in the NaY type molecular sieve containing the metal element Mn in the framework is 0.01-5.

0.

11. The method according to claim 1 or 10, wherein: The reaction temperature of the isomorphous substitution reaction is 300-500°C.

12. The high silicon-to-aluminum ratio Y-type molecular sieve prepared by the preparation method of the high silicon-to-aluminum ratio Y-type molecular sieve according to any one of claims 1 to 11.

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