A process for the preparation of a fluidized bed catalyst of a silicoaluminophosphate molecular sieve

Abstract

The application discloses a preparation method of a fluidized bed catalyst of a silicoaluminophosphate molecular sieve. The method comprises the following steps: a) treating the silicoaluminophosphate molecular sieve in an alcohol solution containing a titanate, and drying to obtain a modified molecular sieve; b) mixing the modified molecular sieve obtained in the step a), a liquid medium, a base material and a binder to form a suspension; c) high-speed shearing the suspension obtained in the step b), and spray drying to obtain a microspheric catalyst; and d) calcining the microspheric catalyst obtained in the step c) to obtain a finished catalyst. The catalyst solves the problems of poor catalytic performance and high abrasion index of the fluidized bed catalyst in the prior art.

Description

Technical Field

[0001] This invention relates to the field of catalyst preparation, and specifically to a method for preparing a fluidized bed catalyst using aluminosilicate phosphate molecular sieves. Background Technology

[0002] Ethylene and propylene are the cornerstones of the chemical industry. Developing coal-based olefin production technologies using coal or natural gas as raw materials is of great practical significance for balancing the supply and demand of low-carbon olefins, reducing dependence on crude oil imports, and promoting national energy security.

[0003] Methanol-to-Olefins (MTO) is a process technology that uses methanol, typically produced from natural gas or coal, to produce polymer-grade ethylene, propylene, and other low-carbon olefins under the action of a catalyst. In the MTO process, as the finished fluidized bed catalyst continuously circulates in the reaction-regeneration system, constant collisions and friction occur between catalysts, between the catalyst and the reactor wall, between the catalyst and the transport pipeline, and between the catalyst and the regeneration system, making catalyst wear unavoidable. Catalyst wear involves two mechanisms: catalyst surface erosion and catalyst breakage. If the catalyst strength is poor, severe wear occurs in the reaction-regeneration system. To maintain the catalyst stock in the system, more fresh catalyst needs to be continuously added during the reaction, increasing production costs. Excessive catalyst powder entering the water treatment system can also cause frequent blockages, increasing the production burden. Therefore, to reduce catalyst wear in the fluidized bed reactor, the catalyst must possess good anti-wear properties. In some cases, improving the wear resistance of a catalyst can reduce its catalytic performance. For example, increasing the catalyst calcination temperature leads to a denser microsphere structure, improving wear resistance. However, this denser structure reduces diffusion performance, resulting in decreased selectivity for ethylene and propylene in the MTO reaction. On the other hand, reducing the production cost of MTO fluidized bed catalysts is also a significant issue. Reports indicate that using double spray drying to improve catalyst wear resistance increases energy consumption during production, hindering cost control.

[0004] CN102527445A discloses a method for preparing a low-wear fluidized bed microsphere catalyst. A slurry is prepared by mixing molecular sieves, a binder, a dispersant, and water. After shearing, the slurry is spray-dried. The resulting microspheres are redispersed in water and subjected to shearing and spraying again. The microspheres are then calcined to obtain the low-wear fluidized bed catalyst. CN103769237A discloses a method for improving the wear resistance of fluidized bed catalysts. Fine catalyst powder with an average particle size of less than 80 micrometers is uniformly mixed with molecular sieves, a binder, a support material, and a liquid medium to form a suspension. The suspension is then subjected to high-speed shearing and spray drying, effectively improving the wear resistance of the finished catalyst. CN101157057A discloses a method for preparing a low-wear catalyst by in-situ synthesis of molecular sieves. First, porous microspheres are prepared by spray molding. Then, the microspheres undergo hydrothermal synthesis treatment, generating an ordered molecular sieve structure inside the porous microspheres, thus obtaining a low-wear microsphere catalyst. CN107971024A discloses a method for preparing a high wear-resistant fluidized bed catalyst. The method involves spray-drying a suspension of a mixture of molecular sieve, binder, support material and liquid medium to obtain a microsphere catalyst. This microsphere catalyst is then dispersed in an alumina-containing solution and spray-dried again. The catalyst strength is improved by coating the outer layer of the catalyst with a layer of alumina with high hardness.

[0005] In summary, although some existing patents address the issue of improving the wear resistance of fluidized bed catalysts, the wear resistance of fluidized bed catalysts still needs to be further improved, while also ensuring that the catalyst's catalytic performance does not decline and that production energy consumption does not increase. Summary of the Invention

[0006] The technical problem this invention aims to solve is the poor wear resistance and low selectivity for ethylene and propylene found in existing fluidized bed catalysts made of silica-alumina molecular sieves. This invention provides a method for preparing a silica-alumina molecular sieve fluidized bed catalyst. The catalyst prepared by this method exhibits high wear resistance and good selectivity for ethylene and propylene.

[0007] The first aspect of this invention provides a method for preparing a fluidized bed catalyst using aluminosilicate phosphate molecular sieves, comprising:

[0008] a) The silica-alumina molecular sieve was treated in an alcohol solution containing titanate and dried to obtain the modified molecular sieve.

[0009] b) Mix the modified molecular sieve, liquid medium, matrix material and binder obtained in step a) to form a suspension;

[0010] c) The suspension obtained in the high-speed shearing step b) is spray-dried to obtain the microsphere catalyst;

[0011] d) Calcining the microsphere catalyst obtained in step c) yields the catalyst.

[0012] According to one aspect of the present invention, the treatment method in step a) involves mixing and stirring a molecular sieve of silica-alumina phosphate and an alcohol solution containing titanate in a certain weight ratio, followed by treatment. The weight ratio of the molecular sieve to the alcohol solution containing titanate is 10–40:100, preferably 10–30:100; the treatment temperature is 30–90°C, preferably 50–90°C; and the treatment time is 30–90 minutes, preferably 30–50 minutes.

[0013] According to one aspect of the present invention, after the treatment in step a), conventional filtration and washing operations are performed before drying. The drying conditions are: temperature of 80–130°C and time of 0.5–12 h.

[0014] According to one aspect of the present invention, the silica-alumina molecular sieve in step a) is washed with water and then subjected to solid-liquid separation before being treated with an alcohol solution containing titanate, and the resulting solid is not dried.

[0015] According to one aspect of the invention, deionized water is added to an alcohol solution containing titanate, wherein the weight ratio of titanate, alcohol and water satisfies the following conditions: titanate: alcohol = 1 to 4: 100, and deionized water: alcohol = 1 to 5: 100.

[0016] According to one aspect of the invention, the titanate is selected from at least one of tetrabutyl titanate and tetraisopropyl titanate, preferably tetrabutyl titanate (purity ≥ 98 wt%).

[0017] According to one aspect of the invention, the alcohol is selected from at least one of ethanol and isopropanol, preferably ethanol.

[0018] According to one aspect of the present invention, the silica-alumina molecular sieve is selected from at least one of SPAO-34 and SPAO-18, preferably SAPO-34 molecular sieve; the Si / Al molar ratio of the SAPO-34 molecular sieve is 0.05 to 0.5:1, and the Si / Al molar ratio of the SPAO-18 molecular sieve is 0.1 to 0.3.

[0019] According to one aspect of the invention, in step b) the suspension, by weight percentage: molecular sieve is preferably 5-40% by weight; binder is preferably 1-20% by weight; matrix material is preferably 5-50% by weight; and liquid medium is preferably 10-89% by weight.

[0020] According to one aspect of the invention, in step b) the suspension, by weight percentage: molecular sieve more preferably 10-30% by weight; binder more preferably 1-10% by weight; matrix material more preferably 10-40% by weight; liquid medium more preferably 15-79% by weight.

[0021] According to one aspect of the present invention, the solid mass content of the suspension in step b) is preferably 20-50%, and the pH value is preferably 2.5-5.5.

[0022] According to one aspect of the invention, in step b), the binder is a sol, the matrix material is clay and / or hydrotalcite, and the liquid medium is deionized water.

[0023] According to one aspect of the invention, in step b), the binder is preferably silica sol or alumina sol; the matrix material is clay and / or hydrotalcite, preferably selected from at least one of kaolin, bentonite and hydrotalcite, and more preferably kaolin.

[0024] According to one aspect of the invention, in step c), the particle size of 90% of the particles in the mixture that are rapidly sheared to the point of origin is preferably less than 5 micrometers.

[0025] According to one aspect of the present invention, the spray drying conditions in step c) are: inlet temperature of 180-300°C, outlet temperature of 100-160°C, and centrifugal speed of 5000-15000 rpm.

[0026] According to one aspect of the present invention, in step d), the calcination temperature is 500-900°C, preferably 550-750°C, the calcination time is 0.5-24 hours, preferably 4-12 hours, and the calcination atmosphere is a flowing atmosphere, preferably flowing air, with the flow driving force coming from a vacuum.

[0027] According to one aspect of the present invention, the catalyst prepared by spray drying, after being calcined at high temperature, has an attrition index of less than 1.00 wt% / h, preferably less than 0.50 wt% / h, more preferably less than 0.30 wt% / h, and even more preferably 0.20 to 0.25 wt% / h.

[0028] According to one aspect of the invention, the catalyst obtained in step d) has an average particle size of 70-130 micrometers, preferably 80-110 micrometers.

[0029] According to one aspect of the invention, in the catalyst obtained in step d), the content of TiO2, calculated as Ti, is 0.500%-1.500% based on the weight of the catalyst.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The silica-alumina molecular sieve fluidized bed catalyst of the present invention exhibits high catalytic performance and a low attrition index. When applied to the methanol-to-olefins (MTO) reaction, it demonstrates high selectivity for low-carbon olefins and a low attrition index. While ensuring the catalytic performance of the MTO fluidized bed catalyst, it does not significantly increase the catalyst production cost, thus obtaining a fluidized bed catalyst with high attrition resistance.

[0032] 2. Existing hydrothermal synthesis methods produce silica-alumina phosphate molecular sieves with grain sizes of only a few hundred nanometers. During the drying process of the molecular sieve powder, these high-surface-energy grains are prone to agglomeration. The agglomerated molecular sieve grains, within the spray-formed catalyst microspheres, cause localized stress differences due to uneven distribution between the molecular sieve and the matrix material, leading to a decrease in the catalyst's wear resistance. In this invention, the surface of the silica-alumina phosphate molecular sieve is modified with tetrabutyl titanate before drying. The modified molecular sieve is less prone to agglomeration, resulting in a more uniform slurry during the catalyst spray drying process, thus producing a silica-alumina phosphate fluidized bed catalyst with a low wear index. Furthermore, the TiO2 generated after calcination of the titanate on the molecular sieve grain surface reduces intergranular micro-stress and improves grain boundary bonding strength, which is also one of the reasons why the catalyst prepared in this invention has higher wear resistance. Attached Figure Description

[0033] Figure 1 The XRD pattern of the SAPO-34 molecular sieve obtained in Example 5;

[0034] Figure 2 The XRD pattern of the SAPO-18 molecular sieve obtained in Example 9;

[0035] Figure 3 This is a SEM image of the fluidized bed catalyst of silica-alumina molecular sieve obtained in Example 1. Detailed Implementation

[0036] The wear index described in this invention was determined on a VINCI D5757-11 fluidized bed wear tester, using the method described in Chapter 7 of Q / SH 361.552-2017.

[0037] In this invention, the wear index ω is expressed as a mass fraction per hour (% / h) and is calculated according to the following formula:

[0038]

[0039] In the formula:

[0040] m5 — The mass of the powder collection system after 5 hours, expressed in grams (g);

[0041] m1 — The mass of the powder collection system after 1 hour, in grams (g);

[0042] m — the numerical value of the sample mass, in grams (g);

[0043] m0 — The mass of the powder collection system before the test, in grams (g);

[0044] 4 — The unit is h.

[0045] The arithmetic mean of the two measurements was taken as the analytical result, and rounded according to GB / T 8170 to an accuracy of 0.01% / h.

[0046] The average particle size of the catalyst described in this invention was determined by a laser particle size analyzer (model: Malvern 2000).

[0047] The morphology of the catalyst described in this invention was determined using a Philips XL300 scanning electron microscope.

[0048] The Ti content in the catalyst described in this invention was tested using ICP. Instrument parameters: Varian 725ES; Test method: Standard curve method. Test conditions are shown in Table 1.

[0049] Table 1

[0050] name Technical parameters name Technical parameters Plasma power 1100W Injection time 45s Ar plasma <![CDATA[15L min -1 ]]> Reading time 5s Auxiliary gas (Ar) <![CDATA[1.5L min -1 ]]> Sample injection pump speed 15rpm Atomizer flow rate <![CDATA[0.75L min -1 ]]> Observation mode radial observation height 10mm Ti wavelength measurement 336.122nm

[0051] The present invention does not have any particular limitation on the high-speed shearing, and it can be carried out in accordance with conventional technical means in the field, which will not be elaborated here.

[0052] The present invention will be described in detail below through embodiments.

[0053] The reagents used in the following examples are commercially available and of analytical grade.

[0054]

Preparation Example 1

[0055] This preparation example illustrates the preparation of the tetrabutyl titanate ethanol solution described in this invention:

[0056] Weigh out 100 parts of ethanol solution and 4 parts of tetrabutyl titanate by weight. Add the tetrabutyl titanate dropwise to the ethanol solution while stirring. Weigh out 5 parts of deionized water and add it to the above solution. Continue stirring until homogeneous.

[0057]

Preparation Example 2

[0058] This preparation example illustrates the preparation of the tetrabutyl titanate ethanol solution described in this invention:

[0059] Weigh 100 parts of ethanol solution and 1 part of tetrabutyl titanate by weight. Add the tetrabutyl titanate dropwise to the ethanol solution while stirring. Weigh 2 parts of deionized water and add them to the above solution. Continue stirring until homogeneous.

[0060]

Preparation Example 3

[0061] This preparation example illustrates the preparation of the tetrabutyl titanate ethanol solution described in this invention:

[0062] Weigh 100 parts of ethanol solution and 2 parts of tetrabutyl titanate by weight. Add the tetrabutyl titanate dropwise to the ethanol solution while stirring. Weigh 3 parts of deionized water and add them to the above solution. Continue stirring until homogeneous.

[0063]

Preparation Example 4

[0064] This preparation example illustrates the preparation of the isopropyl titanate isopropanol solution described in this invention:

[0065] Weigh 100 parts of ethanol solution and 2 parts of isopropyl titanate by weight. Add isopropyl titanate dropwise to the isopropanol solution while stirring. Weigh 3 parts of deionized water and add it to the above solution. Continue stirring until homogeneous.

[0066]

Preparation Example 5

[0067] This preparation example illustrates the preparation of the SAPO-34 molecular sieve described in this invention:

[0068] Weigh out 12.0 parts γ-Al2O3 and 35.0 parts deionized water and mix them evenly to form solution a; mix 23.1 parts phosphoric acid (85% by weight) and 37.5 parts deionized water evenly to form solution b; after mixing a and b, stir at room temperature for 2 hours to form a homogeneous solution c; while stirring, add 20.2 parts triethylamine, 15 parts tetraethylammonium hydroxide (TEAOH), 4.5 parts silica sol (40% by weight) and 10.0 parts deionized water to c in sequence, and stir thoroughly to obtain mixture A.

[0069] Mixture A was placed in a crystallization vessel and heated to 200°C with stirring. After crystallization for 24 hours, the solid product was recovered by solid-liquid separation. The solid product was washed three times with deionized water and then dried. XRD characterization showed that the obtained product was pure phase SAPO-34 (Si / Al molar ratio of 0.15).

[0070]

Preparation Example 6

[0071] This preparation example illustrates the preparation of the silica-alumina molecular sieve fluidized bed catalyst of the present invention:

[0072] The raw materials were weighed according to the following ratio: 16% (by weight) SAPO-34 molecular sieve; 20% (by weight) kaolin; 4% (by weight) alumina sol; and 60% (by weight) deionized water. Except for water, all raw material ratios are dry weight ratios. First, the SAPO-34 molecular sieve and a certain amount of water were mixed and stirred for 1 hour, then subjected to high-speed shearing for 15 minutes. Alumina sol was added, and the mixture was rapidly stirred for 15 minutes, followed by high-speed shearing for 15 minutes. Kaolin was added, and the mixture was stirred for 30 minutes, then subjected to high-speed shearing for 45 minutes to obtain a suspension (solid content 38%, pH 4.2). 90% of the particles in this suspension were found to be smaller than 3.9 micrometers. The suspension was spray-dried (inlet temperature 290℃, outlet temperature 140℃, centrifugation speed 10000 rpm), and then calcined in air at 600℃ for 6 hours to obtain the fluidized bed catalyst of aluminosilicate phosphate molecular sieve.

[0073]

Example 1

[0074] The SAPO-34 molecular sieve prepared by hydrothermal synthesis in Preparation Example 5 was separated into solid and liquid phases. The obtained solid product was washed three times with deionized water and then added to the tetrabutyl titanate ethanol solution obtained in Preparation Example 1 at a weight ratio of 20:100 without drying. The mixture was stirred at 60°C for 30 minutes, filtered to remove the solution, and the obtained solid was washed once with ethanol solution to remove free tetrabutyl titanate. The solid was dried at 110°C for 6 hours to obtain the titanate-modified SAPO-34 molecular sieve.

[0075] The SAPO-34 molecular sieve was weighed with kaolin, alumina sol and deionized water in a weight ratio of 16:20:4:60, and mixed, spray-dried and calcined according to the method described in Preparation Example 6 to obtain a fluidized bed catalyst of silica-alumina molecular sieve.

[0076] The average particle size and TiO2 content of the catalyst obtained in Example 1 are shown in Table 2.

[0077]

Example 2

[0078] The SAPO-34 molecular sieve prepared by hydrothermal synthesis in Preparation Example 5 was separated into solid and liquid phases. The obtained solid product was washed three times with deionized water and then added to the tetrabutyl titanate ethanol solution obtained in Preparation Example 1 at a weight ratio of 20:100 without drying. The mixture was stirred at 30°C for 30 minutes, filtered to remove the solution, and the obtained solid was washed once with ethanol solution to remove free tetrabutyl titanate. The solid was dried at 110°C for 6 hours to obtain the titanate-modified SAPO-34 molecular sieve.

[0079] The SAPO-34 molecular sieve was weighed with kaolin, alumina sol and deionized water in a weight ratio of 16:20:4:60, and mixed, spray-dried and calcined according to the method described in Preparation Example 6 to obtain a fluidized bed catalyst of silica-alumina molecular sieve.

[0080] The average particle size and TiO2 content of the catalyst obtained in Example 2 are shown in Table 2.

[0081]

Example 3

[0082] The SAPO-34 molecular sieve prepared by hydrothermal synthesis in Preparation Example 5 was separated into solid and liquid phases. The obtained solid product was washed three times with deionized water and then added to the tetrabutyl titanate ethanol solution obtained in Preparation Example 1 at a weight ratio of 20:100 without drying. The mixture was stirred at 90°C for 30 minutes, filtered to remove the solution, and the obtained solid was washed once with ethanol solution to remove free tetrabutyl titanate. The solid was dried at 110°C for 6 hours to obtain the titanate-modified SAPO-34 molecular sieve.

[0083] The SAPO-34 molecular sieve was weighed with kaolin, alumina sol and deionized water in a weight ratio of 16:20:4:60, and mixed, spray-dried and calcined according to the method described in Preparation Example 6 to obtain a fluidized bed catalyst of silica-alumina molecular sieve.

[0084] The average particle size and TiO2 content of the catalyst obtained in Example 3 are shown in Table 2.

[0085]

Example 4

[0086] The SAPO-34 molecular sieve prepared by hydrothermal synthesis in Preparation Example 5 was separated into solid and liquid phases. The obtained solid product was washed three times with deionized water and then added to the tetrabutyl titanate ethanol solution obtained in Preparation Example 1 at a weight ratio of 40:100 without drying. The mixture was stirred at 90°C for 30 minutes, filtered to remove the solution, and the obtained solid was washed once with ethanol solution to remove free tetrabutyl titanate. The solid was dried at 110°C for 8 hours to obtain the titanate-modified SAPO-34 molecular sieve.

[0087] The SAPO-34 molecular sieve was weighed with kaolin, alumina sol and deionized water in a weight ratio of 16:20:4:60, and mixed, spray-dried and calcined according to the method described in Preparation Example 6 to obtain a fluidized bed catalyst of silica-alumina molecular sieve.

[0088] The average particle size and TiO2 content of the catalyst obtained in Example 4 are shown in Table 2.

[0089]

Example 5

[0090] The SAPO-34 molecular sieve prepared by hydrothermal synthesis in Preparation Example 5 was separated into solid and liquid phases. The obtained solid product was washed three times with deionized water and then added to the tetrabutyl titanate ethanol solution obtained in Preparation Example 2 at a weight ratio of 15:100 without drying. The mixture was stirred at 90°C for 60 minutes, filtered to remove the solution, and the obtained solid was washed once with ethanol solution to remove free tetrabutyl titanate. The solid was dried at 110°C for 8 hours to obtain the titanate-modified SAPO-34 molecular sieve.

[0091] The SAPO-34 molecular sieve was weighed with kaolin, alumina sol and deionized water in a weight ratio of 16:20:4:60, and mixed, spray-dried and calcined according to the method described in Preparation Example 6 to obtain a fluidized bed catalyst of silica-alumina molecular sieve.

[0092] The average particle size and TiO2 content of the catalyst obtained in Example 5 are shown in Table 2.

[0093]

Example 6

[0094] The SAPO-34 molecular sieve prepared by hydrothermal synthesis in Preparation Example 5 was separated into solid and liquid phases. The obtained solid product was washed three times with deionized water and then added to the tetrabutyl titanate ethanol solution obtained in Preparation Example 2 at a weight ratio of 10:100 without drying. The mixture was stirred at 60°C for 45 minutes, filtered to remove the solution, and the obtained solid was washed once with ethanol solution to remove free tetrabutyl titanate. The solid was dried at 110°C for 8 hours to obtain the titanate-modified SAPO-34 molecular sieve.

[0095] The SAPO-34 molecular sieve was weighed with kaolin, alumina sol and deionized water in a weight ratio of 16:20:4:60, and mixed, spray-dried and calcined according to the method described in Preparation Example 6 to obtain a fluidized bed catalyst of silica-alumina molecular sieve.

[0096] The average particle size and TiO2 content of the catalyst obtained in Example 6 are shown in Table 2.

[0097]

Example 7

[0098] The SAPO-34 molecular sieve prepared by hydrothermal synthesis in Preparation Example 5 was separated into solid and liquid phases. The obtained solid product was washed three times with deionized water and then added to the tetrabutyl titanate ethanol solution obtained in Preparation Example 3 at a weight ratio of 30:100 without drying. The mixture was stirred at 70°C for 45 minutes, filtered to remove the solution, and the obtained solid was washed once with ethanol solution to remove free tetrabutyl titanate. The solid was dried at 110°C for 6 hours to obtain the titanate-modified SAPO-34 molecular sieve.

[0099] The SAPO-34 molecular sieve was weighed with kaolin, alumina sol and deionized water in a weight ratio of 16:20:4:60, and mixed, spray-dried and calcined according to the method described in Preparation Example 6 to obtain a fluidized bed catalyst of silica-alumina molecular sieve.

[0100] The average particle size and TiO2 content of the catalyst obtained in Example 7 are shown in Table 2.

[0101]

Example 8

[0102] The only difference from Example 1 is that the tetrabutyl titanate ethanol solution of Preparation Example 1 is replaced with the tetraisopropyl titanate isopropanol solution of Preparation Example 4.

[0103] The average particle size and TiO2 content of the catalyst obtained in Example 8 are shown in Table 2.

[0104]

Example 9

[0105] The only difference from Example 1 is that SAPO-34 molecular sieve is replaced with SAPO-18 molecular sieve (Si / Al molar ratio of 0.15).

[0106] The average particle size and TiO2 content of the catalyst obtained in Example 9 are shown in Table 2.

[0107] Comparative Example 1

[0108] Using the SAPO-34 molecular sieve from Preparation Example 5, the raw materials were weighed according to the following ratio: 16% (by weight) SAPO-34 molecular sieve; 20% (by weight) kaolin; 4% (by weight) alumina sol; and 60% (by weight) deionized water. Except for water, all raw material ratios here are dry weight ratios. First, the SAPO-34 molecular sieve and a certain amount of water were mixed and stirred for 1 hour, then subjected to high-speed shearing for 15 minutes. Alumina sol was added, and the mixture was rapidly stirred for 15 minutes, followed by high-speed shearing for 15 minutes. Kaolin was added, and the mixture was stirred for 30 minutes, then subjected to high-speed shearing for 45 minutes to obtain a suspension (solid content 38%, pH 4.2). The particle size in this suspension was determined to be less than 3.9 micrometers. The suspension was spray-dried (same as in Example 1), and then calcined in air at 600°C for 6 hours to obtain a fluidized bed catalyst of aluminosilicate phosphate molecular sieve.

[0109] The average particle size and TiO2 content of the catalyst obtained in Comparative Example 1 are shown in Table 2.

[0110] Comparative Example 2

[0111] The only difference from Comparative Example 1 is that the total dry weight of the spray slurry in Comparative Example 1 is considered as 100 parts, and an additional 6 parts by weight of tetrabutyl titanate is added. The re-prepared slurry is spray-dried and calcined to obtain a fluidized bed catalyst of aluminosilicate phosphate molecular sieve.

[0112] The average particle size and TiO2 content of the catalyst obtained in Comparative Example 2 are shown in Table 2.

[0113]

Test Example 1

[0114] The fluidized bed catalysts obtained in Examples 1-9 and Comparative Examples 1-2 were subjected to wear index determination on a D5757-11 fluidized bed wear tester, and the results are shown in Table 3.

[0115]

Test Example 2

[0116] The phosphate silica-alumina molecular sieve catalysts obtained in Examples 1-9 and Comparative Examples 1-2 were subjected to methanol-to-olefins reaction in a small fixed fluidized bed. The reaction conditions were: 40 g catalyst, pure methanol feed, and WHSV of 4 h⁻¹. -1 The reaction temperature was 480℃, and the reaction pressure was atmospheric pressure. The reaction results are shown in Table 3.

[0117] Table 2

[0118]

[0119]

[0120] Table 3

[0121]

[0122] The specific embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing a fluidized bed catalyst using silica-alumina molecular sieves, comprising: a) The silica-alumina molecular sieve was treated in an alcohol solution containing titanate and dried to obtain the modified molecular sieve; b) Mix the modified molecular sieve, liquid medium, matrix material and binder obtained in step a) to form a suspension; c) The suspension obtained in the high-speed shearing step b) is spray-dried to obtain the microsphere catalyst; d) Calcining the microsphere catalyst obtained in step c) yields the catalyst; Before being treated with an alcohol solution containing titanate, the silica-alumina molecular sieve prepared in step a) is washed with water and then separated into solid and liquid phases, and the resulting solid is not dried.

2. The preparation method according to claim 1, characterized in that: The treatment method in step a) is to mix and stir the molecular sieve of silica-alumina phosphate and the alcohol solution containing titanate in a certain weight ratio, and then treat it. The weight ratio of molecular sieve to alcohol solution containing titanate is 10~40:100, the treatment temperature is 30~90℃, and the treatment time is 30~90 minutes.

3. The preparation method according to claim 2, characterized in that: In step a), the weight ratio of molecular sieve to alcohol solution containing titanate is 10~30:100, the treatment temperature is 50~90℃, and the treatment time is 30~50 minutes.

4. The preparation method according to claim 1, characterized in that: When deionized water is added to an alcohol solution containing titanate, the weight ratio of titanate, alcohol and water must satisfy the following conditions: titanate: alcohol = 1~4:100, deionized water: alcohol = 1~5:

100.

5. The preparation method according to claim 1, characterized in that: The titanate is selected from at least one of tetrabutyl titanate and tetraisopropyl titanate; the alcohol is selected from at least one of ethanol and isopropanol; the silica-alumina phosphate molecular sieve is selected from at least one of SAPO-34 and SAPO-18; the Si / Al molar ratio of the SAPO-34 molecular sieve is 0.05~0.5:1, and the Si / Al molar ratio of the SAPO-18 molecular sieve is 0.1~0.

3.

6. The preparation method according to claim 5, characterized in that: The titanate is tetrabutyl titanate; the alcohol is ethanol; and the silica-alumina molecular sieve is SAPO-34.

7. The preparation method according to claim 1, characterized in that: Step b) In the suspension, the weight ratio is calculated as follows: molecular sieve 5~40% by weight; binder 1~20% by weight; matrix material 5~50% by weight; liquid medium 10~90% by weight.

8. The preparation method according to claim 7, characterized in that: Step b) In the suspension, the weight ratio is calculated as follows: molecular sieve 10~30% by weight; binder 1~10% by weight; matrix material 10~40% by weight; liquid medium 15~80% by weight.

9. The preparation method according to claim 1, characterized in that: Step b) The solids content of the suspension is 20-50% and the pH value is 2.5-5.5; And / or, in step c), high-speed shearing is performed until 90% of the particles in the mixture have a size of less than 5 micrometers.

10. The preparation method according to claim 1, characterized in that: Step b) The binder is a sol; the matrix material is clay and / or hydrotalcite; the liquid medium is deionized water.

11. The preparation method according to claim 10, characterized in that: Step b) The binder is silica sol or alumina sol; the matrix material is selected from at least one of kaolin, bentonite and hydrotalcite.

12. The preparation method according to claim 11, characterized in that: Step b) The matrix material is kaolin.

13. The preparation method according to claim 1, characterized in that: In step d), the roasting temperature is 500~900℃, the roasting time is 0.5~24 hours, and the roasting atmosphere is flowing air.

14. The preparation method according to claim 13, characterized in that: In step d), the roasting temperature is 550~750℃ and the roasting time is 4-12 hours.

15. The preparation method according to claim 1, characterized in that: The catalyst prepared by spray drying has a wear index of less than 1.0 wt% / h after high-temperature calcination.

16. The preparation method according to claim 15, characterized in that: The catalyst prepared by spray drying has an attrition index of less than 0.50 wt% / h after high-temperature calcination.

17. The preparation method according to claim 16, characterized in that: The catalyst prepared by spray drying has an attrition index of less than 0.30 wt% / h after high-temperature calcination.

18. The preparation method according to claim 1, characterized in that: The catalyst obtained in step d) has an average particle size of 70-130 micrometers.

19. The preparation method according to claim 18, characterized in that: The catalyst obtained in step d) has an average particle size of 80-110 micrometers.

20. The preparation method according to claim 1, characterized in that: In the catalyst obtained in step d), the content of TiO2, calculated as Ti, is 0.500%-1.500% based on the weight of the catalyst.

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