Catalytic cracking prolific propylene catalyst as well as preparation method and application thereof

Abstract

The invention provides a catalytic cracking prolific propylene catalyst and a preparation method and application thereof, and the preparation method comprises the following steps: reacting a ZSM-5 molecular sieve with trichloroacetic acid and tetraethoxysilane in water to obtain a modified intermediate; mixing the modified intermediate with soluble salt of modified metal and melamine in a composite solvent, filtering, taking a solid sample, and roasting to obtain a metal modified molecular sieve; mixing the metal modified molecular sieve with a Y-type molecular sieve, clay and a binder in water to obtain slurry, carrying out spray drying molding on the slurry to obtain solid particles, and roasting again to obtain the catalytic cracking productive propylene catalyst. After the key component ZSM-5 molecular sieve in the catalyst is modified, the prolific propylene catalyst has higher mass transfer rate, metal is uniformly deposited on the molecular sieve, the metal utilization rate and the catalytic cracking reaction performance are improved, the propylene yield in a catalytic cracking product is improved, and the coke selectivity is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of oil refining catalysis, and in particular to a catalytic cracking catalyst for increasing propylene production, and a preparation method and application thereof. Background Art

[0002] Propylene is an important basic organic chemical raw material. With the continuous growth of propylene demand and the steady expansion of the downstream product market, propylene production has a vital position in the chemical industry. The main sources of propylene are naphtha steam cracking process and refinery fluid catalytic cracking process by-product propylene. Steam cracking has high energy consumption and propylene yield is limited by the composition of raw materials. The by-product propylene of the catalytic cracking process has the advantages of wide raw material sources, high operational flexibility and low production cost.

[0003] With the continuous growth of propylene demand and the steady expansion of downstream product markets, propylene production has played a vital role in the chemical industry. In recent years, the main sources of propylene are naphtha steam cracking process (SC) and refinery fluid catalytic cracking (FCC) process by-product propylene.

[0004] Among conventional catalytic cracking catalysts, ZSM-5 molecular sieve plays a major role in producing more propylene. Usually, in order to improve the performance of ZSM-5 molecular sieve, ZSM-5 molecular sieve is modified with metal. However, although the conventional ZSM-5 molecular sieve metal modification methods such as impregnation and exchange can improve the performance of ZSM-5 molecular sieve catalysts, there are low utilization rates of modified metals or uneven metal loading, which makes the subsequent high-yield propylene catalysts have high coking problems. Summary of the invention

[0005] In order to solve the above technical problems, the purpose of the present invention is to provide a catalytic cracking high-yield propylene catalyst and its preparation method and application, so as to improve the propylene production increasing effect of the high-yield propylene catalyst.

[0006] To achieve the above object, the present invention provides a method for preparing a catalytic cracking catalyst for producing more propylene, which comprises the following steps:

[0007] S1: reacting ZSM-5 molecular sieve with trichloroacetic acid and ethyl orthosilicate to obtain a modified intermediate; wherein the mass ratio of trichloroacetic acid: ZSM-5 molecular sieve is 0.8-3.5:1, and the mass ratio of ethyl orthosilicate: ZSM-5 molecular sieve is 0.2-0.6:1;

[0008] S2: mixing the modified intermediate, a soluble salt of a modified metal and melamine in a composite solvent, filtering and then taking a solid sample for roasting to obtain a metal-modified molecular sieve; wherein the weight ratio of melamine to ZSM-5 molecular sieve is 0.03-0.3:1;

[0009] S3: mixing the metal-modified molecular sieve with Y-type molecular sieve, clay and a binder in water to obtain a slurry, spray-drying the slurry to obtain solid particles, and calcining again to obtain a catalytic cracking catalyst for high-yield propylene.

[0010] Although existing metal modification of ZSM-5 molecular sieve in catalyst (such as impregnation method and exchange method) can improve the performance of ZSM-5 molecular sieve catalyst and adjust its acidity, there are still problems such as low metal utilization and uneven metal loading.

[0011] The preparation method provided by the present invention, when modifying the ZSM-5 molecular sieve, adds melamine to form a complex with the modified metal in the form of flocculent precipitation, and the modified metal in the form of a complex (flocculent precipitation) is more easily and evenly deposited on the ZSM-5 molecular sieve catalyst than in the ionic state (solution), and the modified metal in the flocculent precipitation state is not easy to lose in the subsequent exchange, filtration and other processes, thereby improving the metal utilization rate and the catalytic cracking (cracking) reaction performance of the high-yield propylene catalyst. In addition, the introduction of organic solvents such as ethylene glycol or acetic acid can also improve the dispersion of the ZSM-5 molecular sieve, so that it is fully in contact with the modified metal.

[0012] In addition, the present invention also uses trichloroacetic acid and ethyl orthosilicate to dealuminate and siliconize the ZSM-5 molecular sieve to make it mesoporous, thereby enhancing mass transfer during the reaction process and effectively slowing down carbon deposition of the propylene production catalyst during the catalytic cracking reaction.

[0013] According to a specific embodiment of the present invention, preferably, in S1, the ZSM-5 molecular sieve reacts with trichloroacetic acid and ethyl orthosilicate in water; the concentration of trichloroacetic acid in water is 0.2-1.8 mol / L.

[0014] According to a specific embodiment of the present invention, preferably, in S1, the reaction of ZSM-5 molecular sieve with trichloroacetic acid and ethyl orthosilicate is carried out step by step or simultaneously.

[0015] According to a specific embodiment of the present invention, preferably, in S1, the ZSM-5 molecular sieve is first reacted with trichloroacetic acid and then with ethyl orthosilicate.

[0016] According to a specific embodiment of the present invention, preferably, in S1, the reaction temperature of ZSM-5 molecular sieve and trichloroacetic acid is 70-90° C., and the reaction time is 10-30 min.

[0017] According to a specific embodiment of the present invention, preferably, in S1, the reaction temperature of ZSM-5 molecular sieve and tetraethyl orthosilicate is 60-80° C., and the reaction time is 20-60 min.

[0018] According to a specific embodiment of the present invention, preferably, based on the total mass of the modified intermediate, the modified intermediate contains 92-99.98% of the dry basis mass of ZSM-5 molecular sieve.

[0019] According to a specific embodiment of the present invention, preferably, the silicon-aluminum ratio of the ZSM-5 molecular sieve is 20-300.

[0020] According to a specific embodiment of the present invention, the weight ratio of melamine:ZSM-5 molecular sieve in S2 is 0.03-0.3:1, which means that the weight ratio of melamine:modified intermediate calculated on a dry basis of ZSM-5 molecular sieve is 0.03-0.3:1.

[0021] According to a specific embodiment of the present invention, preferably, in S2, the composite solvent is a mixture of an organic solvent and water, and the organic solvent is acetic acid and / or ethylene glycol.

[0022] According to a specific embodiment of the present invention, preferably, in S2, the mass ratio of organic solvent: water: melamine is 0.4-1:1-3:1.

[0023] According to a specific embodiment of the present invention, preferably, S2 contains 0.02-10% of modified metal in terms of metal oxide, based on the total weight of the metal-modified molecular sieve.

[0024] According to a specific embodiment of the present invention, preferably, in S2, the modified metal includes at least one of Fe, Cu, Ti, Zr, Mn and Zn.

[0025] According to a specific embodiment of the present invention, preferably, the calcination conditions in S2 are: calcination at 480-580° C. for 1-4 h.

[0026] According to a specific embodiment of the present invention, preferably, in S2, the solid sample is dried before calcination, and the drying conditions are: drying at 100-110° C. for 8-14 h.

[0027] According to a specific embodiment of the present invention, preferably, in S3, the mass ratio of metal-modified molecular sieve: Y-type molecular sieve: clay: binder is 5-15: 20-40: 30-50: 5-20.

[0028] According to a specific embodiment of the present invention, preferably, the clay includes at least one of kaolin, halloysite, montmorillonite and attapulgite.

[0029] According to a specific embodiment of the present invention, preferably, the binder includes silica sol and / or alumina sol, more preferably alumina sol.

[0030] According to a specific embodiment of the present invention, preferably, in S3, the particle size of the solid particles obtained by spray drying is 70-90 μm. The solid particles are microsphere catalysts with a particle size of 70-90 μm.

[0031] According to a specific embodiment of the present invention, preferably, in S3, the conditions for the re-calcination are: calcination at 400-550° C. for 20-50 min.

[0032] According to a specific embodiment of the present invention, preferably, the Y-type molecular sieve is a REY molecular sieve.

[0033] The present invention also provides a catalytic cracking catalyst for producing more propylene, which is obtained by the preparation method of the catalytic cracking catalyst for producing more propylene.

[0034] The present invention also provides an application of the catalytic cracking high-yield propylene catalyst in preparing propylene from catalytic cracking heavy catalyst feedstock.

[0035] The heavy catalyst raw material described in the present invention is an industrial catalytic cracking raw material oil, which is a catalytic cracking reaction raw material well known to those skilled in the art.

[0036] The technical solution provided by the present invention has the following beneficial effects:

[0037] The preparation method of the catalytic cracking catalyst for high propylene production provided by the present invention comprises the following steps: firstly, the key component ZSM-5 molecular sieve in the catalyst is subjected to dealumination and silicon supplementation treatment by using trichloroacetic acid and ethyl orthosilicate, so that the molecular sieve has higher mass transfer rate and stability; then, melamine is added to form a complex in the form of flocculent precipitation with the modified metal, so that the modified metal is more easily and evenly deposited on the ZSM-5 molecular sieve catalyst, and the loss of the modified metal with the filtrate in the subsequent exchange and filtration is greatly reduced, so that the metal utilization rate of the catalytic cracking catalyst for high propylene production is improved, the catalytic cracking reaction performance of the catalytic cracking catalyst for high propylene production is improved, and the propylene yield in the catalytic cracking product is further improved, the coke selectivity is reduced, and the catalyst is prevented from being deactivated due to coking. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a nitrogen adsorption-desorption curve of the metal-modified ZSM-5 molecular sieve d of Example 1. DETAILED DESCRIPTION

[0039] 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.

[0040] Sources of raw materials or equipment used in the examples and comparative examples of the present invention:

[0041] Industrial ZSM-5 molecular sieve (ignition loss 8.9%), REY molecular sieve (ignition loss 20.85 / weight%), collected from Lanzhou Petrochemical Catalyst Plant;

[0042] Melamine, acetic acid, ethylene glycol, trichloroacetic acid, ethyl orthosilicate, ferric chloride hexahydrate, cupric chloride dihydrate, titanium sulfate, zirconium chloride, manganese chloride tetrahydrate, and zinc chloride were all analytically pure and were obtained from Sinopharm Chemical Reagent Co., Ltd.;

[0043] Kaolin, China Kaolin Company, kaolinite content 86 / wt%, ignition loss 28.4 / wt%, particle size D(V,0.5), um=2.131;

[0044] Alumina sol, alumina content 18.90% by weight.

[0045] Example 1

[0046] This embodiment provides a catalytic cracking catalyst for producing more propylene, and the preparation method thereof is as follows:

[0047] (1) 1.5 g of melamine, 0.58 g of ethylene glycol and 30 g of deionized water were stirred at 25° C. for 10 min to obtain a solution a;

[0048] (2) 16 g of ZSM-5 molecular sieve with a silicon-aluminum ratio of 35 and 13 g of trichloroacetic acid were added to 60 g of deionized water, stirred at 80° C. for 20 min, then 3.2 g of ethyl orthosilicate was added and stirred for 40 min, and then filtered and washed until neutral to obtain sample b;

[0049] (3) Add sample b to slurry a, mix, and stir for 20 min to obtain slurry c;

[0050] (4) Weighing 2.17 g of ferric chloride hexahydrate, adding it to the slurry c, stirring for 30 min, filtering, drying at 100 ° C. for 14 h, and then calcining at 550 ° C. for 2 h to obtain a metal-modified ZSM-5 molecular sieve d;

[0051] (5) The metal-modified molecular sieve d was mixed with 90 g of deionized water, 84 g of kaolin, 66 g of REY molecular sieve, and 119 g of aluminum sol and stirred for 30 min to obtain a slurry e;

[0052] (6) The e slurry is spray-dried to obtain microsphere solids, and the obtained microsphere solids are calcined at 450° C. for 30 min to obtain catalytic cracking catalyst Cat-1 for high propylene production.

[0053] The nitrogen adsorption and desorption curve of the metal-modified ZSM-5 molecular sieve d in this example is as follows: Figure 1 As shown. Figure 1It can be seen that the metal-modified ZSM-5 molecular sieve of the present invention has a mesoporous structure. It can be seen that the dealumination and siliconization treatment process of the present invention enables the ZSM-5 molecular sieve to have a mesoporous structure, thereby promoting the mass transfer efficiency of the catalytic cracking catalyst for producing more propylene and reducing coke generation.

[0054] Example 2

[0055] This embodiment provides a catalytic cracking catalyst for producing more propylene, and the preparation method thereof is as follows:

[0056] (1) 3.84 g of melamine, 2.72 g of ethylene glycol and 30 g of deionized water were stirred at 25° C. for 10 min to obtain a solution a;

[0057] (2) 16 g of ZSM-5 molecular sieve with a silicon-aluminum ratio of 100 and 40 g of trichloroacetic acid were added to 60 g of deionized water, stirred at 80° C. for 20 min, then 10 g of ethyl orthosilicate was added and stirred for 40 min, and then filtered and washed until neutral to obtain sample b;

[0058] (3) Add sample b to slurry a, mix, and stir for 20 min to obtain slurry c;

[0059] (4) Weighing 1.58 g of copper chloride dihydrate, adding it to slurry c, stirring for 30 min, filtering, drying at 105° C. for 10 h, and then calcining at 480° C. for 4 h to obtain metal-modified ZSM-5 molecular sieve d;

[0060] (5) The metal-modified molecular sieve d was mixed with 60 g of deionized water, 63 g of kaolin, 76 g of USY molecular sieve, and 159 g of aluminum sol and stirred for 20 min to obtain a slurry e;

[0061] (6) The slurry e is spray-dried to obtain microsphere solids, and the obtained microsphere solids are calcined at 400° C. for 50 min to obtain catalytic cracking catalyst Cat-2 for high propylene production.

[0062] Example 3

[0063] This embodiment provides a catalytic cracking catalyst for producing more propylene, and the preparation method thereof is as follows:

[0064] (1) 0.6 g of melamine, 0.5 g of ethylene glycol and 30 g of deionized water were stirred at 25° C. for 10 min to obtain a solution a;

[0065] (2) 25 g of ZSM-5 molecular sieve with a silicon-aluminum ratio of 100 and 40 g of trichloroacetic acid were added to 60 g of deionized water, stirred at 80° C. for 20 min, then 10 g of ethyl orthosilicate was added and stirred for 40 min, and then filtered and washed until neutral to obtain sample b;

[0066] (3) Add sample b to slurry a, mix, and stir for 20 min to obtain slurry c;

[0067] (4) Weighing 0.02 g of titanium sulfate, adding it to the slurry c, stirring for 30 min, filtering, drying at 110 ° C. for 8 h, and then calcining at 580 ° C. for 1 h to obtain a metal-modified ZSM-5 molecular sieve d;

[0068] (5) The metal-modified molecular sieve d was mixed with 90 g of deionized water, 105 g of kaolin, 38 g of REHY molecular sieve, and 119 g of aluminum sol and stirred for 10 min to obtain a slurry e;

[0069] (6) The slurry e is spray-dried to obtain microsphere solids, and the obtained microsphere solids are calcined at 550° C. for 20 min to obtain catalytic cracking catalyst Cat-3 for high propylene production.

[0070] Example 4

[0071] This embodiment provides a catalytic cracking catalyst for producing more propylene, and the preparation method thereof is as follows:

[0072] (1) 1.2 g of melamine, 0.96 g of ethylene glycol and 30 g of deionized water were stirred at 25° C. for 10 min to obtain a solution a;

[0073] (2) 7.5 g of ZSM-5 molecular sieve with a silicon-aluminum ratio of 300 and 60 g of trichloroacetic acid were added to 60 g of deionized water, stirred at 80° C. for 20 min, then 6 g of ethyl orthosilicate was added and stirred for 40 min, and then filtered and washed until neutral to obtain sample b;

[0074] (3) Add sample b to slurry a, mix, and stir for 20 min to obtain slurry c;

[0075] (4) Weighing 0.38 g of zirconium chloride, adding it to the slurry c, stirring for 30 min, filtering, drying at 100 ° C. for 12 h, and then calcining at 550 ° C. for 3 h to obtain a metal-modified ZSM-5 molecular sieve d;

[0076] (5) The metal-modified molecular sieve d was mixed with 90 g of deionized water, 84 g of kaolin, 76 g of REY molecular sieve, and 119 g of aluminum sol and stirred for 30 min to obtain a slurry e;

[0077] (6) The slurry e is spray-dried to obtain microsphere solids, and the obtained microsphere solids are calcined at 450° C. for 40 min to obtain catalytic cracking catalyst Cat-4 for high propylene production.

[0078] Example 5

[0079] This embodiment provides a catalytic cracking catalyst for producing more propylene, and the preparation method thereof is as follows:

[0080] (1) 2.63 g of melamine, 0.60 g of ethylene glycol and 30 g of deionized water were stirred at 25° C. for 10 min to obtain a solution a;

[0081] (2) 13 g of ZSM-5 molecular sieve with a silicon-aluminum ratio of 35 and 31 g of trichloroacetic acid were added to 60 g of deionized water, stirred at 80° C. for 20 min, then 6.3 g of ethyl orthosilicate was added and stirred for 40 min, and then filtered and washed until neutral to obtain sample b;

[0082] (3) Add sample b to slurry a, mix, and stir for 20 min to obtain slurry c;

[0083] (4) 3.02 g of manganese chloride tetrahydrate was weighed and added to the slurry c, stirred for 30 min, filtered, dried at 100 ° C. for 12 h, and then calcined at 550 ° C. for 3 h to obtain a metal-modified ZSM-5 molecular sieve d;

[0084] (5) The metal-modified molecular sieve d was mixed with 120 g of deionized water, 84 g of kaolin, 80 g of REY molecular sieve, and 79 g of aluminum sol and stirred for 30 min to obtain a slurry e;

[0085] (6) The slurry e is spray-dried to obtain microsphere solids, and the obtained microsphere solids are calcined at 470° C. for 25 min to obtain catalytic cracking catalyst Cat-5 for high propylene production.

[0086] Example 6

[0087] This embodiment provides a catalytic cracking catalyst for producing more propylene, and the preparation method thereof is as follows:

[0088] (1) 5.8 g of melamine, 5.8 g of acetic acid and 30 g of deionized water were stirred at 25° C. for 10 min to obtain a solution a;

[0089] (2) 20 g of ZSM-5 molecular sieve with a silicon-aluminum ratio of 35 and 53 g of trichloroacetic acid were added to 60 g of deionized water, stirred at 80° C. for 20 min, then 11 g of ethyl orthosilicate was added and stirred for 40 min, and then filtered and washed until neutral to obtain sample b;

[0090] (3) Add sample b to slurry a, mix, and stir for 20 min to obtain slurry c;

[0091] (4) 3.77 g of zinc chloride was weighed and added to the slurry c, stirred for 30 min, filtered, dried at 100 °C for 12 h, and then calcined at 550 °C for 4 h to obtain a metal-modified ZSM-5 molecular sieve d;

[0092] (5) The metal-modified molecular sieve d was mixed with 100 g of deionized water, 94 g of kaolin, 57 g of REY molecular sieve, and 103 g of aluminum sol and stirred for 30 min to obtain a slurry e;

[0093] (6) The slurry e is spray-dried to obtain microsphere solids, and the obtained microsphere solids are calcined at 450° C. for 30 min to obtain catalytic cracking catalyst Cat-6 for high propylene production.

[0094] Comparative Example 1

[0095] This comparative example provides a catalytic cracking catalyst for producing more propylene, and its preparation method is as follows:

[0096] (1) 20 g of ZSM-5 molecular sieve with a silicon-aluminum ratio of 35 and 100 g of deionized water were stirred at 25° C. for 10 min to obtain a solution a;

[0097] (2) adding 2.89 g of ferric chloride hexahydrate into solution a and stirring for 30 min to obtain solution b;

[0098] (3) Filtering solution b, drying at 100° C. for 12 h, and then calcining at 550° C. for 4 h, to obtain ZSM-5 molecular sieve catalyst powder c modified by metal Fe exchange;

[0099] (4) The modified ZSM-5 molecular sieve powder c was mixed with 100 g of deionized water, 84 g of kaolin, 66 g of REY molecular sieve, and 119 g of aluminum sol and stirred for 30 min to obtain a slurry d;

[0100] (5) The slurry d is spray-dried to obtain microsphere solids, and the obtained microsphere solids are calcined at 450° C. for 30 min to obtain a catalytic cracking catalyst D1 for high propylene production.

[0101] Comparative Example 2

[0102] This comparative example provides a catalytic cracking catalyst for producing more propylene, and its preparation method is as follows:

[0103] 25g of ZSM-5 molecular sieve with a silicon-aluminum ratio of 100, 1.25g of titanium sulfate and 100g of deionized water were mixed evenly at 25°C, and metal Ti was impregnated and modified, and then dried at 100°C for 12h, and then calcined at 550°C for 4h to obtain ZSM-5 molecular sieve catalyst powder modified by metal Ti impregnation;

[0104] The modified ZSM-5 molecular sieve powder was mixed with 100g of deionized water, 105g of kaolin, 38g of USY molecular sieve and 119g of aluminum sol for 30 minutes to obtain slurry d. The slurry d was spray-dried to obtain microsphere solids. The obtained microsphere solids were calcined at 500°C for 30 minutes to obtain catalytic cracking high-yield propylene catalyst D2.

[0105] Comparative Example 3

[0106] This comparative example provides a catalytic cracking catalyst for producing more propylene, and its preparation method is as follows:

[0107] 8g ZSM-5 with a silicon-aluminum ratio of 30 and 0.41g ZrO 2 The particles were fully mixed, 20 g of deionized water was slowly added and fully stirred, the solid-liquid mixture was transferred to a high-temperature reactor, the reactor was taken out after reacting at 240° C. for 6 h, the reaction pressure was normal pressure, and the mixture was cooled to room temperature in air, the reactor was opened and dried at 140° C. for 10 h, and the metal Zr modified ZSM-5 molecular sieve catalyst powder prepared by the hydrothermal method was obtained;

[0108] The modified ZSM-5 molecular sieve powder was mixed with 100g of deionized water, 84g of kaolin, 76g of USY molecular sieve and 119g of aluminum sol for 30 minutes to obtain slurry d. The slurry d was spray-dried to obtain microsphere solids. The obtained microsphere solids were calcined at 470°C for 30 minutes to obtain catalytic cracking high-yield propylene catalyst D3.

[0109] Comparative Example 4 (blank control)

[0110] 20 g of ZSM-5 molecular sieve with a silicon-aluminum ratio of 35 was mixed with 200 g of deionized water, 94 g of kaolin, 57 g of REY molecular sieve, and 103 g of aluminum sol and stirred for 30 min to obtain a slurry;

[0111] The slurry is spray-dried to obtain microsphere solids, and the obtained microsphere solids are calcined at 450° C. for 30 minutes to obtain catalytic cracking catalyst D4 for high propylene production.

[0112] Experimental example

[0113] This experimental example is used to evaluate the performance of the catalytic cracking catalyst for producing more propylene in the above-mentioned embodiments and comparative examples.

[0114] Evaluation and analysis methods:

[0115] The catalytic cracking catalysts used for evaluation are required to be aged for 17 hours at 800°C and 100% steam. The catalytic cracking evaluation conditions of the Advanced Catalytic Cracking Evaluation Unit (ACE) are to place the pretreated catalyst sample in the ACE experimental reactor, the catalytic reaction temperature is 530°C, the catalyst dosage is 9g, the reaction raw material is 3 million tons / year of heavy catalyst raw material of Lanzhou Petrochemical Company, and the catalyst-to-oil ratio is 5.0.

[0116] The catalytic cracking performance evaluation was carried out on the above-mentioned ACE evaluation unit, and the evaluation results are listed in Tables 1 and 2.

[0117] The present invention is evaluated:

[0118] Conversion rate = gasoline yield + liquefied gas yield + dry gas yield + coke yield;

[0119] Light oil yield = gasoline yield + diesel yield;

[0120] Total liquid yield = gasoline yield + diesel yield + liquefied gas yield;

[0121] Coke selectivity = ((100 - conversion rate) x coke yield) / conversion rate.

[0122] Table 1 Evaluation results of catalytic cracking catalysts for producing more propylene in Examples 1-6

[0123]

[0124] Table 2 Evaluation results of catalytic cracking catalysts for producing more propylene in comparative examples 1-4

[0125]

[0126]

[0127] From the data 3 in Table 1 and Table 2, it can be seen that in the catalytic reaction where the high-yield propylene catalyst prepared in each embodiment of the present invention is located, a higher propylene yield and a lower coke selectivity are obtained. It can be seen that the molecular sieve in the high-yield propylene catalyst is subjected to dealumination and siliconization treatment and metal modification in the form of a complex, which can significantly improve the performance of the high-yield propylene catalyst.

[0128] By comparing Example 1 with Comparative Example 1 (all modified metals are Fe), Example 3 with Comparative Example 2 (all modified metals are Ti), and Example 4 with Comparative Example 3 (all modified metals are Zr), it can be seen that compared with the comparative examples, the embodiments of the present invention use dealumination and siliconization treatment and the use of melamine to efficiently and uniformly introduce modified metals, so that the prepared high-yield propylene catalyst has a significant improvement in improving propylene yield and is also improved in reducing coke selectivity.

[0129] Compared with the untreated and unmodified blank catalyst of Comparative Example 4, the propylene yields of the embodiments of the present invention increased to varying degrees after dealumination and siliconization and metal modification in the form of complexes, and all showed excellent propylene yields and lower coke selectivity.

Claims

1. A method for preparing a catalytic cracking catalyst for producing more propylene, comprising the following steps: S1: reacting ZSM-5 molecular sieve with trichloroacetic acid and ethyl orthosilicate to obtain a modified intermediate; wherein, The mass ratio of trichloroacetic acid: ZSM-5 molecular sieve is 0.8-3.5:1; The mass ratio of ethyl orthosilicate: ZSM-5 molecular sieve is 0.2-0.6:1 S2: mixing the modified intermediate, a soluble salt of a modified metal and melamine in a composite solvent, filtering and then taking a solid sample for roasting to obtain a metal-modified molecular sieve; wherein the weight ratio of melamine to ZSM-5 molecular sieve is 0.03-0.3:1; S3: mixing the metal-modified molecular sieve with Y-type molecular sieve, clay and a binder in water to obtain a slurry, spray-drying the slurry to obtain solid particles, and calcining again to obtain a catalytic cracking catalyst for high-yield propylene.

2. The method for preparing a catalytic cracking catalyst for producing more propylene according to claim 1, wherein: In S1, ZSM-5 molecular sieve reacts with trichloroacetic acid and ethyl orthosilicate in water; the concentration of trichloroacetic acid in water is 0.2-1.8 mol / L.

3. The method for preparing a catalytic cracking catalyst for producing more propylene according to claim 1, wherein: In S1, the ZSM-5 molecular sieve is first reacted with trichloroacetic acid and then with ethyl orthosilicate.

4. The method for preparing a catalytic cracking catalyst for producing more propylene according to claim 1, wherein: In S1, the reaction temperature of ZSM-5 molecular sieve and trichloroacetic acid is 70-90°C, and the reaction time is 10-30min; Preferably, the reaction temperature of ZSM-5 molecular sieve and ethyl orthosilicate is 60-80° C., and the reaction time is 20-60 min.

5. The method for preparing a catalytic cracking catalyst for producing more propylene according to claim 1, wherein: Based on the total mass of the modified intermediate, the modified intermediate contains 92-99.98% of the dry basis mass of ZSM-5 molecular sieve; Preferably, the silicon-aluminum ratio of the ZSM-5 molecular sieve is 20-300.

6. The method for preparing a catalytic cracking catalyst for producing more propylene according to claim 1, wherein: The composite solvent is a mixture of an organic solvent and water, and the organic solvent is acetic acid and / or ethylene glycol; Preferably, the mass ratio of organic solvent: water: melamine is 0.4-1:1-3:

1.

7. The method for preparing a catalytic cracking catalyst for producing more propylene according to claim 1, wherein: In S2, based on the total weight of the metal-modified molecular sieve, it contains 0.02-10% of the modified metal in terms of metal oxide.

8. The method for preparing a catalytic cracking catalyst for producing more propylene according to claim 1, wherein: In S2, the modified metal includes at least one of Fe, Cu, Ti, Zr, Mn, and Zn.

9. The method for preparing a catalytic cracking catalyst for producing more propylene according to claim 1, wherein: The calcination conditions in S2 are: calcination at 480-580°C for 1-4h.

10. The method for preparing a catalytic cracking catalyst for producing more propylene according to claim 1, wherein: In S3, the mass ratio of metal modified molecular sieve: Y-type molecular sieve: clay: binder is 5-15:20-40:30-50:5-20.

11. The method for preparing a catalytic cracking catalyst for producing more propylene according to claim 1, wherein: In S3, the particle size of the solid particles obtained by spray drying is 70-90 μm; Preferably, the conditions for the re-calcination are: calcination at 400-550° C. for 20-50 min.

12. A catalytic cracking catalyst for producing more propylene, which is obtained by the preparation method of the catalytic cracking catalyst for producing more propylene according to any one of claims 1 to 11.

13. Use of the catalytic cracking propylene-producing catalyst according to claim 12 in increasing propylene production from catalytic cracking heavy catalyst feedstock.

Images