A catalyst for catalytic cracking for maximizing propylene production, and a method for preparing and using the same

Abstract

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

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil refining catalysis, in particular to a catalytic cracking catalyst for producing propylene and a preparation method and application thereof. BACKGROUND

[0002] Propylene is an important basic organic chemical raw material. With the continuous growth of propylene demand, the downstream product market is steadily expanding, making propylene production play a crucial role in the chemical industry. The main sources of propylene are steam cracking of naphtha and by-product propylene from fluid catalytic cracking process in refineries. Steam cracking has high energy consumption and propylene yield is limited by feedstock composition, while catalytic cracking process has the advantages of wide raw material sources, high operating flexibility and low production cost.

[0003] With the continuous growth of propylene demand, the downstream product market is steadily expanding, making propylene production play a crucial role in the chemical industry. In recent years, the main sources of propylene are steam cracking of naphtha (SC) and by-product propylene from fluid catalytic cracking (FCC) process in refineries.

[0004] In conventional catalytic cracking catalysts, ZSM-5 molecular sieve plays a major role in producing propylene. Usually, in order to improve the performance of ZSM-5 molecular sieve, metal modification of ZSM-5 molecular sieve is carried out. However, although the conventional metal modification methods of ZSM-5 molecular sieve, such as impregnation and exchange, can improve the performance of ZSM-5 molecular sieve catalyst, the modification metal utilization rate is low or the metal loading is uneven, resulting in high coke formation in the subsequent preparation of propylene production catalyst. SUMMARY

[0005] To solve the above technical problems, the purpose of the present application is to provide a catalytic cracking catalyst for producing propylene and a preparation method and application thereof, so as to improve the propylene production effect of the catalyst.

[0006] To achieve the above purpose, the present application provides a preparation method of a catalytic cracking catalyst for producing propylene, which comprises the following steps:

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

[0008] S2: mixing the modified intermediate with a soluble salt of a modified metal and melamine in a composite solvent, filtering, and then taking a solid sample for calcination 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, Y-type molecular sieve, clay and binder in water to obtain a slurry, spray-drying the slurry to obtain solid particles, and calcining again to obtain a catalytic cracking propylene prolific catalyst.

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

[0011] The preparation method provided by the present application can make the modified metal form a complex in a flocculent precipitate state with the modification metal when the ZSM-5 molecular sieve is modified, and the modified metal in the complex (flocculent precipitate) state is more likely to be uniformly deposited on the ZSM-5 molecular sieve catalyst compared to the ion state (solution), and the modified metal in the flocculent precipitate state is not easy to be lost in the subsequent exchange, filtration and other processes, thereby improving the metal utilization rate and improving the catalytic cracking (cracking) reaction performance of the propylene prolific catalyst. In addition, the introduction of the organic solvent such as ethylene glycol or acetic acid can also improve the dispersity of the ZSM-5 molecular sieve and make it fully contact with the modified metal.

[0012] In addition, the ZSM-5 molecular sieve is subjected to dealumination and mesoporous silicon supplementation by using trichloroacetic acid and tetraethyl orthosilicate, which can enhance the mass transfer in the reaction process and effectively slow down the carbon deposition of the propylene prolific catalyst in the catalytic cracking reaction process.

[0013] According to the specific embodiments of the present application, preferably, in S1, the ZSM-5 molecular sieve is reacted with trichloroacetic acid and tetraethyl orthosilicate in water; the concentration of trichloroacetic acid in water is 0.2-1.8 mol / L.

[0014] According to the specific embodiments of the present application, preferably, in S1, the reaction of the ZSM-5 molecular sieve with trichloroacetic acid and tetraethyl orthosilicate is carried out in steps or simultaneously.

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

[0016] According to the specific embodiments of the present application, preferably, in S1, the reaction temperature of the ZSM-5 molecular sieve with trichloroacetic acid is 70-90℃, and the reaction time is 10-30 min.

[0017] According to the specific embodiments of the present application, preferably, in S1, the reaction temperature of the ZSM-5 molecular sieve with tetraethyl orthosilicate is 60-80℃, and the reaction time is 20-60 min.

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

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

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

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

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

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

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

[0025] According to the embodiment of the present application, preferably, in S2, the calcination condition is that the solid sample is calcined at 480-580°C for 1-4h.

[0026] According to the embodiment of the present application, preferably, in S2, the solid sample is further dried before calcination, and the drying condition is that the solid sample is dried at 100-110°C for 8-14h.

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

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

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

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

[0031] According to the specific embodiment of the present application, preferably, in S3, the conditions for the second calcination are: calcination at 400-550 ℃ for 20-50 min.

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

[0033] The present application also provides a catalyst for catalytic cracking for propylene production, which is obtained by the above method for preparing the catalyst for catalytic cracking for propylene production.

[0034] The present application also provides the use of the above catalyst for catalytic cracking for propylene production in the preparation of propylene from heavy catalytic cracking feedstock.

[0035] The heavy catalytic cracking feedstock is an industrial catalytic cracking feedstock, which is a catalytic cracking reaction feedstock known to those skilled in the art.

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

[0037] The method for preparing the catalyst for catalytic cracking for propylene production provided by the present application first performs dealumination and silicon supplementation on the key component ZSM-5 molecular sieve in the catalyst by using trichloroacetic acid and tetraethyl orthosilicate, so that the molecular sieve has a higher mass transfer rate and stability; then, by adding melamine, the modified metal forms a complex in a flocculent precipitate, so that the modified metal is more easily and uniformly deposited on the ZSM-5 molecular sieve catalyst, and the loss of the modified metal with the filtrate in subsequent exchange and filtration is greatly reduced, thereby improving the metal utilization rate of the catalyst for catalytic cracking for propylene production, improving the catalytic cracking reaction performance of the catalyst for catalytic cracking for propylene production, and further improving the propylene yield in the catalytic cracking product, reducing the coke selectivity, and preventing the catalyst from being deactivated due to coke formation. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 The 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, objectives and beneficial effects of the present application, the technical solution of the present application is described in detail below, but it should not be understood as limiting the scope of the present application.

[0040] The raw materials or equipment used in the examples and comparative examples of the present application are as follows:

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

[0042] Melamine, acetic acid, ethylene glycol, trichloroacetic acid, tetraethyl orthosilicate, ferric chloride hexahydrate, cupric chloride dihydrate, titanium sulfate, zirconium chloride, manganese chloride tetrahydrate and zinc chloride are all analytically pure, from National Pharmaceutical Group Chemical Reagent Co., Ltd.;

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

[0044] Aluminum sol, alumina content 18.90 / wt%.

[0045] Example 1

[0046] The present example provides a catalytic cracking propylene-rich catalyst, and the preparation method 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 silica-alumina 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 tetraethyl orthosilicate was added and stirred for 40 min, then the sample b was obtained by suction filtration and washing to neutral;

[0049] (3) Sample b was added to slurry a and stirred for 20 min to obtain slurry c;

[0050] (4) 2.17 g of ferric chloride hexahydrate was weighed and added to slurry c, stirred for 30 min, then suction filtered, dried at 100°C for 14 h, and then calcined at 550°C for 2 h to obtain metal-modified ZSM-5 molecular sieve d;

[0051] (5) 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 slurry e;

[0052] (6) The e slurry was spray dried to form microspheres, and the obtained microspherical solid was calcined at 450°C for 30 min to obtain a catalytic cracking propylene-rich catalyst Cat-1.

[0053] The nitrogen adsorption-desorption curve of the metal-modified ZSM-5 molecular sieve d of the present example is shown in Figure 1 Figure 1. From the figure, it can be seen that the pore volume of the metal-modified ZSM-5 molecular sieve d is 0.21 cm3 / g, and the pore size is 3.8 nm. Figure 1It can be known that the metal modified ZSM-5 molecular sieve has a mesoporous structure. Therefore, the dealumination and silicon supplementing process of the present application makes the ZSM-5 molecular sieve have a mesoporous structure, thereby promoting the mass transfer efficiency of the catalytic cracking propylene-rich catalyst and reducing coke generation.

[0054] Example 2

[0055] The present embodiment provides a catalytic cracking propylene-rich catalyst, and a preparation method thereof is as follows:

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

[0057] (2) 16g of ZSM-5 molecular sieve with a silicon-aluminum ratio of 100 and 40g of trichloroacetic acid were added to 60g of deionized water, stirred at 80℃ for 20min, then 10g of tetraethyl orthosilicate was added and stirred for 40min, then the sample b was obtained by filtration and washing to neutral;

[0058] (3) The sample b was added to the slurry a and stirred for 20min to obtain a slurry c;

[0059] (4) 1.58g of copper chloride dihydrate was weighed and added to the slurry c, stirred for 30min, then filtered, dried at 105℃ for 10h, and then calcined at 480℃ for 4h to obtain a metal modified ZSM-5 molecular sieve d;

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

[0061] (6) The slurry e was spray dried to form a microspherical solid, and the obtained microspherical solid was calcined at 400℃ for 50min to obtain a catalytic cracking propylene-rich catalyst Cat-2.

[0062] Example 3

[0063] The present embodiment provides a catalytic cracking propylene-rich catalyst, and a preparation method thereof is as follows:

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

[0065] (2) 25g of ZSM-5 molecular sieve with a silicon-aluminum ratio of 100 and 40g of trichloroacetic acid were added to 60g of deionized water, stirred at 80℃ for 20min, then 10g of tetraethyl orthosilicate was added and stirred for 40min, then the sample b was obtained by filtration and washing to neutral;

[0066] (3) the sample b is added to the slurry a to mix, stirring for 20 min to obtain a slurry c;

[0067] (4) 0.02 g of titanium sulfate is weighed and added to the slurry c, stirring for 30 min, then suction filtration, drying at 110°C for 8 h, and then calcining at 580°C for 1 h to obtain the metal-modified ZSM-5 molecular sieve d;

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

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

[0070] Example 4

[0071] The present embodiment provides a catalytic cracking propylene prolific catalyst, and the preparation method is as follows:

[0072] (1) 1.2 g of melamine, 0.96 g of ethylene glycol, and 30 g of deionized water are 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 are added to 60 g of deionized water, stirred at 80°C for 20 min, then 6 g of tetraethyl orthosilicate is added and stirred for 40 min, then suction filtration and washing to neutral to obtain a sample b;

[0074] (3) the sample b is added to the slurry a to mix, stirring for 20 min to obtain a slurry c;

[0075] (4) 0.38 g of zirconium chloride is weighed and added to the slurry c, stirring for 30 min, then suction filtration, drying at 100°C for 12 h, and then calcining at 550°C for 3 h to obtain the metal-modified ZSM-5 molecular sieve d;

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

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

[0078] Example 5

[0079] The present embodiment provides a catalytic cracking propylene prolific catalyst, and the preparation method is as follows:

[0080] (1) 2.63 g of melamine, 0.60 g of ethylene glycol and 30 g of deionized water were mixed uniformly at 25 °C under stirring for 10 min to obtain 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 tetraethyl orthosilicate was added and stirred for 40 min, then sample b was obtained by suction filtration and washing to neutral;

[0082] (3) Sample b was added to slurry a and mixed, and stirred for 20 min to obtain slurry c;

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

[0084] (5) 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 slurry e;

[0085] (6) The slurry e was spray dried to form microspheres, and the obtained microspherical solid was calcined at 470 °C for 25 min to obtain a catalytic cracking propylene-rich catalyst Cat-5.

[0086] Example 6

[0087] The present embodiment provides a catalytic cracking propylene-rich catalyst, and the preparation method is as follows:

[0088] (1) 5.8 g of melamine, 5.8 g of acetic acid and 30 g of deionized water were mixed uniformly at 25 °C under stirring for 10 min to obtain 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 tetraethyl orthosilicate was added and stirred for 40 min, then sample b was obtained by suction filtration and washing to neutral;

[0090] (3) Sample b was added to slurry a and mixed, and stirred for 20 min to obtain slurry c;

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

[0092] (5) the modified metal zeolite d is mixed with 100 g of deionized water, 94 g of kaolin, 57 g of REY zeolite, and 103 g of aluminum sol for 30 min of stirring to obtain slurry e;

[0093] (6) the slurry e is spray-dried to form microspheres, and the obtained microspheres are calcined at 450℃ for 30 min to obtain a catalytic cracking propylene-rich catalyst Cat-6.

[0094] Comparative Example 1

[0095] The comparative example provides a catalytic cracking propylene-rich catalyst, and the preparation method is as follows:

[0096] (1) 20 g of ZSM-5 zeolite with a silicon-aluminum ratio of 35 is mixed with 100 g of deionized water at 25℃ for 10 min of stirring to obtain solution a;

[0097] (2) 2.89 g of iron chloride hexahydrate is added to the solution a for exchange stirring for 30 min to obtain solution b;

[0098] (3) the solution b is filtered, dried at 100℃ for 12 h, and then calcined at 550℃ for 4 hours to obtain a metal Fe-exchanged modified ZSM-5 zeolite catalyst powder c;

[0099] (4) the modified ZSM-5 zeolite powder c is mixed with 100 g of deionized water, 84 g of kaolin, 66 g of REY zeolite, and 119 g of aluminum sol for 30 min of stirring to obtain slurry d;

[0100] (5) the slurry d is spray-dried to form microspheres, and the obtained microspheres are calcined at 450℃ for 30 min to obtain a catalytic cracking propylene-rich catalyst D1.

[0101] Comparative Example 2

[0102] The comparative example provides a catalytic cracking propylene-rich catalyst, and the preparation method is as follows:

[0103] 25 g of ZSM-5 zeolite with a silicon-aluminum ratio of 100 is mixed with 1.25 g of titanium sulfate and 100 g of deionized water at 25℃ to obtain a metal Ti-impregnated modified ZSM-5 zeolite catalyst powder after 12 h of drying at 100℃ and 4 hours of calcination at 550℃;

[0104] The modified ZSM-5 molecular sieve powder is mixed with 100 g of deionized water, 105 g of kaolin, 38 g of USY molecular sieve, and 119 g of aluminum sol for 30 min to obtain a slurry d, and the slurry d is spray-dried to form microspheres to obtain a microsphere solid. The microsphere solid is calcined at 500°C for 30 min to obtain a catalytic cracking propylene yield catalyst D2.

[0105] Comparative Example 3

[0106] The present comparative example provides a catalytic cracking propylene yield catalyst, which is prepared according to the following method:

[0107] 8 g of ZSM-5 with a silicon-aluminum ratio of 30 and 0.41 g of ZrO2 particles are thoroughly mixed, 20 g of deionized water is slowly added, and the mixture is thoroughly stirred. The solid-liquid mixture is transferred to a high-temperature reaction kettle, and after reaction at 240°C for 6 h, the reaction kettle is removed. The reaction pressure is atmospheric pressure, and the reaction kettle is cooled to room temperature in air. The reaction kettle is opened and dried at 140°C for 10 h to obtain a metal Zr-modified ZSM-5 molecular sieve catalyst powder prepared by a hydrothermal method;

[0108] The modified ZSM-5 molecular sieve powder is mixed with 100 g of deionized water, 84 g of kaolin, 76 g of USY molecular sieve, and 119 g of aluminum sol for 30 min to obtain a slurry d, and the slurry d is spray-dried to form microspheres to obtain a microsphere solid. The microsphere solid is calcined at 470°C for 30 min to obtain a catalytic cracking propylene yield catalyst D3.

[0109] Comparative Example 4 (blank control)

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

[0111] The slurry is spray-dried to form microspheres to obtain a microsphere solid. The microsphere solid is calcined at 450°C for 30 min to obtain a catalytic cracking propylene yield catalyst D4.

[0112] Experimental Example

[0113] The present experimental example is used to evaluate the performance of the catalytic cracking propylene yield catalysts of the above examples and comparative examples.

[0114] Evaluation and analysis method:

[0115] The catalytic cracking propylene-yielding catalysts for evaluation all need to be pre-aged at 800°C for 17 hours in 100% steam. The catalytic cracking evaluation conditions in the advanced catalytic cracking evaluation device (ACE) are that the pretreated catalyst sample is placed in the ACE experimental reactor, the catalytic reaction temperature is 530°C, the catalyst dosage is 9 g, and the reaction raw material is the 3 million tons / year heavy catalytic cracking raw material of Lanzhou Petrochemical Company, and the catalyst / oil ratio is 5.0.

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

[0117] In the evaluation of the present application:

[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 the catalytic cracking propylene-yielding catalysts of Examples 1-6

[0123]

[0124] Table 2 Evaluation results of the catalytic cracking propylene-yielding catalysts of Comparative Examples 1-4

[0125]

[0126]

[0127] From the data in Tables 1 and 2 (as can be seen, the catalytic reactions in which the propylene-yielding catalysts prepared in each of the embodiments of the present application are located all obtain a higher propylene yield and a lower coke selectivity, which shows that the treatment of the molecular sieve in the propylene-yielding catalyst by dealumination and silicon supplementation and the modification of the metal in the form of a complex can significantly improve the performance of the propylene-yielding catalyst.

[0128] Comparing Example 1 with Comparative Example 1 (the modified metal is Fe), Example 3 with Comparative Example 2 (the modified metal is Ti), and Example 4 with Comparative Example 3 (the modified metal is Zr) respectively, it can be seen that compared with each of the comparative examples, each of the embodiments of the present application improves the propylene yield of the prepared propylene-yielding catalyst by dealumination and silicon supplementation treatment and the efficient and uniform introduction of the modified metal by melamine, and also improves the coke selectivity.

[0129] Compared with the untreated and modified blank catalyst of Comparative Example 4, the propylene yield of each embodiment of the present application is increased to different degrees after the de-alumination and silicon supplementation treatment and the metal modification in the form of a complex, and each embodiment exhibits excellent propylene yield and lower coke selectivity.

Claims

1. A method for preparing a catalytic cracking catalyst for propylene production, comprising the following steps: S1: reacting ZSM-5 molecular sieve with trichloroacetic acid, tetraethyl orthosilicate to obtain a modified intermediate; wherein, The mass ratio of trichloroacetic acid to ZSM-5 molecular sieve is 0.8-3.5:

1. The mass ratio of tetraethyl orthosilicate to ZSM-5 molecular sieve is 0.2-0.6:

1. The reaction temperature of ZSM-5 molecular sieve and trichloroacetic acid is 70-90℃, and the reaction time is 10-30 min. The reaction temperature of ZSM-5 molecular sieve and tetraethyl orthosilicate is 60-80℃, and the reaction time is 20-60 min. S2: mixing the modified intermediate with a soluble salt of modified metal and melamine in a composite solvent, filtering, and then taking a solid sample for calcination to obtain a metal-modified molecular sieve; wherein the weight ratio of melamine to ZSM-5 molecular sieve is 0.03-0.3:1; the composite solvent is a mixture of an organic solvent and water, the organic solvent is acetic acid and / or ethylene glycol, and the mass ratio of organic solvent:water:melamine is 0.4-1:1-3:

1.

2. The process for preparing a catalytic cracking propylene maximizing catalyst according to claim 1, wherein, The modified metal includes at least one of Fe, Cu, Ti, Zr, Mn, and Zn.

3. The process for preparing a catalytic cracking propylene maximizing catalyst according to claim 1, wherein, S3: mixing the metal-modified molecular sieve with Y-type molecular sieve, clay, and binder in water to obtain a slurry, wherein the mass ratio of metal-modified molecular sieve to Y-type molecular sieve is 5-15:20-40; spray drying the slurry to form solid particles, and then calcining again to obtain the catalytic cracking catalyst for propylene production.

4. The process for preparing a catalytic cracking propylene maximizing catalyst according to claim 1, wherein, In S1, ZSM-5 molecular sieve is reacted with trichloroacetic acid and tetraethyl orthosilicate in water; the concentration of trichloroacetic acid in water is 0.2-1.8 mol / L.

5. The process for preparing a catalytic cracking propylene maximizing catalyst according to claim 1, wherein, In S1, ZSM-5 molecular sieve is first reacted with trichloroacetic acid, and then reacted with tetraethyl orthosilicate.

6. The process for preparing a catalytic cracking propylene maximizing catalyst according to claim 1, wherein, The modified intermediate contains 92-99.98% of dry basis ZSM-5 molecular sieve in terms of the total mass of the modified intermediate.

7. The method of making a catalytic cracking propylene maximizing catalyst of claim 1, wherein, The ZSM-5 molecular sieve has a silicon-aluminum ratio of 20-300.

8. The method of making a catalytic cracking propylene maximizing catalyst of claim 1, wherein, In S2, the calcination conditions are 480-580℃ for 1-4 h.

9. The method of making a catalytic cracking propylene maximizing catalyst of claim 1 wherein, In S3, the mass ratio of metal-modified molecular sieve:clay:binder is 5-15:30-50:5-20. In S3, the particle size of the solid particles obtained by spray drying is 70-90 μm. In S3, the calcination conditions are 400-550℃ for 20-50 min. 10.A catalytic cracking catalyst for propylene production, which is obtained by the method for preparing a catalytic cracking catalyst for propylene production according to any one of claims 1-9. 11.The use of the catalytic cracking catalyst for propylene production according to claim 10 in catalytic cracking of heavy catalytic cracking feedstock to increase propylene production.

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