Catalytic cracking composite catalyst, preparation method therefor, and use thereof

Abstract

The present invention relates to the technical field of cracking catalyst preparation. Disclosed are a catalytic cracking composite catalyst and a preparation method therefor. The composite catalyst comprises catalyst A and catalyst B. The bulk density of catalyst A is 0.7-0.79 g / cm3, the bulk density of catalyst B is 0.81-0.87 g / cm3, and the bulk density ratio of catalyst A to catalyst B is 0.88-0.95. The dry-basis weight ratio of Y-type molecular sieves contained in catalyst A to those contained in catalyst B is 2-4:1. The composite catalyst has good wear resistance performance, achieves a high yield of low-carbon olefins and high propylene selectivity in heavy oil catalytic cracking, and increases the yield of low-carbon olefins without increasing the yield of heavy oil and diesel oil.

Description

Catalytic cracking combined catalyst and its preparation method and application

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Chinese patent application 202311489064.8 filed on November 9, 2023, the contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to the technical field of cracking catalyst preparation, and in particular to a catalytic cracking combined catalyst and a preparation method and application thereof. Background Art

[0004] Due to my country's "dual carbon" strategic needs and the impact of new energy vehicles on the traditional fuel vehicle market, my country's refined oil market is becoming saturated. Diesel has passed its consumption peak, gasoline is approaching its consumption peak, and aviation kerosene still has room for growth.

[0005] Given the increasing global demand for chemical products, particularly for chemical feedstocks such as ethylene and propylene, the development of catalytic cracking technology to produce chemicals is not only an effective improvement on catalytic cracking technology, which primarily produces fuel oil products, but also allows for the regulation of product distribution by improving reaction conditions or replacing catalysts. Furthermore, the cost of this transformation is relatively low. Catalytic cracking catalyst technology is a key technology in the current transition from oil refining to chemical production. However, conventional catalytic cracking catalysts produce low yields of light olefins, making it difficult to meet market demand. Furthermore, the yield of heavy oil products in the catalytic cracking products is a key metric for catalytic cracking catalysts in refinery applications. Therefore, the development of catalytic cracking catalysts capable of processing heavy feedstocks and producing high yields of light olefins is highly desirable.

[0006] CN111718231A discloses a method for producing ethylene and propylene by direct catalytic conversion of crude oil. Different catalysts are used for light oil and heavy oil respectively. The light oil uses a catalyst with Y and ZSM-5 molecular sieves as the main active components, while the heavy oil uses a catalyst with a mixture of multiple molecular sieves as the main active component. The steps are complicated and it is not possible to catalytically crack light oil and heavy oil at the same time.

[0007] CN112642472B discloses an aluminum sol binder catalyst for converting hydrocarbon oils to produce light olefins and BTX, as well as its preparation method and application. The catalyst uses FAU and IMF molecular sieves as the main active components. However, as a main catalyst, it is difficult to further increase the light olefin yield during the catalytic cracking process. Furthermore, most current heavy oil catalytic cracking catalysts for producing light olefins are based on a conventional catalytic cracking main catalyst mixed with a small amount of a light olefin production promoter, aiming to reduce secondary reactions such as hydrogen transfer in light olefin products. However, the mixed catalysts formed by adding a propylene adjuvant to the current catalytic cracking catalysts increase the propylene yield while reducing the heavy oil and diesel conversion capacity, resulting in a low heavy oil conversion rate and a high diesel yield.

[0008] Therefore, there is a need to develop a catalytic cracking catalyst that can increase propylene yield without reducing the conversion of heavy oil products and diesel. In other words, this catalyst has the advantage of increasing propylene yield while not increasing the yield of heavy oil products and diesel when catalytically cracking heavy feedstock.

[0009] Summary of the Invention

[0010] The purpose of the present invention is to overcome the problem of low conversion capacity of heavy oil products and diesel by catalytic cracking catalysts in the prior art while increasing the yield of light olefins. The present invention provides a catalytic cracking combination catalyst and its preparation method and application. The combination catalyst has good wear resistance and high propylene selectivity, and while increasing the yield of light olefins, the yield of heavy oil products and diesel is substantially unchanged.

[0011] In order to achieve the above object, the first aspect of the present invention provides a catalytic cracking combination catalyst, wherein the combination catalyst comprises catalyst A and catalyst B; wherein the bulk density of catalyst A is 0.7-0.79 g / cm 3 The bulk density of the catalyst B is 0.81-0.87 g / cm 3 ; The bulk density ratio of catalyst A to catalyst B is 0.88-0.95;

[0012] The weight ratio of the Y-type molecular sieve contained in the catalyst A and the catalyst B respectively is 2-4:1 on a dry basis.

[0013] A second aspect of the present invention provides a method for preparing a catalytic cracking composite catalyst, wherein the method comprises:

[0014] (1) slurrying the molecular sieve, the first binder and water to obtain a pre-bonded molecular sieve slurry;

[0015] (2) thoroughly mixing clay, a second binder, an inorganic acid, and water to form a matrix slurry, and then aging;

[0016] (3) fully mixing the pre-bonded molecular sieve slurry with the matured matrix slurry, and then adding the remaining first binder and mixing evenly to obtain a catalyst slurry;

[0017] (4) homogenizing, spray drying and calcining the catalyst slurry to obtain the catalyst A or catalyst B;

[0018] (5) mixing catalyst A and catalyst B to obtain the combined catalyst;

[0019] Wherein, the bulk density of the catalyst A is 0.7-0.79 g / cm 3 The bulk density of the catalyst B is 0.81-0.87 g / cm 3 ; The bulk density ratio of catalyst A to catalyst B is 0.88-0.95;

[0020] The weight ratio of the Y-type molecular sieve contained in the catalyst A and the catalyst B respectively is 2-4:1 on a dry basis.

[0021] The third aspect of the present invention provides a use of the catalytic cracking combination catalyst described in the first aspect or the catalytic cracking combination catalyst prepared by the method described in the second aspect in heavy oil cracking.

[0022] Through the above technical solution, the present invention can achieve the following technical effects:

[0023] (1) The catalytic cracking combination catalyst provided by the present invention is beneficial to promoting the conversion of heavy oil and diesel on the surface of catalyst B by reducing the content of Y-type molecular sieve in catalyst A and reducing the difference in bulk density between catalyst A and catalyst B, thereby avoiding the problem of increasing the yield of heavy oil and diesel in the catalyst by adding high bulk density ratio components in the traditional method, and more efficiently converting them into gasoline and diffusing them to the active center of the molecular sieve, thereby improving the yield of light olefins.

[0024] (2) The catalytic cracking combination catalyst provided by the present invention is prepared by adding the first binder and the second binder in steps to prepare a high-selectivity (ZSM-5) content combination catalyst, thereby reducing the amount of binder used; and the Y molecular sieve used has a low silicon-aluminum ratio, which is more conducive to combining with the binder. The prepared catalyst has good strength, a low wear index with small deviation, and strong wear resistance.

[0025] (3) The catalytic cracking combination catalyst provided by the present invention can meet the requirements of increasing the yield of light olefins while maintaining the yield of heavy oil products and diesel while reducing the amount of Y molecular sieve used in the catalytic cracking process of heavy oil, and the yield of liquefied gas is high and the concentration of propylene in the liquefied gas is high, thereby greatly improving the overall economic benefits. DETAILED DESCRIPTION

[0026] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0027] The first aspect of the present invention provides a catalytic cracking composite catalyst, wherein the composite catalyst comprises catalyst A and catalyst B; wherein the bulk density of catalyst A is 0.7-0.79 g / cm 3 The bulk density of the catalyst B is 0.81-0.87 g / cm 3 ; The bulk density ratio of catalyst A to catalyst B is 0.88-0.95;

[0028] The weight ratio of the Y-type molecular sieve contained in the catalyst A and the catalyst B respectively is 2-4:1 on a dry basis.

[0029] In the present invention, the bulk density ratio of the catalyst A to the catalyst B is 0.88-0.95, for example, 0.88, 0.89, 0.9, 0.91, 0.92, 0.93, 0.94, 0.95, and any value in the range consisting of any two numerical values; the weight ratio of the Y-type molecular sieve contained in each of the catalysts A and catalyst B on a dry basis is 2-4:1, for example, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, and any value in the range consisting of any two numerical values. Controlling the bulk density of catalyst A, the bulk density of catalyst B, the bulk density ratio of catalyst A to catalyst B, and the weight ratio of the Y-type molecular sieve contained in each of catalysts A and catalyst B on a dry basis within the aforementioned ranges is beneficial for improving the strength of the catalytic cracking combination catalyst and the catalytic activity of the catalytic cracking combination catalyst in the catalytic cracking process of heavy feedstock oil. It is also possible to increase the yield of light olefins and the selectivity of propylene among light olefins while maintaining the yield of heavy oil products and diesel without increasing under the premise of reducing the content of the Y-type molecular sieve, thereby achieving an excellent catalytic effect. The yield of the heavy oil product is related to the processing capacity of the heavy oil feedstock. In the present invention, by controlling the yield of the heavy oil product, the processing capacity of the heavy oil feedstock can be improved.

[0030] Conventional catalytic cracking catalysts have a high content of Y molecular sieve, so they have a clear advantage in converting heavy oil products and diesel. Taking Comparative Examples 1, Comparative Example 4, and Example 1 as examples, in Comparative Example 1, pure catalyst with a Y molecular sieve content of 15% was used for conversion, and the heavy oil product yield was 11.19% and the diesel yield was 19.08%. In Comparative Example 4, the Y molecular sieve dosage was reduced, and the heavy oil product yield was 12.67% and the diesel yield was 19.84%, both of which were significantly improved. In Example 1, when the Y molecular sieve dosage was reduced, the heavy oil yield was 11.28% and the diesel yield was 19.10%, which remained essentially unchanged, but at the same time, the propylene yield increased by 1.19 percentage points. Therefore, the use of a catalytic cracking combination catalyst can solve the problem of increased heavy oil product and diesel yields caused by reduced Y molecular sieve content.

[0031] In some embodiments of the present invention, preferably, the weight ratio of catalyst A to catalyst B is 1-9:1, preferably 7-26:3. In the present invention, controlling the weight ratio of catalyst A to catalyst B within the above range is beneficial to improving the light olefin yield and propylene selectivity of the catalytic cracking combination catalyst, while maintaining the yield of heavy oil products and diesel. Within the preferred range, it is beneficial to make the catalytic cracking combination catalyst have a better catalytic effect. When the weight ratio of catalyst A to catalyst B is less than 1:1, the propylene yield of the catalytic cracking combination catalyst is low, and the yield of heavy oil products and diesel is increased.

[0032] In some embodiments of the present invention, preferably, the pore volume of the catalyst A is 0.31-0.37 cm 3 / g; the pore volume of the catalyst B is 0.29-0.31cm 3 In the present invention, controlling the pore volumes of catalyst A and catalyst B within the above range is beneficial for the catalytic cracking combined catalyst to have better catalytic performance.

[0033] In some embodiments of the present invention, preferably, the catalyst A comprises a Y-type molecular sieve, a modified ZSM-5, a binder, and a clay; wherein, based on the dry weight of the catalyst A, the catalyst A comprises, on a dry basis, 10-25 wt% of the Y-type molecular sieve, 15-35 wt% of the modified ZSM-5, 15-27 wt% of the binder, and 30-50 wt% of the clay. Alternatively, based on the total mass of the catalyst A, the catalyst A comprises, on a dry basis, 10-25 wt% of the Y-type molecular sieve, 15-35 wt% of the modified ZSM-5, 15-27 wt% of the binder, and 30-50 wt% of the clay.

[0034] In some embodiments of the present invention, preferably, the catalyst B comprises a Y-type molecular sieve, modified ZSM-5, a binder, and clay; wherein, based on the dry weight of the catalyst B, the catalyst B comprises, on a dry basis, 3-8 wt% of the Y-type molecular sieve, 25-40 wt% of the modified ZSM-5, 15-27 wt% of the binder, and 30-50 wt% of the clay. Alternatively, based on the total mass of the catalyst B, the catalyst B comprises, on a dry basis, 3-8 wt% of the Y-type molecular sieve, 25-40 wt% of the modified ZSM-5, 15-27 wt% of the binder, and 30-50 wt% of the clay.

[0035] In the present invention, the molecular sieve raw material composition type of catalyst A and catalyst B is the same, and the main difference is that the content of Y-type molecular sieve and modified ZSM-5 molecular sieve is different. The content of Y-type molecular sieve, modified ZSM-5, binder and clay in catalyst A and catalyst B is controlled within the above range, which is conducive to obtaining bulk density and bulk density ratio meeting the requirements of catalyst A and catalyst B, so that catalytic cracking combination catalyst can solve the problem of increased heavy oil product and diesel yield, improve the yield and propylene selectivity of light olefins. Wherein, in the present invention, the content of Y-type molecular sieve, modified ZSM-5, binder and clay in catalyst A and catalyst B is the theoretical calculated amount of raw material added when preparing catalyst.

[0036] In some embodiments of the present invention, preferably, the silicon-aluminum ratio SiO2 / Al2O3 of the Y-type molecular sieve is 3.1-5.

[0037] In some embodiments of the present invention, preferably, the Y-type molecular sieve is selected from ReUSY-type and / or USY-type molecular sieves.

[0038] In some embodiments of the present invention, preferably, the Re2O3 content in the ReUSY molecular sieve is ≤3 wt%.

[0039] In some embodiments of the present invention, preferably, the modified ZSM-5 comprises a modifying element oxide and ZSM-5; wherein the modifying element in the modifying element oxide is selected from at least one of phosphorus, alkaline earth metal elements and transition metal elements, preferably at least two.

[0040] In some embodiments of the present invention, preferably, the alkaline earth metal element is Mg.

[0041] In some embodiments of the present invention, preferably, the transition metal element is selected from at least one of Fe, Co, Ni, Zn and Cu.

[0042] In some embodiments of the present invention, preferably, the content of the modifying element oxide in the modified ZSM-5 is 1.5-5 wt %.

[0043] In some embodiments of the present invention, preferably, the modified ZSM-5 is P2O5-ZnO modified ZSM-5, wherein the mass content of P2O5 is 2-3%, and the mass content of ZnO is 0.1-1%.

[0044] In some embodiments of the present invention, preferably, the binder is selected from alumina and / or silica, preferably alumina.

[0045] In some embodiments of the present invention, preferably, the clay is selected from at least one of kaolin, halloysite and bentonite, preferably kaolin.

[0046] A second aspect of the present invention provides a method for preparing a catalytic cracking composite catalyst, wherein the method comprises:

[0047] (1) slurrying the Y-type molecular sieve, modified ZSM-5, part of the first binder and water to obtain a pre-bonded molecular sieve slurry;

[0048] (2) thoroughly mixing clay, a second binder, an inorganic acid, and water to form a matrix slurry, and then aging;

[0049] (3) fully mixing the pre-bonded molecular sieve slurry with the matured matrix slurry, and then adding the remaining first binder and mixing evenly to obtain a catalyst slurry;

[0050] (4) homogenizing, spray drying and calcining the catalyst slurry to obtain the catalyst A or catalyst B;

[0051] (5) mixing catalyst A and catalyst B to obtain the combined catalyst;

[0052] Wherein, the bulk density of the catalyst A is 0.7-0.79 g / cm 3 The bulk density of the catalyst B is 0.81-0.87 g / cm 3 ; The bulk density ratio of catalyst A to catalyst B is 0.88-0.95;

[0053] The weight ratio of the Y-type molecular sieve contained in the catalyst A and the catalyst B respectively is 2-4:1 on a dry basis.

[0054] In the present invention, the catalysts A and B prepared by the preparation methods have good adaptability to each other, and the difference in wear strength between the catalysts A and B is small, thereby reducing the wear consumption between the two catalysts.

[0055] In step (1):

[0056] In some embodiments of the present invention, preferably, in the preparation method of catalyst A, based on the dry weight of the pre-bonded molecular sieve slurry, the weight ratio of the Y-type molecular sieve and the modified ZSM-5 in the pre-bonded molecular sieve slurry is (10-25): (15-35) on a dry basis.

[0057] In some embodiments of the present invention, preferably, in the preparation method of catalyst B, based on the dry weight of the pre-bonded molecular sieve slurry, the weight ratio of Y-type molecular sieve and modified ZSM-5 in the pre-bonded molecular sieve slurry is (3-8): (25-40) on a dry basis.

[0058] In some embodiments of the present invention, preferably, the silicon-aluminum ratio SiO2 / Al2O3 of the Y-type molecular sieve is 3.1-5. In the present invention, the low silicon-aluminum ratio of the Y-type molecular sieve is conducive to bonding with the binder, thereby improving the anti-wear performance of the catalytic cracking combination catalyst.

[0059] In some embodiments of the present invention, preferably, the Y-type molecular sieve is selected from ReUSY-type and / or USY-type molecular sieves.

[0060] In some embodiments of the present invention, preferably, the Re2O3 content in the ReUSY molecular sieve is ≤3 wt%. In the present invention, controlling the Re2O3 content in the ReUSY molecular sieve within the above range is beneficial for ensuring the hydrothermal stability of the catalyst while reducing the hydrogen transfer capacity of the catalyst, thereby improving the yield of light olefin products.

[0061] In some embodiments of the present invention, preferably, the modifying element contained in the modified ZSM-5 is selected from at least one of phosphorus, alkaline earth metal elements and transition metal elements, and preferably at least two.

[0062] In some embodiments of the present invention, preferably, the alkaline earth metal element is Mg.

[0063] In some embodiments of the present invention, preferably, the transition metal element is selected from at least one of Fe, Co, Ni, Zn and Cu.

[0064] In some embodiments of the present invention, preferably, the content of the modifying element in the modified ZSM-5 is 1.5-5 wt % in terms of oxide. In the present invention, the modified ZSM-5 can be prepared according to known methods, which will not be described in detail herein.

[0065] In some embodiments of the present invention, preferably, the modified ZSM-5 is P2O5-ZnO modified ZSM-5, wherein the mass content of P2O5 is 2-3%, and the mass content of ZnO is 0.1-1%.

[0066] In some embodiments of the present invention, preferably, the first binder is divided into at least a portion of the first binder and a remaining first binder, wherein the portion of the first binder is used in step (1) and the remaining first binder is used in step (3).

[0067] In some embodiments of the present invention, the first binder is preferably selected from at least one of silica sol, alumina sol, and pseudo-boehmite, preferably silica sol and / or alumina sol. In the present invention, a portion of the first binder is used as a molding aid. Combining the portion of the first binder with a Y-type molecular sieve and a modified ZSM-5 produces a catalytic cracking combination catalyst that, when used for the catalytic cracking of heavy oil, can improve the cracking of large molecular hydrocarbons in the matrix, exhibiting a good catalytic cracking effect, and capable of increasing the yield of light olefins while maintaining the yield of heavy oil and diesel.

[0068] In some embodiments of the present invention, preferably, in the process of mixing the Y-type molecular sieve, the modified ZSM-5, a portion of the first binder, and water to obtain the pre-bonded molecular sieve slurry, the present invention does not particularly limit the amount of water used, as long as the Y-type molecular sieve, the modified ZSM-5, and a portion of the first binder can be fully mixed to obtain the pre-bonded molecular sieve slurry. For example, the amount of water used is 35-40% by weight based on the total amount of the pre-bonded molecular sieve slurry. In addition, the amount of water is not particularly limited, but is preferably deionized water.

[0069] In step (2):

[0070] In some embodiments of the present invention, preferably, the second binder is selected from at least one of silica sol, alumina sol and pseudo-boehmite, preferably pseudo-boehmite.

[0071] In some embodiments of the present invention, preferably, on a dry basis, the weight ratio of the first binder to the second binder is (7-12):(8-15).

[0072] In some embodiments of the present invention, preferably, the clay is selected from at least one of kaolin, halloysite and bentonite, preferably kaolin.

[0073] In some embodiments of the present invention, preferably, on a dry basis, the weight ratio of the clay to the second binder is (30-50):(8-15).

[0074] In some embodiments of the present invention, preferably, the inorganic acid is selected from at least one of hydrochloric acid, nitric acid and sulfuric acid.

[0075] In some embodiments of the present invention, preferably, the inorganic acid (in the form of H +The molar ratio of the first binder (calculated on a dry basis) to the second binder (calculated on a dry basis) is 0.1-0.5: 1. In the present invention, adding an inorganic acid to the second binder for moderate peptization is beneficial to improving the fluidity of the formed matrix slurry.

[0076] In some embodiments of the present invention, clay, a second binder, an inorganic acid, and water are mixed to form a matrix slurry. The present invention does not specifically limit the manner of mixing in step (2). Preferably, the mixing is performed under stirring conditions, wherein the stirring conditions are not specifically limited. For example, the stirring conditions can be performed at 100-150 r / min. In the process of forming the matrix slurry, the amount of water used is not particularly limited, as long as the clay, the second binder, and the inorganic acid can be fully mixed to obtain the matrix slurry. For example, the amount of water used is 35-40% by weight based on the total amount of the matrix slurry. Furthermore, the amount of water used is not specifically limited, but is preferably deionized water.

[0077] In some embodiments of the present invention, preferably, the aging operating conditions include: aging temperature of 70-80° C., and aging time of 0.5-1.5 h.

[0078] In step (3):

[0079] In some embodiments of the present invention, preferably, on a dry basis, the weight ratio of the portion of the first binder to the remaining first binder is 1:1-9. That is, in the present invention, the mass of the portion of the first binder accounts for 10-50% of the first binder, and the mass of the remaining first binder accounts for 50-90% of the first binder.

[0080] Among them, in the present invention, the method of adding part of the first binder, the remaining first binder and the second binder in steps is adopted, which is beneficial to increasing the wear resistance of the catalytic cracking combination catalyst.

[0081] In step (4):

[0082] In some embodiments of the present invention, preferably, the homogenization refers to using a well-known device with a dispersing function, such as a high-speed disperser, a colloid mill, etc. to disperse the catalyst slurry at high speed to achieve the effect of reducing the particle size and achieving uniformity.

[0083] In some embodiments of the present invention, preferably, the spray drying temperature is 370-450° C.; the calcination temperature is 400-550° C., and the calcination time is 0.5-2 h.

[0084] In the present invention, the spray drying temperature, the calcination temperature and the time are controlled within the above ranges, which is conducive to the formation of a catalyst with good strength. During the catalytic cracking process of heavy oil, the catalyst can increase the yield of light olefins while ensuring that the yield of heavy oil products and diesel remains basically unchanged.

[0085] In some embodiments of the present invention, it is further preferred that the temperature of the spray drying is 370-450°C and the time is 0.05-10 min; the temperature of the roasting is 400-550°C and the time is 0.5-2h. In the present invention, the heating rate from room temperature to the set roasting temperature is 5-15°C / min, and the roasting atmosphere is an air atmosphere. In the present invention, the temperature and time of the spray drying and roasting treatments are controlled within the above ranges, which is beneficial to the drying and roasting treatments of the catalyst slurry and to the formation of a catalyst with good strength. The catalyst can increase the yield of light olefins while ensuring that the yield of heavy oil and diesel remains basically unchanged during the catalytic cracking of heavy oil. Preferably, the mixing is carried out under stirring conditions, wherein the stirring conditions are not specifically limited. For example, it can be carried out under stirring conditions of 50-70r / min.

[0086] In step (5):

[0087] In some embodiments of the present invention, preferably, the weight ratio of the catalyst A to the catalyst B is 1-9:1, preferably 7-26:3.

[0088] In some embodiments of the present invention, preferably, the mixing process of catalyst A and catalyst B includes but is not limited to one or more mixing methods such as grinding mixing, sieving mixing, and stirring mixing. Preferably, the mixing is carried out under stirring conditions, wherein the stirring conditions are not specifically limited, for example, it can be carried out under stirring conditions of 50-70r / min.

[0089] The third aspect of the present invention provides a use of the catalytic cracking combination catalyst described in the first aspect or the catalytic cracking combination catalyst prepared by the method described in the second aspect in the catalytic cracking of heavy oil.

[0090] In the present invention, unless otherwise specified, the amounts of all materials are referred to on a dry basis.

[0091] The present invention will be described in detail below by way of examples:

[0092] The main analytical methods of the present invention are:

[0093] Pore ​​volume test: measured according to NB / SH / T 0955 standard method;

[0094] Bulk density test: measured according to NB / SH / T 0954 standard method;

[0095] Wear index test: measured according to NB / SH / T 0964 standard method;

[0096] Micro-reaction activity test: determined according to NB / SH / T 0952 standard method;

[0097] Performance evaluation: The reaction performance was evaluated using an ACE device. The feedstock oils used were all ACE standard oils, with properties shown in Table 1. The catalysts were aged at 800°C and 100% by volume steam for 17 h before evaluation. The catalytic reaction temperature was 530°C, and the catalyst-to-oil ratio was 6.

[0098] Heavy feedstock conversion rate (wt%) = 100 (wt%) - heavy oil product yield (wt%) - diesel product yield (wt%); wherein, in the present invention, the heavy feedstock is converted into coke, dry gas, liquefied petroleum gas, gasoline, diesel, and heavy oil products under the action of a catalytic cracking combination catalyst. The liquefied petroleum gas contains C2-C4 olefins.

[0099] C2-C4 olefin yield (wt%) = ethylene yield (wt%) + propylene yield (wt%) + butene yield (wt%);

[0100] Propylene selectivity (wt%) = propylene yield (wt%) × 100 (wt%) / liquefied gas yield (wt%).

[0101] The main raw materials and sources of the present invention are:

[0102] ReUSY-1 molecular sieve: purchased from Lanzhou Petrochemical Catalyst Plant, industrial grade, rare earth content (as Re2O3) is 2.5wt%, silicon-aluminum ratio (SiO2 / Al2O3 molar ratio) is 3.3;

[0103] ReUSY-2 molecular sieve: purchased from Lanzhou Petrochemical Catalyst Plant, industrial grade, rare earth content (as Re2O3) is 3wt%, silicon-aluminum ratio (SiO2 / Al2O3 molar ratio) is 3.2;

[0104] USY molecular sieve: purchased from Lanzhou Petrochemical Catalyst Plant, industrial grade, silicon-aluminum ratio (SiO2 / Al2O3) is 3.2;

[0105] The modified ZSM-5 is P2O5-ZnO modified ZSM-5, purchased from Lanzhou Petrochemical Catalyst Plant, with a phosphorus content (calculated as P2O5) of 2.5 wt% and a zinc content (calculated as ZnO) of 0.5 wt%;

[0106] Silica sol: purchased from Lanzhou Petrochemical Catalyst Plant, solid content 30 wt%;

[0107] Aluminum sol: purchased from Lanzhou Petrochemical Catalyst Plant, solid content 20 wt%;

[0108] Pseudoboehmite: purchased from Lanzhou Petrochemical Catalyst Plant, industrial grade;

[0109] Kaolin: purchased from Lanzhou Petrochemical Catalyst Plant, industrial grade;

[0110] Hydrochloric acid: purchased from Sinopharm Group, analytical grade, concentration 36 wt%.

[0111] Example 1

[0112] Preparation of Catalyst A:

[0113] (1) ReUSY-1 molecular sieve, P2O5-ZnO modified ZSM-5, and part of the aluminum sol were added to deionized water and mixed uniformly, and beaten for 60 minutes to obtain a pre-bonded molecular sieve slurry, wherein the amount of the part of the aluminum sol accounted for 40% of the total amount of the aluminum sol (the sum of the mass of the part of the aluminum sol and the remaining aluminum sol) on a dry basis;

[0114] (2) Under stirring conditions, kaolin, pseudo-boehmite and hydrochloric acid were added to deionized water, mixed evenly, and aged at 60 ° C for 1 h to obtain a matured matrix slurry, wherein the added hydrochloric acid (in the form of H + The molar ratio of diaspore (calculated as Al2O3) to pseudo-boehmite (calculated as Al2O3) is 0.14;

[0115] (3) The molecular sieve slurry was fully mixed with the matured matrix slurry, and the remaining aluminum sol was added and the beating was continued for 30 minutes to obtain a catalyst slurry;

[0116] (4) The obtained catalyst slurry was homogenized, spray-dried at 400°C, and then calcined at 500°C for 1 hour to obtain catalyst A.

[0117] Preparation of Catalyst B:

[0118] The preparation method of catalyst A was followed, except that

[0119] In step (1), USY molecular sieve is used instead of ReUSY-1 molecular sieve, and the amount of the aluminum sol used on a dry basis accounts for 20% of the total amount of the aluminum sol.

[0120] (5) Catalyst A and catalyst B were mixed in a mass ratio of 17:3 to obtain a catalytic cracking composite catalyst.

[0121] The formulations of Catalyst A and Catalyst B (i.e., the weights of the raw materials (on a dry weight basis) used in the preparation process) are shown in Table 2, and the performance parameters of Catalyst A and Catalyst B and the effect of the combined catalyst are shown in Table 3.

[0122] Example 2

[0123] Preparation of Catalyst A:

[0124] The preparation method of catalyst A in Example 1 was followed, except that

[0125] In step (1), USY molecular sieve is used instead of ReUSY-1 molecular sieve. The formula of catalyst A is shown in Table 2. The amount of the partial aluminum sol used on a dry basis accounts for 20% of the total amount of aluminum sol.

[0126] Preparation of Catalyst B:

[0127] The preparation method of catalyst A in Example 1 was followed, except that

[0128] In step (1), USY molecular sieve is used instead of ReUSY-1 molecular sieve. The formula of catalyst B is shown in Table 2. The amount of the partial aluminum sol used on a dry basis accounts for 20% of the total amount of aluminum sol.

[0129] In step (5), catalyst A and catalyst B are mixed in a mass ratio of 1:1 to obtain a catalytic cracking combination catalyst. The performance parameters of catalysts A and B and the effect of the combination catalyst are shown in Table 3.

[0130] Example 3

[0131] Preparation of Catalyst A:

[0132] The preparation method of catalyst A in Example 1 was followed, except that

[0133] In step (1), ReUSY-2 molecular sieve is used instead of ReUSY-1 molecular sieve. The formula of catalyst A is shown in Table 2. The amount of the partial aluminum sol used on a dry basis accounts for 50% of the total amount of the aluminum sol.

[0134] Preparation of Catalyst B:

[0135] The preparation method of catalyst A in Example 1 was followed, except that

[0136] In step (1), USY molecular sieve is used instead of ReUSY-1 molecular sieve. The formula of catalyst B is shown in Table 2. The amount of the partial aluminum sol used on a dry basis accounts for 20% of the total amount of aluminum sol.

[0137] In step (5), catalyst A and catalyst B are mixed in a mass ratio of 17:3 to obtain a catalytic cracking combination catalyst. The performance parameters of catalysts A and B and the effect of the combination catalyst are shown in Table 3.

[0138] Example 4

[0139] Preparation of Catalyst A:

[0140] The preparation method of catalyst A in Example 1 was followed, except that

[0141] In step (1), the formula of catalyst A is shown in Table 2.

[0142] Preparation of Catalyst B:

[0143] The preparation method of catalyst A in Example 1 was followed, except that

[0144] In step (1), USY molecular sieve is used instead of ReUSY-1 molecular sieve. The formula of catalyst B is shown in Table 2. The amount of the partial aluminum sol used on a dry basis accounts for 20% of the total amount of aluminum sol.

[0145] In step (5), catalyst A and catalyst B are mixed in a mass ratio of 9:1 to obtain a catalytic cracking combination catalyst. The performance parameters of catalysts A and B and the effect of the combination catalyst are shown in Table 3.

[0146] Example 5

[0147] Preparation of Catalyst A:

[0148] The preparation method of catalyst A in Example 1 was followed, except that

[0149] In step (1), the formulation of catalyst A is shown in Table 2, and the amount of the partial aluminum sol used accounts for 50% of the total amount of the aluminum sol on a dry basis.

[0150] Preparation of Catalyst B:

[0151] The preparation method of catalyst A in Example 1 was followed, except that

[0152] In step (1), USY molecular sieve is used instead of ReUSY-1 molecular sieve, and the formula of catalyst B is shown in Table 2.

[0153] In step (5), catalyst A and catalyst B are mixed in a mass ratio of 9:1 to obtain a catalytic cracking combination catalyst. The performance parameters of catalysts A and B and the effect of the combination catalyst are shown in Table 3.

[0154] Example 6

[0155] Preparation of Catalyst A:

[0156] The preparation method of catalyst A in Example 1 was followed.

[0157] Preparation of Catalyst B:

[0158] The preparation method of catalyst A in Example 1 was followed.

[0159] The difference is that in step (5), catalyst A and catalyst B are mixed in a mass ratio of 10:1 to obtain a catalytic cracking combination catalyst. The performance parameters of catalysts A and B and the effect of the combination catalyst are shown in Table 3.

[0160] Comparative Example 1

[0161] Catalyst A was prepared according to the method of Example 1, except that the preparation of catalyst B and step (5) were omitted.

[0162] The formulation of Catalyst A is shown in Table 2, and the performance parameters of Catalyst A and the effects of the combined catalyst (ie, Catalyst A) are shown in Table 3.

[0163] Comparative Example 2

[0164] Preparation of Catalyst A:

[0165] The preparation method of catalyst A in Example 1 was followed, except that

[0166] In step (1), USY molecular sieve is used instead of ReUSY-1 molecular sieve. The formula of catalyst A is shown in Table 2. The amount of the partial aluminum sol used on a dry basis accounts for 10% of the total amount of aluminum sol.

[0167] Preparation of Catalyst B:

[0168] The preparation method of catalyst A in Example 1 was followed, except that

[0169] In step (1), USY molecular sieve is used instead of ReUSY-1 molecular sieve. The formula of catalyst B is shown in Table 2. The amount of the partial aluminum sol used on a dry basis accounts for 20% of the total amount of aluminum sol.

[0170] In step (5), catalyst A and catalyst B are mixed in a mass ratio of 1:1 to obtain a catalytic cracking combination catalyst. The performance parameters of catalysts A and B and the effect of the combination catalyst are shown in Table 3.

[0171] Comparative Example 3

[0172] Preparation of Catalyst A:

[0173] The preparation method of catalyst A in Example 1 was followed.

[0174] Preparation of Catalyst B:

[0175] The preparation method of catalyst A in Example 1 was followed, except that

[0176] In step (1), the formulation of catalyst B is shown in Table 2, and the amount of the aluminum sol used on a dry basis accounts for 5% of the total amount of the aluminum sol.

[0177] In step (5), catalyst A and catalyst B are mixed in a mass ratio of 17:3 to obtain a catalytic cracking combination catalyst. The performance parameters of catalysts A and B and the effect of the combination catalyst are shown in Table 3.

[0178] Comparative Example 4

[0179] Preparation of Catalyst A:

[0180] The preparation method of catalyst A in Example 1 was followed.

[0181] Preparation of Catalyst B:

[0182] The preparation method of catalyst A in Example 1 was followed, except that

[0183] In step (1), no Y-type molecular sieve is added, and the aluminum sol is replaced by silica sol, and the amount of the silica sol used on a dry basis accounts for 100% of the total amount of the silica sol;

[0184] In step (3), the remaining silica sol is not added, but 75% by volume phosphoric acid is added to adjust the pH value of the catalyst slurry to 3.

[0185] In step (5), catalyst A and catalyst B are mixed in a mass ratio of 17:3 to obtain a catalytic cracking combination catalyst. The formulations of catalysts A and B are shown in Table 2, and the performance parameters of catalysts A and B and the effect of the combination catalyst are shown in Table 3.

[0186] Comparative Example 5

[0187] Only catalyst A was used, and the preparation method of catalyst A was the same as that of catalyst A in comparative example 2.

[0188] Table 1 Properties of heavy crude oil

[0189] Table 2 Formulations of catalysts A and B

[0190] The content of each component in Table 2 is expressed by weight on a dry basis. R-1 represents ReUSY-1 molecular sieve, R-2 represents ReUSY-2 molecular sieve, and U represents USY molecular sieve. The content of each component in Catalyst A and Catalyst B is the theoretically calculated value based on the feed amount.

[0191] Table 3 Performance parameters of catalysts and effects of combined catalysts

[0192] Table 3 (continued)

[0193] The catalytic cracking combination catalyst provided by the present invention has a small wear index, and is used for catalytic cracking of heavy crude oil with a higher light olefin yield (C2-C4 olefin yield is between 26.51-30.29%) and a higher propylene selectivity (propylene yield is between 13.20-15.30%), a diesel yield between 9.78-12.67%, and a heavy oil product yield between 9.78-11.96%. It can be seen from this that the catalytic cracking combination catalyst provided in the present invention, when catalyzing heavy crude oil, while improving the light olefin yield and propylene yield, makes the diesel yield no more than 12.67%, and the heavy oil product yield no more than 11.96%, that is, does not increase the heavy oil product and diesel yield.

[0194] It can be seen from the results of Examples 1 to 5 that the bulk density of catalyst A, the bulk density of catalyst B, the bulk density of catalyst A to catalyst B, and the weight ratio of the Y-type molecular sieve contained in catalyst A and catalyst B are controlled within the range defined by the present invention. The obtained combined catalyst has both a high light olefin yield and propylene selectivity, and the yield of diesel and heavy oil products is not increased, and the overall effect of catalytic cracking is better.

[0195] Combining the results of Example 1 with those of Example 6, it can be seen that, since Example 6 does not adopt the weight ratio of Catalyst A to Catalyst B defined in the present invention, the light olefin yield and propylene selectivity of the obtained combined catalyst are slightly reduced.

[0196] In combination with Example 1 and Comparative Example 1, it can be seen that since Comparative Example 1 only uses a single catalyst A, the light olefin yield and propylene selectivity of the obtained combined catalyst are lower than those in Example 1; in combination with Example 1, Comparative Example 2 and Comparative Example 3, it can be seen that the weight ratio of the Y-type molecular sieve contained in Catalyst A and Catalyst B in Comparative Example 2 and Comparative Example 3 is not within the range defined by the present invention, and the light olefin yield of the obtained combined catalyst is reduced, and the propylene selectivity is poor; in combination with Example 1 and Comparative Example 4, it can be seen that the catalyst B in Comparative Example 4 does not adopt the preparation method provided by the present invention, but adopts the conventional co-catalyst preparation method, and the wear index deviation of the obtained catalyst B and catalyst A is large, resulting in large wear and consumption between the two catalysts, and the yield of light olefins of the obtained combined catalyst is low.

[0197] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A catalytic cracking combined catalyst, characterized in that: The combined catalyst comprises catalyst A and catalyst B; wherein the bulk density of catalyst A is 0.7-0.79 g / cm 3 The bulk density of the catalyst B is 0.81-0.87 g / cm 3 ; The bulk density ratio of catalyst A to catalyst B is 0.88-0.95; The weight ratio of the Y-type molecular sieve contained in the catalyst A and the catalyst B respectively on a dry basis is 2-4:

1.

2. The combined catalyst according to claim 1, wherein The weight ratio of the catalyst A to the catalyst B is 1-9:

1.

3. The combined catalyst according to claim 1 or 2, wherein: The pore volume of the catalyst A is 0.31-0.37 cm 3 / g; And / or, the pore volume of the catalyst B is 0.29-0.31cm 3 / g.

4. The combined catalyst according to claim 1, wherein Based on the dry weight of catalyst A, the catalyst A comprises, on a dry basis, 10-25 wt % of Y-type molecular sieve, 15-35 wt % of modified ZSM-5, 15-27 wt % of binder and 30-50 wt % of clay.

5. The combined catalyst according to claim 1, wherein Based on the dry weight of catalyst B, the catalyst B contains, on a dry basis, 3-8 wt % of Y-type molecular sieve, 25-40 wt % of modified ZSM-5, 15-27 wt % of binder and 30-50 wt % of clay.

6. A method for preparing a catalytic cracking combined catalyst, characterized in that: The method includes: (1) slurrying the Y-type molecular sieve, modified ZSM-5, part of the first binder and water to obtain a pre-bonded molecular sieve slurry; (2) fully mixing clay, a second binder, an inorganic acid and water to form a matrix slurry, and then aging; (3) fully mixing the pre-bonded molecular sieve slurry with the matured matrix slurry, and then adding the remaining first binder and mixing evenly to obtain a catalyst slurry; (4) homogenizing, spray drying and calcining the catalyst slurry to obtain the catalyst A or catalyst B; (5) mixing catalyst A and catalyst B to obtain the combined catalyst; Wherein, the bulk density of the catalyst A is 0.7-0.79 g / cm 3 The bulk density of the catalyst B is 0.81-0.87 g / cm 3 ; The bulk density ratio of catalyst A to catalyst B is 0.88-0.95; The weight ratio of the Y-type molecular sieve contained in the catalyst A and the catalyst B respectively on a dry basis is 2-4:

1.

7. The method according to claim 6, wherein: In the preparation method of catalyst A, based on the dry weight of the pre-bonded molecular sieve slurry, the weight ratio of the Y-type molecular sieve and the modified ZSM-5 in the pre-bonded molecular sieve slurry is (10-25): (15-35) on a dry basis; And / or, in the preparation method of catalyst B, based on the dry weight of the pre-bonded molecular sieve slurry, the weight ratio of the Y-type molecular sieve and the modified ZSM-5 in the pre-bonded molecular sieve slurry is (3-8): (25-40) on a dry basis; And / or, the Y-type molecular sieve is selected from ReUSY-type and / or USY-type molecular sieve; And / or, the silicon-aluminum ratio SiO2 / Al2O3 of the Y-type molecular sieve is 3.1-5; And / or, the Re2O3 content in the ReUSY type molecular sieve is ≤3wt%; and / or, the modifying element contained in the modified ZSM-5 is selected from at least one of phosphorus, alkaline earth metal elements and transition metal elements, preferably at least two; And / or, the alkaline earth metal element is Mg; And / or, the transition metal element is selected from at least one of Fe, Co, Ni, Zn and Cu; And / or, the content of the modifying element in the modified ZSM-5 is 1.5-5wt% in terms of oxide.

8. The method according to claim 6 or 7, wherein: The first binder is selected from at least one of silica sol, alumina sol and pseudo-boehmite; And / or, the second binder is selected from at least one of silica sol, alumina sol and pseudo-boehmite; and / or, on a dry basis, the weight ratio of the first binder to the second binder is (7-12):(8-15); and / or, the first binder is a part of the first binder and the remaining first binder; and / or, on a dry basis, a weight ratio of the portion of the first binder to the remaining first binder is 1:1-9; and / or, the clay is selected from at least one of kaolin, halloysite and bentonite, preferably kaolin; and / or, on a dry basis, the weight ratio of the clay to the second binder is (30-50):(8-15); And / or, the inorganic acid is selected from at least one of hydrochloric acid, nitric acid and sulfuric acid; And / or, the inorganic acid (in H + The molar ratio of the first binder (on a dry basis) to the second binder (on a dry basis) is 0.1-0.5:

1.

9. The method according to claim 6, wherein: In step (4), the spray drying temperature is 370-450°C, and the time is 0.05-10 min; the calcination temperature is 400-550°C, and the time is 0.5-2 h.

10. Use of the catalytic cracking combination catalyst according to any one of claims 1 to 5 or the catalytic cracking combination catalyst prepared by the method according to any one of claims 6 to 9 in heavy oil cracking.

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