Catalytic cracking combined catalyst as well as preparation method and application thereof

Abstract

The invention relates to the technical field of cracking catalyst preparation, and discloses a catalytic cracking combined catalyst and a preparation method thereof. The combined catalyst comprises a catalyst A and a catalyst B, 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 >, and the bulk density ratio of the catalyst A to the catalyst B is 0.88-0.95; wherein the weight ratio of the Y-type molecular sieves contained in the catalyst A to the catalyst B is (2-4): 1 on a dry basis. The combined catalyst has good wear resistance, has high low-carbon olefin yield and propylene selectivity when being used in heavy oil catalytic cracking, and realizes that the yields of heavy oil and diesel oil are not increased while the yield of low-carbon olefin is increased.

Description

Technical Field

[0001] 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

[0002] 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.

[0003] Based on the increasing global demand for chemical products, especially for chemical raw materials such as ethylene and propylene, the development of catalytic cracking technology to produce chemicals can not only effectively improve the catalytic cracking technology based on fuel oil products, but also achieve the regulation of product distribution by improving reaction conditions or replacing catalysts, and the transformation cost is low. Catalytic cracking catalyst technology is the core technology for the current transformation from oil refining to chemical industry. However, the yield of low-carbon olefins of conventional catalytic cracking catalysts is not high, and it is difficult to meet the market demand. It is very necessary to develop catalytic cracking catalysts that can process heavy oil and produce more low-carbon olefins.

[0004] 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, and 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 impossible to catalytically crack light oil and heavy oil at the same time.

[0005] CN112642472B discloses an aluminum sol binder catalyst for hydrocarbon oil conversion to produce light olefins and BTX, and its preparation method and application, with FAU structure molecular sieve and IMF structure molecular sieve as the catalyst of the main active component, but as the main catalyst, it is difficult to further improve the light olefin yield in the catalytic cracking process. And most of the current heavy oil catalytic cracking catalysts for producing light olefins are mainly based on the method of mixing a small amount of light olefin production-increasing co-catalyst with the traditional catalytic cracking main catalyst, aiming to reduce the secondary reactions such as hydrogen transfer of light olefin products, but the mixed catalyst formed by adding propylene additive to the catalytic cracking catalyst at present, while increasing the propylene yield, the heavy oil and diesel conversion capacity is reduced, resulting in a low heavy oil conversion rate and a high diesel yield.

[0006] Therefore, it is necessary to develop a catalytic cracking catalyst that can increase the yield of propylene without reducing the conversion capacity of heavy oil and diesel. Summary of the invention

[0007] The purpose of the present invention is to overcome the problem that the catalytic cracking catalyst in the prior art has low heavy oil and diesel conversion capacity while improving the yield of light olefins, and to provide a catalytic cracking combined catalyst and its preparation method and application. The combined catalyst has good wear resistance and high propylene selectivity, and while improving the yield of light olefins, the yield of heavy oil and diesel is basically not increased.

[0008] In order to achieve the above-mentioned object, the first aspect of the present invention provides a catalytic cracking combined catalyst, wherein 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;

[0009] 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.

[0010] A second aspect of the present invention provides a method for preparing a catalytic cracking combined catalyst, wherein the method comprises:

[0011] (1) slurrying the molecular sieve, the first binder and water to obtain a pre-bonded molecular sieve slurry;

[0012] (2) fully mixing clay, a second binder, an inorganic acid and water to form a matrix slurry, and then aging;

[0013] (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;

[0014] (4) homogenizing, spray drying and calcining the catalyst slurry to obtain the catalyst A or catalyst B;

[0015] (5) mixing catalyst A and catalyst B to obtain the combined catalyst;

[0016] 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;

[0017] 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.

[0018] The third aspect of the present invention provides an application 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.

[0019] Through the above technical solution, the present invention can achieve the following technical effects:

[0020] (1) The catalytic cracking combination catalyst provided by the present invention, by reducing the content of Y-type molecular sieve in catalyst B and reducing the difference in bulk density between catalyst A and catalyst B, is beneficial to promoting the conversion of heavy oil and diesel on the catalyst surface, 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.

[0021] (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 relatively low silicon-aluminum ratio, which is more conducive to combining with the binder. The prepared catalyst has good strength, a low wear index and a small deviation, and strong wear resistance.

[0022] (3) The catalytic cracking combination catalyst provided by the present invention can achieve the goal of increasing the yield of light olefins while keeping the yield of heavy oil and diesel unchanged during the catalytic cracking of heavy oil, has a high conversion rate, propylene selectivity and propylene yield, a high propylene concentration in the liquefied gas, and greatly improves the overall economic benefits. DETAILED DESCRIPTION

[0023] The endpoints and any values ​​of the ranges disclosed in this article 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 endpoint values ​​of each range, the endpoint values ​​of each range and the 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 as specifically disclosed in this article.

[0024] The first aspect of the present invention provides a catalytic cracking composite catalyst, characterized in that the composite catalyst comprises a catalyst A and a catalyst B; 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;

[0025] 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.

[0026] 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 of any two numerical values; the weight ratio of the Y-type molecular sieve contained in each of the catalyst A and the catalyst B on a dry basis is 2-4:1, for example, it can be 2:1, 2.5:1, 3:1, 3.5:1, 4:1, and any value in the range of any two numerical values. The bulk density of the catalyst A, the bulk density of the catalyst B, the bulk density ratio of the catalyst A to the catalyst B, and the weight ratio of the Y-type molecular sieve contained in each of the catalyst A and the catalyst B on a dry basis are controlled within the range, which is conducive to the prepared catalytic cracking combination catalyst to achieve the improvement of the yield of light olefins while maintaining the conversion rate of heavy oil and diesel without reducing in the heavy oil catalytic cracking process, and has a higher propylene selectivity, and the catalytic cracking combination catalyst has high strength and good catalytic effect.

[0027] 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. In the present invention, controlling the weight ratio of the catalyst A to the catalyst B within the above range is conducive to making the obtained catalytic cracking combination catalyst have a higher light olefin yield and propylene selectivity, and keeping the conversion rate of heavy oil and diesel not reduced. Within the preferred range, it is conducive to making the combination catalyst have a better catalytic effect. The weight ratio of the catalyst A to the catalyst B is less than 1:1, and the propylene yield of the obtained combination catalyst is low, and the yield of heavy oil and diesel is increased.

[0028] 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 obtained combined catalyst to have better catalytic performance.

[0029] In some embodiments of the present invention, preferably, the catalyst A contains Y-type molecular sieve, modified ZSM-5, a binder and clay; wherein, based on the dry weight of the catalyst A, the catalyst A contains, on a dry basis: 10-25 wt % of Y-type molecular sieve, 15-35 wt % of modified ZSM-5, 15-27 wt % of a binder and 30-50 wt % of clay.

[0030] In some embodiments of the present invention, preferably, the catalyst B contains Y-type molecular sieve, modified ZSM-5, a binder and clay; wherein, based on the dry weight of the 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 a binder and 30-50 wt% of clay.

[0031] In the present invention, the contents of Y-type molecular sieve, modified ZSM-5, binder and clay in catalyst A and catalyst B are controlled within the above ranges, which is conducive to obtaining catalyst A and catalyst B with bulk density and bulk density ratio that meet the requirements, so that the obtained catalytic cracking combination catalyst avoids the problem of increased yield of heavy oil and diesel, and improves the yield of light olefins and propylene selectivity.

[0032] A second aspect of the present invention provides a method for preparing a catalytic cracking combined catalyst, wherein the method comprises:

[0033] (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;

[0034] (2) fully mixing clay, a second binder, an inorganic acid and water to form a matrix slurry, and then aging;

[0035] (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;

[0036] (4) homogenizing, spray drying and calcining the catalyst slurry to obtain the catalyst A or catalyst B;

[0037] (5) mixing catalyst A and catalyst B to obtain the combined catalyst;

[0038] 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;

[0039] 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.

[0040] In the present invention, the catalysts A and B prepared by the preparation methods of the catalysts A and B have good adaptability to each other, and the difference in wear strength between the catalysts A and B is small, so that the wear consumption between the two catalysts is low.

[0041] 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 Y-type molecular sieve and modified ZSM-5 in the pre-bonded molecular sieve slurry is (2-5): (3-7) on a dry basis.

[0042] 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.

[0043] In some embodiments of the present invention, preferably, the Y-type molecular sieve is selected from ReUSY-type and / or USY-type molecular sieves.

[0044] 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 silicon-aluminum ratio of the Y-type molecular sieve is relatively low, which is conducive to combining with the binder, thereby improving the anti-wear performance of the catalytic cracking combined catalyst.

[0045] In some embodiments of the present invention, preferably, the Re2O3 content in the ReUSY molecular sieve is ≤3wt%. In the present invention, controlling the Re2O3 content in the ReUSY molecular sieve within the above range is beneficial to ensuring the hydrothermal stability of the catalyst while reducing the hydrogen transfer capacity of the catalyst, thereby improving the yield of light olefin products.

[0046] 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.

[0047] In some embodiments of the present invention, preferably, the alkaline earth metal element is Mg.

[0048] 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;

[0049] 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.

[0050] In some embodiments of the present invention, preferably, the first binder is selected from at least one of silica sol, alumina sol and pseudo-boehmite, preferably alumina sol and / or alumina sol. In the present invention, the first binder is used as a molding aid, and the first binder is combined with Y-type molecular sieve and modified ZSM-5 to obtain a catalytic cracking combination catalyst for heavy oil catalytic cracking, which can improve the cracking of large molecular hydrocarbons in the matrix, has a good catalytic cracking effect, and can simultaneously meet the requirements of increasing the yield of light olefins and keeping the yield of heavy oil and diesel unchanged.

[0051] In the present invention, in step (1), in the process of mixing the Y-type molecular sieve, the modified ZSM-5, a part of the first binder and water to obtain the pre-bonded molecular sieve slurry, the amount of water is not particularly limited, as long as the Y-type molecular sieve, the modified ZSM-5 and a part of the first binder can be fully mixed to obtain the pre-bonded molecular sieve slurry. For example, based on the total amount of the pre-bonded molecular sieve slurry, the amount of water is 35-40% by weight; in addition, the water is not specifically limited, and is preferably deionized water.

[0052] 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.

[0053] 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).

[0054] In some embodiments of the present invention, preferably, the first binder is a part of the first binder and a remaining first binder.

[0055] In some embodiments of the present invention, preferably, on a dry basis, the weight ratio of the part of the first binder to the remaining first binder is 1:1-9.

[0056] In some embodiments of the present invention, preferably, the clay is selected from at least one of kaolin, halloysite and bentonite, preferably kaolin.

[0057] 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).

[0058] 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.

[0059] In some embodiments of the present invention, preferably, the inorganic acid (in the form of 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. 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.

[0060] In the present invention, in step (2), clay, a second binder and an inorganic acid are mixed to form a matrix slurry, wherein the mixing method is not specifically limited. Preferably, the mixing is carried out under stirring conditions, wherein the stirring conditions are not specifically limited. For example, the mixing can be carried out under stirring conditions of 100-150 r / min. In the process of forming the matrix slurry, the amount of water 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, based on the total amount of the matrix slurry, the amount of water is 35-40% by weight; in addition, the water is not specifically limited, and is preferably deionized water.

[0061] In some embodiments of the present invention, preferably, in step (4), the temperature of the spray drying is 370-450°C, and the time is 0.05-10min; 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 treatment are controlled within the above range, which is beneficial to the drying and roasting treatment of the catalyst slurry, and is beneficial 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.

[0062] In the present invention, preferably, in step (5), 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, stirring mixing, etc. 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.

[0063] In the present invention, a method of adding part of the first binder, the remaining first binder and the second binder step by step is adopted, which is beneficial to increasing the wear resistance of the catalytic cracking combination catalyst.

[0064] 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 catalytic cracking of heavy oil.

[0065] In the present invention, unless otherwise specified, the amounts of all materials are referred to on a dry basis.

[0066] The present invention will be described in detail below by way of examples:

[0067] The main analytical methods of the present invention are:

[0068] Pore ​​volume test: measured according to NB / SH / T 0955 standard method;

[0069] Bulk density test: measured according to NB / SH / T 0954 standard method;

[0070] Wear index test: measured according to NB / SH / T 0964 standard method;

[0071] Micro-reaction activity test: Determined according to NB / SH / T 0952 standard method;

[0072] Performance evaluation: The reaction performance was evaluated by ACE device. The raw oil used was ACE standard oil. The properties are shown in Table 1. The catalyst was aged at 800℃ and 100 volume % steam for 17h before evaluation. The catalytic reaction temperature was 530℃ and the catalyst-oil ratio was 6.

[0073] Conversion rate (wt%) = 100 (wt%) - heavy oil yield (wt%) - diesel yield (wt%);

[0074] C2-C4 olefin yield (wt%) = ethylene yield (wt%) + propylene yield (wt%) + butene yield (wt%);

[0075] Propylene selectivity (wt%) = propylene yield (wt%) × 100 (wt%) / liquefied gas yield (wt%).

[0076] The main raw materials and sources of the present invention:

[0077] ReUSY-1 molecular sieve: purchased from Lanzhou Petrochemical Catalyst Plant, industrial grade, rare earth content (in terms of Re2O3) is 2.5wt%, silicon-aluminum ratio (SiO2 / Al2O3 molar ratio) is 3.3;

[0078] 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;

[0079] USY molecular sieve: purchased from Lanzhou Petrochemical Catalyst Factory, industrial grade, silicon-aluminum ratio (SiO2 / Al2O3) is 3.2;

[0080] Modified ZSM-5: purchased from Lanzhou Petrochemical Catalyst Plant, with a phosphorus content (as P2O5) of 2.5wt% and a zinc content (as ZnO) of 0.5wt%;

[0081] Silica sol: purchased from Lanzhou Petrochemical Catalyst Factory, solid content 30 wt%;

[0082] Aluminum sol: purchased from Lanzhou Petrochemical Catalyst Factory, solid content is 20 wt%;

[0083] Pseudo-boehmite: purchased from Lanzhou Petrochemical Catalyst Factory, industrial grade, solid content 69 wt%;

[0084] Kaolin: purchased from Lanzhou Petrochemical Catalyst Plant, industrial grade, solid content 71 wt%;

[0085] Hydrochloric acid: purchased from Sinopharm Group, analytical grade, concentration 36% by weight.

[0086] Example 1

[0087] Preparation of Catalyst A:

[0088] (1) ReUSY-1 molecular sieve, P-Zn modified ZSM-5 and aluminum sol were added to deionized water and mixed evenly, and slurried for 60 minutes to obtain a pre-bonded molecular sieve slurry, wherein the amount of the aluminum sol accounted for 40% of the total amount of the aluminum sol on a dry basis;

[0089] (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 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;

[0090] (3) The molecular sieve slurry and the matrix slurry were fully mixed, and the remaining aluminum sol was added, and the slurry was continued for 30 minutes. The obtained mixed slurry was homogenized, spray-dried at 400°C, and then calcined at 500°C for 1 hour to obtain catalyst A.

[0091] Preparation of Catalyst B:

[0092] The preparation method of catalyst A was followed, except that

[0093] In step (1), USY molecular sieve is used instead of ReUSY 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.

[0094] Catalyst A and catalyst B were mixed at a mass ratio of 17:3 to obtain a catalytic cracking combined catalyst. The formulas of catalyst A and catalyst B 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.

[0095] Example 2

[0096] Preparation of Catalyst A:

[0097] The preparation method of catalyst A in Example 1 was followed, except that

[0098] In step (1), USY molecular sieve is used instead of ReUSY 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.

[0099] Preparation of Catalyst B:

[0100] The preparation method of catalyst A in Example 1 was followed, except that

[0101] In step (1), USY molecular sieve is used instead of ReUSY 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.

[0102] Catalyst A and catalyst B are mixed at a mass ratio of 1:1 to obtain a catalytic cracking combined catalyst. The formulas of catalyst A and catalyst B 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.

[0103] Example 3

[0104] Preparation of Catalyst A:

[0105] The preparation method of catalyst A in Example 1 was followed, except that

[0106] In step (1), ReUSY-2 molecular sieve is used instead of ReUSY-1 molecular sieve, and the amount of the aluminum sol used on a dry basis accounts for 50% of the total amount of the aluminum sol.

[0107] Preparation of Catalyst B:

[0108] The preparation method of catalyst A in Example 1 was followed, except that

[0109] In step (1), USY molecular sieve is used instead of ReUSY 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.

[0110] Catalyst A and catalyst B were mixed at a mass ratio of 17:3 to obtain a catalytic cracking combined catalyst. The formulas of catalyst A and catalyst B 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.

[0111] Example 4

[0112] Preparation of Catalyst A:

[0113] The preparation method of catalyst A in Example 1 was followed.

[0114] Preparation of Catalyst B:

[0115] The preparation method of catalyst A in Example 1 was followed, except that

[0116] In step (1), USY molecular sieve is used instead of ReUSY 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.

[0117] Catalyst A and catalyst B were mixed at a mass ratio of 9:1 to obtain a catalytic cracking combined catalyst. The formulas of catalyst A and catalyst B 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.

[0118] Example 5

[0119] Preparation of Catalyst A:

[0120] The preparation method of catalyst A in Example 1 was followed, except that

[0121] In step (1), the amount of the aluminum sol used on a dry basis accounts for 50% of the total amount of the aluminum sol.

[0122] Preparation of Catalyst B:

[0123] The preparation method of catalyst A in Example 1 was followed, except that

[0124] In step (1), USY molecular sieve is used instead of ReUSY molecular sieve.

[0125] Catalyst A and catalyst B were mixed at a mass ratio of 9:1 to obtain a catalytic cracking combined catalyst. The formulas of catalyst A and catalyst B 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.

[0126] Example 6

[0127] Preparation of Catalyst A:

[0128] The preparation method of catalyst A in Example 1 was followed.

[0129] Preparation of Catalyst B:

[0130] The preparation method of catalyst A in Example 1 was followed.

[0131] Catalyst A and catalyst B were mixed at a mass ratio of 10:1 to obtain a catalytic cracking combined catalyst. The formulas of catalyst A and catalyst B 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.

[0132] Comparative Example 1

[0133] Catalyst A was prepared according to the method of Example 1, except that catalyst B was not added to the combined catalyst.

[0134] The formula of catalyst A is shown in Table 2, and the performance parameters of catalyst A and the effect of the combined catalyst are shown in Table 3.

[0135] Comparative Example 2

[0136] Preparation of Catalyst A:

[0137] The preparation method of catalyst A in Example 1 was followed, except that

[0138] In step (1), USY molecular sieve is used instead of ReUSY molecular sieve, and the amount of the aluminum sol used on a dry basis accounts for 10% of the total amount of the aluminum sol.

[0139] Preparation of Catalyst B:

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

[0141] In step (1), USY molecular sieve is used instead of ReUSY 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.

[0142] Catalyst A and catalyst B are mixed at a mass ratio of 1:1 to obtain a catalytic cracking combined catalyst. The formulas of catalyst A and catalyst B 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.

[0143] Comparative Example 3

[0144] Preparation of Catalyst A:

[0145] The preparation method of catalyst A in Example 1 was followed.

[0146] Preparation of Catalyst B:

[0147] The preparation method of catalyst A in Example 1 was followed, except that

[0148] In step (1), the amount of the aluminum sol used on a dry basis accounts for 5% of the total amount of the aluminum sol.

[0149] Catalyst A and catalyst B were mixed at a mass ratio of 17:3 to obtain a catalytic cracking combined catalyst. The formulas of catalyst A and catalyst B 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.

[0150] Comparative Example 4

[0151] Preparation of Catalyst A:

[0152] The preparation method of catalyst A in Example 1 was followed.

[0153] Preparation of Catalyst B:

[0154] The preparation method of catalyst A in Example 1 was followed, except that

[0155] In step (1), no Y molecular sieve is added, and the amount of the silica sol on a dry basis accounts for 100% of the total amount of the silica sol;

[0156] In step (3), no silica sol is added, and 75% phosphoric acid is added to the obtained mixed slurry to adjust the pH value to 3.

[0157] Catalyst A and catalyst B were mixed at a mass ratio of 17:3 to obtain a catalytic cracking combined catalyst. The formulas of catalyst A and catalyst B 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.

[0158] Table 1 Properties of crude oil

[0159] project ACE Evaluation Standard Oil <![CDATA[Density (20 °C) / (kg / cm 3 )]]> 0.90 Residual carbon, m% 0.47 Saturation fraction / S,m% 56.51 Aromatic content / Ar,m% 33.51 Gum / R,m% 5.55 Asphaltene, m / % 4.61 Carbon content, m% 86.88 Hydrogen content, m% 12.66

[0160] Table 2 Catalyst formulation

[0161]

[0162]

[0163] The content of each component in Table 2 is the weight percentage on a dry basis.

[0164] Table 3 Performance parameters of catalysts and effects of combined catalysts

[0165]

[0166] Table 3 (continued)

[0167]

[0168] The catalytic cracking combination catalyst provided by the present invention has a small wear index, is used for catalytic cracking of heavy oil, has a higher yield of light olefins and a higher selectivity of propylene, and does not increase the yield of heavy oil and diesel.

[0169] From the results of Examples 1 to 5, it can be seen 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 each of catalyst A and catalyst B are controlled within the range defined by the present invention, and the obtained combined catalyst has a high light olefin yield and propylene selectivity at the same time, and the yield of diesel and heavy oil is not increased, and the comprehensive effect of catalytic cracking is better. Combining the results of Example 1 with Example 6, it can be seen that in Example 6, since the weight ratio of catalyst A to catalyst B defined by the present invention is not adopted, the light olefin yield and propylene selectivity of the obtained combined catalyst are slightly reduced.

[0170] 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 of 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 in Comparative Example 4, Catalyst B does not adopt the preparation method provided by the present invention, but adopts the conventional co-catalyst preparation method, and the wear index deviation between the obtained Catalyst B and Catalyst A is large, resulting in large wear and consumption between the two catalysts, and the light olefin yield of the obtained combined catalyst is low.

[0171] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope 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, preferably 7-26:

3.

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; Preferably, the pore volume of the catalyst B is 0.29-0.31 cm 3 / g.

4. The combined catalyst according to any one of claims 1 to 3, 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 any one of claims 1 to 3, 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 (2-5): (3-7) on a dry basis; Preferably, 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; Preferably, the Y-type molecular sieve is selected from ReUSY-type and / or USY-type molecular sieve; Preferably, the silicon-aluminum ratio SiO2 / Al2O3 of the Y-type molecular sieve is 3.1-5; Preferably, the Re2O3 content in the ReUSY type molecular sieve is ≤3wt%; 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, preferably at least two; Preferably, the alkaline earth metal element is Mg; Preferably, the transition metal element is selected from at least one of Fe, Co, Ni, Zn and Cu; Preferably, the content of the modifying element in the modified ZSM-5 is 1.5-5 wt % 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, preferably alumina sol and / or alumina sol; Preferably, the second binder is selected from at least one of silica sol, alumina sol and pseudo-boehmite, preferably pseudo-boehmite; Preferably, on a dry basis, the weight ratio of the first binder to the second binder is (7-12):(8-15); Preferably, the first binder is a part of the first binder and the remaining first binder; Preferably, on a dry basis, the weight ratio of the part of the first binder to the remaining first binder is 1:1-9; Preferably, the clay is selected from at least one of kaolin, halloysite and bentonite, preferably kaolin; Preferably, on a dry basis, the weight ratio of the clay to the second binder is (30-50):(8-15); Preferably, the inorganic acid is selected from at least one of hydrochloric acid, nitric acid and sulfuric acid; Preferably, the inorganic acid (in the form of 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 any one of claims 6 to 8, 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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