Large-grained pseudo-boehmite, its preparation method, and catalytic cracking catalyst with medium-large pore structure and its preparation method

Abstract

The application discloses a catalytic cracking catalyst with mesopore and macropore structures and a preparation method thereof. The catalytic cracking catalyst contains 15-60 wt% of molecular sieve, 5-40 wt% of first binder of large-grained pseudo-boehmite calculated based on alumina, 0-15 wt% of second binder and 20-80 wt% of clay based on dry weight. The large-grained pseudo-boehmite has a grain size of 6-10 nm. The total pore volume of the catalytic cracking catalyst is 0.4-0.5 mL / g. The preparation method comprises the following steps: preparing the first binder of large-grained pseudo-boehmite by a carbonization method, adding hydrochloric acid to gelatinize the large-grained pseudo-boehmite, adding the clay, the molecular sieve and the second binder, spray-drying and molding, calcining, washing and drying. The large-grained pseudo-boehmite is prepared by the following steps: neutralizing sodium metaaluminate solution with carbon dioxide to form a gel, aging the slurry by gradually increasing the temperature in stages after the gel is formed, filtering the slurry, continuously washing and drying after the aging. The catalytic cracking catalyst has good abrasion performance while retaining the mesopore and macropore structures. When applied to a catalytic cracking process, the catalytic cracking catalyst can significantly improve heavy oil conversion rate, reduce coke formation and optimize product distribution.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of catalytic cracking catalysts; more particularly, the present application relates to a large-grained pseudo-boehmite and a preparation method thereof, and a catalytic cracking catalyst with a medium-large pore structure and a preparation method thereof. BACKGROUND

[0002] Since the first commercial fluid catalytic cracking (FCC) unit was put into operation in 1942, catalytic cracking has gradually developed into a core processing technology in the oil refining industry, and is the most important secondary processing process and an important way to improve the processing depth of crude oil and increase the yield of light oil. In recent years, with the increasing seriousness of the heavy and poor quality of crude oil, improving the heavy oil conversion rate has become an effective means to adjust the product structure and increase economic benefits in the oil refining field, which forces the FCC catalyst to develop towards an open pore structure with more medium-large pores. In order to eliminate diffusion limitations, the optimal range of catalyst pore size is 2-6 times the diameter of heavy oil macromolecules, and this part of the pore is mainly provided by the active matrix. Therefore, improving the pore structure of the catalyst matrix is the top priority in the research of heavy oil cracking catalysts.

[0003] Kaolin is a main component of catalytic cracking catalysts, and it is reported that acid-base modification can increase the specific surface area and pore volume of kaolin. Zhao Chen (Industrial Catalysis, 15(1), 2007, 14) et al. prepared an Inner Mongolia kaolin catalyst matrix by alkali treatment, and the pore size could reach 10 nm, and the cracking activity was enhanced. CN109692676A discloses a kaolin modification method and its application in catalytic cracking catalysts, and a macroporous kaolinite with an average pore diameter of 2-50 nm is obtained by calcining and treating kaolin with an acid solution in the presence of a pore expander. The catalytic cracking catalyst prepared therefrom has good cracking performance, metal pollution resistance and carbon deposition resistance.

[0004] Catalytic cracking catalysts also regulate the pore structure by introducing medium-large pore silicon-aluminum materials. Zheng Jinyu et al. (Petroleum Refining and Chemical Engineering, 46(10), 2015, 39) synthesized a silicon-aluminum material with a pseudo-boehmite structure by introducing silicon during the synthesis of pseudo-boehmite, and the pore volume could reach 0.98 cm 3 / g, the specific surface area was 425.0 m 2 / g, and the average pore diameter reached 10 nm. The catalyst prepared by using the material has good heavy oil conversion capacity and coke selectivity. CN109304223A discloses a catalytic cracking catalyst and a preparation method thereof, and the catalyst contains a medium-large pore silicon-aluminum material, and its anhydrous chemical expression in terms of oxide weight is: (0-0.3)Na2O:(2-18)Al2O3:(82-98)SiO2; the pore volume thereof is 0.8-2 ml / g, and the specific surface area is 150-350 m 2 / g, the introduction of the meso-macroporous silica-alumina material significantly increases the pore volume of the catalyst.

[0005] The heavy oil conversion capacity of the catalyst can be improved by modifying the alumina to improve the performance of the matrix. CN111744491A, CN112237909A, etc. modify the alumina by calcination combined with rare earth modified alumina and silicon modified alumina to optimize the pore structure. For catalytic cracking catalyst, the catalyst has high resistance to heavy metal pollution, high cracking performance and optimal product distribution.

[0006] In addition, a template is introduced during the preparation of the catalyst, and the template is removed by high temperature calcination after the catalyst is formed by using the space occupation effect, and a meso-macroporous catalytic cracking catalyst can also be obtained. US4624773 discloses a method for preparing a macroporous catalytic cracking catalyst using rigid template carbon black. The introduction of carbon black can produce at least 0.10 cm 3 / g above 100 nm. CN1831090A discloses a method for synthesizing a macroporous catalytic cracking catalyst by a particle template method, i.e. by introducing an organic polymer with a particle size of 5-1500 nm to synthesize a macroporous catalyst. The volume fraction of the pore diameter greater than 5 nm in the catalyst can be arbitrarily adjusted within the range of 5%-74%; the pore diameter range can be arbitrarily selected within the range of 5-2000 nm, and the catalyst has high cracking activity and good selectivity.

[0007] The binder has an important influence on the pore structure and strength of the cracking catalyst. CN105983400A discloses a preparation method of a mesoporous alumina binder and its application in a heavy oil catalytic cracking catalyst. The invention prepares a mesoporous alumina binder by introducing a triblock polymer template P123. Compared with the traditional binder, the mesoporous alumina binder has a mesoporous channel structure, a large specific surface area and a large pore volume. The catalyst prepared by using the binder has an effective meso-macroporous hierarchical pore channel distribution, which increases the heavy oil conversion rate and the light oil yield, and reduces the coke yield and the heavy oil yield.

[0008] CN105688977A discloses a preparation method of a catalytic cracking catalyst containing pseudoboehmite. By using unmodified pseudoboehmite and silicon modified pseudoboehmite in combination, the influence of conventional pseudoboehmite peptization on the macropore of the catalyst is reduced while the adhesion performance is retained. The prepared catalyst has good wear resistance index, high macropore volume, strong heavy oil conversion capacity and good coke selectivity.

[0009] However, the above methods for preparing the catalytic cracking catalyst have difficulty in simultaneously considering the macropore structure and strength of the catalyst, or have high energy consumption, long process, and high economic cost in the preparation process. Therefore, there is still a need for a catalytic cracking catalyst with low preparation cost and good abrasion resistance index and rich mesopores and macropores. SUMMARY

[0010] In order to solve the above problems of simultaneously considering the mesopore and macropore structure and strength and maintaining a low production cost, the present application provides a catalytic cracking catalyst with mesopore and macropore structure and a preparation method thereof.

[0011] In one aspect, the present application provides a mesopore and macropore catalytic cracking catalyst containing 15-60 wt% of a molecular sieve, 5-40 wt% of a first binder of large-grained pseudo-boehmite calculated as alumina, 0-15 wt% of a second binder, and 20-80 wt% of clay, based on the dry basis weight, the particle size of the large-grained pseudo-boehmite being 6-10 nm, and the total pore volume of the catalytic cracking catalyst being 0.4-0.5 mL / g.

[0012] In one embodiment, the catalytic cracking catalyst contains 25-40 wt% of a molecular sieve, 10-30 wt% of a first binder of large-grained pseudo-boehmite calculated as alumina, 2-10 wt% of a second binder, and 30-50 wt% of clay.

[0013] In one embodiment, the catalytic cracking catalyst according to the present application, wherein the clay is selected from one or more of kaolin, rectorite, diatomite, montmorillonite, bentonite, and sepiolite.

[0014] In one embodiment, the catalytic cracking catalyst according to the present application, wherein the molecular sieve is selected from one or more of a Y-type molecular sieve, a Beta-type zeolite, a shape-selective zeolite, an MCM zeolite, an L zeolite, an aluminum phosphate molecular sieve, and a silicon-aluminum phosphate molecular sieve.

[0015] In one embodiment, the catalytic cracking catalyst according to the present application, wherein the molecular sieve comprises a Y-type molecular sieve.

[0016] Optionally, in one embodiment of the catalytic cracking catalyst according to the present application, the molecular sieve further comprises other molecular sieves, and the other molecular sieves are one or more of a Beta-type zeolite, a shape-selective zeolite, an MCM zeolite, an L zeolite, an aluminum phosphate molecular sieve, and a silicon-aluminum phosphate molecular sieve.

[0017] In one embodiment, the catalytic cracking catalyst according to the present application, wherein the Y-type molecular sieve is a NaY-type molecular sieve or a modified Y-type molecular sieve.

[0018] In one embodiment, according to the catalytic cracking catalyst of the present invention, the modified Y-type molecular sieve is REY, HY, REHY, USY or REUSY molecular sieve.

[0019] In one embodiment, according to the catalytic cracking catalyst of the present invention, the second binder is selected from one or more of silica sol, aluminum sol, phosphate aluminum sol, and peptized ordinary pseudo-boehmite.

[0020] In another aspect, the present invention provides a method for preparing the aforementioned catalytic cracking catalyst, comprising the following steps:

[0021] (1) A large-grain pseudo-boehmite first binder was prepared by carbonization as follows:

[0022] a. neutralizing a sodium aluminate solution with carbon dioxide gas to form a gel, wherein the concentration of the sodium aluminate solution is 15 to 60 g Al2O3 / L as an oxide, the volume concentration of the carbon dioxide gas is 15 to 50%, the gelling temperature is below 50 ° C, and the gelling endpoint pH is 9 to 11;

[0023] b. The gelled slurry is placed in a sealed container for staged aging, wherein the first stage is heated to 50-100°C for aging for 30-120 minutes, and the second stage is heated to 100-220°C for aging for 1-10 hours;

[0024] c. The aged slurry was filtered and washed continuously with deionized water at 60 to 90°C;

[0025] d. The filter cake obtained after washing is dried to obtain the large-grain pseudo-boehmite first binder;

[0026] (2) mixing the large-grain pseudo-boehmite obtained in step (1) with deionized water and beating into a slurry, adding hydrochloric acid with a concentration of 36-38% to the slurry at a molar ratio of n(HCl) / n(Al2O3)=0.1-0.3 while stirring, and acidifying for 0.5-1 hour to obtain a peptized large-grain pseudo-boehmite first binder with a solid content of 10-30 weight %;

[0027] (3) mixing the peptized large-grain pseudo-boehmite first binder obtained in step (2) with molecular sieve, clay and deionized water, and then adding a second binder and mixing to prepare a catalytic cracking catalyst slurry with a solid content of 20 to 40 weight percent, wherein the slurry contains, on a dry basis, 15 to 60 weight percent of the molecular sieve, 5 to 40 weight percent of the large-grain pseudo-boehmite first binder calculated as alumina, 0 to 15 weight percent of the second binder, and 20 to 80 weight percent of the clay;

[0028] (4) The slurry prepared in step (3) is subjected to spray drying, calcination, washing and drying in this order to prepare the catalytic cracking catalyst comprising large crystal pseudo-boehmite.

[0029] In one embodiment, the preparation method according to the present application, wherein the concentration of the sodium aluminate solution in step (1)a is 15-60 g Al203 / L as calculated as oxide, and the volume concentration of the carbon dioxide gas is 25-50%.

[0030] In one embodiment, the preparation method according to the present application, wherein in step (1)b, the first stage is aged at 60-80°C for 40-80 min, and the second stage is aged at 120-180°C for 2-6 h.

[0031] In one embodiment, the preparation method according to the present application, wherein in step (1)c, the continuous washing is performed using deionized water at 80-90°C.

[0032] In one embodiment, the preparation method according to the present application, wherein in step (3), the catalytic cracking catalyst slurry contains 25-40 wt% of the molecular sieve, 10-30 wt% of the large crystal pseudo-boehmite first binder calculated as alumina, 2-10 wt% of the second binder, and 30-50 wt% of the clay, based on the dry weight.

[0033] In one embodiment, the preparation method according to the present application, wherein the clay is selected from one or more of kaolin, rectorite, diatomite, montmorillonite, bentonite, and sepiolite.

[0034] In one embodiment, the preparation method according to the present application, wherein the molecular sieve is selected from one or more of Y-type molecular sieve, Beta-type zeolite, shape-selective zeolite, MCM zeolite, L zeolite, aluminum phosphate molecular sieve, and silicon aluminum phosphate molecular sieve.

[0035] In one embodiment, the preparation method according to the present application, wherein the molecular sieve comprises Y-type molecular sieve.

[0036] In one embodiment, the preparation method according to the present application, wherein the Y-type molecular sieve is NaY-type molecular sieve or modified Y-type molecular sieve.

[0037] In one embodiment, the preparation method according to the present application, wherein the modified Y-type molecular sieve is REY, HY, REHY, USY, or REUSY molecular sieve.

[0038] In one embodiment, the preparation method according to the present application, wherein the second binder is selected from one or more of silica sol, aluminum sol, phosphorus aluminum sol, and peptized ordinary pseudo-boehmite.

[0039] The catalytic cracking catalyst according to the present application is prepared by introducing large-particle pseudo-boehmite having good peptization property during the preparation process, which can be stacked to form meso-macropore structure while ensuring the adhesion, thereby preparing a catalytic cracking catalyst having both strength and meso-macropore structure. Also, the large-particle pseudo-boehmite is prepared by carbonization method, and the production cost of the meso-macropore catalytic cracking catalyst is low. The catalytic cracking catalyst having meso-macropore structure according to the present application has excellent heavy oil conversion ability, coke selectivity, heavy metal pollution resistance and product distribution when applied to heavy oil cracking due to the abundant meso-macropore structure. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 The pore size distribution of the catalytic cracking catalyst prepared in Example 1, Comparative Example 1 and Comparative Example 3. DETAILED DESCRIPTION

[0041] The present application will be further described by the accompanying drawings and examples. The features and advantages of the present application will become more apparent from these descriptions.

[0042] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as there is no conflict.

[0043] The present application provides a catalytic cracking catalyst having meso-macropore structure, which contains 15 to 60 wt% of molecular sieve, 5 to 40 wt% of large-particle pseudo-boehmite first binder in terms of alumina, 0 to 15 wt% of second binder and 20 to 80 wt% of clay based on the dry weight, the particle size of the large-particle pseudo-boehmite is in the range of 6 to 10 nm, and the total pore volume of the catalytic cracking catalyst is 0.4 to 0.5 mL / g.

[0044] The catalytic cracking catalyst according to the present application preferably contains 25 to 40 wt% of molecular sieve, 10 to 30 wt% of large-particle pseudo-boehmite first binder in terms of alumina, 2 to 10 wt% of second binder and 30 to 50 wt% of clay.

[0045] In the catalytic cracking catalyst according to the present application, the clay can be selected from one or more of kaolin, rectorite, diatomite, montmorillonite, bentonite and sepiolite; the molecular sieve can be selected from one or more of Y-type molecular sieve, Beta-type zeolite, shape-selective zeolite, MCM zeolite, L zeolite, aluminum phosphate molecular sieve and silicon aluminum phosphate molecular sieve, and preferably contains Y-type molecular sieve, which can be NaY-type molecular sieve or modified Y-type molecular sieve such as REY, HY, REHY, USY or REUSY.

[0046] In the catalytic cracking catalyst of the present application, the second binder can be selected from one or more of silica sol, alumina sol, phospho-alumina sol, and peptized ordinary pseudo-boehmite, wherein the peptized ordinary pseudo-boehmite refers to the pseudo-boehmite product commonly used in the art, and the crystal grain is usually 3-4 nm.

[0047] In the catalytic cracking catalyst of the present application, the first binder and the second binder are contained, the large-grain pseudo-boehmite as the first binder has the grain size controlled in the range of 6-10 nm, and the large-grain accumulation in the above grain size range can form a meso-macropore structure, thus the catalyst formed has a total pore volume of 0.4-0.5 mL / g, and the large-grain pseudo-boehmite first binder endows the catalyst with abundant meso-macropores, thereby improving the heavy oil conversion capacity and the coke selectivity of the catalyst. Meanwhile, the first binder is combined with the second binder, further improving the wear resistance of the catalyst and ensuring the strength of the catalyst.

[0048] In another aspect, the present application provides a preparation method of the aforementioned catalytic cracking catalyst, comprising the following steps:

[0049] (1) preparing the large-grain pseudo-boehmite first binder by the carbonization method as follows:

[0050] a. neutralizing a sodium meta-aluminate solution with carbon dioxide gas to form a gel, wherein the sodium meta-aluminate solution has a concentration of 15-60 g Al2O3 / L in terms of oxide, the carbon dioxide gas has a volume concentration of 15-50%, the gelation temperature is lower than 50°C, and the gelation end point pH value is 9-11;

[0051] b. loading the gelled slurry into a sealed container for staged temperature aging, wherein the first stage is heated to 50-100°C for aging for 30-120 min, and the second stage is heated to 100-220°C for aging for 1-10 h;

[0052] c. filtering the aged slurry and continuously washing with deionized water at 60-90°C;

[0053] d. drying the filter cake obtained after washing to obtain the large-grain pseudo-boehmite first binder;

[0054] (2) mixing the large-grain pseudo-boehmite prepared in step (1) with deionized water to form a slurry, adding hydrochloric acid with a concentration of 36-38% to the slurry according to the molar ratio of n(HCl) / n(Al2O3)=0.1-0.3 while stirring, and acidizing for 0.5-1 h to obtain a peptized large-grain pseudo-boehmite first binder with a solid content of 10-30% by weight;

[0055] (3) mixing and stirring the first binder of the colloidal large-particle pseudo-boehmite prepared in step (2) with the molecular sieve, clay and deionized water to obtain a slurry of the catalytic cracking catalyst having a solid content of 20-40% by weight, which contains 15-60% by weight of the molecular sieve, 5-40% by weight of the large-particle pseudo-boehmite first binder calculated as alumina, 0-15% by weight of the second binder and 20-80% by weight of the clay, based on the dry weight;

[0056] (4) spray drying, calcining, washing and drying the slurry prepared in step (3) to obtain the catalytic cracking catalyst containing the large-particle pseudo-boehmite.

[0057] The concentration of the sodium aluminate solution used in step (la) is 15-60 g Al203 / L as calculated as the oxide, and the volume concentration of the carbon dioxide gas is preferably 25-50%.

[0058] The closed container used in step (lb) is required to be resistant to high temperature, pressure and acid and alkali corrosion, and can be a glass container, a stainless steel container or a reaction kettle. In this step, the temperature is raised in stages for aging, i.e. first programmed to 50-100°C for aging for 30-120 min, preferably to 60-80°C for aging for 40-80 min, then programmed to 100-220°C for aging for 1-10 h, preferably to 120-180°C for aging for 2-6 h, at a rate of 4-6°C / min. By controlling the temperature and time of the two-stage aging, the number of crystal nuclei and the crystal growth rate can be controlled to obtain the large-particle pseudo-boehmite.

[0059] The deionized water used in step (lc) can be at a temperature of 60-90°C, preferably 80-90°C. The washing method is continuous washing, and the washing time can be half an hour, i.e. deionized water is continuously added during the filtration process, and no re-slurry is added after the first slurry until the washing is completed, so that the water and solid system is always in dynamic equilibrium.

[0060] The drying temperature in step (Id) can be 60-120°C, preferably 70-100°C, and the drying time is 2-4 h.

[0061] In the preparation method of the present application, the order of adding the clay, molecular sieve and colloidal large-particle pseudo-boehmite in step (3) is not particularly limited.

[0062] In the preparation method of the present application, the method and conditions of spray drying in step (4) are well known to those skilled in the art, and the process conditions are generally that the spray tower furnace temperature is controlled at 400-600°C, and the spray tail gas temperature is controlled at 100-300°C; the calcination in step (4) can be carried out at a temperature of 350-800°C, preferably 400-650°C, and the calcination time can be 0.5-6h, preferably 1-4h, and can be carried out in any atmosphere, for example in air; the washing in step (4), i.e. removal of various impurity ions brought in by the catalyst preparation steps by ion exchange, uses water washing and / or ammonium salt washing.

[0063] In the preparation method of the present application, the molecular sieve, clay and second binder used are as described above for the catalytic cracking catalyst provided by the present application.

[0064] It should be noted that in the present application, the peptized ordinary pseudo-boehmite refers to the existing or commercially available pseudo-boehmite product, so as to be distinguished from the large particle size pseudo-boehmite according to the present application.

[0065] According to the catalytic cracking catalyst preparation method of the present application, the control of the pseudo-boehmite grain size is achieved by two-stage temperature rising aging in the preparation process, and large grains with a particle size in the range of 6-10nm are obtained, and the large grain pseudo-boehmite can stack into mesopore and macropore structures while ensuring the adhesion, thereby preparing a catalyst with both strength and mesopore and macropore structures. In addition, the large grain pseudo-boehmite is prepared by carbonization method, which maintains the relatively low production cost of the catalytic cracking catalyst. The mesopore and macropore catalyst prepared by the present application has excellent heavy oil conversion capacity, coke selectivity, heavy metal resistance and product distribution when applied to heavy oil cracking.

[0066] The following examples will further illustrate the present application, which is intended to help the reader better understand the essence of the present application and the beneficial effects brought by it, but should not be understood as any limitation on the scope of the present application.

[0067] Examples

[0068] The raw materials used in the following examples and comparative examples are described as follows:

[0069] The sodium alumininate was provided by Shandong Aluminum Factory;

[0070] The kaolin was a special kaolin for cracking catalyst produced by Suzhou China Kaolin Co., Ltd., with a solid content of 76% by weight;

[0071] The molecular sieve was provided by Qilu Branch of Sinopec Catalyst Co., Ltd., with a solid content of 78% by weight;

[0072] The aluminum sol was provided by Qilu Branch of Sinopec Catalyst Co., Ltd., with an alumina content of 21% by weight;

[0073] Hydrochloric acid was provided by the National Pharmaceutical Group Chemical Reagent Co., Ltd., analytical pure, mass concentration 36.0-38.0%.

[0074] The crystal structure of the sample was characterized by an X-ray powder diffractometer of PHILIPS company, Cu Kα ray, tube voltage 40 kV, tube current 40 mA, scanning speed 2° / min, scanning range 5°-70°. The calculation formula of pseudo-boehmite grain was as follows: wherein K = 1.075, λ is the wavelength of anode radiation Kα1 spectrum, β1 is the integral width of 041, 130 diffraction peak of pseudo-boehmite, and θ is the Bragg diffraction angle of diffraction peak.

[0075] An ASAP 2405N V1.01 automatic adsorption instrument of American Micromeritics company was used, low-temperature static nitrogen adsorption volumetric method, the sample was in 1.33×10 -2 Pa, vacuum degassing at 300°C for 4 h, N2 as adsorption medium, the adsorption-desorption isotherm of the sample was determined at 77.4 K. The specific surface area (S BET ) of the sample was calculated according to the BET formula, the volume of N2 adsorbed by the sample at relative pressure p / p0 = 0.98 was converted into the volume of liquid nitrogen, i.e. the total pore volume.

[0076] Micro-activity index: the micro-activity of light oil of the sample was evaluated according to the standard method of RIPP92-90 (see Petroleum and Chemical Industry Analysis Method (RIPP Test Method) edited by Yang Cuiding et al., published by Science Press in 1990), the catalyst loading was 5.0 g, the reaction temperature was 460°C, the raw oil was straight-run light diesel oil with a distillation range of 235-337°C, the product composition was analyzed by gas chromatography, and the light oil micro-activity was calculated according to the product composition.

[0077] Example 1

[0078] A sodium metaaluminate solution with a concentration of 40 g Al2O3 / L was subjected to a gelation reaction with carbon dioxide gas with a volume fraction of 45%, and the carbon dioxide gas flow rate was 2 L / min, and the end point pH value was controlled to be 10.5. After the obtained slurry was transferred to a reaction kettle, it was first programmed to be heated (heating rate 5°C / min) to 65°C for aging for 45 min, and then programmed to be heated (heating rate 5°C / min) to 135°C for aging for 4 h. After the aging was completed, the obtained slurry was subjected to solid-liquid separation, and was continuously washed with deionized water at 80°C for half an hour to obtain a product filter cake from which impurities were removed, which was dried at 100°C for 3 h, and was crushed to obtain a pseudo-boehmite powder PB1, and the physicochemical properties of which are shown in Table 1.

[0079] Take 115.2 g of large-grained pseudo-boehmite PB1 with a solid content of 76% by weight and add 324.8 g of deionized water, stir for 20 min. Add 17.6 g of hydrochloric acid with a concentration of 36-38% and acidify for 60 min to obtain a peptized large-grained pseudo-boehmite. Take 212.6 g of kaolin with a solid content of 79% by weight and add 874.2 g of deionized water and stir for 20 min, then add 153.2 g of HSY-12 molecular sieve with a solid content of 78% by weight and continue to stir for 20 min. Then add the peptized large-grained pseudo-boehmite and stir for 20 min. Finally, add 109.1 g of aluminum sol with a solid content of 22% by weight and stir for 20 min to obtain a final catalyst slurry, which is subjected to spray drying and molding, calcined at 500°C for 2 h, and then washed and dried to obtain the catalytic cracking catalyst CAT1 of the application. Among them, the CAT1 catalyst obtained contains 30% by weight of HSY-12 molecular sieve, 42% by weight of kaolin, 22% by weight of large-grained pseudo-boehmite, and 6% by weight of aluminum sol on a dry basis.

[0080] Example 2

[0081] A sodium metaaluminate solution with a concentration of 30 g Al2O3 / L is subjected to a gelation reaction with carbon dioxide gas with a volume fraction of 45%, and the carbon dioxide gas flow rate is 2 L / min, and the end point pH value is controlled to be 10.5. After the obtained slurry is transferred to a reaction kettle, it is first programmed to heat (heating rate 5°C / min) to 70°C and aged for 50 min, and then programmed to heat (heating rate 5°C / min) to 150°C and aged for 4 h. After the aging is completed, the obtained slurry is subjected to solid-liquid separation, and is continuously washed with 90°C deionized water for half an hour to obtain a filter cake of the impurity-removed product, which is dried at 100°C for 3 h and pulverized to obtain pseudo-boehmite powder PB2, and the physicochemical properties of which are shown in Table 1.

[0082] Take 115.2 g of large-grained pseudo-boehmite PB1 with a solid content of 76% by weight and add 324.8 g of deionized water, stir for 20 min. Add 17.6 g of hydrochloric acid with a concentration of 36-38% and acidify for 60 min to obtain a peptized large-grained pseudo-boehmite. Take 212.6 g of kaolin with a solid content of 79% by weight and add 874.2 g of deionized water and stir for 20 min, then add 153.2 g of HSY-12 molecular sieve with a solid content of 78% by weight and continue to stir for 20 min. Then add the peptized large-grained pseudo-boehmite and stir for 20 min. Finally, add 109.1 g of aluminum sol with a solid content of 22% by weight and stir for 20 min to obtain a final catalyst slurry, which is subjected to spray drying and molding, calcined at 500°C for 2 h, and then washed and dried to obtain the catalytic cracking catalyst CAT1 of the application. Among them, the CAT1 catalyst obtained contains 30% by weight of HSY-12 molecular sieve, 42% by weight of kaolin, 22% by weight of large-grained pseudo-boehmite, and 6% by weight of aluminum sol on a dry basis.

[0083] Example 3

[0084] A sodium aluminate solution with a concentration of 20 g Al203 / L was subjected to a gelation reaction with carbon dioxide gas with a volume fraction of 33%, and the carbon dioxide gas flow rate was 2 L / min, and the end point pH value was controlled to be 10.5. After the obtained slurry was transferred to a reaction kettle, it was first programmed to heat (heating rate 5°C / min) to 70°C for aging for 60 min, and then programmed to heat (heating rate 5°C / min) to 170°C for aging for 5 h. After the aging was completed, the obtained slurry was subjected to solid-liquid separation, and was continuously washed with 90°C deionized water for half an hour to obtain an impurity-removed product filter cake, which was dried at 100°C for 3 h, and was crushed to obtain a pseudo-boehmite powder PB3. The physicochemical properties of the pseudo-boehmite powder PB3 are shown in Table 1.

[0085] A large-grained pseudo-boehmite PB3 with a solid content of 80% by weight was taken in an amount of 109.5 g, and was added to 330.4 g of deionized water, and was stirred for 20 min. 17.6 g of hydrochloric acid with a concentration of 36-38% was added, and was acidified for 60 min to obtain a peptized large-grained pseudo-boehmite. Kaolin with a solid content of 79% by weight was taken in an amount of 212.6 g, and was added to 874.2 g of deionized water, and was stirred for 20 min. Then, HSY-12 molecular sieve with a solid content of 78% by weight was taken in an amount of 153.2 g, and was continuously stirred for 20 min. The peptized large-grained pseudo-boehmite was further added, and was stirred for 20 min. Finally, an aluminum sol with a solid content of 22% by weight was taken in an amount of 109.1 g, and was stirred for 20 min to obtain a final catalyst slurry, which was subjected to spray drying and molding, and was calcined at 500°C for 2 h, and was then washed and dried to obtain the catalytic cracking catalyst CAT3 of the present application. In the obtained CAT3 catalyst, the HSY-12 molecular sieve, the kaolin, the large-grained pseudo-boehmite, and the aluminum sol are contained in amounts of 30% by weight, 42% by weight, 22% by weight, and 6% by weight, respectively, on a dry basis.

[0086] Example 4

[0087] A sodium aluminate solution with a concentration of 15 g Al203 / L was subjected to a gelation reaction with carbon dioxide gas with a volume fraction of 25%, and the carbon dioxide gas flow rate was 1 L / min, and the end point pH value was controlled to be 11. After the obtained slurry was transferred to a reaction kettle, it was first programmed to heat (heating rate 5°C / min) to 75°C for aging for 70 min, and then programmed to heat (heating rate 5°C / min) to 180°C for aging for 5 h. After the aging was completed, the obtained slurry was subjected to solid-liquid separation, and was continuously washed with 90°C deionized water for half an hour to obtain an impurity-removed product filter cake, which was dried at 100°C for 3 h, and was crushed to obtain a pseudo-boehmite powder PB4. The physicochemical properties of the pseudo-boehmite powder PB4 are shown in Table 1.

[0088] Take 106.9 g of large-grained pseudo-boehmite PB4 with a solid content of 82 wt% and add 333.1 g of deionized water, stir for 20 min. Add 17.6 g of hydrochloric acid with a concentration of 36-38% and acidify for 60 min to obtain a peptized large-grained pseudo-boehmite. Take 212.6 g of kaolin with a solid content of 79 wt% and add 874.2 g of deionized water, stir for 20 min, then add 153.2 g of HSY-12 molecular sieve with a solid content of 78 wt%, continue to stir for 20 min. Then add the peptized large-grained pseudo-boehmite and stir for 20 min. Finally, add 109.1 g of aluminum sol with a solid content of 22 wt% and stir for 20 min to obtain a final catalyst slurry, which is spray-dried and molded, calcined at 500°C for 2 h, then washed and dried to obtain the catalytic cracking catalyst CAT4 of the application. Among them, the CAT4 catalyst obtained contains 30 wt% of HSY-12 molecular sieve, 42 wt% of kaolin, 22 wt% of large-grained pseudo-boehmite, and 6 wt% of aluminum sol on a dry basis.

[0089] Comparative Example 1

[0090] Take 119.2 g of ordinary pseudo-boehmite dPB1 (produced by Shandong Aluminum Factory) with a solid content of 74 wt% and add 320.7 g of deionized water, stir for 20 min. Add 17.6 g of hydrochloric acid with a concentration of 36-38% and acidify for 60 min to obtain a peptized pseudo-boehmite. Take 212.6 g of kaolin with a solid content of 79 wt% and add 874.2 g of deionized water, stir for 20 min, then add 153.2 g of HSY-12 molecular sieve with a solid content of 78 wt%, continue to stir for 20 min. Then add the peptized pseudo-boehmite and stir for 20 min. Finally, add 109.1 g of aluminum sol with a solid content of 22 wt% and stir for 20 min to obtain a final catalyst slurry, which is spray-dried and molded, calcined at 500°C for 2 h, then washed and dried to obtain the catalyst dCAT1. Among them, the dCAT1 catalyst obtained contains 30 wt% of HSY-12 molecular sieve, 42 wt% of kaolin, 22 wt% of pseudo-boehmite, and 6 wt% of aluminum sol on a dry basis.

[0091] Comparative Example 2

[0092] Take 121.8g solid content of 72wt% macroporous pseudo-boehmite dPB2 (produced by Shandong Aluminum Factory) added to 318.2g deionized water, stirring for 20min. Add 17.6g of 36-38% concentration hydrochloric acid acidification for 60min, to get the peptized pseudo-boehmite. Take 212.6g solid content of 79wt% kaolin added to 874.2g deionized water stirring for 20min, then add 153.2g solid content of 78wt% HSY-12 molecular sieve, continue to stir for 20min. Then add the peptized pseudo-boehmite stirring for 20min. Finally add 109.1g solid content of 22wt% aluminum sol, stirring for 20min, to get the final catalyst slurry, spray drying molding, calcination at 500℃ for 2h, then washing, drying, to get the catalyst dCAT2. Among them, the dCAT2 catalyst obtained contains HSY-12 molecular sieve 30wt%, kaolin 42wt%, pseudo-boehmite 22wt%, aluminum sol 6wt% on a dry basis.

[0093] Comparative Example 3

[0094] The binder was prepared according to the method described in CN105983400A example 2, the specific steps are as follows:

[0095] The triblock template P123 was fully dissolved in ethanol, concentrated nitric acid and aluminum isopropyl alcohol were added for reaction, aging at 60℃ and calcination at 700℃ for 4h, the template was removed to get mesoporous alumina, noted as dPB3.

[0096] According to the preparation method of the reference example, the peptized mesoporous alumina, HSY-12 molecular sieve, kaolin and aluminum sol were formed into a catalyst slurry, spray drying molding, calcination, washing, drying, to get the catalyst dCAT3. The dCAT3 catalyst obtained contains HSY-12 molecular sieve 30wt%, kaolin 42wt%, mesoporous alumina 22wt%, aluminum sol 6wt%.

[0097] The following table 1 and table 2 show the properties of the pseudo-boehmite in example 1-4 and comparative example 1-3, and the composition and properties of the obtained catalyst. As shown in table 1, the crystallinity and grain size of the pseudo-boehmite prepared according to the method of the application are obviously higher than that of the pseudo-boehmite in the comparative example. As shown in the pore size distribution of Figure 1 the catalyst containing macroporous pseudo-boehmite according to the application has abundant macroporous structure, and as shown in table 2, the total pore volume is obviously higher than that of the comparative example and the attrition performance is excellent.

[0098] Table 1 performance index of pseudo-boehmite in example 1-4 and comparative example 1-3

[0099] Number Crystallinity, % Grain size, nm Na20, % Specific surface area, m 2 / g]] Total pore volume, mL / g PB1 94.2 6.5 0.0686 210.42 0.58 PB2 93.8 7.7 0.0641 192.55 0.64 PB3 99.8 8.5 0.0564 173.56 0.68 PB4 96.5 9.5 0.0507 120.32 0.76 dPB1 88.6 4.1 0.0721 230.29 0.40 dPB2 68.8 3.3 0.0584 307.14 0.80 dPB3 81.62 3.9 0.0734 214.97 0.66

[0100] Table 2 Compositions and physico-chemical properties of catalysts in Examples 1-4 and Comparative Examples 1-3

[0101]

[0102]

[0103] Note: dCAT2 is too weak to perform ACE evaluation, dCAT3 is weak to perform ACE evaluation.

[0104] The cracking reaction performance of the catalysts obtained in the above examples and comparative examples was evaluated. After the obtained catalysts were aged at 800 DEG C for 17 hours under 100% steam, their catalytic cracking reaction performance was evaluated in a small fixed fluidized bed reactor (ACE), and the properties of the raw oil in the ACE experiment are shown in Table 3, and the evaluation results are shown in Table 4.

[0105] Table 3 Properties of raw oil

[0106]

[0107] Table 4 Cracking performance of catalysts in Examples 1-4 and Comparative Examples 1-3

[0108]

[0109] As can be seen from Table 4, compared with the comparative examples, the catalysts containing large-grained pseudo-boehmite of the present application have higher heavy oil conversion rate, increased light oil yield, and good coke selectivity when applied to heavy oil cracking.

[0110] As can be seen from Table 4, compared with the comparative examples, the catalysts containing large-grained pseudo-boehmite of the present application have higher heavy oil conversion rate, increased light oil yield, and good coke selectivity when applied to heavy oil cracking.

[0111] The above describes the present application in conjunction with preferred embodiments, however, these embodiments are only exemplary and illustrative. On this basis, various substitutions and improvements can be made to the present application, and all fall within the scope of the present application.

Claims

1. A catalytic cracking catalyst having a meso-macroporous structure, consisting of 15-60 wt% of molecular sieve, 5-40 wt% of first binder of large-grained pseudo-boehmite calculated as alumina, 0-15 wt% of second binder and 20-80 wt% of clay, based on dry weight, the large-grained pseudo-boehmite having a grain size in the range of 6-10 nm, the catalytic cracking catalyst having a total pore volume of 0.4-0.5 mL / g; wherein the second binder being one or more selected from the group consisting of silica sol, alumina sol, phospho-alumina sol, and peptized ordinary pseudo-boehmite having a grain size in the range of 3-4 nm; the first binder of large-grained pseudo-boehmite of the catalytic cracking catalyst being prepared by the following method, comprising: a. neutralizing a sodium meta-aluminate solution with carbon dioxide gas to form a slurry, wherein the sodium meta-aluminate solution has a concentration of 15-60 g Al203 / L calculated as oxide, the carbon dioxide gas has a volume concentration of 15-50%, the temperature of neutralization is below 50°C, and the pH value at the end of neutralization is 9-11; b. loading the slurry after neutralization into a sealed container for aging by stepwise temperature increase, wherein the first stage is to increase the temperature to 50-100°C for aging for 30-120 min, and the second stage is to increase the temperature to 100-220°C for aging for 1-10 h; c. filtering the slurry after aging and continuously washing with deionized water at 60-90°C; and d. drying the filter cake after washing to obtain the first binder of large-grained pseudo-boehmite.

2. The catalytic cracking catalyst according to claim 1, wherein containing 25-40 wt% of molecular sieve, 10-30 wt% of first binder of large-grained pseudo-boehmite calculated as alumina, 2-10 wt% of second binder and 30-50 wt% of clay, based on dry weight.

3. The catalytic cracking catalyst according to claim 1, wherein, the clay being one or more selected from the group consisting of kaolin, rectorite, diatomite, montmorillonite, bentonite and sepiolite; and the molecular sieve being one or more selected from the group consisting of Y-type molecular sieve, Beta-type zeolite, shape-selective zeolite, MCM zeolite, L zeolite, aluminum phosphate molecular sieve and silicon-aluminum phosphate molecular sieve.

4. The catalytic cracking catalyst according to claim 3, wherein, the molecular sieve comprising Y-type molecular sieve.

5. The catalytic cracking catalyst of claim 4, wherein, the Y-type molecular sieve being NaY-type molecular sieve or modified Y-type molecular sieve, the modified Y-type molecular sieve being REY, HY, REHY, USY or REUSY molecular sieve.

6. The catalytic cracking catalyst of claim 1 wherein, in step a, the volume concentration of the carbon dioxide gas is 25-50%.

7. The catalytic cracking catalyst of claim 1 wherein, in step b, the first stage is to increase the temperature to 60-80°C for aging for 40-80 min, and the second stage is to increase the temperature to 120-180°C for aging for 2-6 h.

8. The catalytic cracking catalyst of claim 1, wherein, in step c, the continuous washing is performed with deionized water at 80-90°C.

9. A method for preparing the catalytic cracking catalyst of claim 1, comprising the following steps: (1) preparing a first binder of large-grained pseudo-boehmite by carbonization method: (2) mixing the large-grain pseudo-boehmite obtained in step (1) with deionized water and beating the mixture into a slurry; adding hydrochloric acid having a mass concentration of 36 to 38% to the slurry at a molar ratio of n(HCl) / n(Al2O3)=0.1 to 0.3 while stirring; and acidifying the mixture for 0.5 to 1 hour to obtain a peptized large-grain pseudo-boehmite first binder having a solid content of 10 to 30 weight percent; (3) mixing the peptized large-grain pseudo-boehmite first binder obtained in step (2) with molecular sieve, clay and deionized water, and then adding a second binder and mixing to prepare a catalytic cracking catalyst slurry with a solid content of 20 to 40 weight percent, wherein the slurry contains, on a dry basis, 15 to 60 weight percent of molecular sieve, 5 to 40 weight percent of the large-grain pseudo-boehmite first binder calculated as alumina, 0 to 15 weight percent of the second binder and 20 to 80 weight percent of clay; and (4) The slurry obtained in step (3) is spray-dried, calcined, washed and dried in sequence to obtain a catalytic cracking catalyst containing the large-grain pseudo-boehmite.

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