Catalytic cracking additives, their preparation methods, their applications in catalytic cracking, and methods to improve the selectivity of C4 olefins

Abstract

This invention relates to the field of catalytic cracking additives, providing a catalytic cracking additive, its preparation method, its application in catalytic cracking, and a method for improving the selectivity of C4 olefins. The additive, based on a dry weight basis, contains 15-40 wt% β-zeolite, 10-50 wt% highly colloidal macroporous boehmite, and 10-75 wt% clay; wherein the highly colloidal macroporous boehmite has an alumina content of 98-100 wt%; the pore volume V1 of the highly colloidal macroporous boehmite is 0.45-0.7 mL / g, and the colloidal index DI is 95-100%; the pore volume V2 of the highly colloidal macroporous boehmite after colloidal dissolution is 0.4-0.55 mL / g. When applied to the catalytic cracking process, this additive can significantly improve the yield and selectivity of C4 olefins.

Description

Technical Field

[0001] This invention relates to the field of catalytic cracking additives, specifically to a catalytic cracking additive and its preparation method, its application in the production of C4 olefins by catalytic cracking, and a method for improving the selectivity of C4 olefins in catalytic cracking reactions. Background Technology

[0002] The introduction of clean gasoline standards presents challenges to both gasoline cleanliness and octane rating. Meeting these standards requires increasing the proportion of low-sulfur, low-aromatic, and high-octane alkylated gasoline in the gasoline pool. However, due to a shortage of C4 olefin feedstock, many alkylation units are operating below capacity. Statistics show that nearly 70% of global C4 olefins come from catalytic cracking units; therefore, increasing the C4 olefin yield from catalytic cracking is a crucial way to alleviate the feedstock shortage for alkylation units and a vital link in promoting the transformation of refining towards chemical production. Using catalytic cracking catalysts or additives that can increase C4 olefin production is the most economical and effective method.

[0003] β-zeolite possesses both acid catalytic properties and structural selectivity, making it a key active component in catalysts for increasing the production of C4 olefins. Binders are also a major component of catalytic cracking catalysts or additives. While ensuring the catalyst's wear resistance, they can synergistically work with molecular sieves to improve the catalyst's activity and hydrothermal stability. Commonly used binders include alumina sol, silica sol, and acidified pseudoboehmite.

[0004] US6355591 discloses a catalytic cracking aid containing 4-20 wt% aluminum phosphate, 1-40 wt% ZSM-5, Beta zeolite and mixtures thereof, and 40-90 wt% clay, which can increase liquefied gas production.

[0005] CN1055105C discloses a cracking catalyst that produces high levels of isobutylene and isopentene, comprising 6-30 wt% of a five-membered ring high-silica zeolite containing phosphorus and rare earth elements, 5-20 wt% of USY zeolite, 1-5 wt% of β-zeolite, 30-60 wt% of clay, and 15-30 wt% of inorganic oxides. This catalyst exhibits high isobutylene and isopentene production under catalytic cracking process conditions, and can also co-produce high-octane gasoline.

[0006] CN103785456A discloses a cracking additive for increasing the concentration of low-carbon olefins, comprising a modified β-molecular sieve, a phosphorus-aluminum inorganic binder containing a first clay, other inorganic binders, and Group VIII metal additives, with or without a second clay; the phosphorus-aluminum inorganic binder containing the first clay comprises an aluminum component, a phosphorus component, and the first clay; the phosphorus and transition metal modified β-molecular sieve has a phosphorus content of 1-10 wt% as P2O5 and a metal content of 0.5-10 wt% as metal oxides. This cracking catalyst composition, when applied to the catalytic cracking of petroleum hydrocarbons, can increase the yield of catalytic cracked liquefied petroleum gas (LPG), increase the concentration of low-carbon olefins in LPG, especially isobutylene, while simultaneously increasing the ethylene to dry gas ratio and improving the octane number of gasoline. When the additive is blended in a large proportion, it does not affect the heavy oil conversion capacity of the main catalyst.

[0007] Although existing catalysts or additives for increasing the production of low-carbon olefins can achieve the goal of increasing the production of C4 olefins to a certain extent, the catalytic cracking process still needs to be improved to achieve higher C4 olefin selectivity. Summary of the Invention

[0008] The purpose of this invention is to overcome the problem of low selectivity of C4 olefins in the prior art, and to provide a catalytic cracking aid, its preparation method, its application in catalytic cracking, and a method for improving the selectivity of C4 olefins.

[0009] During the research process of this invention, the inventors recognized that existing technologies mainly rely on increasing the yield of liquefied petroleum gas (LPG) to increase the yield of C4 olefins. However, the concentration of C4 olefins in LPG does not change significantly, resulting in low selectivity for C4 olefins. Furthermore, the catalyst promoters lack abundant mesoporous and macroporous structures, which hinders the rapid diffusion of the generated C4 olefins, making them prone to secondary reactions and thus reducing yield and selectivity. Based on the above understanding, the inventors of this invention propose the technical solution of this invention.

[0010] To achieve the above objectives, a first aspect of the present invention provides a catalytic cracking additive, wherein, based on the dry weight of the additive, the additive contains 15-40 wt% β-zeolite, 10-50 wt% highly colloidal macroporous pseudoboehmite, and 10-75 wt% clay; wherein the highly colloidal macroporous pseudoboehmite contains 98-100 wt% alumina; the highly colloidal macroporous pseudoboehmite has a pore volume V1 of 0.45-0.7 mL / g and a colloidal index DI of 95-100%; and the highly colloidal macroporous pseudoboehmite, after colloidal dissolution, has a pore volume V2 of 0.4-0.55 mL / g.

[0011] A second aspect of the present invention provides a method for preparing a catalytic cracking additive, wherein the preparation method includes:

[0012] (1) A highly soluble macroporous pseudoboehmite is mixed with water and pulped, and a first acid is added to the obtained product for acidification to obtain an acidified slurry; wherein, the alumina content in the highly soluble macroporous pseudoboehmite is 98-100wt%; the pore volume V1 of the highly soluble macroporous pseudoboehmite is 0.45-0.7mL / g, and the gel solubility index DI is 95-100%; the pore volume V2 of the highly soluble macroporous pseudoboehmite after gelation is 0.4-0.55mL / g;

[0013] (2) Clay, β-zeolite and water are mixed to form a slurry, and then the acidified slurry is mixed to form a catalyst slurry;

[0014] (3) The catalyst slurry is spray-dried, shaped, and calcined to obtain a catalytic cracking aid;

[0015] The amount of highly colloidal macroporous pseudoboehmite, clay, and β-zeolite used in the catalytic cracking aid obtained is such that, on a dry basis, the catalytic cracking aid contains 15-40 wt% β-zeolite, 10-50 wt% highly colloidal macroporous pseudoboehmite, and 10-75 wt% clay.

[0016] A third aspect of the present invention provides a catalytic cracking aid prepared by the preparation method of the present invention.

[0017] The fourth aspect of this invention provides the application of the catalytic cracking aid of this invention in the catalytic cracking production of C4 olefins.

[0018] The fifth aspect of the present invention provides a method for improving the selectivity of C4 olefins in catalytic cracking reactions.

[0019] Through the above technical solution, this invention introduces a highly colloidal macroporous boehmite component into the provided catalytic cracking additive, which can improve the additive's wear resistance while simultaneously accumulating a rich mesoporous structure. When this additive is used in the catalytic cracking process, C4 olefins can rapidly diffuse out through the additive's abundant mesoporous structure, preventing further secondary reactions and thus improving the yield and selectivity of C4 olefins. Furthermore, the high colloidal solubility of the macroporous boehmite also improves the strength of the additive. Detailed Implementation

[0020] The endpoints and any values ​​of the ranges 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 endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0021] The first aspect of this invention provides a catalytic cracking additive, wherein, based on the dry weight of the additive, the additive contains 15-40 wt% β-zeolite, 10-50 wt% highly colloidal macroporous pseudoboehmite, and 10-75 wt% clay; wherein the highly colloidal macroporous pseudoboehmite contains 98-100 wt% alumina; the highly colloidal macroporous pseudoboehmite has a pore volume V1 of 0.45-0.7 mL / g and a colloidal index DI of 95-100%; and the pore volume V2 of the highly colloidal macroporous pseudoboehmite after colloidal dissolution is 0.4-0.55 mL / g.

[0022] In this invention, the pore volume V1 of the highly colloidal macroporous pseudoboehmite is the pore volume of the product obtained after calcining the highly colloidal macroporous pseudoboehmite at 600°C for 3 hours, measured by N2 adsorption. The pore volume V2 of the highly colloidal macroporous pseudoboehmite after colloidal treatment is the pore volume of the product obtained after drying the colloidal solution obtained by acid colloidal treatment of the highly colloidal macroporous pseudoboehmite during colloidal index testing, followed by calcination at 600°C for 3 hours, measured by N2 adsorption. Compared to the pore volume V1 of the highly colloidal macroporous pseudoboehmite, V2 does not show a significant decrease, indicating that the highly colloidal macroporous pseudoboehmite has a high pore volume retention during acid colloidal treatment.

[0023] In some embodiments of the present invention, preferably, the additive contains 20-40 wt% β-zeolite, 15-45 wt% highly colloidal macroporous pseudoboehmite, and 15-65 wt% clay.

[0024] The catalytic cracking additive provided by the present invention has a rich mesoporous structure. According to the pore distribution measured by low-temperature nitrogen adsorption, in some embodiments, preferably, the total pore volume of the additive is not less than 0.2 mL / g, and more preferably 0.2-0.3 mL / g.

[0025] In some embodiments of the present invention, preferably, the pore volume of mesopores with a pore size of 5-100 nm as determined by peak fitting method accounts for more than 60% of the total pore volume, preferably 65-80%.

[0026] In some embodiments of the present invention, preferably, the wear index of the additive is not greater than 2. The highly colloidal macroporous pseudoboehmite used in the present invention has strong adhesive properties, which makes the prepared additive have good wear resistance. This is beneficial for reducing additive loss in the catalytic cracking reaction process, reducing the impact of abrasive fines on the equipment, and enhancing the operational flexibility of the catalytic unit.

[0027] In some embodiments of the present invention, preferably, the β-zeolite is selected from at least one of hydrogen-form β-zeolite, sodium-form β-zeolite, phosphorus-modified β-zeolite, and metal-modified β-zeolite, and is preferably hydrogen-form β-zeolite. It can be commercially available, for example, from Sinopec Catalyst Co., Ltd.

[0028] In some embodiments of the present invention, preferably, the molar ratio of SiO2 to Al2O3 in the β-zeolite is 20-50:1.

[0029] In some embodiments of the present invention, preferably, the clay is selected from at least one of kaolin, rettoite, diatomaceous earth, montmorillonite, bentonite, and sepiolite.

[0030] Compared with the prior art, the catalytic cracking promoter of the present invention has a rich mesoporous structure, with 5-100 nm mesopores accounting for more than 60% of the total pore volume. When used in the catalytic cracking process, it is beneficial to enhance the diffusion ability of reactants and products, thereby significantly improving the yield and selectivity of C4 olefins.

[0031] A second aspect of the present invention provides a method for preparing a catalytic cracking additive, wherein the preparation method includes:

[0032] (1) A highly soluble macroporous pseudoboehmite is mixed with water and pulped, and a first acid is added to the obtained product for acidification to obtain an acidified slurry; wherein, the alumina content in the highly soluble macroporous pseudoboehmite is 98-100wt%; the pore volume V1 of the highly soluble macroporous pseudoboehmite is 0.45-0.7mL / g, and the gel solubility index DI is 95-100%; the pore volume V2 of the highly soluble macroporous pseudoboehmite after gelation is 0.4-0.55mL / g;

[0033] (2) Clay, β-zeolite and water are mixed to form a slurry, and then the acidified slurry is mixed to form a catalyst slurry;

[0034] (3) The catalyst slurry is spray-dried, shaped, and calcined to obtain a catalytic cracking aid;

[0035] The amount of highly colloidal macroporous pseudoboehmite, clay, and β-zeolite used in the catalytic cracking aid obtained is such that, on a dry basis, the catalytic cracking aid contains 15-40 wt% β-zeolite, 10-50 wt% highly colloidal macroporous pseudoboehmite, and 10-75 wt% clay.

[0036] In some embodiments of the present invention, preferably, in step (1), the first acid is selected from hydrochloric acid, nitric acid, sulfuric acid, oxalic acid, and phosphoric acid.

[0037] In some embodiments of the present invention, preferably, the amount of the first acid added satisfies the following: the molar ratio of hydrogen ions contained in the first acid to the highly colloidal macroporous pseudoboehmite on a dry basis, calculated as Al2O3, is 0.1-0.3:1, i.e., the acid-aluminum ratio.

[0038] In some embodiments of the present invention, preferably, the acidification time is 0.5-2 hours.

[0039] In some embodiments of the present invention, preferably, the solid content of the acidified slurry is 10-30 wt%.

[0040] In some embodiments of the present invention, preferably, the highly soluble macroporous pseudoboehmite is prepared by the following method:

[0041] a) Mix hydrated alumina and / or amorphous alumina, water, and a second acid to obtain a mixed slurry;

[0042] b) The mixed slurry is subjected to a hydrothermal reaction, and the resulting product is dried to obtain the highly colloidal macroporous pseudoboehmite.

[0043] In some embodiments of the present invention, preferably, the alumina concentration in the mixed slurry is 5-50 wt%, more preferably 6-40 wt%, and more preferably 8-20 wt%.

[0044] In some embodiments of the present invention, preferably, the molar ratio of the second acid to alumina in the mixed slurry is 0.02-0.8, more preferably 0.08-0.6.

[0045] In some embodiments of the present invention, preferably, the second acid is selected from inorganic acids and / or organic acids; wherein the inorganic acid is selected from at least one of hydrochloric acid, nitric acid and sulfuric acid, and the organic acid is selected from at least one of formic acid, acetic acid and oxalic acid.

[0046] In some embodiments of the present invention, preferably, the hydrothermal reaction temperature is 90-220°C, more preferably 100-200°C; and the hydrothermal reaction time is 6-48h, more preferably 6-42h.

[0047] In some embodiments of the present invention, preferably, the drying temperature is 60-120°C, more preferably 80-110°C.

[0048] During the research process, the inventors of this invention discovered that in the preparation process of pseudoboehmite by hydrothermal synthesis, by controlling the type and concentration of raw material alumina, the molar ratio of acid to alumina, the temperature and time of hydrothermal aging, etc., the pseudoboehmite prepared in this way has a high colloidal index, and the product obtained after colloidal treatment can still maintain a large pore volume. Existing technologies cannot obtain pseudoboehmite with the characteristics of this invention.

[0049] In some embodiments of the present invention, preferably, in step (2) of the method for preparing the catalytic cracking additive, the β zeolite is selected from at least one of hydrogen-form β zeolite, sodium-form β zeolite, phosphorus-modified β zeolite, and metal-modified β zeolite, and preferably hydrogen-form β zeolite.

[0050] In some embodiments of the present invention, preferably, the molar ratio of SiO2 to Al2O3 in the β-zeolite is 20-50:1.

[0051] In some embodiments of the present invention, preferably, the clay is selected from at least one of kaolin, rettoite, diatomaceous earth, montmorillonite, bentonite, and sepiolite.

[0052] In this invention, the mixing in step (2) can be carried out at 25-40°C, so that the components can be in full contact.

[0053] In some embodiments of the present invention, preferably, the solid content of the catalyst slurry is 20-50 wt%.

[0054] A third aspect of the present invention provides a catalytic cracking aid prepared by the preparation method of the present invention.

[0055] Based on the dry weight of the additive, the additive contains 15-40 wt% β-zeolite, 10-50 wt% highly soluble macroporous pseudoboehmite, and 10-75 wt% clay; wherein the highly soluble macroporous pseudoboehmite contains 98-100 wt% alumina; the highly soluble macroporous pseudoboehmite has a pore volume V1 of 0.45-0.7 mL / g and a gel solubility index DI of 95-100%; and the highly soluble macroporous pseudoboehmite has a pore volume V2 of 0.4-0.55 mL / g after gelation.

[0056] The obtained catalytic cracking additive has the properties of the additives mentioned above in this invention, which will not be repeated here.

[0057] The fourth aspect of this invention provides the application of the catalytic cracking aid of this invention in the catalytic cracking production of C4 olefins.

[0058] The fifth aspect of the present invention provides a method for improving the selectivity of C4 olefins in catalytic cracking reactions.

[0059] When the catalytic cracking additive according to the present invention is used in the catalytic cracking process, it can be added alone to the catalytic cracking reactor or used in combination with the catalytic cracking catalyst. When used in combination with the catalytic cracking catalyst, the amount of the catalytic cracking additive is preferably 1-50 wt%, more preferably 5-40 wt%, based on the total amount of the catalytic cracking additive and the catalytic cracking catalyst.

[0060] The present invention will be described in detail below through embodiments. This is intended to help better understand the essence of the invention and its beneficial effects, but should not be construed as limiting the scope of the invention.

[0061] The raw materials used in the preparation of the catalytic cracking additive in the following examples are described below:

[0062] Amorphous alumina rapid descaling powder (86.4 wt% dry basis), Shandong Branch of Aluminum Corporation of China;

[0063] Boehmite USA (85wt% on dry basis), Shandong Yantai Heng Hui Chemical Co., Ltd.;

[0064] Aluminum sulfate solution (alumina concentration of 104 g / L), Zibo Qimao Catalyst Co., Ltd.

[0065] SB boehmite, Sasol;

[0066] Boehmite produced by carbonization, Shandong Branch of Aluminum Corporation of China Limited;

[0067] Industrial agent (industrial catalyst), brand name HSC, Sinopec Catalyst Co., Ltd. Qilu Branch, main properties are shown in Table 4;

[0068] The kaolin has a solid content of 76 wt%; the properties of conventional boehmite and mesoporous boehmite are shown in Table 1; the acidified boehmite has a solid content of 12.0 wt%; it is acidified with hydrochloric acid, and the molar ratio of acid (HCl) to alumina is 0.2; the hydrogen-form β-zeolite used has a solid content of 75 wt%, a SiO2 / Al2O3 molar ratio of 25, and a Na2O content of 0.15 wt%.

[0069] The analysis and evaluation methods are explained below:

[0070] Method for measuring the gel solubility index: Weigh 10g of boehmite, calcine at 600℃ for 3h, cool in a desiccator until room temperature, and weigh to obtain W0g. Calculate the dry basis weight a0 = W0 / 10. Weigh the boehmite weight m1 = 6 / a0g. Place m1g of boehmite in a 100mL PTFE cup, add deionized water to 40g, stir evenly with a magnetic rotor, then add 20mL of 0.19N dilute nitric acid solution and stir magnetically for 20min. Pour the entire solution into a centrifuge tube and centrifuge at 1900 rpm for 20min. Pour off the upper colloidal solution, place it in a weighed crucible, dry at 80℃, calcine at 600℃ for 3h, cool in a desiccator until room temperature, and weigh to obtain m2g. The gel solubility index DI = (m2 / 6) × 100%.

[0071] Specific surface area and pore volume analysis: A Micromeritics ASAP 2405N V1.01 automated adsorption analyzer was used, employing the low-temperature static nitrogen adsorption capacity method. The sample surface area was 1.33 × 10⁻⁶ pores. -2 The sample was degassed under vacuum at 300℃ for 4 hours using N2 as the adsorption medium, and the adsorption-desorption isotherm was measured at 77.4K. The specific surface area of ​​the sample was calculated according to the BET formula, and the volume of N2 adsorbed by the sample at a relative pressure p / p0 = 0.98 was measured and converted to liquid nitrogen volume, i.e., total pore volume. The pore size distribution was obtained from BJH desorption data, and the pore volume of 5-100 nm mesopores was obtained using peak fitting.

[0072] Additive strength: A certain amount of additive is placed in a fixed device and polished under a constant airflow for 5 hours. The average percentage of wear in the last four hours (excluding the first hour) is called the wear index of the additive, expressed as % per hour. The method and standard are: airlift method Q / SYLS0518-2002.

[0073] Example 1

[0074] Add 6g of concentrated HCl (36-38wt%) to 350g of deionized water, and then add 54g of amorphous alumina fast-release powder and 18.5g of pseudoboehmite USA (85wt% on a dry basis) in sequence while stirring. The resulting mixed slurry has an alumina concentration of 14.6wt% and an acid / alumina molar ratio of 0.098. After stirring evenly, transfer the mixed slurry to a 500mL autoclave reactor and place it in a homogeneous reactor. Stir at 10 rpm and maintain the temperature at 150℃ for 24 hours. After cooling, remove the slurry after reaction and dry it in an oven. Maintain the temperature at 80℃ for 24 hours to obtain hydrated alumina P1.

[0075] Characterized by XRD, P1 has a pseudoboehmite structure. The relative crystallinity and grain size are listed in Table 1.

[0076] The colloidal index DI of P1 was measured and listed in Table 1. When measuring the colloidal index, the upper colloidal solution was dried and calcined to obtain alumina, denoted as J1. P1 was calcined at 600℃ for 3 hours to obtain alumina Z1; the composition of Z1 was characterized by XRF, and the results are listed in Table 2. The pore volume V1 of Z1 and the pore volume V2 of J1 were measured using N2 adsorption, and the results are listed in Table 2.

[0077] Take 21.4 g of highly colloidal macroporous pseudoboehmite P1 with a solid content of 70 wt% and add it to 104 g of deionized water, stir for 30 min. Add 3.0 g of 36 wt% hydrochloric acid and acidify for 60 min to obtain an acidified sample of highly colloidal macroporous pseudoboehmite.

[0078] Take 85.5g of kaolin with a solid content of 76wt% and add 320.7g of deionized water to slurry for 60min. Then add 26.6g of Hβ molecular sieve with a solid content of 75wt% and stir for 30min. Then add the above-mentioned highly colloidal macroporous pseudoboehmite acidified sample and stir for 30min to obtain the final catalyst slurry. Spray dry and shape it, and calcine it at 550℃ for 1.5h to obtain the catalytic cracking aid C1 of the present invention.

[0079] Catalytic cracking additive C1, on a dry basis, contains 20 wt% Hβ molecular sieve, 65 wt% kaolin, and 15 wt% highly colloidal macroporous pseudoboehmite. The relevant properties of catalytic cracking additive C1 are shown in Table 3.

[0080] Example 2

[0081] Take 2.2L of aluminum sulfate solution, add deionized water while stirring to prepare a 4.0L solution, and put it into raw material reactor A. Take 1000mL of sodium aluminate solution (self-made, alumina concentration 220g / L, caustic coefficient 1.65) and put it into raw material reactor B. Add 2L of deionized water to a 3L neutralization reactor, adjust the temperature to 50℃, turn on the stirring and feed pumps for raw materials A and B, and carry out a continuous parallel flow neutralization reaction. The neutralization pH is 8.5, the neutralization temperature is 50℃, the residence time is 20min, and the slurry is collected. After neutralization, filter the collected slurry and wash it with 60L of deionized water at 50℃ to obtain a filter cake.

[0082] Add 10g of concentrated HCl (36-38wt%) to 200g of deionized water, and add 200g of the filter cake (28.8wt% on a dry basis) prepared above while stirring. The resulting mixed slurry has an alumina concentration of 11.3wt% and an acid / alumina molar ratio of 0.177. After stirring evenly, transfer the mixed slurry to a 500mL self-pressurized reactor and place it in a homogeneous reactor. Stir at 10 rpm and maintain the temperature at 150℃ for 12 hours. After cooling, remove the slurry after reaction and place it in an oven to dry at 90℃ for 24 hours to obtain hydrated alumina P2.

[0083] XRD characterization revealed that P2 has a pseudoboehmite structure, and the relative crystallinity and grain size are listed in Table 1.

[0084] The colloidal index DI of P2 was measured and listed in Table 1. When measuring the colloidal index, the upper colloidal solution was dried and calcined to obtain alumina, denoted as J2. P2 was calcined at 600℃ for 3 hours to obtain alumina Z2; the composition of Z2 was characterized by XRF, and the results are listed in Table 2. The pore volumes V1 of Z2 and V2 of J2 were measured using N2 adsorption, and are listed in Table 2.

[0085] Take 31.4 g of highly colloidal macroporous pseudoboehmite P2 with a solid content of 70 wt% and add it to 152 g of deionized water, stir for 30 min. Add 4.4 g of 36% hydrochloric acid and acidify for 60 min to obtain an acidified sample of highly colloidal macroporous pseudoboehmite.

[0086] Take 69.7g of kaolin with a solid content of 76wt% and add 261.5g of deionized water to slurry for 60min. Then add 33.3g of Hβ molecular sieve with a solid content of 75wt% and stir for 30min. Next, add the above-mentioned highly colloidal macroporous pseudoboehmite acidified sample and stir for 30min to obtain the final catalyst slurry. Spray dry and shape it, and calcine it at 550℃ for 1.5h to obtain the catalytic cracking aid C2 of the present invention.

[0087] Catalytic cracking additive C2, on a dry basis, contains 25 wt% Hβ molecular sieve, 53 wt% kaolin, and 22 wt% highly colloidal macroporous pseudoboehmite. The relevant properties of catalytic cracking additive C2 are shown in Table 3.

[0088] Example 3

[0089] Add 9.25g of concentrated HNO3 (68wt%) and 54g of amorphous alumina fast-desorption powder to 350g of deionized water. The resulting mixed slurry has an alumina concentration of 11.2wt% and an acid / alumina molar ratio of 0.202. After stirring evenly, transfer the mixed slurry to a 500mL self-pressurized reactor and place it in a homogeneous reactor. Stir at 10 rpm and maintain the temperature at 150℃ for 48 hours. After cooling, remove the slurry after reaction and dry it in an oven. Maintain the temperature at 80℃ for 24 hours to obtain hydrated alumina P3.

[0090] XRD characterization revealed that P3 exhibits a pseudoboehmite structure. The relative crystallinity and grain size are listed in Table 1.

[0091] The colloidal index DI of P3 was measured and listed in Table 1. When measuring the colloidal index, the upper colloidal solution was dried and calcined to obtain alumina, denoted as J3. P3 was calcined at 600℃ for 3 hours to obtain alumina Z3; the composition of Z3 was characterized by XRF, and the results are listed in Table 2. The pore volume V1 of Z3 and the pore volume V2 of J3 were measured using N2 adsorption, and the results are listed in Table 2.

[0092] Take 35.7g of highly colloidal macroporous pseudoboehmite P3 with a solid content of 70wt% and add it to 173g of deionized water, stir for 30min. Add 5g of 36wt% hydrochloric acid and acidify for 90min to obtain an acidified sample of highly colloidal macroporous pseudoboehmite.

[0093] 59.2g of kaolin with a solid content of 76wt% was added to 222g of deionized water and stirred for 60min. Then, 33.3g of Hβ molecular sieve with a solid content of 75wt% was added and stirred for 30min. Next, the above-mentioned highly colloidal macroporous pseudoboehmite acidified sample was added and stirred for 60min to obtain the final catalyst slurry. This slurry was spray-dried and calcined at 550℃ for 1.5h to obtain the catalytic cracking aid C3 of the present invention.

[0094] Catalytic cracking additive C3, on a dry basis, contains 30 wt% Hβ molecular sieve, 45 wt% kaolin, and 25 wt% highly colloidal macroporous pseudoboehmite. The relevant properties of catalytic cracking additive C3 are shown in Table 3.

[0095] Example 4

[0096] Add 37.5g concentrated HNO3 (68wt%), 225g amorphous alumina fast-desorption powder, and 75g pseudoboehmite USA to 250g deionized water. The resulting mixed slurry has an alumina concentration of 40.0wt% and an acid / alumina molar ratio of 0.362. After stirring evenly, transfer the mixed slurry to a 500mL self-pressurized reactor and place it in a homogeneous reactor. Stir at 10 rpm and maintain the temperature at 150℃ for 24 hours. After cooling, remove the slurry after reaction and dry it in an oven. Maintain the temperature at 80℃ for 24 hours to obtain hydrated alumina P4.

[0097] XRD characterization revealed that P4 exhibits a pseudoboehmite structure. The relative crystallinity and grain size are listed in Table 1.

[0098] The colloidal index DI of P4 was measured and listed in Table 1. For the colloidal index measurement, the upper colloidal solution was dried and calcined to obtain alumina, denoted as J4. P4 was calcined at 600℃ for 3 hours to obtain alumina Z4; the composition of Z4 was characterized by XRF, and the results are listed in Table 2. The pore volume V1 of Z4 and the pore volume V2 of J4 were measured using N2 adsorption, and the results are listed in Table 2.

[0099] Take 42.9g of highly colloidal macroporous pseudoboehmite P4 with a solid content of 70wt% and add it to 207g of deionized water, stir for 30min. Add 6g of 36wt% hydrochloric acid and acidify for 60min to obtain an acidified sample of highly colloidal macroporous pseudoboehmite.

[0100] 46.1g of kaolin with a solid content of 76wt% was added to 172.7g of deionized water and stirred for 60min. Then, 46.7g of Hβ molecular sieve with a solid content of 75wt% was added and stirred for 30min. Next, the above-mentioned highly colloidal macroporous pseudoboehmite acidified sample was added and stirred for 60min to obtain the final catalyst slurry. This slurry was spray-dried and calcined at 550℃ for 1.5h to obtain the catalytic cracking aid C4 of the present invention.

[0101] Catalytic cracking additive C4, on a dry basis, contains 35 wt% Hβ molecular sieve, 35 wt% kaolin, and 30 wt% highly colloidal macroporous pseudoboehmite. The relevant properties of catalytic cracking additive C4 are shown in Table 3.

[0102] Example 5

[0103] 94g of acetic acid (36wt%) and 186g of amorphous alumina fast-release powder were added to 214g of deionized water, resulting in an alumina concentration of 35.0wt% and an acid / alumina molar ratio of 0.331. After stirring evenly, the mixture was transferred to a 500mL autoclave reactor and placed in a homogeneous reactor. The stirring speed was 10 rpm, and the temperature was maintained at 125℃ for 48 hours. After cooling, the reaction slurry was removed, dried in an oven, and maintained at 110℃ for 24 hours to obtain hydrated alumina P5.

[0104] XRD characterization revealed that P5 exhibits a pseudoboehmite structure. The relative crystallinity and grain size are listed in Table 1.

[0105] The colloidal index DI of P5 was measured and listed in Table 1. For the colloidal index measurement, the upper colloidal solution was dried and calcined to obtain alumina, denoted as J5. P5 was calcined at 600℃ for 3 hours to obtain alumina Z5; the composition of Z5 was characterized by XRF, and the results are listed in Table 2. The pore volume V1 of Z5 and the pore volume V2 of J5 were measured using N2 adsorption, and the results are listed in Table 2.

[0106] Take 54.3g of highly colloidal macroporous pseudoboehmite P5 with a solid content of 70wt% and add it to 262g of deionized water, stir for 30min. Add 7.6g of 36% hydrochloric acid and acidify for 60min to obtain an acidified sample of highly colloidal macroporous pseudoboehmite.

[0107] 28.9 g of kaolin with a solid content of 76 wt% was added to 108.6 g of deionized water and stirred for 60 min. Then, 53.4 g of Hβ molecular sieve with a solid content of 75 wt% was added and stirred for 30 min. Next, the above-mentioned highly colloidal macroporous pseudoboehmite acidified sample was added and stirred for 60 min to obtain the final catalyst slurry. This slurry was spray-dried and calcined at 550℃ for 1.5 h to obtain the catalytic cracking aid C5 of this invention.

[0108] Catalytic cracking additive C5, on a dry basis, contains 40 wt% Hβ molecular sieve, 22 wt% kaolin, and 38 wt% highly colloidal macroporous pseudoboehmite. The relevant properties of catalytic cracking additive C5 are shown in Table 3.

[0109] Comparative Example 1

[0110] SB boehmite was used as a comparative sample CP1 and characterized by XRD. CP1 has a boehmite structure, and its relative crystallinity and grain size are listed in Table 1.

[0111] The colloidal index DI of CP1 was measured and listed in Table 1. For the colloidal index measurement, the upper colloidal solution was dried and calcined to obtain alumina, denoted as CJ1. CP1 was calcined at 600℃ for 3 hours to obtain alumina CZ1; the composition of CZ1 was characterized by XRF, and the results are listed in Table 2. The pore volume V1 of CZ1 and the pore volume V2 of CJ1 were measured using N2 adsorption, and the results are listed in Table 2.

[0112] The catalytic cracking aid DC1 was prepared according to the method in Example 1, and contained 20 wt% Hβ molecular sieve, 65 wt% kaolin, and 15 wt% CP1 boehmite. The relevant properties of the catalytic cracking aid DC1 are shown in Table 3.

[0113] Comparative Example 2

[0114] Using carbonized pseudoboehmite as a comparative sample CP2, XRD characterization was performed. CP2 has a pseudoboehmite structure, and its relative crystallinity and grain size are listed in Table 1.

[0115] The colloidal index DI of CP2 was measured and listed in Table 1. For the colloidal index measurement, the upper colloidal solution was dried and calcined to obtain alumina, denoted as CJ2. CP2 was calcined at 600℃ for 3 hours to obtain alumina CZ2; the composition of CZ2 was characterized by XRF, and the results are listed in Table 2. The pore volumes V1 of CZ2 and V2 of CJ2 were measured using N2 adsorption and are listed in Table 2.

[0116] The catalytic cracking aid DC2 was prepared according to the method in Example 1, and contained 20 wt% Hβ molecular sieve, 65 wt% kaolin, and 15 wt% CP2 boehmite. The relevant properties of the catalytic cracking aid DC2 are shown in Table 3.

[0117] Comparative Example 3

[0118] Add 54g of amorphous alumina fast-release powder to 350g of deionized water to obtain a mixed slurry with an alumina concentration of 11.5wt%. After stirring evenly, transfer the mixed slurry to a 500mL self-pressurized reactor and place it in a homogeneous reactor. Stir at 10 rpm and maintain the temperature at 130℃ for 24 hours. After cooling, remove the slurry after reaction and pour it into a vacuum filter funnel. Add 5L of 90℃ deionized water for washing. Place the filter cake in an oven to dry and maintain the temperature at 120℃ for 24 hours to obtain hydrated alumina CP3.

[0119] XRD characterization revealed that CP3 has a pseudoboehmite structure. The relative crystallinity and grain size are listed in Table 1.

[0120] The colloidal index (DI) of CP3 was measured and listed in Table 1. For the colloidal index measurement, the upper colloidal solution was dried and calcined to obtain alumina, denoted as CJ3. CP3 was calcined at 600℃ for 3 hours to obtain alumina CZ3; the composition of CZ3 was characterized by XRF, and the results are listed in Table 2. The pore volume V1 of CZ3 and the pore volume V2 of CJ3 were measured using N2 adsorption and are listed in Table 2.

[0121] The catalytic cracking aid DC3 was prepared according to the method in Example 1, and contained 20 wt% Hβ molecular sieve, 65 wt% kaolin, and 15 wt% CP3 boehmite. The relevant properties of the catalytic cracking aid DC3 are shown in Table 3.

[0122] Comparative Example 4

[0123] Add 1.55g of concentrated HNO3 (68wt%) to 350g of deionized water, and add 54g of amorphous alumina fast-release powder. The resulting mixed slurry has an alumina concentration of 11.5wt%. After stirring evenly, transfer the mixed slurry to a 500mL self-pressurized reactor and place it in a homogeneous reactor. Stir at 10 rpm and maintain the temperature at 150℃ for 4 hours. After cooling, remove the slurry after reaction and pour it into a vacuum filter funnel. Add 5L of 90℃ deionized water for washing. Place the filter cake in an oven to dry and maintain the temperature at 80℃ for 24 hours to obtain hydrated alumina CP4.

[0124] XRD characterization revealed that CP4 has a pseudoboehmite structure. The relative crystallinity and grain size are listed in Table 1.

[0125] The colloidal index (DI) of CP4 was measured and is listed in Table 1. For the colloidal index measurement, the upper colloidal solution was dried and calcined to obtain alumina, denoted as CJ4. CP4 was calcined at 600℃ for 3 hours to obtain alumina CZ4; the composition of CZ4 was characterized by XRF, and the results are listed in Table 2. The pore volume V1 of CZ4 and the pore volume V2 of CJ4 were measured using N2 adsorption, and are listed in Table 2.

[0126] The catalytic cracking aid DC4 was prepared according to the method in Example 1, and contained 20 wt% Hβ molecular sieve, 65 wt% kaolin, and 15 wt% CP4 boehmite. The relevant properties of the catalytic cracking aid DC4 are shown in Table 3.

[0127] Table 1

[0128] Example Relative crystallinity, % Grain size, nm DI, % P1 84.3 10.2 98.6 P2 76.5 5.5 99.1 P3 81.1 7.9 96.5 P4 77.7 8.5 98.8 P5 82.4 5.5 99.5 Comparative Example CP1 83.7 4.9 99.2 CP2 81.5 4.3 99.6 CP3 113.1 12.3 65.1 CP4 76.7 8.0 23.5

[0129] Table 2

[0130]

[0131]

[0132] Table 3

[0133]

[0134] As can be seen from the examples, comparative examples, and the data in Tables 1 and 2, the hydrothermal synthesis of boehmite using the method provided by this invention in the examples exhibits a high colloidal index, and the product obtained after colloidal treatment still maintains a large pore volume. While the colloidal indices of comparative samples CP1 and CP2 are consistent with the properties of the product of this invention, the pore volume V2 of CJ1 and CJ2 after colloidal treatment and subsequent drying and calcination is lower than the 0.40 mL / g specification of the product of this invention. In Comparative Example 3, no acid was added, resulting in an unqualified acid-aluminum ratio parameter. In Comparative Example 4, the hydrothermal aging time was unqualified, therefore, no boehmite meeting the requirements was obtained. The pore volume V1 of the calcined sample CP3 is lower than the 0.45 mL / g specification of the product of this invention. Although the pore volume V1 of the calcined sample CP4 is consistent with the properties of the product of this invention, its colloidal properties are poor, and the pore volume V2 of CJ3 and CJ4 after colloidal treatment and subsequent drying and calcination is lower than the 0.40 mL / g specification of the product of this invention.

[0135] As shown in Table 3, compared with comparative samples DC1 and DC2, the additive of this invention containing highly soluble macroporous pseudoboehmite exhibits a significantly increased pore volume while maintaining comparable wear performance. Furthermore, the 5-100 nm pore volume accounts for over 60% of the total pore volume, demonstrating a rich mesoporous structure. Comparative samples DC3 and DC4, due to the poor soluble nature of the pseudoboehmite, could not yield products with acceptable strength, and also had smaller pore volumes.

[0136] Evaluation of catalytic cracking additives: The mixture of catalytic cracking additives and industrial additives was pre-aged at 800°C and 100% vol% steam for 17 hours in a fixed-bed aging unit, and then evaluated in an ACE unit. The properties of the feedstock are shown in Table 5. The reaction temperature was 500°C, the weight ratio of additive to feedstock (mixture to feedstock) was approximately 6, and the weight hourly space velocity of the feedstock was 16 s. -1 .

[0137] Evaluation example

[0138] The additives C1 to C5, which utilize highly colloidal macroporous pseudoboehmite and are prepared according to the method of the present invention, and the additives DC1 to DC2, prepared in the comparative examples, were respectively mixed with industrial agents at a mass ratio of 2:8 to form catalyst mixtures (referred to as Examples 6-10 and Comparative Examples 5-6). The catalyst mixtures were aged at 800°C and 100% water vapor for 17 hours in a fixed-bed aging apparatus. Then, the aforementioned catalytic cracking additives were evaluated in an ACE unit, and the results are shown in Table 6.

[0139] The product distribution data in Table 6 correspond to the yields of each product component (dry gas, liquefied gas, gasoline, diesel, heavy oil, and coke).

[0140] Wherein, conversion rate % = gasoline yield % + liquefied petroleum gas yield % + dry gas yield % + coke yield %;

[0141] C4 olefin selectivity % = C4 olefin yield % / conversion %; C4 olefins include butene and butadiene (of which, the yield of butadiene is very low, almost zero);

[0142] The percentage of butene concentration in liquefied petroleum gas (LPG) refers to the content of butene in LPG. Butene includes 1-butene, 2-butene (trans-2-butene and cis-2-butene), and isobutene.

[0143] Table 4

[0144]

[0145]

[0146] Table 5

[0147]

[0148] Table 6

[0149]

[0150]

[0151] Table 6 (continued)

[0152]

[0153] Table 6 (continued)

[0154]

[0155] The results in Table 6 show that, compared with the comparative example, the catalytic cracking aid prepared in the embodiments of the present invention, when used in the catalytic cracking reaction of hydrocarbon oil, improves the yield of C4 olefins in the catalytic cracking reaction products, significantly improves the selectivity of C4 olefins, and significantly improves the concentration of butene in liquefied petroleum gas.

[0156] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A catalytic cracking aid, characterized in that, Based on the dry weight of the additive, the additive contains 15-40 wt% β-zeolite, 10-50 wt% highly colloidal macroporous pseudoboehmite, and 10-75 wt% clay; wherein the highly colloidal macroporous pseudoboehmite contains 98-100 wt% alumina; the highly colloidal macroporous pseudoboehmite has a pore volume V1 of 0.45-0.7 mL / g and a colloidal index DI of 95-100%; and the highly colloidal macroporous pseudoboehmite has a pore volume V2 of 0.4-0.55 mL / g after colloidal treatment.

2. The adjuvant according to claim 1, wherein, The additive contains 20-40 wt% β-zeolite, 15-45 wt% highly colloidal macroporous pseudoboehmite, and 15-65 wt% clay.

3. The adjuvant according to claim 1 or 2, wherein, The total pore volume of the additive is not less than 0.2 mL / g.

4. The adjuvant according to claim 3, wherein, The total pore volume of the additive is 0.2-0.3 mL / g.

5. The adjuvant according to claim 1 or 2, wherein, In the additive, the volume of mesopores with a pore size of 5-100 nm, as determined by peak fitting method, accounts for more than 60% of the total pore volume.

6. The adjuvant according to claim 5, wherein, In the additive, the volume of mesopores with a pore size of 5-100 nm, as determined by peak fitting method, accounts for 65-80% of the total pore volume.

7. The adjuvant according to claim 1 or 2, wherein, The wear index of the additive is no greater than 2.

8. The adjuvant according to claim 1 or 2, wherein, The β-zeolite is selected from at least one of hydrogen-type β-zeolite, sodium-type β-zeolite, phosphorus-modified β-zeolite, and metal-modified β-zeolite.

9. The adjuvant according to claim 8, wherein, The β-zeolite is a hydrogen-type β-zeolite.

10. The adjuvant according to claim 1 or 2, wherein, In the β-zeolite, the molar ratio of SiO2 to Al2O3 is 20-50:

1.

11. The adjuvant according to claim 1 or 2, wherein, The clay is selected from at least one of kaolin, rettoite, diatomite, montmorillonite, bentonite, and sepiolite.

12. A method for preparing a catalytic cracking additive, wherein, The preparation method includes: (1) The highly soluble macroporous pseudoboehmite is mixed with water and pulped, and the first acid is added to the obtained product for acidification to obtain an acidified slurry; wherein, the alumina content in the highly soluble macroporous pseudoboehmite is 98-100wt%; the pore volume V1 of the highly soluble macroporous pseudoboehmite is 0.45-0.7 mL / g, and the gelation index DI is 95-100%; the pore volume V2 of the highly soluble macroporous pseudoboehmite after gelation is 0.4-0.55mL / g; (2) Clay, β-zeolite and water are mixed to form a slurry, and then the slurry is mixed with the acidified slurry to form a catalyst slurry; (3) The catalyst slurry is spray-dried, shaped, and calcined to obtain a catalytic cracking aid; The amount of highly colloidal macroporous pseudoboehmite, clay, and β-zeolite used in the catalytic cracking aid obtained is such that, on a dry basis, the catalytic cracking aid contains 15-40 wt% β-zeolite, 10-50 wt% highly colloidal macroporous pseudoboehmite, and 10-75 wt% clay.

13. The preparation method according to claim 12, wherein, The first acid is selected from hydrochloric acid, nitric acid, sulfuric acid, oxalic acid, and phosphoric acid.

14. The preparation method according to claim 12, wherein, The amount of the first acid added satisfies the following condition: the molar ratio of hydrogen ions contained in the first acid to the highly colloidal macroporous pseudoboehmite (based on Al2O3) is 0.1-0.3:

1.

15. The preparation method according to claim 12, wherein, The acidification time is 0.5-2 h.

16. The preparation method according to claim 12, wherein, The solid content of the acidified slurry is 10-30 wt%.

17. The preparation method according to claim 12, wherein, The highly soluble macroporous pseudoboehmite was prepared by the following method: a) Mix hydrated alumina and / or amorphous alumina, water, and a second acid to obtain a mixed slurry; b) The mixed slurry is subjected to a hydrothermal reaction, and the resulting product is dried to obtain the highly colloidal macroporous pseudoboehmite.

18. The preparation method according to claim 17, wherein, The alumina concentration in the mixed slurry is 5-50 wt%.

19. The preparation method according to claim 18, wherein, The alumina concentration in the mixed slurry is 6-40 wt%.

20. The preparation method according to claim 19, wherein, The alumina concentration in the mixed slurry is 8-20 wt%.

21. The preparation method according to claim 17, wherein, In the mixed slurry, the molar ratio of acid to alumina is 0.02-0.

8.

22. The preparation method according to claim 21, wherein, In the mixed slurry, the molar ratio of acid to alumina is 0.08-0.

6.

23. The preparation method according to claim 17, wherein, The second acid is selected from inorganic acids and / or organic acids; wherein the inorganic acid is selected from at least one of hydrochloric acid, nitric acid and sulfuric acid, and the organic acid is selected from at least one of formic acid, acetic acid and oxalic acid.

24. The preparation method according to claim 17, wherein, The hydrothermal reaction temperature is 90-220℃; the hydrothermal reaction time is 6-48h.

25. The preparation method according to claim 24, wherein, The hydrothermal reaction temperature is 100-200℃; the hydrothermal reaction time is 6-42h.

26. The preparation method according to claim 17, wherein, The drying temperature is 60-120℃.

27. The preparation method according to claim 26, wherein, The drying temperature is 80-110℃.

28. The preparation method according to claim 12, wherein, In step (2), the solid content of the catalyst slurry is 20-50 wt%.

29. The preparation method according to claim 12, wherein, The β-zeolite is selected from at least one of hydrogen-type β-zeolite, sodium-type β-zeolite, phosphorus-modified β-zeolite, and metal-modified β-zeolite.

30. The preparation method according to claim 29, wherein, The β-zeolite is a hydrogen-type β-zeolite.

31. The preparation method according to claim 12, wherein, In the β-zeolite, the molar ratio of SiO2 to Al2O3 is 20-50:

1.

32. The preparation method according to claim 12, wherein, The clay is selected from at least one of kaolin, rettoite, diatomite, montmorillonite, bentonite, and sepiolite.

33. A catalytic cracking additive prepared by the preparation method according to any one of claims 12-32.

34. The use of a catalytic cracking aid according to any one of claims 1-11 and 33 in the catalytic cracking production of C4 olefins.

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