CN116265108A

CN116265108A - Preparation method of catalytic cracking catalyst for producing more gasoline

Info

Publication number: CN116265108A
Application number: CN202111558378.XA
Authority: CN
Inventors: 郑云锋; 孙书红; 蔡进军; 黄校亮; 景丽; 潘志爽; 刘涛; 段宏昌; 吕鹏刚
Original assignee: Petrochina Co Ltd
Current assignee: Petrochina Co Ltd
Priority date: 2021-12-17
Filing date: 2021-12-17
Publication date: 2023-06-20

Abstract

The invention relates to a preparation method of a high-yield gasoline catalytic cracking catalyst, which solves the problems of higher slurry oil and low gasoline yield of the existing heavy oil efficient conversion catalyst. The preparation method comprises the following steps: adding an aluminum source into a sodium carboxymethyl cellulose aqueous solution in parallel to obtain a mixed base solution, regulating the pH value of the mixed base solution to 6.5-9.0 by controlling the aluminum source, and aging for one time to obtain a pseudo-boehmite precursor; then adding acid to adjust the pH value to 2.0-4.0 to obtain dispersed pseudo-boehmite crystal grains, then adding an alkaline silicon source under the stirring condition, continuously stirring, carrying out secondary aging, filtering, washing with water, pulping, and preparing the silicon-containing pseudo-boehmite slurry; mixing and stirring water, a binder, clay, yttrium modified low-unit cell molecular sieve and the prepared silicon-containing pseudo-boehmite slurry, and then spray drying to prepare the heavy oil high-efficiency conversion catalyst.

Description

Preparation method of catalytic cracking catalyst for producing more gasoline

Technical Field

The invention belongs to the field of oil refining catalysts, and particularly relates to a preparation method of a high-efficiency heavy oil conversion catalytic cracking catalyst for producing more gasoline.

Background

Because of the adjustment of the oil consumption structure in China, the consumption diesel-gasoline ratio starts to decline year by year after reaching the peak value of 2.31 in 2005, and the consumption diesel-gasoline ratio is reduced to 1.64 in the first half of 2015, and is further reduced to 1.06 in 2030. And compared with diesel, the price difference of the gasoline is higher than 1000 yuan/ton, and the reduction of the diesel-gasoline ratio is an effective means for improving quality and enhancing efficiency of enterprises. Therefore, the method reduces the ratio of produced diesel to gasoline, enhances the efficient conversion of heavy oil, maximizes the production of more gasoline, and becomes an important direction for adjustment of domestic oil refining enterprises.

Gasoline is one of the light petroleum products with the largest dosage, catalytic cracking is the main production device of gasoline, and about 75% of gasoline in China is catalytic gasoline. Catalytic cracking is a catalytic process, and the catalyst plays a central role in FCC, and the differences of physicochemical properties and acid distribution influence the conversion rate of raw materials and the selectivity of products. However, the source of raw oil of the partial catalytic cracking device in China is complex, the proportion of blended slag oil is large, the heavy metal content is high, the difficulty in producing more gasoline is large, and the further reduction of the diesel-gasoline ratio is severely restricted. Catalytic cracking is a parallel sequential reaction, gasoline molecules can be further converted into liquefied gas, the yield of the liquefied gas is increased along with the increase of the conversion rate, and the yield of the gasoline is in a trend of rising and then falling. The method for reducing the conversion of the diesel oil into the gasoline and reducing the further conversion of the gasoline into the liquefied gas is a core of the catalytic device for maximally reducing the diesel-gasoline ratio, and is also a key for producing more gasoline.

CN1624079a discloses a hydrocarbon cracking catalyst containing modified faujasite, which is obtained by performing an exchange reaction on faujasite, a phosphorus compound and an ammonium compound, introducing a rare earth solution into the exchange slurry for further reaction, and performing filtration, washing and water vapor roasting treatment. The prepared catalyst has good activity stability, high gasoline yield, low coke yield, and strong heavy oil cracking capability and heavy metal pollution resistance.

Qi Yanping et al (fuel chemistry report, 2006 34 (6), 685) synthesized large pore catalytic cracking catalysts by adding polystyrene pellets of different particle sizes and different contents, and found that the addition of polystyrene pellets not only introduced macropores, but also improved catalyst activity and product gasoline yield.

CN103506153B discloses a catalytic cracking catalyst for reducing coke yield and producing gasoline, which comprises 10-50wt% of modified Y-type molecular sieve, molecular sieve with unit cell constant of 2.420-2.440nm, P of 0.05-6% and RE ₂ O ₃ 0.03-10% and a specific hydroxy nest concentration of less than 0.35mmol/g. The catalytic cracking catalyst provided by the invention can reduce coke formation, improve the utilization rate of heavy oil and improve the selectivity of gasoline. However, the modified Y-type molecular sieve is obtained by using NaY molecular sieve as raw material, using rare earth-containing substance and phosphorus-containing substance and adopting three exchange procedures and three hydrothermal treatments, and the process is complicated.

Heavy oil is used as main raw material for catalytic cracking, its molecular diameter is between 2.5 and 15nm, and its optimum pore size is 2-6 times of that of raw material, so that its optimum pore size range is 5-100nm. The Y-type molecular sieve is the main active center of the cracking catalyst, but the pore diameter of the Y-type zeolite is 0.74nm, small and medium molecular hydrocarbon in the raw oil can enter the inner pores of the zeolite to undergo cracking reaction, and large molecular hydrocarbon is difficult to enter the inner pores of the zeolite, so that the heavy oil cracking capability of the Y-type zeolite is poor. The traditional cracking catalysts for improving the heavy oil conversion depth all use an ultra-stable Y-type molecular sieve in the catalyst. For example, hydrothermal preparation methods of ultrastable Y-type molecular sieves are provided in CN1060976, CN1060977, CN1128673, CN1005405, CN1119206, CN1065844, US5340957, US5206194, US4273753, US4438178, US4584287 and US4429053, but the above methods easily cause defects in the crystal structure of the molecular sieve, and the obtained ultrastable Y-type molecular sieve has low heavy oil cracking activity.

Catalytic cracking reactions are parallel relay reactions. Because the heavy oil has larger molecular size, the heavy oil is difficult to enter the molecular sieve for direct reaction, in order to improve the heavy oil cracking capability of the catalyst, the matrix of the cracking catalyst usually has macropores and certain acidity which can be entered by heavy oil macromolecules, the macromolecules in the heavy oil can be firstly converted into medium-sized molecules in the matrix of Kong Zhonglie, and then the medium-sized molecules enter zeolite pore channels with stronger acidity and are further cracked into smaller molecules.

For heavy oil cracking, improving accessibility of heavy oil macromolecules to active centers, and enhancing pre-cracking of heavy oil macromolecules is a key to enhancing heavy oil conversion; the quality of pre-cracking will also severely restrict the ability of subsequent reactions to produce diesel, gasoline, lower olefins. Since heavy oil molecules are primarily cracked on a catalyst substrate, improvement of heavy oil conversion ability should be pursued from the aspect of improving pore structure, acidity, hydrothermal stability, etc. of the substrate material. In order to solve the problems, early American INTERCA company develops a bottom oil cracking auxiliary agent (BCA-105), which mainly adopts a high-activity matrix technology, does not contain molecular sieves, and achieves a certain effect when used in a device with better quality of foreign raw materials. Engelhard corporation introduced a Converter bottoms cracking aid that had a greater heavy oil conversion capacity due to the unique DMS matrix technology employed. However, since domestic crude oil is relatively heavier, the molecular weight is larger, the heavy metal content is high, and the foreign heavy oil efficient conversion catalyst is not well applied in China, the development of the heavy oil efficient conversion catalyst suitable for China's conditions is urgently needed.

The active matrix of the catalytic cracking catalyst is mainly pseudo-boehmite, and the content of the pseudo-boehmite in the oil refining catalyst is about 20%. At present, the pore volume of the pseudo-boehmite widely used in industry is 0.4cm ³ About/g, specific surface area 250-400m ² Between/g, no B acid; with the increasing heaviness and inferior quality of crude oil, the pore structure, acid strength, acid type and the like of conventional pseudo-boehmite cannot meet the requirements of processing heavy crude oil.

The catalytic cracking catalyst prepared from the common pseudo-boehmite is difficult to meet the requirement of heavy oil macromolecule cracking, and in the process of producing the pseudo-boehmite, the pseudo-boehmite can be modified by adding one or more elements. The common modifying element is silicon element, which is beneficial to enhancing the acidity of pseudo-boehmite and improving the pore structure and the thermal stability of the carrier after being added. After the silicon atoms are introduced, the pseudo-boehmite still keeps the original configuration without great change, but the physical and chemical properties of the pseudo-boehmite, such as acidity, granularity, pore structure and pore performance, can be obviously modulated, so that the pore adsorptivity, catalytic performance and activity and selectivity of the pseudo-boehmite are changed. There are many methods for preparing silicon-containing pseudo-boehmite, such as co-current coprecipitation method, fractional precipitation method, dipping method, etc., and the silicon source used mainly includes kaolin, ethyl orthosilicate, water glass, etc. There have been a number of literature or patent reports on the synthesis of siliceous pseudo-boehmite.

CN102139204a discloses synthesis of pseudo-boehmite containing amorphous silica alumina, but the patent uses industry mature pseudo-boehmite as raw material, then carries out post-modification to synthesize silicon-containing pseudo-boehmite, and the characteristics of the synthesized silicon-containing pseudo-boehmite are limited by the characteristics of the industry pseudo-boehmite, and the method is only suitable for hydrotreating, in particular for preparing middle distillate hydrotreating catalyst carrier.

CN03147975.8 discloses a mesoporous silica-alumina material with pseudo-boehmite phase structure, which has stronger macromolecule cracking capability, higher conversion rate of raw oil and lower heavy oil yield. The method has the defects that mesoporous silicon-aluminum is prepared by adopting a sol-gel method, a porous material is obtained by controlling the condensation between two ions of aluminosilicate, a low-concentration silicon source and an aluminum source are adopted for reaction, and the product yield is low; the steps are complex, and the requirements on the pH value and the reaction temperature are high; high temperature drying and calcination are required.

CN 106040217a and CN 105688977B disclose a preparation method of catalytic cracking promoter/catalyst containing pseudo-boehmite, which has strong heavy oil conversion capability and good coke selectivity, but the nature of silicon-containing pseudo-boehmite is limited by the physicochemical properties of industrial pseudo-boehmite.

CN 104445317B discloses a method for preparing modified pseudo-boehmite. Firstly, deionized water, activated alumina, aluminum hydroxide and a silicon source are mixed and stirred; then homogenizing and refining pretreatment is carried out; adding alkali to adjust the pH value to 8-11; then carrying out hydrothermal reaction, controlling the reaction temperature to be 100-250 ℃ and the reaction time to be 1-48h; solid-liquid separation and washing; drying and crushing to obtain pseudo-boehmite powder. The preparation method has the defects that in the preparation process, not only high-temperature and high-pressure crystallization equipment is needed, but also refining equipment such as a sand mill or a ball mill is needed, the process is complicated, and the prepared silicon-containing pseudo-thin specific surface area is not high, but only 280cm ² /g。

CN 03157163.8 discloses a synthesis of silica-alumina containing pseudo-boehmite structure, which has higher catalytic cracking activity after high temperature activation. The silicon-containing compound solution is directly or co-currently introduced into pseudo-boehmite slurry, so as to increase the content of tetra-coordinated aluminum to improve the strength of alumina and the acid content, and the prepared silicon-containing aluminum oxide has high cracking activity. The disadvantage is that the crystallinity of the silicon pseudo-thin material is not high, and the higher cracking activity is used as a hydrogenation catalyst carrier, so that the liquid yield is reduced.

Wang Dongmei [ Petroleum refining and chemical industry, 2015, 46 (5), 70-75 ]]The synthesis of a siliceous pseudo-boehmite is reported. The three materials of aluminum sulfate solution, sodium metaaluminate solution and kaolin suspension are parallel-flow, and the obtained slurry is further mixed with Na ₂ CO ₃ The solution flows in parallel, and is aged, washed and driedSiO is obtained through the processes of roasting and the like ₂ Silicon-containing Al with mass fraction of 25.9% ₂ O ₃ . The silicon-containing pseudo-boehmite has low cost and simple preparation process, and the pore volume of the silicon-containing aluminum oxide can reach 0.866cm ³ And/g, wherein the proportion of macropores with the pore diameter of more than 20nm reaches 52.63.

CN 1915486B describes a hydrated alumina having pseudo-boehmite structure containing additives selected from one or several compounds containing alkaline earth metals, lanthanide metals, silicon, gallium, boron or phosphorus elements. Acidifying pseudo-boehmite (acid aluminum ratio is 0.01-0.5), and aging for 0-24 hours at room temperature-90 ℃; the final product is mixed with additives. The hydrated alumina is particularly suitable as a matrix and binder material for the preparation of catalytic cracking catalysts.

Different catalytic reactions require different acid centers, the B acid center generates a carbonium ion cracking reaction during the catalytic reaction, and the L acid center generates a carbonium ion reaction and a free radical reaction. The B acid in the FCC catalyst is mainly provided by the active component molecular sieve, and the L acid is provided by the carrier. For the catalytic cracking catalyst, the B acid active site in the matrix is critical to the pre-cracking reaction, but the traditional matrix material mainly contains the L acid active site, and basically has no B acid active site, and the L acid active site has lower activity, is difficult to promote heavy oil conversion, and is mainly subjected to free radical reaction and easy to coke. On the contrary, the hydrocarbon molecules react on the surface of the active site of the B acid basically according to a carbonium ion mechanism, and have higher activity, so that the hydrocarbon molecules can be effectively promoted to be cracked to generate liquid products. The acid center in conventional pseudo-boehmite is mainly an L-acid formed from hexacoordinated non-framework aluminum, without a B-acid center. It has been reported in patents and literature that the B acid center can be introduced into pseudo-boehmite by special processes or elemental modifications.

CN 102949989B discloses a silica-alumina catalytic material with pseudo-boehmite crystal phase structure, which contains both B acid and L acid center. The preparation process includes (1) neutralizing aluminium source and alkali solution at room temperature to 85 deg.c to form gel with final pH value of 7-11; (2) According to SiO ₂ :Al ₂ O ₃ 1 (2-3) adding silicon source, aging at room temperature to 90deg.C for 1-10Hours; (3) removing impurity ions by ammonium exchange or acid exchange; (4) re-pulping the filter cake and then performing treatment according to fluosilicic acid; mixing 1 weight ratio of dry material= (0.01-0.12) with fluosilicic acid, and reacting at room temperature to 80 ℃ for 0.5-2 hours; (5) filtering, washing and drying for 10-20 hours. The silicon-containing pseudo-thin has higher activity and larger specific surface area and pore volume, and has the defect that the ratio of pyridine infrared B acid to L acid measured at 200 ℃ of the catalytic material is only 0.085-0.100.

CN 106807352B discloses an active mesoporous silica-alumina catalytic material having a pseudo-boehmite crystalline phase structure. The preparation process comprises the following steps: stirring vigorously Al ₂ (S0 ₄ ) ₃ The solution and ammonia water are in parallel flow for forming glue, the glue forming temperature is 30 ℃, the pH value is kept at 10.0, meanwhile, the metered water glass solution and the glue forming slurry are mixed in parallel flow mode, and the temperature is raised to 60 ℃ for ageing for 2 hours after the slurry is mixed; and (3) ammonium salt exchange is carried out on the solid precipitate after filtration for 0.5 hour at 70 ℃, and the active mesoporous silicon-aluminum catalytic material is obtained after filtration and water washing. The active mesoporous silica-alumina catalytic material has a large pore volume, but the amount of B acid is low, and the ratio of the amount of B acid to the amount of L acid is only 0.055-0.085, so that the activity of the material is low.

CN 106582597B discloses a silica sol modified alumina, its preparation method and application. (1) Acidifying and peptizing the pseudo-boehmite slurry by inorganic acid to obtain pseudo-boehmite sol; (2) Adding silica sol into pseudo-boehmite sol to obtain a first mixture; (3) Adjusting the pH value of the first mixture within the range of pH=1-11, and then reacting for a period of time under heating conditions to obtain a second mixture; (4) Crystallizing the second mixture to obtain a third mixture; (5) And filtering, washing, drying and roasting the third mixture to obtain the silicon modified alumina. The disadvantage is that the physicochemical properties of the modified silicon-containing pseudothin depend on the properties of the pseudoboehmite raw material, are limited by the low surface area of the industrial pseudothin, and the specific surface area of the synthesized silicon-containing pseudothin is low.

Zheng Jinyu et al (Petroleum theory, journal (Petroleum processing), 26 (6), 2010, 846) modification of pseudo-boehmite with tetraethyl orthosilicate, the modification being carried out by acid-catalyzed reaction, lifting, in order to bring silicon atoms into the pseudo-boehmite crystal phaseA series of complex reaction steps such as temperature aging, filtering, washing, drying, high-temperature roasting and the like, wherein silicon hydroxyl groups are condensed with aluminum hydroxyl groups, and silicon enters a crystalline phase, so that the hydrothermal stability and acidity of the alumina are modulated. However, the pore volume and the pore diameter of the pseudo-boehmite before and after the silicon modification are not obviously changed, and the silicon modification only obviously improves the hydrothermal stability of the material and introduces B acid; meanwhile, as the silicon modified pseudo-boehmite is subjected to high-temperature roasting at 550 ℃, the high-temperature roasting of the pseudo-boehmite causes a large amount of condensation of surface hydroxyl groups, the peptization performance of the pseudo-boehmite is greatly reduced, the bonding performance of the pseudo-boehmite is deteriorated, the abrasion resistance index of the catalyst/auxiliary agent is obviously reduced under the same alumina sol condition, the content of the binder such as alumina sol is required to be greatly increased to ensure the strength of the catalyst/auxiliary agent, and the cost is inevitably increased. The method for preparing the silicon modified alumina has more steps, and simultaneously, the pseudo-boehmite is subjected to r-Al after high-temperature roasting ₂ O ₃ In order to ensure the strength of the catalyst, the content of the binder such as alumina sol needs to be greatly increased, resulting in increased cost.

CN108940247a discloses a high-activity catalytic material, which has a characteristic diffraction peak of pseudo-boehmite structure, and the ratio of the number of B acid centers to the number of L acid centers measured by pyridine infrared at 200 ℃ is 0.10-0.23. The preparation method of the catalytic material comprises the following steps: simultaneously adding a silicon source and an alkaline aluminum source into a container in a parallel flow mode under the condition of stirring at the temperature of between room temperature and 60 ℃ to control the pH value to be 13-14 for mixing into glue, then adding an acidic aluminum source into the container, controlling the end point pH value of a slurry system to be 8.0-10.5, then carrying out constant temperature treatment at the temperature of between 40 and 80 ℃, washing and filtering, and carrying out ion exchange on the obtained solid precipitate to remove impurity ions, wherein the weight ratio of the silicon source to the aluminum source is 1: (1.2 to 5.7) a silicon source in terms of silicon oxide and an aluminum source in terms of aluminum oxide, being the sum of the basic aluminum source and the acidic aluminum source. However, the preparation method emphasizes that the two materials of the silicon source and the sodium metaaluminate are added in the same time, the aim is to maintain the pH of the system between 13 and 14, then the acidic aluminum source is dripped, and the end point PH is controlled to be 8.0 to 10.5 after dripping. The slow speed of acidic aluminum source drops can cause deviation from the environment of generating pseudo-thin phases, so that the synthesized pseudo-thin phases have low crystallinity and weak diffraction peaks; in addition, the silicon material prepared by the process is mainly distributed in a bulk phase, and the Al/Si atomic ratio of the surface of the silicon material is larger than that of the bulk phase, so that the synthesized pseudo-thin film has a certain B acid, and the ratio of the B acid to the L acid of the material is smaller when the silicon material is modified by the same addition amount of silicon.

CN101746793a discloses a preparation method of mesoporous hollow alumina particles: the method comprises the steps of dropwise adding a polysaccharide electrolyte solution into boehmite sol, standing and ageing for 1-48 hours, separating and taking out formed spherical particles, cleaning and drying, and calcining for 8 hours at 650 ℃ to obtain mesoporous hollow alumina particles. The polysaccharide electrolyte is added after the boehmite sol is formed, and the polysaccharide mainly plays a role of a hard template: a layer of boehmite is arranged around the polysaccharide liquid drops, on the other hand, the negative charge of the polysaccharide neutralizes the positive charge of the boehmite, and the boehmite colloid particles are precipitated in a coagulation way, so that boehmite precipitation is generated on the spherical interface where the polysaccharide electrolyte solution contacts with the boehmite sol liquid drops, hollow boehmite spheres are formed macroscopically, and finally, the mesoporous hollow alumina particles are obtained through calcination. The mesoporous hollow alumina particles are of a boehmite structure, and can not be directly used for preparing a catalytic cracking catalyst because a great amount of nitric acid needs to be refluxed for 1h at 80 ℃ to be dissolved in acid.

CN103601226a discloses a method for preparing boehmite, which takes sodium metaaluminate aqueous solution as raw material, and introduces carbon dioxide to prepare boehmite, and is characterized by comprising the following steps: 1) Adding aluminum hydroxide into 10-40% sodium hydroxide aqueous solution with the mass concentration of 90-105 ℃ in batches to prepare sodium metaaluminate solution with the alumina content of 200-450 g/L, adding soluble cellulose derivative or soluble starch derivative which is 2-5% of the mass of the alumina, and stirring for 1-2 h; 2) Diluting the solution in the step 1) into a sodium metaaluminate solution with the alumina content of 10-80 g/L; 3) Controlling the reaction temperature to be 20-60 ℃, and introducing carbon dioxide gas with the mass concentration of 30-80% of carbon dioxide from the lower part of the sodium metaaluminate solution under stirring to neutralize the solution until the pH value of the solution is 10-11; 4) Adding urea accounting for 1-3% of the mass of the alumina into the solution in the step 3), uniformly stirring, continuously introducing carbon dioxide gas, and neutralizing until the pH value of the solution is 9-10; 5) And 4) standing and aging the solution at 20-60 ℃ for 0.5-6 h, separating solid from liquid, washing the solid, and drying to obtain the boehmite. The preparation process forms boehmite precipitation, and the boehmite precipitation has a structure different from pseudo boehmite and cannot be directly used for preparing a catalytic cracking catalyst.

Although there are various methods for preparing silicon-containing pseudoboehmite in the prior art, and the properties of the obtained pseudoboehmite are excellent in some aspects, there are a number of disadvantages in these preparation methods: (1) The metal alkoxide is high in price, inflammable, toxic and not easy to store, and the alkoxide of different types has different hydrolysis speeds, so that the preparation process of the material is complex and not easy to control; (2) The silicon-containing pseudo-thin synthesized by adopting the modification after the industrial pseudo-thin has high cost, and the pore volume and the acidity are greatly dependent on the advantages and disadvantages of the industrial pseudo-thin; (3) The synthesized siliceous pseudo-thin needs to be roasted, needs to be acidified again or has poor peptization property when preparing the catalytic cracking catalyst, and needs to consume a large amount of binder when preparing the catalyst; (4) The synthesized silicon-containing pseudo-thin B has less acid, the ratio of B/L acid is not high enough, the activity is low, the coke generation is high, the pore volume is small, and the method is not suitable for the requirements of heavy oil macromolecule cracking on a matrix.

In summary, in order to improve the pore structure and the acid distribution of the catalytic cracking catalyst matrix and enhance the efficient conversion of heavy oil, researchers have developed a great number of synthesis and preparation researches of mesoporous and macroporous silica-alumina materials, and the pore structure and the acid distribution are improved to a certain extent, but the existing synthesized silica-alumina materials still have the problems of high cost, small B/L acid ratio, low activity, need for subsequent acidification, need for pore structure improvement and the like.

Therefore, the research on the preparation method of the catalytic cracking matrix material with large pore volume, large specific surface area and high B/L acid ratio and the preparation of the high-efficiency conversion catalytic cracking catalyst for producing the heavy oil of the high-yield gasoline by combining with the molecular sieve are significant in improving the yield of the catalyst gasoline and the high-efficiency conversion of the heavy oil.

Disclosure of Invention

Based on the above, the main purpose of the invention is to provide a preparation method of a high-yield gasoline catalytic cracking catalyst, which solves the problems of high slurry oil and insufficient gasoline yield of the existing heavy oil efficient conversion catalyst.

Therefore, the invention provides a preparation method of a high-yield gasoline catalytic cracking catalyst, which comprises the following steps:

(1) Adding sodium metaaluminate aqueous solution and strong acid aluminum salt aqueous solution as aluminum sources into sodium carboxymethyl cellulose aqueous solution in parallel to obtain mixed base solution, regulating the pH of the mixed base solution to 6.5-9.0 by controlling the aluminum source sources, and aging at 40-80 ℃ for the first time to obtain pseudo-boehmite precursor; adding acid into the pseudo-boehmite precursor to adjust the pH value to 2.0-4.0, obtaining dispersed pseudo-boehmite crystal grains, then adding an alkaline silicon source under the stirring condition, continuously stirring, aging for the second time at the temperature of 40-80 ℃, filtering, washing with water, pulping, and preparing the silicon-containing pseudo-boehmite slurry;

(2) Mixing and stirring water, a binder, clay, yttrium modified low-unit cell molecular sieve and the silicon-containing pseudo-boehmite slurry prepared in the step (1) to obtain mixed slurry, and then spray-drying to prepare the heavy oil efficient conversion catalyst; based on 100 parts by mass of a dry catalyst, the catalyst comprises 20-45 parts of yttrium modified low-unit cell molecular sieve, 13-65 parts of clay, 5-12 parts of binder and 10-30 parts of siliceous pseudo-boehmite slurry, preferably 35-42 parts of yttrium modified low-unit cell molecular sieve, 22-42 parts of clay, 8-11 parts of binder and 15-25 parts of siliceous pseudo-boehmite slurry.

Specifically, the generation of the pseudo-thin precursor is related to the amount of sodium ions and sulfate radicals, the content ratio of the two aluminum sources is not absolutely related, and the good pseudo-thin precursor can be formed as long as the pH of the system reaches a proper range.

The preparation method of the productive gasoline catalytic cracking catalyst provided by the invention is characterized in that preferably, in the preparation of the silicon-containing pseudo-boehmite slurry, the concentration of the sodium carboxymethyl cellulose aqueous solution is 1-3wt%, and the dosage of the sodium carboxymethyl cellulose aqueous solution is 2-10% of the total mass of the aluminum source calculated by aluminum oxide calculated by sodium carboxymethyl cellulose.

The preparation method of the productive gasoline catalytic cracking catalyst provided by the invention is characterized in that preferably, in the preparation of the silicon-containing pseudo-boehmite slurry, the addition amount of the alkaline silicon source is 1-40% of the total mass of the aluminum source calculated by aluminum oxide calculated by silicon dioxide.

In the preparation method of the high-yield gasoline catalytic cracking catalyst, preferably, the addition amount of the alkaline silicon source in the preparation of the silicon-containing pseudo-boehmite slurry is 5-30% of the total mass of the aluminum source in terms of aluminum oxide in terms of silicon dioxide, and more preferably 10-25%.

The preparation method of the high-yield gasoline catalytic cracking catalyst provided by the invention is characterized in that preferably, the pH value of the mixed base solution is regulated to 7.0-8.7 in the preparation of the silicon-containing pseudo-boehmite slurry.

The preparation method of the productive gasoline catalytic cracking catalyst provided by the invention is that preferably, the pH value of the pseudo-boehmite precursor is adjusted to 2.5-3.8 in the preparation of the silicon-containing pseudo-boehmite slurry; the acid is an inorganic acid, more preferably, the inorganic acid is one of hydrochloric acid, sulfuric acid, nitric acid, formic acid, acetic acid and phosphoric acid, still more preferably hydrochloric acid, sulfuric acid or nitric acid; the secondary aging temperature is 50-60 ℃.

The preparation method of the productive gasoline catalytic cracking catalyst provided by the invention is characterized in that preferably, the secondary aging time is longer than the primary aging time in the preparation of the silicon-containing pseudo-boehmite slurry; further preferably, the time of the primary aging is 3min-2h; the secondary aging time is 0.5-4h.

The preparation method of the high-yield gasoline catalytic cracking catalyst provided by the invention is characterized in that the continuous stirring time is 10-120min, the primary aging time is 3min-0.5h, and the secondary aging time is 1-2h in the preparation of the silicon-containing pseudo-boehmite slurry.

The preparation method of the productive gasoline catalytic cracking catalyst provided by the invention is characterized in that preferably, the water washing in the preparation of the silicon-containing pseudo-boehmite slurry also comprises at least one sodium ion exchange, and the filtration and the water washing are carried out after each sodium ion exchange so as to reduce the sodium content; further preferably, the sodium ion exchange is an ammonium salt exchange, wherein the ammonium salt is selected from one of ammonium chloride, ammonium sulfate, ammonium bisulfate, ammonium carbonate, ammonium bicarbonate, ammonium phosphate, ammonium nitrate and ammonium oxalate, and even further preferably ammonium chloride or ammonium nitrate.

The preparation method of the productive gasoline catalytic cracking catalyst provided by the invention is that, preferably, the strong acid aluminum source in the preparation of the silicon-containing pseudo-boehmite slurry is selected from one or more of aluminum chloride, aluminum sulfate, aluminum nitrate and alum; the alkaline silicon source is selected from one of potassium silicate, water glass and alkaline silica sol.

The preparation method of the high-yield gasoline catalytic cracking catalyst provided by the invention is that, preferably, the silicon-containing pseudo-boehmite in the silicon-containing pseudo-boehmite slurry has pseudo-boehmite crystalline phase with specific surface area of 300-500m ² Per g, pore volume is 0.5-1.5mL/g, B acid is enriched, and ratio B/L of B acid to L acid measured by pyridine adsorption method at 200 ℃ is more than or equal to 0.21.

The preparation method of the multi-product gasoline catalytic cracking catalyst provided by the invention has no roasting and acidification processes in the process of preparing the silicon-containing pseudo-boehmite slurry by filtering, washing and pulping in the preparation of the silicon-containing pseudo-boehmite slurry.

The preparation method of the productive gasoline catalytic cracking catalyst provided by the invention can directly use the silicon-containing pseudo-boehmite slurry in the preparation of the silicon-containing pseudo-boehmite slurry as a raw material for preparing the catalytic cracking catalyst or an auxiliary agent; the slurry can also be dried at a temperature of not higher than 120 ℃ after being filtered.

The preparation method of the productive gasoline catalytic cracking catalyst provided by the invention is that preferably, clay in the preparation of the siliceous pseudo-boehmite slurry is selected from one or more of kaolin, halloysite, montmorillonite, diatomite, sepiolite, halloysite, hydrotalcite, bentonite, acidified or alkali-dissolved kaolin and acidified or alkali-dissolved halloysite, and further preferably, kaolin and halloysite; the binder is aluminum sol and/or silica sol.

In the preparation method of the multi-product gasoline catalytic cracking catalyst provided by the invention, in the step (2), the adding sequence of each component is not particularly limited, and the components can be added sequentially or simultaneously, and the mixed slurry is formed by mixing and stirring after the components are added, preferably, the solid content of the mixed slurry is usually 35-45%, preferably 38-42% based on 100% of the mass of the mixed slurry.

The preparation method of the high-yield gasoline catalytic cracking catalyst provided by the invention is preferable that the spraying condition in the step (2) is the conventional operation condition for preparing the cracking catalyst, wherein the inlet temperature is 300-800 ℃, the tail gas temperature is 100-400 ℃, and the spraying pressure is 10-60 kg.

The preparation method of the multi-product gasoline catalytic cracking catalyst provided by the invention is that the yttrium modified low-unit cell molecular sieve in the step (2) is preferably a conventional commercial Y-type molecular sieve, the unit cell is 2.430-2.445nm, and the catalyst is obtained by impregnating and modifying yttrium chloride or yttrium nitrate with the concentration of 0.5-2.0%.

The preparation method of the multi-product gasoline catalytic cracking catalyst provided by the invention does not need to add acid for acidification in the step (2). The conventional pseudo-boehmite needs to be moderately peptized by adding acid, and the silicon-containing pseudo-boehmite slurry has good fluidity and does not need to be peptized by adding acid again.

The B acid and the L acid are measured by pyridine adsorption infrared spectroscopy (Py-FTIR). Pyridine adsorption infrared spectroscopy is a common measurement means, and is described in oil refining and chemical industry, 2004, 15 (4): 28-29; once amphiphilic, alumina carrier surface chemistry vs Ni-W/gamma-Al ₂ O ₃ Investigation of the Effect of hydrogenation catalyst Activity [ D]The infrared spectrum is disclosed for measuring the surface acidity of solid acid catalyst.

The preparation method of the silicon-containing pseudo-boehmite slurry provided by the invention synthesizes macroporous pseudo-boehmite aggregate by a double-aluminum method, and sodium carboxymethyl cellulose is introduced in the process, and as the sodium carboxymethyl cellulose solution is weak alkaline, the sodium carboxymethyl cellulose solution is matched with an alkaline system for synthesizing pseudo-boehmite by the double-aluminum method; on one hand, the sodium carboxymethyl cellulose can play a role of a buffer solution to prevent the pH value of a solution formed by parallel flow of double aluminum from being too high or too low to form a non-pseudo-boehmite phase; on the other hand, the sodium carboxymethyl cellulose is a polymer and has a pore-forming function, so that the pore volume of the pseudo-boehmite can be properly increased; meanwhile, under the existence of sodium carboxymethyl cellulose, the double aluminum raw material is slightly aged, aggregated is shallow, particles are small, and after being slightly acidified, the double aluminum raw material is dispersed into positively charged monodisperse pseudo-thin small crystal grains, so that the double aluminum raw material has good dispersibility, large contact area and meeting with negatively charged silicate, can generate Si-O-Al bonds, generates a large number of four-coordinated silicon-aluminum structural units, and is beneficial to forming a large number of B acid centers.

The pseudo-boehmite slurry product obtained by the preparation method provided by the invention not only has the characteristic of pseudo-boehmite mesopore structure, but also is rich in B acid centers, has stronger macromolecule cracking capability than the existing pseudo-boehmite or silicon-containing pseudo-boehmite material, and can obviously enhance heavy oil conversion in the catalytic cracking process. The silicon-containing pseudo-boehmite slurry prepared by the method does not need roasting or acidification, can be widely applied to the preparation of catalytic materials, catalytic cracking catalysts or auxiliaries, and is more convenient to use.

For the catalyst for efficiently converting heavy oil into high-yield gasoline, the heavy oil conversion capability and the high-yield gasoline of the catalyst are improved, on one hand, the presplitting of heavy oil macromolecules is required to be enhanced, and the heavy oil is cracked into small molecules such as gasoline and diesel oil as far as possible; on the other hand, the acid strength and acid density of the molecular sieve must be optimized, the activity stability of the molecular sieve is improved, as much diesel oil as possible is converted into gasoline, and meanwhile, the probability that the gasoline is further converted into small molecules such as liquefied gas is reduced. The silicon-aluminum material has the characteristics of large pore volume, large specific surface area and high B/L acid ratio, and can maximally convert heavy oil; compared with the conventional Y molecular sieve, the Y molecular sieve with low unit cell has high silicon-aluminum ratio, small unit cell size, weak hydrogen transfer, strong acidity, high acid density after yttrium modification, better activity and hydrothermal stability, is favorable for converting diesel oil into gasoline, and can maximally improve the yield of the gasoline.

In summary, the invention relates to a preparation method of a high-yield gasoline catalytic cracking catalyst, which solves the problems of high slurry oil and low gasoline yield of the existing heavy oil efficient conversion catalyst. The productive gasoline catalyst is prepared by mixing and stirring water, binder, clay, yttrium modified low-unit cell molecular sieve and silicon-containing pseudo-boehmite slurry, and then spray forming, roasting, washing with water and drying. Compared with the conventional pseudo-thin or modified pseudo-thin, the silicon-containing pseudo-thin diaspore has more abundant B acid center, large pore volume and high activity, and is beneficial to the pre-cracking of heavy oil macromolecules; a large amount of yttrium modified low-unit cell molecular sieves can react with relay, so that a large amount of diesel oil is continuously cracked into gasoline, and the gasoline yield is maximally improved.

Drawings

Fig. 1 is XRD diffractograms of example 1 and comparative example 1.

Wherein: example 1 characteristic peaks of pseudo-boehmite were found at 14, 28, 38, 49, 65, no SiO was present ₂ Is a characteristic peak of (1), which indicates SiO ₂ The pseudo-boehmite skeleton is entered and well dispersed; comparative example 1 shows that not only characteristic peaks of pseudo-boehmite but also impurity peaks of gibbsite appear, and that pH control in synthesis is important for synthesis of silicon-containing pseudo-boehmite, and pseudo-boehmite tends to generate crystal form of more stable gibbsite in a stronger alkaline environment.

Detailed Description

The following describes embodiments of the present invention in detail: the present example is implemented on the premise of the technical scheme of the present invention, and detailed implementation modes and processes are given, but the protection scope of the present invention is not limited to the following examples, and experimental methods without specific conditions are not noted in the following examples, and generally according to conventional conditions.

Analysis method

10g of the silicon-aluminum material prepared in the example or the comparative example is taken, dried at 80 ℃ for 24 hours, and then subjected to related physicochemical property analysis.

1. Determination of silicon content.

Silicon content was measured on a ZSX Primus X-ray fluorescence spectrometer manufactured by Rigaku corporation of Japan.

2. And (5) measuring the phase.

The phase of the sample was measured by using a D/max-2200PC type X-ray diffractometer from Japanese physics Co.

3. Specific surface area and pore volume.

Sample cell structure measurement the cell structure of the sample was measured using an Autosorb-6B physical adsorption instrument manufactured by Quantachrome company, USA. Weighing about 0.05g of a sample to be measured in a specific sample tube, and degassing and preprocessing the sample at 300 ℃ for 8 hours in a vacuum environment to remove water and impurities. Adsorption-desorption analysis was performed at 77K liquid nitrogen temperature, and specific surface area and pore volume were calculated using BET and BJH equations, respectively.

4. Specific method for measuring B, L acid.

Wherein the B acid and the L acid which are measured by pyridine infrared are obtained by using a pyridine temperature programming infrared spectrometry. The sample is pressed into a tablet by self-supporting, is placed in an in-situ tank of an infrared spectrometer for sealing, is heated to 350 ℃ and is vacuumized to 10 DEG C ^-3 Pa, and removing gas molecules adsorbed by the sample after keeping the temperature for 1 hour; cooling to room temperature, introducing pyridine vapor to maintain adsorption equilibrium for 30 min, heating to 200deg.C, and vacuumizing to 10 ^-3 Pa and desorbing for 30 min under the vacuum degree, cooling to room temperature, and scanning with 1400-1700cm ^-1 And obtaining a pyridine adsorption infrared spectrogram of the sample subjected to desorption at 200 ℃. According to 1540cm in pyridine adsorption infrared spectrogram ^-1 And 1450cm ^-1 The intensity of the characteristic absorption peak, the relative amounts of B acid centers and L acid centers were calculated.

5. Specific methods of measuring micro-activity.

Microreaction Activity: the samples were previously treated at 800℃for 17 hours with 100% steam. The reaction raw material is light diesel oil in hong Kong, the reaction temperature is 460 ℃, the reaction time is 70 seconds, the dried silicon-aluminum material is 5.0 g, and the weight ratio of the catalyst to the oil is 3.2. Total conversion was taken as microreaction.

6. Evaluation of catalyst Performance

The reaction performance is evaluated by adopting an ACE device, the raw oil is Xinjiang vacuum wide fraction wax oil and Xinjiang vacuum residuum, the mixing ratio is 30%, the reaction temperature is 510 ℃, and the catalyst-oil ratio is 5.0. The catalyst was aged for 17 hours at 800℃with 100% steam before evaluation.

Example 1

Dissolving 1g of sodium carboxymethyl cellulose in 100mL of water as a base solution, vigorously stirring and co-current adding a sodium metaaluminate aqueous solution (46 mL,100 g/L) and an industrial aluminum sulfate aqueous solution (100 mL,46 g/L) into the base solution to obtain a mixed base solution, controlling the pH of the system at 7.2 and the temperature of 65 ℃, and aging for 30min to obtain a pseudo-boehmite precursor; then adding hydrochloric acid for light acidification, controlling the pH value of the system to 2.6, obtaining monodisperse pseudo-thin crystal grains, adding water glass (12 mL,50 g/L) under intense stirring, continuing stirring for 10-60min, aging for 1h at 65 ℃, filtering, washing, exchanging ammonium chloride, filtering, washing, pulping, and preparing the silicon-containing pseudo-thin diaspore slurry SB-A with the acid of Kong Fu B.

Example 2

Dissolving 2.4g of sodium carboxymethyl cellulose in 100mL of water as a base solution, vigorously stirring and co-current adding a sodium metaaluminate aqueous solution (23 mL,100 g/L) and an industrial aluminum sulfate aqueous solution (50 mL,46 g/L) into the base solution to obtain a mixed base solution, controlling the pH of the system at 8.6 and 45 ℃, and aging for 30min to obtain a pseudo-boehmite precursor; then adding nitric acid for light acidification, controlling the pH value of the system to 3.7, obtaining monodisperse pseudo-thin crystal grains, adding water glass (13 mL,50 g/L) under intense stirring, continuing stirring for 10-60min, aging for 1h at 53 ℃, filtering, washing, exchanging ammonium chloride, filtering, washing, pulping, and preparing the silicon-containing pseudo-thin diaspore slurry SB-B with large Kong Fu B acid.

Example 3

Dissolving 1.2g of sodium carboxymethyl cellulose in 100mL of water as a base solution, vigorously stirring and co-current adding a sodium metaaluminate aqueous solution (55 mL,100 g/L) and an industrial aluminum sulfate aqueous solution (120 mL,46 g/L) into the base solution to obtain a mixed base solution, controlling the pH of the system at 6.6 and 55 ℃, and aging for 30min to obtain a pseudo-boehmite precursor; then adding hydrochloric acid for light acidification, controlling the pH value of the system to 2.3, obtaining monodisperse pseudo-thin crystal grains, adding water glass (17 mL,50 g/L) under intense stirring, continuing stirring for 10-60min, aging for 1h at 63 ℃, filtering, washing with water, exchanging ammonium chloride, filtering, washing with water, pulping, and preparing the silicon-containing pseudo-thin diaspore slurry SB-C with large Kong Fu B acid.

Example 4

Dissolving 1.5g of sodium carboxymethyl cellulose in 100mL of water as a base solution, vigorously stirring and co-current adding a sodium metaaluminate aqueous solution (23 mL,100 g/L) and an industrial aluminum sulfate aqueous solution (50 mL,46 g/L) into the base solution to obtain a mixed base solution, controlling the pH of the system at 7.2 and 58 ℃, and aging for 30min to obtain a pseudo-boehmite precursor; then adding hydrochloric acid for light acidification, controlling the pH value of the system to 2.8, obtaining monodisperse pseudo-thin crystal grains, adding water glass (25 mL,50 g/L) under intense stirring, continuing stirring for 10-60min, aging for 1h at 65 ℃, filtering, washing, exchanging ammonium chloride, filtering, washing, pulping, and preparing the silicon-containing pseudo-thin diaspore slurry SB-D with the acid of Kong Fu B.

Example 5

Dissolving 2.9g of sodium carboxymethyl cellulose in 100mL of water as a base solution, vigorously stirring and co-current adding a sodium metaaluminate aqueous solution (46 mL,100 g/L) and an industrial aluminum sulfate aqueous solution (100 mL,46 g/L) into the base solution to obtain a mixed base solution, controlling the pH of the system at 8.0 and 65 ℃, and aging for 30min to obtain a pseudo-boehmite precursor; then adding hydrochloric acid for light acidification, controlling the pH value of the system to 3.8, obtaining monodisperse pseudo-thin crystal grains, adding water glass (44 mL,50 g/L) under intense stirring, continuing stirring for 10-60min, aging for 1h at 70 ℃, filtering, washing with water, ammonium nitrate exchange, filtering, washing with water, pulping, and obtaining the silicon-containing pseudo-thin diaspore slurry SB-E with large Kong Fu B acid.

Comparative example 1

Dissolving 1g of sodium carboxymethyl cellulose in 100mL of water as a base solution, vigorously stirring and co-current adding a sodium metaaluminate aqueous solution (46 mL,100 g/L) and an industrial aluminum sulfate aqueous solution (100 mL,46 g/L) into the base solution to obtain a mixed base solution, controlling the pH of the system at 9.7 and the temperature of 65 ℃, and aging for 30min to obtain a pseudo-boehmite precursor; then adding hydrochloric acid for light acidification, controlling the pH value of the system to 2.6, obtaining monodisperse pseudo-thin crystal grains, adding water glass (12 mL,50 g/L) under intense stirring, continuing stirring for 10-60min, aging for 1h at 65 ℃, filtering, washing, exchanging ammonium chloride, filtering, washing, pulping, and obtaining the silicon-containing pseudo-thin diaspore slurry DB-a with the acid of Kong Fu B.

Comparative example 2

Dissolving 2.4g of sodium carboxymethyl cellulose in 100mL of water as a base solution, vigorously stirring and co-current adding a sodium metaaluminate aqueous solution (23 mL,100 g/L) and an industrial aluminum sulfate aqueous solution (50 mL,46 g/L) into the base solution to obtain a mixed base solution, controlling the pH of the system at 6.5 and 45 ℃, and aging for 30min to obtain a pseudo-boehmite precursor; then adding nitric acid for light acidification, controlling the pH value of the system to 3.7, obtaining monodisperse pseudo-thin crystal grains, adding water glass (13 mL,50 g/L) under intense stirring, continuing stirring for 10-60min, aging for 1h at 53 ℃, filtering, washing, exchanging ammonium chloride, filtering, washing, pulping, and preparing the silicon-containing pseudo-thin diaspore slurry DB-B with large Kong Fu B acid.

Comparative example 3

An active mesoporous silica-alumina catalytic material is synthesized according to CN 106807352B. With Al ₂ (S0 ₄ ) ₃ The solution and ammonia water are used as reaction raw materials, the parallel flow gel forming mode is adopted, and the Al is stirred vigorously ₂ (S0 ₄ ) ₃ Mixing the solution and ammonia water to form a gel, controlling the gel forming temperature to be 30 ℃, keeping the pH value of a gel forming system to be 10.0, mixing the metered water glass solution and the gel forming slurry in a parallel flow mode, realizing online addition of a silicon source, and heating to 60 ℃ for aging for 2 hours after a certain amount of mixed slurry is collected; after filtration the solid precipitate obtained is taken up on a dry precipitate basis: hinging salt: h20 The weight ratio of the catalyst to the catalyst is 1:1:15, and the catalyst is exchanged for 0.5 hour at 70 ℃, and the active mesoporous silica-alumina catalytic material DB-c provided by the invention is obtained after filtering and washing.

Comparative example 4

An active mesoporous silica-alumina catalytic material is synthesized according to CN 101746793A. 100 milliliters of aluminum nitrate aqueous solution with the concentration of 21.2 weight percent is prepared by taking aluminum nitrate nonahydrate as a raw material, aqueous ammonia solution with the concentration of 25-28 weight percent is gradually dripped under continuous stirring, the pH value of the system is more than 9.2 when 28 grams of aqueous ammonia solution is reached, the aqueous ammonia solution is stirred, and a boehmite precipitation filter cake is obtained after repeated centrifugal filtration and cleaning, and water is added into the filter cake to dilute the filter cake into a boehmite suspension with the concentration of 20 weight percent. 8 g of the boehmite suspension is taken, then 8 g of 2mol/L nitric acid solution is added, and after uniform mixing, the mixture is refluxed and stirred for 1h at 80 ℃ to obtain clear and transparent boehmite sol. 5.0wt.% NaCMCl25 (sodium carboxymethyl cellulose 125) solution is added into the obtained boehmite sol by a dropper to obtain white transparent hollow spheres, the hollow boehmite spheres are collected after standing and aging for 48 hours, and the mesoporous hollow alumina particles DB-d are obtained after drying at 100 ℃ and calcining at 650 ℃ for 8 hours.

Comparative example 5

An active mesoporous silica-alumina catalytic material is synthesized according to CN 201710382478.9. Adding small amount of deionized water into beaker, mixing tetraethoxysilane and sodium metaaluminate solution (Al) in parallel flow mode under stirring at room temperature ₂ O ₃ 160g/L, caustic ratio 2.55) are added into a beaker at the same time to mix into glue, so that the two materials are ensured to be added completely in the same time, and the pH value is 13.4; then Al (NO) ₃ ) ₃ Solution (concentration Al) ₂ O ₃ 60 g/L) was added thereto and the final pH of the slurry system was controlled to 10.2, followed by constant temperature treatment at 80℃for 2 hours; after washing and filtration the solid precipitate obtained is taken up on a dry precipitate basis: ammonium salt: h ₂ O=1: 0.6:10 by weight was exchanged at 60℃for 0.5 hour, and the catalytic material obtained by filtration and washing with water was designated DB-e.

Table 1 physicochemical properties of catalytic materials prepared in examples and comparative examples

For silicon modified pseudo-boehmite, the formation of the acid center is mainly due to the formation of effective Si-O-Al bonds, which form the basis of the acid center. As can be seen from examples 1-5 of Table 1, with the introduction of silicon, the amount of B acid generated can be increased, and the micro-reactivity of the material can be improved; with the introduction of silicon, B acid: l acid (200 ℃) tends to increase and then decrease; microactivity of silicon-aluminum materials and B acid: the ratio of L-acid, specific surface area and pore volume are related to one another.

The Si-O-Al bond formed in the conventional amorphous silicon aluminum material is relatively less, and mainly because the aggregation trend of a silicon source and an aluminum source is relatively large, the polymerization degree of primary ions in an aqueous solution is relatively large, so that the proportion of Si-O-Al bond formed by further bonding of the primary ions of silicon and aluminum is very low, and the acidity of the obtained silicon aluminum material is relatively low. Compared with the comparative example, the in-situ synthesized pseudo-boehmite small particles are moderately and slightly acidified and dispersed into pseudo-thin small grains, so that the contact probability of the pseudo-thin grains and a silicon source can be increased, more Si-O-Al bonds can be conveniently generated, more B acid centers can be generated, the ratio of B/L acid is improved, the micro-reaction activity is increased, and the heavy oil conversion capability is improved.

Example 6

Adding chemical water into an 18-liter stirring kettle, adding a binder, clay, a low-unit-cell Y molecular sieve and the silicon-containing pseudo-boehmite slurry prepared in the example 1 under stirring, mixing and stirring for 30 minutes, and overgrinding. The resulting slurry was spray dried at an inlet temperature of 500 c and a tail gas temperature of 180 c, then calcined at 540 c for half an hour, washed with 5 times of water, dried at 80 c overnight, and dried to give a productive gasoline catalyst-1, which was characterized and reaction evaluated, and the effect of the catalyst is shown in table 2.

Example 7

Adding chemical water into an 18-liter stirring kettle, adding a binder, clay, a low-unit-cell Y molecular sieve and the silicon-containing pseudo-boehmite slurry prepared in the example 2 under stirring, mixing and stirring for 30 minutes, and overgrinding. The resulting slurry was spray dried at an inlet temperature of 500 c and a tail gas temperature of 180 c, then calcined at 540 c for half an hour, washed with 5 times of water, dried at 80 c overnight, and dried to give a productive gasoline catalyst-2, which was characterized and reaction evaluated, and the effect of the catalyst is shown in table 2.

Example 8

Adding chemical water into an 18-liter stirring kettle, adding a binder, clay, a low-unit-cell Y molecular sieve and the silicon-containing pseudo-boehmite slurry prepared in the example 3 under stirring, mixing and stirring for 30 minutes, and overgrinding. The resulting slurry was spray dried at an inlet temperature of 500 c and a tail gas temperature of 180 c, then calcined at 540 c for half an hour, washed with 5 times of water, dried at 80 c overnight, and dried to give a productive gasoline catalyst-3, which was characterized and reaction evaluated, and the effect of the catalyst is shown in table 2.

Example 9

Adding chemical water into an 18-liter stirring kettle, adding a binder, clay, a low-unit-cell Y molecular sieve and the silicon-containing pseudo-boehmite slurry prepared in the example 4 under stirring, mixing and stirring for 30 minutes, and overgrinding. The resulting slurry was spray dried at an inlet temperature of 500 c and a tail gas temperature of 180 c, then calcined at 540 c for half an hour, washed with 5 times of water, dried at 80 c overnight, and dried to give a productive gasoline catalyst-4, which was characterized and reaction evaluated, and the effect of the catalyst is shown in table 2.

Example 10

Adding chemical water into an 18-liter stirring kettle, adding a binder, clay, a low-unit-cell Y molecular sieve and the silicon-containing pseudo-boehmite slurry prepared in the example 5 under stirring, mixing and stirring for 30 minutes, and overgrinding. The resulting slurry was spray dried at an inlet temperature of 500 c and a tail gas temperature of 180 c, then calcined at 540 c for half an hour, washed with 5 times of water, dried at 80 c overnight, and dried to give a productive gasoline catalyst-5, which was characterized and reaction evaluated, and the effect of the catalyst is shown in table 2.

Comparative example 6

Adding chemical water into an 18-liter stirring kettle, adding a binder, clay, a Y molecular sieve and the silicon-aluminum material prepared in comparative example 1 under stirring, adding a proper amount of hydrochloric acid for acidification (the mass of hydrochloric acid is 18% of the mass of the silicon-aluminum material), mixing and stirring for 30 minutes, and overgrinding. The resulting slurry was spray dried at an inlet temperature of 500 c and a tail gas temperature of 180 c, then calcined at 540 c for half an hour, washed with 5 times water, and dried at 80 c overnight to give comparative catalyst-1, which was characterized and reaction evaluated and the catalyst effect is shown in table 2.

Comparative example 7

Adding chemical water into an 18-liter stirring kettle, adding a binder, clay, a Y molecular sieve and the silicon-aluminum material prepared in comparative example 2 under stirring, adding a proper amount of hydrochloric acid for acidification (the mass of hydrochloric acid is 18% of the mass of the silicon-aluminum material), mixing and stirring for 30 minutes, and overgrinding. The resulting slurry was spray dried at an inlet temperature of 500 c and a tail gas temperature of 180 c, then calcined at 540 c for half an hour, washed with 5 times water, and dried at 80 c overnight to give comparative catalyst-2, which was characterized and reaction evaluated and the catalyst effect is shown in table 2.

Comparative example 8

Adding chemical water into an 18-liter stirring kettle, adding a binder, clay, a Y molecular sieve and the silicon-aluminum material prepared in comparative example 3 under stirring, adding a proper amount of hydrochloric acid for acidification (the mass of hydrochloric acid is 18% of the mass of the silicon-aluminum material), mixing and stirring for 30 minutes, and overgrinding. The resulting slurry was spray dried at an inlet temperature of 500 c and a tail gas temperature of 180 c, then calcined at 540 c for half an hour, washed with 5 times water, and dried at 80 c overnight to give comparative catalyst-3, which was characterized and reaction evaluated and the catalyst effect is shown in table 2.

Comparative example 9

Adding chemical water into an 18-liter stirring kettle, adding a binder, clay, a Y molecular sieve and the silicon-aluminum material prepared in comparative example 4 under stirring, adding a proper amount of hydrochloric acid for acidification (the mass of hydrochloric acid is 18% of the mass of the silicon-aluminum material), mixing and stirring for 30 minutes, and overgrinding. The resulting slurry was spray dried at an inlet temperature of 500 c and a tail gas temperature of 180 c, then calcined at 540 c for half an hour, washed with 5 times water, and dried at 80 c overnight to give comparative catalyst-4, which was characterized and reaction evaluated and the catalyst effect is shown in table 2.

Comparative example 10

Adding chemical water into an 18-liter stirring kettle, adding a binder, clay, a Y molecular sieve and the silicon-aluminum material prepared in comparative example 5 under stirring, adding a proper amount of hydrochloric acid for acidification (the mass of hydrochloric acid is 18% of the mass of the silicon-aluminum material), mixing and stirring for 30 minutes, and overgrinding. The resulting slurry was spray dried at an inlet temperature of 500 c and a tail gas temperature of 180 c, then calcined at 540 c for half an hour, washed with 5 times water, and dried at 80 c overnight to give comparative catalyst-5, which was characterized and reaction evaluated and the catalyst effect is shown in table 2.

Table 2 formulation (mass%) and effect of typical catalyst

As can be seen from table 2, the formulations of comparative agent 1 and catalyst 1, comparative agent 2 and catalyst 2, comparative agent 3 and catalyst 3, comparative agent 4 and catalyst 4, comparative agent 5 and catalyst 5 are identical and can be completely compared; because the silicon-aluminum material is a main place for pre-cracking heavy oil macromolecules, the pore structure and physical and chemical properties such as acidity of the silicon-aluminum material have great influence on the pre-cracking of heavy oil, and compared with the conventional pseudo-thinning or modified pseudo-thinning, the silicon-aluminum material has more abundant B acid centers, large pore volume and high activity, and is beneficial to the pre-cracking of heavy oil macromolecules. Under the condition that other formulas are the same, the catalyst containing the silicon-aluminum material obviously has better heavy oil conversion capability, and the oil slurry or heavy oil yield is obviously reduced; compared with the conventional Y molecular sieve, the Y molecular sieve with low unit cell has high silicon-aluminum ratio, small unit cell size, weak hydrogen transfer, strong acidity, high acid density after yttrium modification, better activity and hydrothermal stability, is favorable for converting diesel oil into gasoline, and can maximally improve the yield of the gasoline. Compared with the catalyst with the same formula, the gasoline yield of the catalyst of the technology can be increased by 1.1-1.8 percent. The silicon-containing pseudo-boehmite slurry combines with yttrium modified low-unit cell molecular sieve technology, and solves the problems of high slurry oil and low gasoline yield of the traditional catalyst.

The invention designs the high-efficiency conversion catalyst for the heavy oil and the high-yield gasoline aiming at the high-efficiency conversion mechanism of the heavy oil and the high-yield gasoline, and optimizes the high-activity matrix material, the yttrium-modulated low-unit cell Y molecular sieve and the like. ACE evaluation results show that compared with the traditional catalyst, the catalytic cracking catalyst for the productive gasoline has the advantages that the heavy oil conversion capability is obviously enhanced, and the gasoline yield is obviously increased.

Of course, the present invention is capable of other various embodiments and its several details are capable of modification and variation in light of the present invention by one skilled in the art without departing from the spirit and scope of the invention.

Claims

1. The preparation method of the high-yield gasoline catalytic cracking catalyst is characterized by comprising the following steps of:

2. The method for preparing a high-yield gasoline catalytic cracking catalyst according to claim 1, wherein the concentration of the sodium carboxymethyl cellulose aqueous solution is 1-3wt%, and the dosage of the sodium carboxymethyl cellulose aqueous solution is 2-10% of the total mass of the aluminum source in terms of aluminum oxide in terms of sodium carboxymethyl cellulose.

3. The method for preparing a high yield gasoline catalytic cracking catalyst according to claim 1, wherein the amount of the alkaline silicon source added is 1% -40% of the total mass of the aluminum source calculated as aluminum oxide calculated as silicon dioxide.

4. A method for preparing a productive gasoline catalytic cracking catalyst as defined in claim 3 wherein said basic silicon source is added in an amount of 5% -30% by weight of silica based on the total mass of said aluminum source based on alumina, preferably 10% -25%.

5. The method for producing a gasoline-rich catalytic cracking catalyst according to claim 1, wherein in step (1), the pH of the mixed base solution is adjusted to 7.0 to 8.7.

6. The method for preparing a high yield gasoline catalytic cracking catalyst according to claim 1, wherein in step (1), the pH of the pseudo-boehmite precursor is adjusted to 2.5-3.8; the acid is an inorganic acid, preferably, the inorganic acid is one of hydrochloric acid, sulfuric acid, nitric acid, formic acid, acetic acid and phosphoric acid, more preferably hydrochloric acid, sulfuric acid or nitric acid; the secondary aging temperature is 50-60 ℃.

7. The method for preparing a productive gasoline catalytic cracking catalyst according to claim 1, characterized in that said secondary aging is longer than said primary aging; preferably, the primary aging time is 3min-2h; the secondary aging time is 0.5-4h.

8. The method for preparing a high yield gasoline catalytic cracking catalyst according to claim 1, wherein in step (1), the continuous stirring time is 10-120min, the primary aging time is 3min-0.5h, and the secondary aging time is 1-2h.

9. The method for preparing a catalyst for catalytic cracking of high yield gasoline according to claim 1, wherein in step (1), the washing with water further comprises at least one sodium ion exchange, filtering and washing with water after each sodium ion exchange, preferably, the sodium ion exchange is ammonium salt exchange, wherein the ammonium salt is selected from one of ammonium chloride, ammonium sulfate, ammonium bisulfate, ammonium carbonate, ammonium bicarbonate, ammonium phosphate, ammonium nitrate and ammonium oxalate, more preferably, ammonium chloride or ammonium nitrate.

10. The method for preparing the multi-product gasoline catalytic cracking catalyst according to claim 1, wherein the strong acid aluminum source is one or more selected from aluminum chloride, aluminum sulfate, aluminum nitrate and alum; the alkaline silicon source is selected from one of potassium silicate, water glass and alkaline silica sol.

11. The method for preparing a catalyst for catalytic cracking of high yield gasoline as claimed in claim 1, wherein the silicon-containing pseudo-boehmite in the silicon-containing pseudo-boehmite slurry has pseudo-boehmite crystal phase with specific surface area of 300-500m ² Per g, pore volume is 0.5-1.5mL/g, and ratio B/L of B acid to L acid measured by pyridine adsorption method at 200 ℃ is more than or equal to 0.21.

12. The method for preparing the productive gasoline catalytic cracking catalyst according to claim 1, wherein the clay is selected from one or more of kaolin, halloysite, montmorillonite, diatomaceous earth, sepiolite, halloysite, hydrotalcite, bentonite, acidified or alkali-dissolved kaolin, acidified or alkali-dissolved halloysite, preferably one or two of kaolin and halloysite; the binder is aluminum sol and/or silica sol.

13. The method for preparing a multi-product gasoline catalytic cracking catalyst according to claim 1, wherein the solid content of the mixed slurry is 35-45%, preferably 38-42%.

14. The method for preparing a high yield gasoline catalytic cracking catalyst according to claim 1, wherein in step (2), the spray drying conditions are: the inlet temperature is 300-800 ℃, the tail gas temperature is 100-400 ℃, and the spraying pressure is 10-60 kg.

15. The method for preparing the multi-product gasoline catalytic cracking catalyst according to claim 1, wherein the yttrium modified low-cell molecular sieve is obtained by impregnating and modifying a Y-type molecular sieve with a cell size of 2.430-2.445nm with a yttrium chloride solution or a yttrium nitrate solution with a weight percentage of 0.5-2.0%.