CN117225459A

CN117225459A - Catalytic cracking catalyst and preparation method thereof

Info

Publication number: CN117225459A
Application number: CN202210643128.4A
Authority: CN
Inventors: 孙书红; 郑云锋; 陈淑琨; 杜晓辉; 刘超伟; 刘涛; 孙雪芹; 任世宏; 刘璞生; 谢鑫
Original assignee: Petrochina Co Ltd
Current assignee: Petrochina Co Ltd
Priority date: 2022-06-07
Filing date: 2022-06-07
Publication date: 2023-12-15

Abstract

The invention provides a catalytic cracking catalyst and a preparation method thereof, wherein the catalytic cracking catalyst comprises the following components in percentage by weight as 100 percent: 15-50% of rare earth ultrastable Y-type molecular sieve based on dry basis, 10-60% of clay based on dry basis, 1-4% of yttrium based on oxide and 5-35% of binder based on oxide; wherein, the rare earth in the rare earth ultrastable Y-type molecular sieve is calculated by oxide, and the weight of the catalytic cracking catalyst is calculated as 100%, and the rare earth content in the rare earth ultrastable Y-type molecular sieve is not more than 3%. The catalyst of the invention utilizes the characteristics of small unit cell and more mesopores of the low-content rare earth ultrastable Y molecular sieve, and yttrium is additionally added on the basis of the low-content rare earth ultrastable Y molecular sieve, so that the activity stability of the catalyst is better, the mass transfer, cracking reaction and selective hydrogen transfer reaction processes are facilitated, the olefin content of gasoline is reduced, the selectivity of the catalytic cracking reaction is improved, and the coke generation is reduced.

Description

Catalytic cracking catalyst and preparation method thereof

Technical Field

The invention belongs to the field of oil refining catalysts, relates to a catalytic cracking catalyst, and in particular relates to a catalytic cracking catalyst for reducing the olefin content of gasoline and a preparation method thereof.

Background

Environmental regulations strictly limit the olefin content of commercial gasoline, and the national VI standard for automotive gasoline requires that the olefin content of gasoline be no more than 18% by volume. The ratio of the catalytic cracking gasoline in the gasoline blending component in China is more than 50%, so that the olefin content of the catalytic cracking gasoline has a great influence on the olefin content of the blending gasoline in the gasoline pool of the refinery. The relatively high olefin content of the catalytic cracking gasoline affects the burden of subsequent gasoline hydrotreatment, and the current approaches for reducing the olefin content of the gasoline comprise: (1) The method can effectively reduce the olefin content of the gasoline, but consumes hydrogen, increases the gasoline treatment cost and treatment burden, and reduces the gasoline octane number; (2) The catalytic gasoline is recycled and modified through specific process technologies, such as a double riser, an auxiliary riser and the like, and the process needs to modify a conventional catalytic cracking device, increases equipment investment, changes device product distribution and has limited operation stability; (3) In the catalytic cracking process, the catalyst or the auxiliary agent is used for reducing the olefin content of the gasoline, so that the equipment investment is not increased, and the method is a flexible and simple gasoline olefin reduction way.

In the aspects of olefin reduction catalyst and auxiliary agent research and development, chinese patent CN1322928C discloses a cracking catalyst for reducing the olefin content of catalytically cracked gasoline, wherein the catalyst contains 10-50 wt% of CDY molecular sieve, the CDY molecular sieve is prepared in a liquid-solid combined exchange mode, the rare earth content is 12-22 wt% calculated as rare earth oxide, rare earth ions are all positioned in a small cage of the molecular sieve, and no peak appears at the position of chemical shift of 0ppm in a 27Al MAS NMR spectrum. The catalyst can greatly reduce the olefin content of the catalytic cracking gasoline and has strong heavy oil conversion capability.

Chinese patent CN101081369B discloses a rare earth-containing high silicon Y-type zeolite and its preparation method, the silicon-aluminum ratio of said zeolite is 5-30, initial unit cell constant is 2.430-2.460 nm, rare earth content is 10-20 wt%, the ratio of equilibrium unit cell to initial unit cell constant is at least 0.985, X-ray diffraction analysis shows that its two diffraction peak intensities are respectively equal to (12.43+ -0.06) DEG and (11.87+ -0.06) DEG ₁ /I ₂ Greater than 1. The zeolite is prepared by a gas phase superstable method and then by rare earth ion exchange, the structure of the zeolite is more optimized, and the thermal stability, the hydrothermal stability, the cracking activity and the olefin reduction performance are improved.

Chinese patent CN1230496C discloses a petroleum hydrocarbon cracking catalyst containing rare earth Y-type zeolite and its preparation method, and the catalyst is characterized by that the rare earth Y-type zeolite adopts RE ₂ O ₃ Counting, wherein the content of rare earth in the crystal is 4-15 wt%, the unit cell constant is 2.450-2.458 nm, and the differential thermal collapse temperature is 1000-1056 ℃; the catalyst is prepared by drying rare earth-containing Y-type zeolite to a water content of less than 10 wt%, and then carrying out the following steps: the weight ratio of Y-type zeolite=0.1-0.9:1, and introducing silicon tetrachloride gas carried by dry air for reactionThe rare earth Y-type zeolite is obtained after the drying air is used for blowing and the cation removing water is used for washing to remove the soluble byproducts, and then the rare earth Y-type zeolite is obtained after the rare earth Y-type zeolite is mixed with raw materials including rare earth and binder for pulping, and spray drying and molding are carried out. Compared with the heavy oil olefin reduction catalyst prepared by the prior art, the catalyst can reduce the zeolite consumption by 5-25 wt%, has the characteristics of good activity, high hydrothermal stability, strong heavy oil conversion capability and good selectivity of gasoline, dry gas and coke, and can reduce the olefin content of catalytic cracking gasoline.

Chinese patent CN1278773C discloses a catalyst for reducing olefin content in gasoline and its preparation method, the catalyst is composed of molecular sieve active component, amorphous silicon-aluminum oxide and kaolin, wherein the active component is composed of 0.5-10% (weight percentage of the catalyst) rare earth-ZSM-5/ZSM-11 co-crystallized molecular sieve, 15-40% rare earth Y molecular sieve (weight percentage of the catalyst). The composite molecular sieve, alumina and kaolin are uniformly mixed, spray-formed, dried and treated by water vapor to prepare the catalyst. The catalyst has the characteristics of reducing the olefin content of gasoline and keeping the octane number of the gasoline at least not to be reduced.

Chinese patent CN1247744C discloses a catalyst for cracking diesel oil with reduced olefins and its preparation method, the catalyst contains 5-45 wt% of phosphorus and rare earth composite modified Y zeolite (or ultrastable rare earth Y zeolite), the ultrastable rare earth Y zeolite is obtained by using sodium Y zeolite as raw material, through rare earth exchange and first roasting, then reacting with rare earth, phosphorus-containing substance and ammonium salt, and second roasting. The catalyst consists of 5-45 wt% of ultrastable rare earth Y zeolite, 0.5-30 wt% of one or more other zeolite, 0.5-70 wt% of clay, 1.0-65 wt% of high temperature resistant inorganic oxide, 0.3-2.5 wt% of phosphorus and 1.5-6.0 wt% of rare earth oxide. The preparation method of the catalyst comprises the steps of mixing the zeolite component, clay and precursors of high-temperature-resistant inorganic oxide in proportion, homogenizing, spraying and post-treating to obtain a catalyst finished product. The catalyst has strong olefin reducing capability, high diesel oil yield, low coke yield and strong heavy oil cracking capability.

Chinese patent CN100395029C discloses a method for preparing a cracking catalyst for reducing olefin content in gasoline and producing more liquefied gas, which comprises uniformly mixing clay, deionized water and phosphorus-containing compound to obtain clay slurry, uniformly mixing molecular sieve, deionized water, phosphorus-containing compound and rare earth compound to obtain molecular sieve slurry, uniformly mixing binder, deionized water and optional inorganic acid to obtain binder slurry; and uniformly mixing the clay slurry, the molecular sieve slurry and the binder slurry, and drying. The catalyst has higher liquefied gas yield, especially high propylene concentration in liquefied gas, and reduces the olefin content of gasoline while maintaining higher gasoline yield and gasoline octane number.

Chinese patent CN1100849C discloses a catalytic cracking catalyst and a method for preparing the same, the catalyst is composed of 1-54 wt% of Y-type molecular sieve, 1-20 wt% of ZSM-5 molecular sieve, 35-60 wt% of carrier and 10-25 wt% of binder, the Y-type molecular sieve is REY, REHY, USY or REUSY; the ZSM-5 molecular sieve is a hydrogen type molecular sieve modified by two or more elements of zinc, gallium and rare earth elements; the carrier is SiO ₂ 、Al ₂ O ₃ 、MgO、ZrO ₂ The modifying element used in the carrier is zinc, phosphorus, rare earth element or their mixture, the content of the modifying element in the carrier is 0.01-25 wt%. The catalyst can reduce the olefin content of gasoline and improve the octane number of the gasoline.

Chinese patent CN1309472C discloses a catalytic cracking catalyst and a method for preparing the same, the catalyst is composed of 60-87 wt% of kaolin, 10-30 wt% of metal modified Y-type molecular sieve and 3-10 wt% of binder, based on the total weight of the catalyst. Wherein, the modifying element used by the metal modified Y-shaped molecular sieve is one or more of copper, iron, zinc, cobalt, titanium, nickel, antimony, vanadium, manganese and molybdenum, and the content of the modified metal in the Y-shaped molecular sieve is 4-30 percent (calculated by the weight percentage of the modified metal oxide in the modified Y-shaped molecular sieve). The sulfur content of the gasoline produced by the catalyst is reduced by 50-70 wt%, the olefin content of the gasoline is reduced by 20-40 volume percent, and the octane number of the gasoline is increased by 0.3-2.0 units.

Chinese patent CN 103084199B discloses a catalyst for cracking alkali-resistant nitrogen-reducing olefin and its preparation method, the catalyst comprises cracking active component, mesoporous silica-alumina material, binder and clay, wherein the cracking active component comprises a first Y-type molecular sieve and a second Y-type molecular sieve, the rare earth content in the first Y-type molecular sieve is 8-23 wt% calculated by rare earth oxide, and the iron content is Fe ₂ O ₃ 0.1 to 3.0 wt% in terms of CuO, 0 to 3.0 wt% in terms of copper content, and P in terms of phosphorus content ₂ O ₅ 0-2.0 wt% and sodium oxide content of 0.1-2.5 wt%; the second Y-type molecular sieve is a phosphorus and rare earth modified Y-type molecular sieve. The preparation method of the catalyst comprises the steps of preparing slurry containing cracking active components, mesoporous silica-alumina materials, binders and clay, spray drying, washing and drying. The catalyst is used for the catalytic cracking of hydrocarbon oil with higher content of basic nitrogen, and has higher conversion rate and lower content of gasoline olefin.

Chinese patent CN 1332758C discloses a REY molecular sieve containing phosphorus and amorphous silica, its preparation method and application ³¹ In the P MAS NMR spectrum, the sum of peak areas of peaks with chemical shift of-15+/-2 ppm and-23+/-2 ppm accounts for more than 85 percent of the total peak area, and the rare earth content of the molecular sieve is calculated by RE ₂ O ₃ 12 to 20 weight percent of phosphorus content expressed as P ₂ O ₅ 1 to 4 wt% of amorphous silicon oxide based on SiO ₂ 5 to 10 weight percent. The molecular sieve has the function of reducing the olefin content of gasoline and better coke selectivity, and can be used as an active component of a catalytic cracking catalyst.

Chinese patent CN 107973315B discloses a Y molecular sieve containing phosphorus and rare earth and its preparation method, the unit cell parameter of the molecular sieve is 24.35-24.55 angstrom; the molecular sieve has a phosphorus content of 0.3 to 10 wt.%; the rare earth content of the molecular sieve is 0.5-19 wt%; the Al distribution parameter D of the molecular sieve meets the following conditions: d is more than or equal to 0.4 and less than or equal to 0.9, and the mesoporous volume of the molecular sieve accounts for 25-65% of the total pore volume; the ratio of the amount of the strong acid to the total acid of the molecular sieve is 20-60%, and the ratio of the amount of the acid B to the amount of the acid L is 20-100. The catalyst prepared by taking the molecular sieve as an active component has excellent heavy oil conversion capability, higher gasoline and liquefied gas yields, lower coke yields and lower gasoline olefin content when used for heavy oil cracking reaction. The molecular sieve is prepared by dealuminizing silicon tetrachloride gas, dealuminizing acid solution composed of organic acid and inorganic acid, dealuminizing inorganic base treatment, fluosilicic acid and other compound acid, and has the problems of complex preparation process, high operation difficulty and environmental pollution.

Chinese patent CN 102812109B discloses a high light olefin FCC catalyst composition and method for cracking hydrocarbons to maximize the production of light olefins. The catalyst composition comprises at least one zeolite, preferably a Y-type zeolite, having catalytic cracking activity under catalytic cracking conditions, said zeolite having a small amount of yttrium exchanged on the zeolite in a specific ratio to rare earth metal. Wherein the amount of yttrium exchanged on the zeolite is from 1.75 to 0.175 wt% of the zeolite and the weight ratio of yttrium exchanged on the zeolite to rare earth metal is from 3 to 50. The catalyst and process of the present invention provide increased light olefin yields and gasoline olefin yields during the FCC process as compared to conventional lanthanum containing Y-zeolite FCC catalysts.

Chinese patent CN 101104817B discloses a catalytic cracking auxiliary agent for improving heavy oil conversion capability and its preparation method, which is prepared by mixing natural sepiolite and one or two of natural kaolin minerals or calcined kaolin minerals as raw materials, and then spray forming, roasting, in situ crystallization and modification of composite elements. SiO in the auxiliary agent ₂ /Al ₂ O ₃ The molar ratio of NaY molecular sieve of 4.0-6.0 is 20-90%, rare earth oxide is 1.0-20%, al ₂ O ₃ 25 to 50 percent of MgO, 1.0 to 20 percent of sodium oxide and less than 0.5 percent of sodium oxide, and the specific surface is more than or equal to 300m ² Per gram, the pore volume is more than or equal to 0.25ml/g. The additive can improve the heavy oil conversion capability, has high activity, strong heavy metal pollution resistance and good cracking reaction selectivity, and can also reduce the olefin content of the gasoline and improve the octane number of the gasoline.

Chinese patent CN 1151237C discloses a catalytic cracking auxiliary agent for reducing olefin content in gasoline, which is composed of rare earth-containing Y-zeolite, rare earth-containing MFI structure zeolite, clay, alumina and phosphorus, wherein the ratio of rare earth in the rare earth-containing Y-zeolite to rare earth in the MFI structure zeolite is 0.05-200:1. The auxiliary agent is obtained by uniformly mixing rare earth-containing Y-type zeolite treated by phosphorus-containing compound solution, MFI structure zeolite treated by rare earth solution, clay and matrix synthesized by double aluminum binder, spray drying, then carrying out post-treatment by phosphorus-containing compound solution, filtering and drying. The auxiliary agent can reduce the olefin content in the gasoline of the catalytic cracking product by 5-9 percent.

Chinese patent CN 1156555C discloses a catalytic cracking auxiliary agent and its preparation method, the auxiliary agent is composed of 5-65 wt% of ZSM-5 molecular sieve, 15-60 wt% of carrier and 10-40 wt% of binder, wherein the ZSM-5 molecular sieve is hydrogen type and is modified by modified element phosphorus, zinc and at least one rare earth element; the preparation of the auxiliary agent is to modify the hydrogen-type ZSM-5 molecular sieve with Zn and rare earth elements, add the modified ZSM-5 molecular sieve and carrier into the aluminum phosphate sol binder, mix and pulp, homogenize, and then filter, spray dry and bake the mixture to obtain the auxiliary agent. Under the condition of conventional catalytic cracking, the addition of the auxiliary agent accounts for 1-15% of the total weight of the catalytic cracking catalyst, so that the content of olefin in the catalytic cracking gasoline can be reduced by 3-25%, and the research octane number of the gasoline is improved by 0.5-3 units.

Chinese patent CN1201864C discloses an FCC catalyst for reducing olefin content in gasoline and a preparation method thereof, the catalyst comprising zeolite-type active component, amorphous silica-alumina oxide and kaolin. Wherein the active component is composed of ZSM-5 of 0.5-5 wt%, rare earth Y zeolite of 0.5-15 wt%, phosphor of 20-40 wt% and rare earth composite modified ultrastable Y zeolite. The composite molecular sieve is uniformly mixed with alumina, a binder and kaolin, and then the FCC catalyst is prepared after spraying, solidification, washing and drying. Compared with the conventional catalyst, the catalyst can obviously reduce the olefin content of the gasoline on the premise of ensuring that the product distribution and the octane number of the gasoline are basically unchanged. However, the patent adopts rare earth Y zeolite, and the rare earth Y zeolite has high rare earth content and strong hydrogen transfer capability, so that the olefin content in gasoline can be effectively reduced, but the yield of catalytic cracking coke is high. In addition, in order to improve coke selectivity, phosphorus and rare earth are adopted to compound and modify ultrastable Y zeolite, phosphide can bring environmental pollution problem, and is limited to be used in industrial production at present.

Chinese patent CN1191124C discloses a cracking catalyst for paraffin-based raw oil, which is composed of Y-type molecular sieve, MFI-structure molecular sieve, beta-molecular sieve, clay, alumina and phosphorus, wherein the amount of precipitated rare earth is RE ₂ O ₃ 0.05 to 12 wt%; the catalyst is prepared by treating a molecular sieve consisting of a Y-type molecular sieve treated by a rare earth hydroxide solution and a molecular sieve with an MFI structure with a phosphorus-containing compound solution, drying, roasting, mixing with aluminum sol and/or pseudo-boehmite and clay, homogenizing, roasting at 500 ℃ or spray-drying, and then post-treating with the phosphorus-containing compound solution. The catalyst can reduce the olefin content of the gasoline and simultaneously maintain the RON octane number of the gasoline unchanged. However, this patent uses a rare earth hydroxide solution to treat a Y-type molecular sieve in which the amount of precipitated rare earth is RE ₂ O ₃ 0.05 to 12 weight percent. If the rare earth content in the molecular sieve is low, the amplitude of reducing the olefin content in the gasoline is not large, and if the rare earth content in the molecular sieve is high, the method is favorable for reducing the olefin content in the gasoline, but the hydrogen transfer capability is strong, and the catalytic cracking coke yield is high. In addition, to improve coke selectivity, the molecular sieve or catalyst is treated with phosphide, which causes environmental pollution, and is currently limited in use in industrial production

In the prior art, the design of the olefin reduction catalyst strengthens the hydrogen transfer reaction capability, and can promote olefin saturation or convert light olefin components of gasoline into liquefied gas through cracking. However, continuous hydrogen transfer increases the yield of catalytically cracked coke, and the selectivity of the catalytic cracking reaction is poor, while the yield of liquefied gas is also limited by the compressors of the refinery units. In the prior art, phosphorus is adopted to modify molecular sieves or catalysts or auxiliary agents, so that phosphorus causes environmental pollution and is limited in industrial production; the prior art uses dehydrogenating elements such as copper, iron, zinc, or zinc aluminate spinel materials to increase coke formation; the silicon tetrachloride is used for improving the activity stability of the molecular sieve, the process has high requirements on production conditions, has strict limits on the tightness of a device and the water content in the molecular sieve treatment process, and has high operation difficulty; the prior art adopts high-content rare earth, increases the hydrogen transfer activity of the catalyst and the auxiliary agent, and truly reduces the olefin content in the gasoline, but improves the yield of the catalytic cracking coke. In order to improve the reaction selectivity, the prior art dealuminates and desilicates the molecular sieve by methods such as acid-base treatment and the like, and mesoporous is formed in the molecular sieve, but the prior art is obviously not suitable for industrial production process, and the treatment cost of the molecular sieve is high. In a word, the prior art meets the requirement of reducing olefin in the catalytic cracking gasoline, but inevitably causes the problems of poor selectivity of the catalytic cracking reaction, increased coke yield, environmental pollution, complex production process or increased preparation cost, etc. Therefore, in order to meet the requirements of catalytic cracking gasoline for reducing olefin and simultaneously having better selectivity of catalytic cracking reaction, although the recent catalyst and auxiliary agent preparation technology exists, further researches on a catalyst which is environment-friendly, simple and feasible in process, and good in activity, hydrothermal stability and cracking reaction selectivity are needed.

Disclosure of Invention

The invention provides a catalytic cracking catalyst and a preparation method thereof, which are used for solving the problems that the catalytic cracking catalyst in the prior art is difficult to consider the activity selectivity and the catalyst stability.

In order to achieve the above object, the present invention provides a catalytic cracking catalyst comprising, based on 100% by weight of the catalytic cracking catalyst: 15-50% of rare earth ultrastable Y-type molecular sieve based on dry basis, 10-60% of clay based on dry basis, 1-4% of yttrium based on oxide and 5-35% of binder based on oxide;

wherein the rare earth in the rare earth ultrastable Y-type molecular sieve is calculated by oxide, and the rare earth content in the rare earth ultrastable Y-type molecular sieve is not more than 3 percent based on 100 percent of the weight of the rare earth ultrastable Y-type molecular sieve.

The catalytic cracking catalyst of the invention further comprises lanthanide rare earth, wherein the lanthanide rare earth is calculated by oxide, and the weight content of the lanthanide rare earth in the catalytic cracking catalyst is 0.001-3%.

The catalytic cracking catalyst of the invention further comprises other molecular sieves, wherein the weight content of the other molecular sieves in the catalytic cracking catalyst is 0.001-15% on a dry basis; the other molecular sieves are MFI structure shape selective molecular sieves and/or USY molecular sieves.

The catalytic cracking catalyst of the invention, wherein the catalytic cracking catalyst further comprises magnesium and/or inorganic oxide carrier materials; the magnesium is calculated by oxide, the inorganic oxide carrier material is calculated by oxide, the magnesium content in the catalytic cracking catalyst is 0-3%, and the inorganic oxide carrier material content is 0-30%.

The average grain diameter of the catalytic cracking catalyst is 48-70 mu m, and the unit cell constant of the rare earth ultrastable Y-type molecular sieve is 2.440-2.460 nm.

The catalytic cracking catalyst of the invention, wherein the rare earth content in the rare earth ultrastable Y-type molecular sieve is 0.5-3 wt%, and the rare earth is at least one of yttrium and lanthanide rare earth.

The catalytic cracking catalyst of the invention, wherein the clay is at least one selected from kaolin, halloysite, montmorillonite, kieselguhr, sepiolite and bentonite; the binder is at least one selected from pseudo-boehmite, alumina sol, silica sol and silica-alumina gel.

The catalytic cracking catalyst provided by the invention, wherein the inorganic oxide carrier material is at least one selected from white carbon black, an alumina material containing B acid center and a silica-alumina material containing B acid center.

In order to achieve the above purpose, the present invention also provides a preparation method of the catalytic cracking catalyst, comprising the following steps:

mixing and pulping the rare earth ultrastable Y-type molecular sieve, clay, yttrium-containing compound and binder, then spraying and forming slurry, drying, solidifying and washing to prepare the catalytic cracking catalyst.

The invention relates to a preparation method of a catalytic cracking catalyst, wherein a rare earth ultrastable Y-type molecular sieve and an yttrium-containing compound are firstly mixed and stirred, then mixed and pulped with clay and a binder, slurry is spray-molded, dried, solidified and washed to prepare the catalytic cracking catalyst; wherein the yttrium-containing compound is selected from at least one of yttrium halide, yttrium nitrate, yttrium carbonate, yttrium oxide, and yttrium hydroxide.

The invention relates to a preparation method of a catalytic cracking catalyst, wherein a lanthanide rare earth compound is also added into slurry, and the lanthanide rare earth compound is at least one selected from lanthanide rare earth halide, lanthanide rare earth nitrate, lanthanide rare earth carbonate, lanthanide rare earth oxide and lanthanide rare earth hydroxide.

The invention has the beneficial effects that:

the catalyst of the invention utilizes the characteristics of small unit cell and more mesopores of the low-content rare earth ultrastable Y molecular sieve, and yttrium is additionally added on the basis of the low-content rare earth ultrastable Y molecular sieve, so that the activity stability of the catalyst is better, the mass transfer, cracking reaction and selective hydrogen transfer reaction processes are facilitated, the olefin content of gasoline is reduced, the selectivity of the catalytic cracking reaction is improved, and the coke generation is reduced.

Drawings

FIG. 1 is a graph showing the BJH pore distribution curves of the aluminous material APM-7 of example 5 and of an industrial pseudo-boehmite.

Detailed Description

The following describes the present invention in detail, and the present examples are implemented on the premise of the technical solution of the present invention, and detailed embodiments and processes are given, but the scope of protection of the present invention is not limited to the following examples, in which the experimental methods of specific conditions are not noted, and generally according to conventional conditions.

The invention provides a catalytic cracking catalyst, which comprises the following components in percentage by weight based on 100% of the catalytic cracking catalyst: 15-50% of rare earth ultrastable Y-type molecular sieve based on dry basis, 10-60% of clay based on dry basis, 1-4% of yttrium based on oxide and 5-35% of binder based on oxide;

The rare earth content of the rare earth ultrastable Y-type molecular sieve in the catalytic cracking catalyst is lower, the rare earth accounts for not more than 3% of the mass content of the rare earth ultrastable Y-type molecular sieve, and meanwhile, the catalyst is also mixed with additional yttrium rare earth, so that the problem that the high rare earth content ultrastable Y-type molecular sieve is too strong in hydrogen transfer capacity, and the catalyst is easy to coke can be avoided, and the lower olefin content in gasoline produced by heavy oil catalytic cracking can be ensured.

In detail, the rare earth in the catalyst is partially loaded on the rare earth ultrastable Y-type molecular sieve, and is partially added in a mixing way, and the rare earth which is mixed with other raw materials of the catalyst in the mixing way has the effect of trapping heavy metals such as nickel and vanadium in the use process of the catalyst, so that the reduction of the activity and selectivity of the catalyst caused by the pollution of heavy metals in raw oil to the catalyst is avoided, and in addition, the rare earth can partially enter the crystal structure of the Y-type molecular sieve through solid phase migration in the use process of the catalyst, so that the effect same as that of ion exchange rare earth is achieved, namely the activity of the catalyst is improved, and the structure of the molecular sieve is stabilized.

In one embodiment, the rare earth content of the rare earth ultrastable Y-type molecular sieve of the present invention is 0.5 to 3 wt% (based on 100% of the weight of the rare earth ultrastable Y-type molecular sieve) based on the rare earth oxide, preferably 1 to 2 wt%; the rare earth in the rare earth ultrastable Y-type molecular sieve is selected from one or more of yttrium and lanthanide rare earth. The method for preparing the rare earth ultrastable Y-type molecular sieve is not particularly limited, and in an embodiment, the rare earth ultrastable Y-type molecular sieve can be prepared by ion exchange and hydrothermal ultrastable methods. Compared with the ultrastable Y molecular sieve with high rare earth content, the ultrastable Y molecular sieve with low rare earth content is easy to form more mesopores, is beneficial to the mass transfer process of reaction raw oil molecules and product molecules, and reduces coke generation.

The kind of clay in the catalyst is not particularly limited in the present invention, and clay conventionally used in catalytic cracking catalysts in the art may be used. For example, one or more of kaolin, halloysite, montmorillonite, diatomaceous earth, sepiolite and bentonite, preferably kaolin or halloysite.

The kind of the binder in the catalyst is not particularly limited in the present invention, and the binder conventionally used in the catalytic cracking catalyst in the art may be used. For example, it is one or more of pseudo-boehmite, alumina sol, silica sol and silica gel, preferably pseudo-boehmite and alumina sol.

In addition to the rare earth ultra-stable Y-type molecular sieve, yttrium is additionally added into the catalytic cracking catalyst, so that the content of olefin in the obtained gasoline is lower when the catalytic cracking catalyst is used for catalytic cracking of raw oil.

In one embodiment, the unit cell constant of the rare earth ultrastable Y-type molecular sieve is 2.440-2.460 nm, and the average particle size of the catalytic cracking catalyst is 48-70 mu m. The rare earth ultrastable Y-type molecular sieve has smaller unit cell constant and more mesoporous formed, is beneficial to the mass transfer process of reaction raw oil molecules and product molecules, and reduces coke generation. In addition, the average particle size of the catalytic cracking catalyst is lower, which is beneficial to promoting the mass transfer process of reactants and product molecules in the catalyst, reducing the occurrence of adverse side reactions caused by long-time residence of hydrocarbon molecules in the catalyst, and increasing the total surface area and the outer surface of the catalyst, thereby providing more active centers for the reaction and improving the selectivity of the catalytic cracking reaction on the premise of improving the olefin reduction capability.

In one embodiment, the catalytic cracking catalyst of the invention further comprises lanthanide rare earth, wherein the weight content of the lanthanide rare earth in the catalytic cracking catalyst is 0.001-3% in terms of oxide. In the present invention, the lanthanide rare earth exists mainly in the form of oxide in the catalytic cracking catalyst, for example, in the form of oxide which is easily formed by roasting the lanthanide rare earth-containing compound.

In one embodiment, the catalytic cracking catalyst further comprises other molecular sieves, wherein the weight content of the other molecular sieves in the catalytic cracking catalyst is 0.001-15% on a dry basis. In another embodiment, the other molecular sieve is an MFI structure shape selective molecular sieve and/or a USY molecular sieve. In yet another embodiment, the other molecular sieves include 0 to 10 weight percent MFI structure shape selective molecular sieve on a dry basis and 0 to 5 weight percent USY molecular sieve on a dry basis (100% total weight of the catalytic cracking catalyst).

In one embodiment, the catalytic cracking catalyst of the present invention further comprises an inorganic oxide support material; the content of the inorganic oxide carrier material in the catalytic cracking catalyst is 0-30%, and further 0.001-30% in terms of oxide.

Wherein, the inorganic oxide carrier material is selected from one or more of white carbon black, alumina material containing B acid center and silica-alumina material containing B acid center. The alumina material containing B acid center, the silica-alumina material containing B acid center, has high pore volume, large specific surface area, double pore distribution, high heat stability and higher acid amount, and contains B acid center.

The invention adopts one or more oxide carrier materials selected from white carbon black, alumina materials containing B acid center and silica-alumina materials containing B acid center, can improve the pore canal structure of the catalyst, is beneficial to promoting the mass transfer process of reactants and product molecules in the catalyst, and can avoid excessive hydrogen transfer reaction and reduce side reaction while reducing the olefin content of gasoline; meanwhile, the alumina material containing the B acid center and the silica-alumina material containing the B acid center have higher acid quantity, contain the B acid center, can improve the conversion performance of heavy oil, is more beneficial to converting heavy oil and diesel oil with low olefin content into gasoline fraction, dilutes olefin in the gasoline fraction, and ensures that the total liquid yield (liquefied gas+gasoline+diesel oil) of the catalytic cracking reaction is higher.

In one embodiment, the catalytic cracking catalyst of the present invention further comprises magnesium; the content of magnesium in the catalytic cracking catalyst is 0-3% by oxide, and further 0.001-3%. In the present invention, magnesium is mainly present in the catalytic cracking catalyst in the form of an oxide, for example, an oxide formed easily by calcining a magnesium-containing compound.

In a specific embodiment, the catalytic cracking catalyst of the invention comprises, based on 100% by weight of the catalyst, 15-50% by weight of a rare earth ultrastable Y-type molecular sieve (wherein the rare earth oxide content in the molecular sieve is not more than 3% based on the mass of the rare earth ultrastable Y-type molecular sieve), 0-15% by weight of other molecular sieves based on the dry basis, 10-60% by weight of clay based on the dry basis, 1-4% by weight of yttrium based on the oxide, 0-3% by weight of lanthanide rare earth based on the oxide, 0-3% by weight of magnesium based on the oxide, 0-30% by weight of inorganic oxide carrier material based on the oxide, and 5-35% by weight of binder based on the oxide.

In another embodiment, the catalytic cracking catalyst of the present invention preferably has the following composition: based on the weight of the catalyst as 100 percent, the catalyst comprises 15 to 40 percent of rare earth ultrastable Y-type molecular sieve based on dry basis, 0 to 10 percent of other molecular sieve based on dry basis, 20 to 60 percent of clay based on dry basis, 1 to 3 percent of yttrium based on oxide, 0 to 2 percent of lanthanide rare earth based on oxide, 0 to 2 percent of magnesium based on oxide, 2 to 15 percent of inorganic oxide carrier material based on oxide and 10 to 30 percent of binder based on oxide; the average grain diameter of the catalyst is 52-70 mu m, wherein the unit cell constant of the rare earth ultrastable Y-type molecular sieve is 2.440-2.460 nm.

The catalyst contains yttrium, lanthanide rare earth, magnesium and the like, which are beneficial to improving the activity and heavy metal pollution resistance of the catalyst, and modulating the acid active center distribution of the catalyst, so that the catalyst is more beneficial to improving the conversion rate of catalytic cracking reaction and reducing the coke yield.

In an embodiment, the invention also provides a preparation method of the catalytic cracking catalyst, which comprises the following steps:

In another embodiment, the method for preparing the catalytic cracking catalyst of the present invention comprises the steps of:

the rare earth ultrastable Y-type molecular sieve and yttrium-containing compound are firstly mixed and stirred, then mixed and pulped with clay and binder, and the slurry is spray-formed, dried, solidified and washed to prepare the catalytic cracking catalyst.

Wherein the yttrium-containing compound is selected from at least one of yttrium halide, yttrium nitrate, yttrium carbonate, yttrium oxide, and yttrium hydroxide.

In one embodiment, the slurry further comprises a lanthanide rare earth compound selected from at least one of a lanthanide rare earth halide, a lanthanide rare earth nitrate, a lanthanide rare earth carbonate, a lanthanide rare earth oxide, and a lanthanide rare earth hydroxide. In another embodiment, the lanthanide rare earth is a lanthanum-rich rare earth, a cerium-rich rare earth, pure lanthanum, or pure cerium.

In one embodiment, a magnesium-containing compound is also added to the slurry.

In one embodiment, the catalytic cracking catalyst of the present invention is prepared by: the rare earth ultrastable Y-type molecular sieve and yttrium-containing compound are firstly mixed and stirred for 15-120 min, then mixed and pulped with clay, lanthanide rare earth compound, inorganic oxide carrier material and binder, and finally the slurry is spray-formed, dried, solidified and washed to obtain the catalyst. Wherein, the pseudo-boehmite is used after acid peptization.

Wherein, the binder needs to be peptized by adding acid, and the acid is inorganic acid, which can be one or more of hydrochloric acid, sulfuric acid and nitric acid; then aging for 0.5-3 hours at 40-90 ℃.

The spray forming and drying of the catalytic cracking catalyst is a technology known to the person skilled in the art, and the technological conditions are that the furnace temperature of a spray tower is controlled to be 450-550 ℃, and the temperature of spray tail gas is controlled to be 200-300 ℃. The invention controls the sieving distribution of the spray-formed catalyst microspheres by controlling the spray forming conditions such as spray pressure, nozzle size and the like, so that the average particle size of the catalyst is relatively smaller, and the average particle size of the catalyst is kept in the range of 48-70 mu m.

Therefore, the invention provides a catalyst and a preparation method thereof, which are different from the existing method, and the selective conversion of gasoline olefins is realized by improving the diffusion, selective hydrogen transfer reaction and cracking reaction of the catalyst, so that excessive coking reaction in the catalytic cracking process is reduced. The catalytic cracking catalyst provided by the invention has the characteristics of simple preparation process, smaller average particle size, high 17h hydrothermal aging activity, low gasoline olefin content, low heavy oil yield and better coke selectivity.

The catalytic cracking catalyst of the invention can be used singly or can be used in combination with octane number auxiliary agent according to the need when being applied to the heavy oil catalytic cracking reaction, and the invention is not particularly limited.

The technical scheme of the invention will be further described in detail through specific examples. The inorganic oxide support material used in the examples below is a silica alumina material containing B acid centers, specifically APM-7, manufactured by the petrochemical company, orchis, china.

Table 1 shows the acidity data for APM-7 and commercial pseudo-boehmite (comparative material). As shown in Table 1, the total amount of the acids L and B of APM-7 was 91.50 and 197.36. Mu. Mol/g, respectively, and the ratio of the acids B/L was as high as 2.2. The comparative material contained only L acid centers, the total acid content of L acid was 213.61. Mu. Mol/g, and the total acid content was lower than APM-7.

Table 1 characterization of the infrared acidity of the silica alumina material APM-7 containing B acid centers

FIG. 1 is a graph showing the BJH pore distribution curves of the aluminous material APM-7 of example 5 and of an industrial pseudo-boehmite. As shown in FIG. 1, APM-7 has two pore channel distributions of mesopores and macropores, while the industrial pseudo-boehmite material has single pore distribution only between 2 nm and 4nm, and can have a pore diameter of 3.4nm.

Example 1

2.421 kg of kaolin (dry basis, china Kaolin company industry product, hereinafter the same) and 0.948 kg of alumina sol (containing Al ₂ O ₃ 18.98wt%, manufactured by catalyst factory of Lanzhou petrochemical company, the same applies below), 68.3g lanthanum chloride and 6.0 kg deionized water are added into a beating tank for beating, and then 1.429 kg quasi-thin aluminum water is addedStone (63.0 wt% solids, product of Shanxi aluminum mill, hereinafter the same) was stirred for 1 hour, 136mL of concentrated hydrochloric acid was further added, and after stirring for 1.5 hours, it was aged at 65℃for 2 hours.

0.9 kg REUSY molecular sieve (dry basis, na ₂ O content 1.1 wt%, RE ₂ O ₃ The catalyst microspheres are obtained by mixing and pulping catalyst microspheres with the content of 2.0wt percent, the silicon-aluminum ratio of 5.1, the same as the description below, produced by catalyst factories of Lanzhou petrochemical company, 229g of yttrium nitrate and 1.4 kg of deionized water for 1 hour, adding the mixture into the pulping tank, pulping, homogenizing and controlling spray drying conditions.

Roasting, washing to reduce sodium and drying the catalyst microsphere obtained by spray drying to obtain the cracking catalyst CAT-1.

The catalyst CAT-1 comprises the following components: 53.8% by weight of kaolin, 20% by weight of alumina from pseudo-boehmite, 4.0% by weight of alumina from alumina sol, 1.5% by weight of yttria from yttrium nitrate, 0.7% by weight of lanthanum oxide from lanthanum chloride, and 20% by weight of REUSY type molecular sieve. The results of the particle size analysis of CAT-1 are shown in Table 2.

Comparative example 1

1.956 kg of kaolin, 1.897 kg of alumina sol, 68.3g of lanthanum chloride and 4.43 kg of deionized water are added into a pulping tank for pulping, then 1.429 kg of pseudo-boehmite is added, stirring is carried out for 1 hour, 136mL of concentrated hydrochloric acid is added, stirring is carried out for 1.5 hours, and aging is carried out for 2 hours at 65 ℃.

1.575 kg of REHY molecular sieve (dry basis, na ₂ O content 1.1 wt%, RE ₂ O ₃ 8.0wt percent, produced by catalyst factories of Lanzhou petrochemical company, the same applies below), and 2.49 kg of deionized water are mixed and pulped for 1 hour, then the mixture is added into the pulping tank, pulped and homogenized, and the catalyst microsphere is obtained according to the conventional spray drying conditions.

And roasting, washing, reducing sodium and drying the catalyst microspheres obtained by spray drying to obtain the high rare earth content comparative cracking catalyst DCAT-1 prepared under the conventional spray condition.

The composition of the catalyst DCAT-1 is: 36.3% by weight of kaolin, 20% by weight of alumina from pseudo-boehmite, 8% by weight of alumina from alumina sol, 0.7% by weight of lanthanum oxide from lanthanum chloride, and 35% by weight of REHY type molecular sieve. The results of the particle size analysis of DCAT-1 are shown in Table 2.

Example 2

3.102 kg of kaolin, 1.958 kg of alumina sol and 3.1 kg of deionized water are added into a pulping tank for pulping, then 0.746 kg of pseudo-boehmite and 28g of lanthanum oxide are added, the mixture is stirred for 0.5 hours, 70mL of concentrated hydrochloric acid is added, the mixture is stirred for 2.0 hours, and the mixture is aged for 1.5 hours at 70 ℃.

2.348 kg REUSY molecular sieve, 99g yttrium chloride (calculated as oxide), 168g magnesium chloride and 2.56 kg deionized water are mixed and pulped for 1.5 hours, then added into the pulping tank, pulped and homogenized for 2 hours, and spray drying conditions are controlled to obtain the catalyst microsphere.

Roasting, washing to reduce sodium and drying the catalyst microsphere obtained by spray drying to obtain the cracking catalyst CAT-2.

The catalyst CAT-2 comprises the following components: 47.1% by weight of kaolin, 8% by weight of alumina from pseudo-boehmite, 7% by weight of alumina from alumina sol, 1.8% by weight of yttria from yttrium chloride, 0.6% by weight of magnesia from magnesium chloride, 0.5% by weight of lanthanum oxide, 35% by weight of REUSY molecular sieve and 38% by weight of catalyst gel forming solid content. The results of the particle size analysis of CAT-2 are shown in Table 2.

Example 3

2.370 kg of kaolin (dry basis), 0.440 kg of alumina sol (calculated on alumina), 28g of cerium oxide and 2.67 kg of deionized water are added into a pulping tank for pulping, then 0.44 kg of pseudo-boehmite (calculated on dry basis) is added, stirred for 1.0 hour, 40mL of concentrated nitric acid is added, stirred for 1.0 hour, and then aged for 1.2 hours at 50 ℃.

1.76 kg (dry basis) of REUSY molecular sieve, 0.33 kg (dry basis) of high-silicon ZSM-5 molecular sieve (obtained from Lanzhou petrochemical company, silicon-aluminum ratio more than 300), 99g of yttrium oxide, 33g of magnesium oxide and 2.84 kg of deionized water are mixed and pulped for 0.5 hour, and then added into the pulping tank, pulped and homogenized for 1.8 hours, and spray drying conditions are controlled, so that the catalyst microspheres are obtained.

Roasting, washing to reduce sodium and drying the catalyst microsphere obtained by spray drying to obtain the cracking catalyst CAT-3.

The catalyst CAT-3 comprises the following components: 43.1% by weight of kaolin, 8% by weight of alumina from pseudo-boehmite, 8% by weight of alumina from alumina sol, 1.8% by weight of yttrium oxide, 0.6% by weight of magnesium oxide, 0.5% by weight of cerium oxide, 6% by weight of high-silicon ZSM-5 molecular sieve and 32% by weight of REUSY type molecular sieve. The results of the particle size analysis of CAT-3 are shown in Table 2.

Example 4

1.69 kg (on a dry basis) of kaolin, 0.4 kg (on an alumina basis) of alumina sol, 35g (on a lanthana basis) of lanthanum carbonate and 5.7 kg of deionized water were added to a pulping tank for pulping, then 0.95 kg (on a dry basis) of pseudo-boehmite was added, stirred for 3.0 hours, 150 g of concentrated hydrochloric acid was added, stirred for 0.5 hours, and then aged at 75 ℃ for 2.0 hours.

1.75 kg (dry basis) of REUSY molecular sieve, 50 g (dry basis) of low-silicon ZSM-5 molecular sieve (from Lanzhou petrochemical company, silicon-aluminum ratio 31), 424g of yttrium nitrate and 2.5 kg of deionized water are mixed and pulped for 1.7 hours, and then added into the pulping tank, and the pulping is carried out for 1.2 hours, and the spray drying condition is controlled, so as to obtain the catalyst microsphere.

Roasting, washing to reduce sodium and drying the catalyst microsphere obtained by spray drying to obtain the cracking catalyst CAT-4.

The catalyst CAT-4 comprises the following components: 33.8% by weight of kaolin, 19% by weight of alumina from pseudo-boehmite, 8% by weight of alumina from alumina sol, 2.5% by weight of yttria from yttrium nitrate, 0.7% by weight of lanthanum oxide from lanthanum carbonate, 1% by weight of low-silicon ZSM-5 molecular sieve and 35% by weight of REUSY type molecular sieve. The results of the particle size analysis of CAT-4 are shown in Table 2.

Example 5

1.62 kg (on a dry basis) of kaolin, 0.5 kg (on an alumina basis) of alumina sol, 35g (on a ceria basis) of cerium carbonate and 4.0 kg of deionized water were added to a pulping tank for pulping, then 0.7 kg (on a dry basis) of pseudo-boehmite was added, stirred for 1.6 hours, 109 g of concentrated hydrochloric acid was added, stirred for 1.4 hours, and then aged at 62℃for 1.2 hours.

1.5 kg (dry basis) of REUSY molecular sieve, 0.3 kg (dry basis) of high-silicon ZSM-5 molecular sieve (obtained from Lanzhou petrochemical company, silicon-aluminum ratio more than 300), 373g of yttrium nitrate, 35g (magnesium oxide basis) of magnesium carbonate and 2.4 kg of deionized water are mixed and pulped for 1.3 hours, then added into the pulping tank, 1684g of silicon-aluminum material APM-7 (solid content 11.88%) is added, pulping and homogenizing are carried out for 2.2 hours, and spray drying conditions are controlled, so as to obtain the catalyst microspheres.

Roasting, washing to reduce sodium and drying the catalyst microsphere obtained by spray drying to obtain the cracking catalyst CAT-5.

The catalyst CAT-5 comprises the following components: 32.4% by weight of kaolin, 14% by weight of alumina from pseudo-boehmite, 10% by weight of alumina from alumina sol, 2.2% by weight of silica alumina APM-7 4% by weight of yttrium oxide from yttrium nitrate, 0.7% by weight of cerium oxide from cerium carbonate, 0.7% by weight of magnesium oxide from magnesium carbonate, 30% by weight of REUSY type molecular sieve and 6% by weight of high-silicon ZSM-5 molecular sieve. The results of the particle size analysis of CAT-5 are shown in Table 2.

Comparative example 2

A comparative cracking catalyst DCAT-2 was prepared in the same manner as in example 5, except that 1.62 kg (dry basis) of kaolin was changed to 1.82 kg (dry basis) of kaolin, and no silica alumina material APM-7 was added.

The composition of the catalyst DCAT-2 is: 36.4% by weight of kaolin, 14% by weight of alumina from pseudo-boehmite, 10% by weight of alumina from alumina sol, 2.2% by weight of yttria from yttrium nitrate, 0.7% by weight of ceria from cerium carbonate, 0.7% by weight of magnesia from magnesium carbonate, 30% by weight of REUSY molecular sieve and 6% by weight of high silicon ZSM-5 molecular sieve. The results of the particle size analysis of DCAT-2 are shown in Table 2.

Example 6

1.155 kg (on a dry basis) of kaolin, 0.85 kg (on an alumina basis) of alumina sol, 5g (on a rare earth oxide basis) of rare earth chloride (obtained from Lanzhou petrochemical company, rare earth oxide concentration 289.3 g/L), 508.3g of magnesium chloride, 0.3 kg (on a dry basis) of pseudo-boehmite and 0.86 kg of deionized water were added to a pulping tank to be pulped for 1 hour, 45 g of concentrated hydrochloric acid was added thereto, and after stirring for 0.5 hour, the mixture was aged at 70℃for 2 hours.

2.3 kg (dry basis) of REUSY molecular sieve, 0.1 kg (dry basis) of high-silicon ZSM-5 molecular sieve (from Lanzhou petrochemical company, silicon-aluminum ratio more than 300), 644g of yttrium nitrate and 3.3 kg of deionized water are mixed and pulped for 0.5 hour, and then added into the pulping tank, pulped and homogenized for 0.5 hour, and spray drying conditions are controlled to obtain the catalyst microspheres.

Roasting, washing to reduce sodium and drying the catalyst microsphere obtained by spray drying to obtain the cracking catalyst CAT-6.

The catalyst CAT-6 comprises the following components: 23.1% by weight of kaolin, 6% by weight of alumina from pseudo-boehmite, 17% by weight of alumina from alumina sol, 3.8% by weight of yttria from yttrium nitrate, 0.1% by weight of rare earth oxide from rare earth chloride, 2% by weight of magnesia from magnesium chloride, 46% by weight of REUSY molecular sieve and 2% by weight of high-silicon ZSM-5 molecular sieve. The results of the particle size analysis of CAT-6 are shown in Table 2.

Comparative example 3

Rare earth phosphate containing PREY-2 molecular sieves were prepared as in example 6 of CN1201864C, and catalyst DCAT-3 of comparative example 3 was prepared as in catalyst H of examples 7-14 of CN 1201864C.

Preparing a rare earth phosphate PREY-2 molecular sieve:

3.0kg of NaY zeolite is weighed and added into a stainless steel reaction tank, 1.5kg of ammonium sulfate, 280g of rare earth oxide and 30kg of deionized water are added, the pH value of an exchange system is regulated to 3.0-3.5 by hydrochloric acid under the stirring condition, the temperature is raised to 95-100 ℃, the exchange is carried out for 0.5-1 hour, and the once-exchanged rare earth-containing Y-type molecular sieve is prepared by filtering and washing. Then carrying out hydrothermal ultrastable treatment on the exchanged molecular sieve, wherein the treatment condition is 600 ℃, and the roasted molecular sieve is subjected to secondary exchange under the following exchange conditions: 1.5kg of ammonium sulfate, 30kg of deionized water, 400g of ammonium phosphate, pH value of 3.0-3.5, temperature of 95-100 ℃ and exchange time of 0.5-1 hour. Then, ammonia water is used for adjusting the pH value to about 7, 120g of rare earth oxide is added, and the two-phase two-baking PREY-2 molecular sieve is obtained after the hydrothermal roasting treatment process of 600 ℃ is carried out after the filtering, the water washing and the drying.

The comparative catalyst DCAT-3 was prepared by spraying, solidifying, washing and drying after uniformly mixing 5.0% REY, 1.5% ZSM-5, 34% PREY-2, 21% alumina, 11% alumina sol, 27.5% kaolin and a proper amount of deionized water. The results of the particle size analysis of DCAT-3 are shown in Table 2.

TABLE 2 results of particle size analysis of catalysts, μm

Catalyst	D(0.1)	D(0.5)	D(0.9)
				Example 1 catalyst CAT-1	27.463	48.191	73.406
Example 2 catalyst CAT-2	36.083	60.433	97.735
				Example 3 catalyst CAT-3	33.815	58.656	94.203
Example 4 catalyst CAT-4	30.464	52.589	89.076
				Example 5 catalyst CAT-5	37.269	63.921	100.165
Example 6 catalyst CAT-6	34.623	61.102	96.325
				Comparative example 1 comparative catalyst DCAT-1	40.576	71.002	106.380
Comparative example 2 comparative catalyst DCAT-2	39.661	65.147	104.587
				Comparative example 3 comparative catalyst DCAT-3	42.236	75.042	114.488

The catalyst CAT-1 prepared in example 1, the catalyst CAT-5 prepared in example 5 and the comparative catalyst DCAT-1 prepared in comparative example 1 and the comparative catalyst DCAT-2 prepared in comparative example 2 were subjected to a 100% water vapor aging treatment at 800℃for 10 hours, and then were subjected to respective catalytic cracking reaction performance evaluations on a heavy oil micro-reverse evaluation Apparatus (ACE), and the evaluation results are shown in Table 3.

TABLE 3 results of catalytic cracking reaction selectivity evaluation

As shown in Table 3, compared with the catalyst DCAT-1 prepared in comparative example 1, the catalyst CAT-1 prepared in example 1 of the invention has a molecular sieve content lower than 15 percent, but the conversion rate is improved by 2.38 percent, and the total liquid yield and coke factor are equivalent to those of the catalyst of comparative example 1, thus indicating that the catalyst CAT-1 of the invention has better cracking reaction activity and selectivity; compared with the catalyst DCAT-1 prepared in comparative example 1, the catalyst CAT-1 prepared in example 1 of the invention reduces the olefin content in gasoline by 4.47 percent, improves the RON octane number by 0.47 units, and shows that the catalyst CAT-1 of the invention has the characteristics of reducing the olefin content in gasoline and not reducing the octane number of gasoline.

Further, as shown in table 3, compared with the catalyst DCAT-2 prepared in comparative example 2, the catalyst CAT-5 prepared in example 5 of the present invention has improved conversion and total liquid yield due to the addition of the aluminosilicate APM-7 having the B acid center and the hierarchical pore structure, and the reduction of the olefin content in gasoline by 2.45 percentage points, which indicates that the catalyst added with the inorganic oxide carrier material has better cracking reaction activity and selectivity on the premise of reducing the olefin content in gasoline.

The catalysts CAT-2, CAT-3, CAT-4 and CAT-6 prepared in example 2, example 3, example 4 and catalyst DCAT-3 prepared in comparative example 3 were subjected to a 100% water vapor aging treatment at 800℃for 10 hours, and then the catalytic cracking reaction performance was evaluated on a riser evaluation device, wherein the catalyst CAT-2+8 wt% PCA-OCT octane number auxiliary in example 2 was the catalyst CAT-2 according to example 2: the PCA-OCT octane number auxiliary agent (weight percentage) =92%: 8% is compounded, the PCA-OCT octane number auxiliary agent is produced by China petrochemical institute organization, the brand is PCA-OCT, and the evaluation results are shown in Table 4.

TABLE 4 evaluation results of catalytic cracking reactions

As shown in Table 4, compared with the catalyst DCAT-3 prepared in comparative example 3, the catalyst CAT-2 prepared in example 2 of the invention is compounded with 8 wt% of PCA-OCT octane number additive, the conversion rate is increased by 0.66 percentage points under the condition that the reaction temperature is reduced by 10 ℃, the total liquid yield is increased, the coke yield is reduced, the gasoline olefin is reduced by 10.41 percentage points, the octane number is not reduced, and the catalyst CAT-2 of the invention has the characteristics of reducing the olefin content of the gasoline and not reducing the octane number of the gasoline after being compounded with the octane number additive, and meanwhile, the cracking reaction selectivity is better. Compared with the catalyst DCAT-3 prepared in the comparative example 3, the catalysts CAT-3 and CAT-6 prepared in the examples 3 and 6 of the invention show the same characteristics of reducing the olefin content of gasoline, not reducing the octane number of the gasoline and having better reaction selectivity; the catalyst CAT-4 prepared in the embodiment 4 of the invention has the characteristics of obviously reducing the octane number of gasoline and improving the reaction selectivity, and as the catalyst does not contain a shape selective molecular sieve, the RON octane number is slightly lower than that of the contrast agent DCAT-3, and in the actual industrial application process, the octane number auxiliary agent can be compounded according to the requirement of the device on the octane number of gasoline.

In conclusion, the mass transfer, cracking reaction and hydrogen transfer reaction processes in the catalytic cracking reaction process are regulated, so that the cracking and conversion of olefin in the gasoline distillation range are promoted, and the coke generation caused by excessive hydrogen transfer reaction is reduced; meanwhile, the catalyst keeps better activity stability, and the heavy oil and diesel oil fractions with low olefin content are promoted to be converted into gasoline fractions. The catalyst takes a rare earth ultrastable Y-type molecular sieve with low rare earth content as a main active component, and yttrium and lanthanide rare earth are additionally added into the catalyst; in the preparation process of the catalyst, the spraying condition is controlled, so that the catalyst is screened relatively finely, the external surface area and the activity of the catalyst are improved, and the diffusion path of reactants and product molecules in the catalyst microspheres is shortened.

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 as defined in the appended claims.

Claims

1. A catalytic cracking catalyst, characterized in that the catalytic cracking catalyst comprises, based on 100% by weight of the catalytic cracking catalyst: 15-50% of rare earth ultrastable Y-type molecular sieve based on dry basis, 10-60% of clay based on dry basis, 1-4% of yttrium based on oxide and 5-35% of binder based on oxide;

2. The catalytic cracking catalyst of claim 1, further comprising a lanthanide rare earth, wherein the lanthanide rare earth is present in the catalytic cracking catalyst in an amount of from 0.001 to 3% by weight, calculated as oxide.

3. The catalytic cracking catalyst of claim 1, further comprising an additional molecular sieve, wherein the additional molecular sieve is present in the catalytic cracking catalyst in an amount of from 0.001 to 15% by weight on a dry basis; the other molecular sieves are MFI structure shape selective molecular sieves and/or USY molecular sieves.

4. The catalytic cracking catalyst of claim 1, further comprising magnesium and/or an inorganic oxide support material; the magnesium is calculated by oxide, the inorganic oxide carrier material is calculated by oxide, the magnesium content in the catalytic cracking catalyst is 0-3%, and the inorganic oxide carrier material content is 0-30%.

5. The catalytic cracking catalyst of claim 1, wherein the average particle size of the catalytic cracking catalyst is 48-70 μm and the unit cell constant of the rare earth ultrastable Y-type molecular sieve is 2.440-2.460 nm.

6. The catalytic cracking catalyst according to claim 1, wherein the rare earth content in the rare earth ultrastable Y-type molecular sieve is 0.5 to 3 wt%, based on 100% by weight of the rare earth ultrastable Y-type molecular sieve, wherein the rare earth is at least one of yttrium and lanthanide rare earth.

7. The catalytic cracking catalyst of claim 1, wherein the clay is selected from at least one of kaolin, halloysite, montmorillonite, diatomaceous earth, sepiolite, bentonite; the binder is at least one selected from pseudo-boehmite, alumina sol, silica sol and silica-alumina gel.

8. The catalytic cracking catalyst of claim 4, wherein the inorganic oxide support material is selected from at least one of white carbon black, an alumina material containing B acid centers, and a silica alumina material containing B acid centers.

9. The method for preparing a catalytic cracking catalyst as claimed in any one of claims 1 to 8, comprising the steps of:

10. The method for preparing the catalytic cracking catalyst according to claim 9, wherein the rare earth ultrastable Y-type molecular sieve and the yttrium-containing compound are mixed and stirred firstly, then mixed and pulped with clay and a binder, and the slurry is spray-formed, dried, solidified and washed to prepare the catalytic cracking catalyst; wherein the yttrium-containing compound is selected from at least one of yttrium halide, yttrium nitrate, yttrium carbonate, yttrium oxide, and yttrium hydroxide.

11. The method for preparing a catalytic cracking catalyst according to claim 9, wherein a lanthanide rare earth compound is further added into the slurry, and the lanthanide rare earth compound is at least one selected from the group consisting of lanthanide rare earth halides, lanthanide rare earth nitrates, lanthanide rare earth carbonates, lanthanide rare earth oxides, and lanthanide rare earth hydroxides.