CN108452827B

CN108452827B - Catalytic cracking catalyst

Info

Publication number: CN108452827B
Application number: CN201710093670.6A
Authority: CN
Inventors: 周灵萍; 张蔚琳; 许明德; 张杰潇; 田辉平; 朱玉霞
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2017-02-21
Filing date: 2017-02-21
Publication date: 2020-03-24
Anticipated expiration: 2037-02-21
Also published as: CN108452827A

Abstract

A catalytic cracking catalyst comprises a modified Y-shaped molecular sieve containing phosphorus and rare earth, an alumina binder and clay, wherein the modified Y-shaped molecular sieve containing phosphorus and rare earth contains 4-11 wt% of rare earth, 0.05-10 wt% of phosphorus and 0.1-0.7 wt% of sodium oxide, the pore volume is 0.33-0.39 mL/g, the volume of 2-100 nm pores accounts for 15-30% of the total pore volume, the unit cell constant is 2.440-2.455 nm, non-framework aluminum accounts for less than 20% of the total aluminum, the lattice collapse temperature is greater than 1050 ℃, and the ratio of B acid amount to L acid amount is not less than 2.50. The catalytic cracking catalyst has high heavy oil cracking activity, good coke selectivity, high gasoline yield, high liquefied gas yield and high total liquid yield.

Description

Catalytic cracking catalyst

Technical Field

The invention relates to a catalytic cracking catalyst and a preparation method thereof.

Background

With the increasing weight of the catalytic cracking raw oil and the stricter environmental regulations, the catalytic cracking catalyst is required to improve the heavy oil conversion capacity and simultaneously produce more gasoline. The key to obtaining high yield gasoline is that the active component of the catalyst, i.e. rare earth high-silicon Y-type zeolite, can keep the crystal structure intact, has very high thermal and hydrothermal stability, and has stronger acidity and low acid density.

At present, the hydrothermal method is mainly adopted for industrially preparing the high-silicon Y-type zeolite. The rare earth-containing high-silicon Y-type zeolite can be prepared by carrying out rare earth ion exchange and high-temperature roasting on NaY zeolite for multiple times, which is the most conventional method for preparing the high-silicon Y-type zeolite, but the defect of preparing the rare earth high-silicon Y-type zeolite by a hydrothermal method is that: because the structure of the zeolite can be damaged by too harsh hydrothermal treatment conditions, the Y-type zeolite with high silica-alumina ratio can not be obtained; while the production of extra-framework aluminum is beneficial for improving the stability of the zeolite and forming new acid centers, the excess extra-framework aluminum reduces the selectivity of the zeolite; in addition, many dealuminization cavities in the zeolite cannot be timely supplemented by silicon migrated from the framework, so that lattice defects of the zeolite are often caused, and the crystal retention of the zeolite is low; therefore, the thermal and hydrothermal stability of the rare earth-containing high-silicon Y-type zeolite prepared by the hydrothermal method is poor, which is shown in that the lattice collapse temperature is low, and the crystallinity retention rate and the specific surface area retention rate are low after hydrothermal aging.

In U.S. Pat. Nos. 4,849,287 and 4,4429053, NaY zeolite is exchanged with rare earth ions and then treated with water vapor, in the method, the aluminum removal of zeolite is difficult in the water vapor treatment process due to the shielding effect and support of the rare earth ions, the unit cell parameters of zeolite before the water vapor treatment are increased to 2.465-2.475 nm, the unit cell parameters after the treatment are 2.420-2.464 nm, and the temperature required for reducing the unit cell parameters is high (593-733 ℃).

In the processes provided in US5340957 and US5206194, SiO of NaY zeolite is used as the starting material₂/Al₂O₃The ratio is 6.0, which is also a rare earth exchange of NaY followed by hydrothermal treatment, with the same disadvantages of the aforementioned US4584287 and US 4429053.

Gas phase chemical processes are another important process for preparing high silica zeolites first reported by Beyer and Mankui in 1980. The gas phase chemical method generally adopts SiCl under the protection of nitrogen₄Reacting with anhydrous NaY zeolite at a certain temperature. Fully utilizes SiCl in the whole reaction process₄The supplied foreign Si source completes dealuminization and silicon supplement reaction at one time through isomorphous substitution. But gas phase ultrastable molecular sieves do not have secondary pores. U.S. Pat. Nos. 4,42737,178, U.S. Pat. No. 4,4438178, Chinese patent Nos. CN1382525A, CN1194941A and CN1683244A disclose the use of SiCl₄A process for preparing ultra-stable Y-type zeolite by gas-phase chemical dealumination. However, the existing gas-phase ultrastable molecular sieve still has the problem of low activity when used for heavy oil cracking, can not meet the processing requirements of heavy oil and poor oil, and directly influences the product distribution and economic benefit of a catalytic cracking device.

In order to make the molecular sieve meet the requirements of processing heavy oil and poor oil at present, the prior art carries out ion exchange modification and surface modification of rare earth, phosphorus and the like on the Y-type molecular sieve.

CN1330981A discloses a phosphorus-containing Y-type zeolite and a preparation method thereof. The said Y-type zeolite contains P, Si component and RE componentThe silicon component is supported by impregnating the zeolite with a solution of a silicon compound, in the form of SiO₂The content of the silicon component is 1-15 wt% calculated by P₂O₅The content of the phosphorus component is 0.1-15 wt%, and the content of the rare earth component is 0.2-15 wt% calculated by rare earth oxide. The molecular sieve is obtained by co-soaking rare earth-containing Y-type zeolite and a solution containing silicon and phosphorus, drying and then carrying out hydrothermal roasting at the temperature of 550-850 ℃. The phosphorus-containing Y-type zeolite has high crystallinity after hydrothermal treatment and good catalytic performance, and the cracking catalyst containing the Y-type zeolite has strong heavy oil conversion capacity and good product distribution.

CN1353086A discloses a method for preparing a Y-shaped molecular sieve containing phosphorus and rare earth, and the obtained Y-shaped molecular sieve can remarkably reduce the olefin content of FCC gasoline and simultaneously can keep good coke selectivity. The method comprises the steps of firstly carrying out mixed exchange on a NaY molecular sieve by using ammonium ions and rare earth ions, carrying out hydrothermal roasting, and then carrying out reaction and combination on the NaY molecular sieve and a phosphorus compound by 0.2-10 wt% (in terms of P)₂O₅Calculated), and then carrying out hydrothermal roasting. The ultrastable Y-type molecular sieve containing phosphorus and rare earth prepared by the method has the advantages of large unit cell constant, low ultrastable degree and low crystal retention degree of the molecular sieve.

CN1506161 discloses an active component of a rare earth ultrastable Y molecular sieve, wherein the modified molecular sieve contains 8-25 wt% of rare earth oxide and 0.1-3.0 wt% of phosphorus; 0.3 to 2.5 wt% of sodium oxide, 30 to 55% of crystallinity and 2.455 to 2.472nm of unit cell constant. The molecular sieve is prepared by using NaY zeolite as a raw material, performing rare earth exchange and first roasting to obtain 'once-exchanged once-roasted' rare earth NaY, reacting with rare earth, phosphorus-containing substances and ammonium salt, and performing second roasting treatment to obtain modified Y zeolite modified by phosphorus and rare earth. The coke yield of the modified molecular sieve is moderate. The molecular sieve prepared by the method has high rare earth content, large unit cell constant and influenced coke selectivity.

CN1317547A discloses a phosphorus and rare earth compound modified Y zeolite and a preparation method thereof, the molecular sieve is prepared by mixing and exchanging NaY zeolite with rare earth and ammonium salt, then carrying out hydrothermal roasting treatment, reacting with phosphorus compound, and then carrying out secondary roasting treatmentWherein RE₂O₃The weight ratio of the ammonium salt to the Y zeolite is 0.02-0.18, the weight ratio of the ammonium salt to the Y zeolite is 0.1-1.0, the weight ratio of the P to the Y zeolite is 0.003-0.05, the roasting temperature is 250-750 ℃, the water vapor condition is 5-100%, and the time is 0.2-3.5 hours. The ultrastable Y-type molecular sieve containing phosphorus and rare earth prepared by the method has the advantages of large unit cell constant, low ultrastable degree and low crystal retention degree of the molecular sieve.

CN02103910.0 provides a method for preparing 'one-exchange one-baking' modified faujasite, which is obtained by carrying out primary exchange reaction on faujasite, a phosphorus compound and an ammonium compound, then introducing a rare earth solution into the exchange slurry for further reaction, and carrying out filtration, washing and water vapor roasting treatment. The catalyst prepared by using the zeolite as an active component has low cracking activity and low heavy oil conversion rate.

The cracking catalyst of the existing ultrastable Y-type molecular sieve containing phosphorus and rare earth has low heavy oil cracking activity and poor coke selectivity.

Disclosure of Invention

One of the technical problems to be solved by the invention is to provide a catalytic cracking catalyst suitable for heavy oil catalytic cracking processing, which has high thermal and hydrothermal stability, high gasoline yield, strong heavy oil conversion capacity and low coke selectivity. The second technical problem to be solved by the invention is to provide a preparation method of the catalytic cracking catalyst.

The invention provides a catalytic cracking catalyst, which comprises 10-50 wt% of phosphorus-containing and rare earth modified Y-shaped molecular sieve, 10-40 wt% of alumina binder and 10-80 wt% of clay on a dry basis, wherein the content of rare earth oxide in the phosphorus-containing and rare earth super-stable modified Y-shaped molecular sieve (Y-shaped molecular sieve is also called Y-shaped zeolite) is 4-11 wt%, and the content of phosphorus is P₂O₅The content is 0.05-10 wt%, the content of sodium oxide is 0.1-0.7 wt%, the total pore volume is 0.33-0.39 mL/g, the percentage of the pore volume of the secondary pores with the pore diameter of 2-100 nm of the modified Y-type molecular sieve in the total pore volume of the modified Y-type molecular sieve is 15-30%, the unit cell constant is 2.440-2.455 nm, and the unit cell constant is preferably 2.440-2.455 nmSelected framework silicon to aluminum ratio (SiO)₂/Al₂O₃Molar ratio) is: 7-14, the percentage of non-framework aluminum content in the molecular sieve in the total aluminum content is not higher than 20%, the lattice collapse temperature is not lower than 1050 ℃, and the ratio of the B acid amount to the L acid amount in the total acid amount of the modified Y-type molecular sieve measured by a pyridine adsorption infrared method at 200 ℃ is not lower than 2.50.

In the catalytic cracking catalyst provided by the invention, the lattice collapse temperature of the modified Y-type molecular sieve containing phosphorus and rare earth is not lower than 1050 ℃, preferably, the lattice collapse temperature of the molecular sieve is 1055-1080 ℃, for example, 1057-1075 ℃.

In the catalytic cracking catalyst provided by the invention, the ratio of the B acid amount to the L acid amount in the total acid amount of the modified Y-type molecular sieve containing phosphorus and rare earth, which is measured at 200 ℃ by using a pyridine adsorption infrared method, is preferably 2.6-4.0, for example 2.7-3.3.

In the catalytic cracking catalyst provided by the invention, the unit cell constant of the modified Y-type molecular sieve containing phosphorus and rare earth is 2.440-2.455 nm, for example, 2.440-2.453 nm.

In the catalytic cracking catalyst provided by the invention, the modified Y-type molecular sieve containing phosphorus and rare earth is a high-silicon Y-type molecular sieve, and the framework silicon-aluminum ratio (SiO) of the modified Y-type molecular sieve is₂/Al₂O₃Molar ratio) of 7.3 to 14, for example: 8.5 to 12.6.

In the catalytic cracking catalyst provided by the invention, the percentage of non-framework aluminum content in the modified Y-type molecular sieve containing phosphorus and rare earth in the total aluminum content is not higher than 20%, for example, 13-19 wt%.

In the catalytic cracking catalyst provided by the invention, the modified Y-shaped molecular sieve containing phosphorus and rare earth has a crystal retention of over 35%, for example 38-48% or 35-45%, after aging for 17 hours at 800 ℃ under normal pressure and in a 100 volume% steam atmosphere. The normal pressure is 1 atm.

In the catalytic cracking catalyst provided by the invention, the relative crystallinity of the modified Y-shaped molecular sieve containing phosphorus and rare earth is not less than 60%, preferably, the relative crystallinity of the modified Y-shaped molecular sieve is 60-70%, for example, 60-66%.

In one embodiment, the modified Y-type molecular sieve containing phosphorus and rare earth has a specific surface area of 600-670 m²The/g is, for example, 610 to 660m²/g。

Preferably, in the catalytic cracking catalyst provided by the invention, the total pore volume of the modified Y-type molecular sieve containing phosphorus and rare earth is 0.35-0.39 mL/g, for example, 0.36-0.375 mL/g.

In the catalytic cracking catalyst provided by the invention, the pore volume of the modified Y-type molecular sieve containing phosphorus and rare earth, which is a secondary pore with the pore diameter (diameter) of 2.0-100 nm, accounts for 15-30% of the total pore volume, and preferably 20-30%.

In the catalytic cracking catalyst provided by the invention, the modified Y-shaped molecular sieve containing phosphorus and rare earth contains rare earth elements and RE₂O₃The content of the rare earth oxide is 4-11 wt%, preferably 4.5-10 wt%.

In the catalytic cracking catalyst provided by the invention, the modified Y-shaped molecular sieve containing phosphorus and rare earth contains phosphorus modified elements, and P in the modified Y-shaped molecular sieve₂O₅(i.e. with P)₂O₅The phosphorus content) is 0.05 to 10 wt%, for example 0.1 to 6 wt%, preferably 0.1 to 5 wt%.

In the catalytic cracking catalyst provided by the invention, the content of sodium oxide in the modified Y-type molecular sieve containing phosphorus and rare earth is not more than 0.7%, and can be 0.3-0.7% by weight, such as 0.35-0.60% by weight or 0.4-0.55% by weight.

The catalytic cracking catalyst provided by the invention can also contain other molecular sieves besides the modified Y-type molecular sieve, and the content of the other molecular sieves is, for example, 0-40 wt%, for example, 0-30 wt% or 1-20 wt% on a dry basis based on the weight of the catalytic cracking catalyst, the other molecular sieves are selected from the molecular sieves used in the catalytic cracking catalyst, such as one or more of zeolite with MFI structure, Beta zeolite, other Y-type zeolite and non-zeolite molecular sieve, preferably, the content of the other Y-type molecular sieve is not more than 40 wt%, for example, 1-40 wt% or 0-20 wt% on a dry basis, the other Y-type zeolite is, for example, one or more of REY, REHY, DASY, SOY and PSRY, the MFI structure zeolite is, for example, one or more of HZSM-5, ZRP and ZSP, the Beta zeolite is, for example, H β, the non-zeolite molecular sieves are, such as one or more of aluminum phosphate (AlPO) molecular sieves and phosphorus-aluminum-silicon-aluminum (SAPO) molecular sieves.

In the catalytic cracking catalyst provided by the invention, the content of the modified Y-type molecular sieve containing phosphorus and rare earth is 10-50 wt%, preferably 15-45 wt%, for example 25-40 wt% on a dry basis.

In the catalytic cracking catalyst provided by the invention, the clay is selected from one or more of clays used as a cracking catalyst component, such as one or more of kaolin, halloysite, montmorillonite, diatomite, halloysite, saponite, rectorite, sepiolite, attapulgite, hydrotalcite and bentonite. These clays are well known to those of ordinary skill in the art. Preferably, the content of the clay in the catalytic cracking catalyst provided by the invention is 20-55 wt% or 30-50 wt% on a dry basis.

The content of the alumina binder in the catalytic cracking catalyst provided by the invention is 10-40 wt%, for example 20-35 wt%, the alumina binder of the invention is selected from one or more of alumina, hydrated alumina and alumina sol of various forms commonly used in cracking catalysts, for example, one or more selected from gamma-alumina, η -alumina, theta-alumina, chi-alumina, pseudoboehmite (pseudoboehmite), diaspore (Boehmite), Gibbsite (Gibbsite), bayer (bayer) or alumina sol, preferably pseudoboehmite and alumina sol, for example, the catalytic cracking catalyst contains 2-15 wt%, preferably 3-10 wt% of alumina sol, and 10-30 wt%, preferably 15-25 wt% of pseudoboehmite in terms of alumina.

The invention provides a preparation method of a catalytic cracking catalyst, which comprises the steps of preparing the modified Y-shaped molecular sieve containing phosphorus and rare earth, forming slurry by raw materials comprising the modified Y-shaped molecular sieve containing phosphorus and rare earth, an alumina binder, clay and water, and carrying out spray drying, wherein the method for preparing the modified Y-shaped molecular sieve containing phosphorus and rare earth comprises the following steps:

(1) contacting the NaY molecular sieve with a rare earth solution to perform an ion exchange reaction, filtering and washing to obtain a Y-type molecular sieve containing rare earth with a conventional unit cell size and reduced sodium oxide content; wherein the rare earth solution is also called rare earth salt solution;

(2) modifying the Y-type molecular sieve with the reduced sodium oxide content and the conventional unit cell size containing rare earth, and optionally drying to obtain the Y-type molecular sieve with the reduced unit cell constant, wherein the modifying treatment is to roast the Y-type molecular sieve with the reduced sodium oxide content and the conventional unit cell size containing rare earth for 4.5-7 hours at the temperature of 350-480 ℃ in an atmosphere containing 30-90 vol% of water vapor (also called 30-90 vol% of water vapor atmosphere or 30-90 vol% of water vapor), so as to obtain the Y-type molecular sieve with the reduced unit cell constant;

(3) carrying out phosphorus modification treatment on the obtained Y-shaped molecular sieve with the reduced unit cell constant by using a phosphorus compound, and drying to obtain the Y-shaped molecular sieve with the reduced unit cell constant containing phosphorus; wherein the water content of the reduced phosphorus-containing unit cell constant Y-type molecular sieve sample preferably does not exceed 1 wt.%;

(4) mixing the phosphorus-containing Y-type molecular sieve sample obtained in the step (3) with SiCl₄Gas is contacted and reacted at the temperature of 200-650 ℃, wherein SiCl is preferred₄: the weight ratio of the Y-type molecular sieve with reduced unit cell constant obtained in the step (2) on a dry basis is 0.1-0.7: 1, reacting for 10 minutes to 5 hours, and then washing and filtering to obtain the modified Y-type molecular sieve.

In the catalytic cracking catalyst provided by the invention, the modified Y-shaped molecular sieve containing phosphorus and rare earth has high crystallinity, a secondary pore structure, high thermal and hydrothermal stability, higher heavy oil conversion activity, lower coke selectivity, higher gasoline yield, higher light oil yield and total liquid yield. The catalyst is used for heavy oil catalytic cracking, and has the advantages of high gasoline yield, high light oil yield, strong heavy oil cracking capability, high coke selectivity and high hydrothermal stability.

In the preparation method of the catalytic cracking catalyst, the preparation method of the modified Y-shaped molecular sieve containing phosphorus and rare earth can prepare the high-silicon Y-shaped molecular sieve containing phosphorus and rare earth and having a certain secondary pore structure and high crystallinity, high thermal stability and high hydrothermal stability, the molecular sieve has uniform aluminum distribution and less non-framework aluminum content, the modified Y-shaped molecular sieve is used for heavy oil conversion, the coke selectivity is good, the heavy oil cracking activity is high, and the gasoline yield, the liquefied gas yield and the total liquid yield of the molecular sieve used for heavy oil conversion can be improved.

The catalytic cracking catalyst provided by the invention can be used for converting heavy oil or poor oil.

Detailed Description

The catalytic cracking catalyst provided by the invention contains 10-50 wt% of modified Y-type molecular sieve containing phosphorus and rare earth, 10-40 wt% of alumina binder and 10-80 wt% of clay on a dry basis, wherein the weight of the catalyst is taken as a reference. Preferably, the catalytic cracking catalyst contains 25-40 wt% of modified Y-type molecular sieve containing phosphorus and rare earth on a dry basis, 20-35 wt% of alumina binder on an alumina basis, and 30-50 wt% of clay on a dry basis.

In one embodiment of the catalytic cracking catalyst provided by the invention, the content of the rare earth oxide in the modified Y-type molecular sieve containing phosphorus and rare earth is 4-11 wt%, preferably 4.5-10 wt%; p in the modified Y-shaped molecular sieve₂O₅Content (i.e. with P)₂O₅The phosphorus content) is 0.05 to 10 wt.%, for example 0.1 to 6 wt.%, preferably 0.1 to 5 wt.%; the content of sodium oxide is 0.1-0.7 wt%, preferably 0.3-0.7 wt%, the total pore volume is 0.33-0.39 mL/g, the pore volume of secondary pores with the pore diameter of 2-100 nm accounts for 15-30%, preferably 20-30%, the unit cell constant is 2.440-2.455 nm, and the framework silicon-aluminum ratio (SiO)₂/Al₂O₃The molar ratio) is 7-14, and the modified Y-type molecular sieve has a non-framework structureThe percentage of the aluminum content in the total aluminum content is not higher than 20%, preferably 13-19%, the relative crystallinity is not lower than 60%, the lattice collapse temperature is 1055-1080 ℃, and the ratio of the B acid amount to the L acid amount in the total acid amount of the modified Y-type molecular sieve measured by a pyridine adsorption infrared method at 200 ℃ is not lower than 2.50, preferably 2.6-4.0.

In the catalytic cracking catalyst provided by the invention, the ultrastable Y-type molecular sieve containing phosphorus and rare earth is a gas-phase ultrastable modified Y-type molecular sieve containing phosphorus and rare earth, and the preparation process comprises the step of contacting the Y-type molecular sieve with silicon tetrachloride to carry out dealuminization and silicon supplement reaction.

In the preparation method of the modified Y-shaped molecular sieve containing phosphorus and rare earth, the NaY molecular sieve and the rare earth solution are subjected to ion exchange reaction in the step (1) to obtain the Y-shaped molecular sieve containing rare earth with the conventional unit cell size and the reduced sodium oxide content. The NaY molecular sieve can be purchased commercially or prepared according to the existing method, and in one embodiment, the unit cell constant of the NaY molecular sieve is 2.465-2.472 nm, and the framework silicon-aluminum ratio (SiO)₂/Al₂O₃Molar ratio) of 4.5 to 5.2, a relative crystallinity of 85% or more, for example, 85 to 95%, and a sodium oxide content of 13.0 to 13.8% by weight. The NaY molecular sieve and the rare earth solution are subjected to ion exchange reaction, the exchange temperature is preferably 15-95 ℃, for example 65-95 ℃, and the exchange time is preferably 30-120 minutes, for example 45-90 minutes. NaY molecular sieve (dry basis) rare earth salt (RE)₂O₃Meter) H₂O is 1:0.01 to 0.18:5 to 15 by weight. In one embodiment, the ion exchange reaction of the NaY molecular sieve and the rare earth solution comprises the following steps of mixing the NaY molecular sieve, rare earth salt and H₂The exchange between rare earth ions and sodium ions is carried out by mixing NaY molecular sieve (also called NaY zeolite), rare earth salt and water at a weight ratio of 1: 0.01-0.18: 5-15, and stirring at 15-95 ℃, for example, 65-95 ℃, preferably for 30-120 minutes. Mixing NaY molecular sieve, rare earth salt and water to form a mixture, forming slurry by the NaY molecular sieve and the water, adding rare earth salt and/or aqueous solution of the rare earth salt into the slurry, wherein the rare earth solution is the solution of the rare earth salt,the rare earth salt is preferably rare earth chloride and/or rare earth nitrate. The rare earth such as one or more of La, Ce, Pr, Nd and misch metal, preferably, the misch metal contains one or more of La, Ce, Pr and Nd, or further contains at least one of rare earth other than La, Ce, Pr and Nd. The washing in step (1) is intended to wash out exchanged sodium ions, and for example, deionized water or decationized water may be used for washing. Preferably, the rare earth content of the rare earth-containing Y-type molecular sieve with the reduced sodium oxide content obtained in step (1) and the conventional unit cell size is calculated as RE₂O₃4.5 to 13 wt%, for example 5.5 to 13 wt%, or 5.5 to 12 wt%, or 4.5 to 11.5 wt%, and the content of sodium oxide is not more than 9.5 wt%, for example 5.5 to 9.5 wt%, or 5.5 to 8.5 wt%, and the cell constant is 2.465nm to 2.472 nm.

In the preparation method of the modified Y-shaped molecular sieve containing phosphorus and rare earth, in the step (2), the Y-shaped molecular sieve containing rare earth and having a conventional unit cell size is roasted for 4.5-7 hours at the temperature of 350-480 ℃ under the atmosphere of 30-90 vol% of water vapor, preferably, the roasting temperature in the step (2) is 380-460 ℃, the roasting atmosphere is 40-80 vol% of water vapor, and the roasting time is 5-6 hours. The water vapor atmosphere contains 30-90% by volume of water vapor and also contains other gases, such as one or more of air, helium or nitrogen. The Y-type molecular sieve with the reduced unit cell constant in the step (2) has the unit cell constant of 2.450 nm-2.462 nm.

In the method for preparing the catalytic cracking catalyst, the phosphorus and rare earth containing method comprises the following steps of (3) carrying out phosphorus modification treatment on the Y-type molecular sieve with the reduced unit cell constant obtained in the step (2) by using a phosphorus compound to introduce phosphorus into the molecular sieve, wherein the phosphorus modification treatment generally comprises the step of contacting the Y-type molecular sieve with the reduced unit cell constant obtained in the step (2) with an exchange liquid, wherein the exchange liquid contains the phosphorus compound, and the contacting is generally carried out at 15-100 ℃, preferably 30-95 ℃ for 10-100 minutes, then filtering and washing are carried out. Wherein the weight ratio of water to molecular sieve in the exchange liquid is 2-5, preferably 3-4, phosphorus (as P)₂O₅Calculated) and the weight ratio of the molecular sieve is as follows: 0.0005 to 0.10, preferably 0.001 to 0.05. The phosphorus compound can be one or more of phosphoric acid, ammonium phosphate, ammonium dihydrogen phosphate and diammonium hydrogen phosphate. The washing is performed by using water with the weight 5-15 times of that of the molecular sieve, such as decationized or deionized water.

In one embodiment of the preparation method of the catalytic cracking catalyst, the phosphorus modification treatment conditions are as follows: adding the Y-type molecular sieve powder sample with the reduced unit cell constant into an exchange solution containing a phosphorus compound, carrying out exchange reaction for 10-100 minutes at 15-100 ℃, filtering and washing; wherein the weight ratio of water to molecular sieve in the exchange liquid is 2-5, preferably 3-4, phosphorus (as P)₂O₅Calculated) and the weight ratio of the molecular sieve is as follows: 0.0005 to 0.10, preferably 0.001 to 0.05.

In the preparation method of the catalytic cracking catalyst, the molecular sieve obtained by roasting in the preparation step (3) of the modified Y-shaped molecular sieve containing phosphorus and rare earth is dried, so that the water content in the Y-shaped molecular sieve with the reduced unit cell constant is preferably not more than 1 weight percent. The drying can be carried out by conventional methods, such as pneumatic drying, oven drying, and flash drying.

In the preparation method of the modified Y-shaped molecular sieve containing phosphorus and rare earth, the SiCl is adopted in the step (4)₄: the weight ratio of the Y-type molecular sieve (calculated on a dry basis) is preferably 0.3-0.6: 1, the reaction temperature is preferably 350-500 ℃, and the washing method in the step (3) can adopt a conventional washing method, and can be washed by water, such as decationized water or deionized water, so as to remove Na remained in the zeolite⁺，Cl^-And Al³⁺Etc. soluble by-products, for example the washing conditions may be: the weight ratio of the washing water to the molecular sieve can be 5-20: 1, typically molecular sieve: h₂The weight ratio of O is 1: 6-15, the pH value is preferably 2.5-5.0, and the washing temperature is 30-60 ℃. Preferably, the washing is performed such that no free Na is detected in the washing solution after washing⁺，Cl^-And Al³⁺Plasma, general washingNa in the molecular sieve sample⁺，Cl^-And Al³⁺The respective contents of ions do not exceed 0.05 wt.%.

The preparation method of the catalytic cracking catalyst provided by the invention comprises the following steps:

(1) carrying out ion exchange reaction on a NaY molecular sieve (also called NaY zeolite) and a rare earth solution, filtering and washing to obtain a Y-type molecular sieve containing rare earth and having a conventional unit cell size and reduced sodium oxide content; the ion exchange is carried out for 30-120 minutes under the conditions of stirring and the temperature of 15-95 ℃, preferably 65-95 ℃;

(2) roasting the rare earth-containing Y-type molecular sieve with the normal unit cell size and the reduced sodium oxide content for 4.5-7 hours at the temperature of 350-480 ℃ in the atmosphere containing 30-90 vol% of water vapor, and drying to obtain the Y-type molecular sieve with the reduced unit cell constant and the water content of less than 1 wt%; the unit cell constant of the Y-type molecular sieve with the reduced unit cell constant is 2.450 nm-2.462 nm;

(3) adding the Y-type molecular sieve with the reduced unit cell constant into an exchange solution containing a phosphorus compound, carrying out exchange reaction for 10-100 minutes at 15-100 ℃, filtering and washing; wherein the weight ratio of water to molecular sieve in the exchange liquid is 2-5, preferably 3-4, phosphorus (as P)₂O₅Calculated) to the molecular sieve in a weight ratio of 0.0005 to 0.10, preferably 0.001 to 0.05, and drying to obtain a phosphorus-containing Y-type molecular sieve with a reduced unit cell constant and a water content of less than 1 wt%;

(4) mixing the phosphorus-containing Y-type molecular sieve with SiCl vaporized by heating, wherein the water content of the Y-type molecular sieve is less than 1 wt%₄Gas contact of SiCl₄: the weight ratio of the Y-type molecular sieve with the water content lower than 1 wt% and the reduced unit cell constant (calculated by dry basis) is 0.1-0.7: 1, carrying out contact reaction for 10 minutes to 5 hours at the temperature of 200-650 ℃, and washing and filtering to obtain the modified Y-type molecular sieve provided by the invention.

The catalyst of the present invention can be prepared by the methods disclosed in patents CN1098130A and CN 1362472A. Typically comprising the steps of forming a slurry comprising the modified Y-type molecular sieve, a binder, clay and water, spray drying, and optionally further comprising the steps of washing and drying. The spray drying, washing and drying are the prior art, and the invention has no special requirements.

The following examples further illustrate the invention but are not intended to limit the invention thereto.

In the examples and comparative examples, the NaY molecular sieve (also called NaY zeolite) was supplied by the chinese petrochemical catalyst co, zeuginese, inc, and had a sodium oxide content of 13.5 wt% and a framework silica to alumina ratio (SiO) of₂/Al₂O₃Molar ratio) of 4.6, unit cell constant of 2.470nm, relative crystallinity of 90%; the chlorinated rare earth and the nitric acid rare earth are chemical pure reagents produced by Beijing chemical plants. The pseudoboehmite is an industrial product produced by Shandong aluminum factories, and has the solid content of 61 percent by weight; the kaolin is kaolin specially used for a cracking catalyst produced by Suzhou China kaolin company, and has the solid content of 76 weight percent; the alumina sol was provided by the Qilu division of China petrochemical catalyst, Inc., in which the alumina content was 21% by weight.

The analysis method comprises the following steps: in each comparative example and example, the elemental content of the zeolite was determined by X-ray fluorescence spectroscopy; the unit cell constants and relative crystallinity of the zeolite were measured by X-ray powder diffraction (XRD) using RIPP 145-90 and RIPP146-90 standard methods (compiled by petrochemical analysis method (RIPP test method), Yankee et al, scientific Press, published in 1990), and the framework silica-alumina ratio of the zeolite was calculated from the following formula: SiO 2₂/Al₂O₃＝(2.5858-a₀)×2/(a₀-2.4191)]Wherein, a₀Is the unit cell constant in nm; the total silicon-aluminum ratio of the zeolite is calculated according to the content of Si and Al elements measured by an X-ray fluorescence spectrometry, and the ratio of the framework Al to the total Al can be calculated by the framework silicon-aluminum ratio measured by an XRD method and the total silicon-aluminum ratio measured by an XRF method, so that the ratio of non-framework Al to the total Al can be calculated. The crystal structure collapse temperature was determined by Differential Thermal Analysis (DTA).

In each comparative example and example, the acid center type of the molecular sieve and its acid amount were determined by infrared analysis using pyridine adsorption. Experiment ofThe instrument comprises the following steps: model Bruker IFS113V FT-IR (fourier transform infrared) spectrometer, usa. Experimental method for measuring acid content at 200 ℃ by using pyridine adsorption infrared method: and (3) carrying out self-supporting tabletting on the sample, and placing the sample in an in-situ cell of an infrared spectrometer for sealing. Heating to 400 deg.C, and vacuumizing to 10 deg.C^-3And Pa, keeping the temperature for 2h, and removing gas molecules adsorbed by the sample. The temperature is reduced to room temperature, pyridine vapor with the pressure of 2.67Pa is introduced to keep the adsorption equilibrium for 30 min. Then heating to 200 ℃, and vacuumizing to 10 DEG C^-3Desorbing for 30min under Pa, reducing to room temperature for spectrography, scanning wave number range: 1400cm^-1～1700cm^-1And obtaining the pyridine absorption infrared spectrogram of the sample desorbed at 200 ℃. According to pyridine absorption infrared spectrogram of 1540cm^-1And 1450cm^-1The strength of the adsorption peak is characterized to obtain the total content in the molecular sieve

Relative amount of acid center (B acid center) to Lewis acid center (L acid center).

In each of the comparative examples and examples, the secondary pore volume was determined as follows: measuring total pore volume of the molecular sieve according to adsorption isotherm, measuring micropore volume of the molecular sieve according to T mapping method from adsorption isotherm, subtracting micropore volume from total pore volume to obtain secondary pore volume,

the chemical reagents used in the comparative examples and examples are not specifically noted, and are specified to be chemically pure.

Example 1

2000 g of NaY molecular sieve (dry basis) is added into 20L of decationized aqueous solution and stirred to be mixed evenly, 600ml of RE (NO) is added₃)₃Solution (rare earth solution concentration in RE)₂O₃319g/L), stirring, heating to 90-95 ℃, keeping for 1 hour, then filtering, washing, drying filter cake at 120 ℃, obtaining crystal cell constant of 2.471nm, sodium oxide content of 7.0 wt%, RE₂O₃Y-type molecular sieve with 8.8 wt% of rare earth, and 50 vol% of rare earth at 390 deg.CRoasting for 6 hours in an atmosphere of% water vapor and 50 vol% air to obtain a Y-type molecular sieve with a unit cell constant of 2.455nm, cooling, adding the molecular sieve to 6 liters of aqueous solution containing 35 g of phosphoric acid, heating to 90 ℃, carrying out phosphorus modification treatment for 30 minutes, filtering and washing the molecular sieve, drying a filter cake to make the water content of the filter cake lower than 1 wt%, and then carrying out SiCl₄: y-type molecular sieve (dry basis) ═ 0.5: 1, by weight, introducing SiCl vaporized by heating₄Reacting gas at 400 ℃ for 2 hours, washing the reacted gas with 20 liters of decationized water, and filtering the washed gas to obtain the modified Y-type molecular sieve, which is marked as SZ1 and has the physicochemical properties shown in Table 1, wherein the relative crystallinity of the molecular sieve before and after the aging of SZ1 is analyzed by an XRD method after the exposed SZ1 is aged for 17 hours at 800 ℃, 1atm and 100 percent of water vapor, and the relative crystallinity retention after the aging is calculated, and the result is shown in Table 2, wherein:

714.5 g of an alumina sol having an alumina content of 21% by weight were added to 1565.5 g of decationized water, stirring was started, and 2763 g of kaolin having a solids content of 76% by weight were added and dispersed for 60 minutes. 2049 g of pseudo-boehmite with the alumina content of 61 wt% is taken and added into 8146 g of decationized water, 210ml of hydrochloric acid with the mass concentration of 36% is added under the stirring state, dispersed kaolin slurry is added after acidification is carried out for 60 minutes, 1500 g (dry basis) of ground SZ1 molecular sieve is added, after uniform stirring, spray drying and washing treatment are carried out, and the catalyst is obtained after drying and is marked as SC 1. The obtained SC1 catalyst contains 30 wt% of SZ1 molecular sieve, 42 wt% of kaolin, 25 wt% of pseudo-boehmite and 3 wt% of alumina sol.

Example 2

2000 g of NaY molecular sieve (dry basis) is added into 25L of decationized aqueous solution and stirred to be mixed evenly, 800ml of RECl is added₃Solutions (with RE)₂O₃The solution concentration is measured as: 319g/L), stirring, heating to 90-95 ℃, and keeping for 1 hourThen, the mixture is filtered, washed, and the filter cake is dried at 120 ℃ to obtain a crystal cell constant of 2.471nm, a sodium oxide content of 5.5 wt%, based on RE₂O₃Measuring a Y-type molecular sieve with the rare earth content of 11.3 weight percent, roasting for 5.5 hours at the temperature of 450 ℃ and under the condition of 80 percent water vapor to obtain the Y-type molecular sieve with the unit cell constant of 2.461nm, cooling, adding the molecular sieve into 6 liters of aqueous solution dissolved with 268 grams of ammonium phosphate, heating to 60 ℃, carrying out phosphorus modification treatment for 50 minutes, filtering and washing the molecular sieve, drying a filter cake to ensure that the water content is lower than 1 weight percent, and then carrying out SiCl treatment according to the weight percent₄: y-type zeolite 0.6: 1, by weight, introducing SiCl vaporized by heating₄The gas was reacted at 480 ℃ for 1.5 hours, then washed with 20 liters of decationized water and filtered to give a modified Y molecular sieve, noted SZ 2. The physicochemical properties are shown in Table 1, and the results are shown in Table 2, wherein the crystallinity of the zeolite before and after aging of SZ2 is analyzed by XRD method after aging of SZ2 in an exposed state at 800 ℃ for 17 hours and 100% of water vapor, and the relative crystal retention after aging is calculated.

714.5 g of an alumina sol having an alumina content of 21% by weight were added to 1565.5 g of decationized water, stirring was started, and 2763 g of kaolin having a solids content of 76% by weight were added and dispersed for 60 minutes. 2049 g of pseudo-boehmite with the alumina content of 61 wt% is added into 8146 g of decationized water, 210ml of chemically pure hydrochloric acid is added under the stirring state, dispersed kaolin slurry is added after acidification is carried out for 60 minutes, 1500 g (dry basis) of ground SZ2 molecular sieve is added, after uniform stirring, spray drying and washing treatment are carried out, and the catalyst is obtained after drying and is recorded as SC 2. The obtained SC2 catalyst contains 30 wt% of SZ2 molecular sieve, 42 wt% of kaolin, 25 wt% of pseudo-boehmite and 3 wt% of alumina sol.

Example 3

2000 g of NaY molecular sieve (dry basis) is added into 22L of decationized aqueous solution and stirred to be mixed evenly, and 570ml of RECl is added₃Solutions (with RE)₂O₃The concentration of the rare earth solution is 319g/L), stirring, heating to 90-95 ℃, keeping stirring for 1 hour, filtering and washingWashing, drying the filter cake at 120 deg.C to obtain crystal cell constant of 2.471nm, sodium oxide content of 7.5 wt%, and RE₂O₃Metering a Y-type molecular sieve with the rare earth content of 8.5 weight percent, roasting for 5 hours at the temperature of 470 ℃ and under the condition of 70 volume percent of water vapor to obtain the Y-type molecular sieve with the unit cell constant of 2.458nm, cooling, adding the molecular sieve into 6 liters of aqueous solution dissolved with 95 g of diammonium hydrogen phosphate, heating to 40 ℃, carrying out phosphorus modification treatment for 80 minutes, filtering and washing the molecular sieve, drying a filter cake until the water content is lower than 1 weight percent, and then carrying out SiCl treatment₄: y-type zeolite 0.4: 1, by weight, introducing SiCl vaporized by heating₄The gas was reacted at a temperature of 500 ℃ for 1 hour, then washed with 20 liters of decationized water and filtered to obtain a modified Y-type molecular sieve, noted SZ 3. The physicochemical properties are shown in Table 1, and the results are shown in Table 2, wherein the crystallinity of the zeolite before and after aging of SZ3 is analyzed by XRD method after aging of SZ3 in a naked state at 800 ℃ for 17 hours and 100% of water vapor, and the relative crystal retention after aging is calculated.

714.5 g of an alumina sol having an alumina content of 21% by weight were added to 1565.5 g of decationized water, stirring was started, and 2763 g of kaolin having a solids content of 76% by weight were added and dispersed for 60 minutes. 2049 g of pseudo-boehmite with the alumina content of 61 wt% is added into 8146 g of decationized water, 210ml of chemically pure hydrochloric acid is added under the stirring state, dispersed kaolin slurry is added after acidification is carried out for 60 minutes, 1500 g (dry basis) of ground SZ3 molecular sieve is added, after uniform stirring, spray drying and washing treatment are carried out, and the catalyst is obtained after drying and is recorded as SC 3. The obtained SC3 catalyst contains 30 wt% of SZ3 molecular sieve, 42 wt% of kaolin, 25 wt% of pseudo-boehmite and 3 wt% of alumina sol.

Comparative example 1

2000 g of NaY molecular sieve (dry basis) is added into 20L of decationized aqueous solution, stirred to be uniformly mixed, and 1000 g of (NH) is added₄)₂SO₄Stirring, heating to 90-95 deg.C, holding for 1 hr, filtering, washing, drying at 120 deg.C, and steaming at 650 deg.C under 100% water vaporRoasting for 5 hr for hydrothermal modification, adding into 20L of decationized aqueous solution, stirring, mixing, adding 1000 g (NH)₄)₂SO₄Stirring, heating to 90-95 ℃, keeping for 1 hour, then filtering, washing, drying a filter cake at 120 ℃, roasting for 5 hours at 650 ℃ under 100% of water vapor, and carrying out second hydrothermal modification treatment to obtain the rare earth-free hydrothermal ultrastable Y-shaped molecular sieve which is subjected to twice ion exchange and twice hydrothermal ultrastable and is recorded as DZ 1. The physicochemical properties are shown in Table 1, and the results are shown in Table 2, wherein the crystallinity of the zeolite before and after aging of DZ1 is analyzed by XRD method after aging DZ1 in naked state at 800 deg.C for 17 hr with 100% water vapor, and the relative crystal retention after aging is calculated.

DZ1 molecular sieve, kaolin, water, pseudo-boehmite binder and alumina sol are formed into slurry according to a conventional preparation method of a catalytic cracking catalyst, the slurry is spray-dried to prepare a microspherical catalyst, and the prepared catalytic cracking catalyst is marked as DC1 (refer to the preparation method of example 1). Wherein, the obtained DC1 catalyst contains 30 wt% of DZ1 molecular sieve, 42 wt% of kaolin, 25 wt% of pseudo-boehmite and 3 wt% of alumina sol.

Comparative example 2

2000 g of NaY molecular sieve (dry basis) is added into 20L of decationized aqueous solution, stirred to be uniformly mixed, and 1000 g of (NH) is added₄)₂SO₄Stirring, heating to 90-95 ℃ for 1 hour, filtering, washing, drying the filter cake at 120 ℃, performing hydrothermal modification treatment at 650 ℃, roasting with 100% water vapor for 5 hours, adding into 20L of decationized aqueous solution, stirring to mix uniformly, adding 200ml of RE (NO)₃)₃Solutions (with RE)₂O₃The concentration of the rare earth solution is measured as follows: 319g/L) and 900 g (NH)₄)₂SO₄Stirring, heating to 90-95 ℃ for 1 hour, filtering, washing, drying the filter cake at 120 ℃, and then performing second hydrothermal modification treatment (the temperature is 650 ℃, and the roasting is performed for 5 hours under 100% of water vapor) to obtain the rare earth-containing hydrothermal ultrastable Y-type molecular sieve with twice ion exchange and twice hydrothermal ultrastable, and the molecular sieve is marked as DZ2. The physicochemical properties are shown in Table 1, and the results are shown in Table 2, wherein the crystallinity of the zeolite before and after aging of DZ2 is analyzed by XRD method after aging DZ2 in naked state at 800 deg.C for 17 hr with 100% water vapor, and the relative crystal retention after aging is calculated.

DZ2 molecular sieve, kaolin, water, pseudo-boehmite binder and alumina sol are formed into slurry according to a conventional preparation method of a catalytic cracking catalyst, the slurry is spray-dried to prepare a microspherical catalyst, and the prepared catalytic cracking catalyst is marked as DC2 (refer to the preparation method of example 1). Wherein, the obtained DC2 catalyst contains 30 wt% of DZ2 molecular sieve, 42 wt% of kaolin, 25 wt% of pseudo-boehmite and 3 wt% of alumina sol.

Comparative example 3

2000 g of NaY molecular sieve (dry basis) is added into 22L of decationized aqueous solution and stirred to be mixed evenly, and 570ml of RECl is added₃Solutions (with RE)₂O₃The calculated concentration of the rare earth solution is 319g/L), stirring, heating to 90-95 ℃, keeping stirring for 1 hour, then filtering, washing, drying a filter cake at 120 ℃, and obtaining the rare earth solution with the unit cell constant of 2.471nm, the sodium oxide content of 7.5 weight percent and the RE content₂O₃Measuring Y-type molecular sieve with 8.5 wt% of rare earth, adding the molecular sieve into 6L of aqueous solution dissolved with 95 g of diammonium hydrogen phosphate, heating to 40 ℃, carrying out phosphorus modification treatment for 80 minutes, filtering and washing the molecular sieve, drying a filter cake, drying the filter cake until the water content is lower than 1 wt%, and then carrying out SiCl-based treatment₄: y-type zeolite 0.4: 1, by weight, introducing SiCl vaporized by heating₄The gas was reacted at 580 ℃ for 1.5 hours, then washed with 20 liters of decationized water and filtered to give a modified Y molecular sieve designated DZ 3. The physicochemical properties are shown in Table 1, and the results are shown in Table 2, wherein the crystallinity of zeolite before and after aging of SZ3 is analyzed by XRD method after aging DZ3 in naked state with 100% steam at 800 deg.C for 17 hr, and the relative crystal retention after aging is calculated.

DZ3 molecular sieve, kaolin, water, pseudo-boehmite binder and alumina sol are formed into slurry according to a conventional preparation method of a catalytic cracking catalyst, the slurry is spray-dried to prepare a microspherical catalyst, and the prepared catalytic cracking catalyst is marked as DC3 (refer to the preparation method of example 1). Wherein, the obtained DC3 catalyst contains 30 wt% of DZ3 molecular sieve, 42 wt% of kaolin, 25 wt% of pseudo-boehmite and 3 wt% of alumina sol.

Examples 4 to 6

The light oil micro-reverse activity of the catalytic cracking catalysts SC1, SC2, and SC3 prepared in examples 1 to 3 were evaluated after 100% steam aging at 800 ℃ for 4 hours or 17 hours, respectively, and the evaluation results are shown in table 3.

Evaluation method of light oil micro-inverse activity:

the light oil micro-reverse activity of the sample is evaluated by adopting a standard method of RIPP92-90 (see the edition of petrochemical analysis method (RIPP test method), Yangcui et al, scientific publishing company, published in 1990), the catalyst loading is 5.0g, the reaction temperature is 460 ℃, the raw oil is Hongkong light diesel oil with the distillation range of 235-337 ℃, the product composition is analyzed by gas chromatography, and the light oil micro-reverse activity is calculated according to the product composition.

Light oil Microreactivity (MA) (gasoline production at less than 216 ℃ in product + gas production + coke production)/total feed × 100%.

Comparative examples 4 to 6

After aging the catalysts DC1, DC2 and DC3 at 800 ℃ for 4 hours or 17 hours with 100% steam (17 hours with 100% steam aging means aging for 17 hours in a 100% steam atmosphere), the light oil micro-reactivity was evaluated. See example 6 for evaluation, and the results are shown in Table 3.

Examples 7 to 9

After the catalysts SC1, SC2 and SC3 were aged at 800 ℃ for 17 hours in an atmosphere of 100% steam, the catalytic cracking reaction performance was evaluated in a small fixed fluidized bed reactor (ACE), and cracked gas and product oil were collected separately and analyzed by gas chromatography. The catalyst loading is 9g, the reaction temperature is 500 ℃, and the weight hourly space velocity is 16h^－1The weight ratio of the base oil is shown in Table 5, the properties of the raw materials for the ACE test are shown in Table 4, and the evaluation results are shown in Table 5.

Comparative examples 7 to 9

Comparative examples 7-9 illustrate the catalytic cracking reaction performance of the catalytic cracking catalysts prepared with the ultrastable Y-zeolite prepared by the methods provided in comparative examples 1-3.

The catalytic cracking performance of the DC1, DC2, and DC3 catalysts after 17 hours 100% steam aging at 800 ℃ (17 hours 100% steam aging means aging for 17 hours in 100% steam atmosphere) was evaluated in a small fixed fluidized bed reactor (ACE), the evaluation method is shown in example 7, the properties of the raw materials for the ACE experiments are shown in table 4, and the evaluation results are shown in table 5.

TABLE 1

As can be seen from Table 1, the modified Y-type molecular sieve containing phosphorus and rare earth provided by the invention has the following advantages: the modified Y-type molecular sieve has low content of sodium oxide, less non-framework aluminum content when the silicon-aluminum content of the modified Y-type molecular sieve is higher, the pore volume of 2.0-100 nm secondary pores in the molecular sieve accounts for higher percentage of the total pore volume, the B acid/L acid (the ratio of the total B acid content to the L acid content) is higher, the crystallinity value measured when the content of rare earth is higher when the unit cell constant of the molecular sieve is smaller is higher, and the thermal stability is high.

TABLE 2

As can be seen from Table 2, the modified Y-type molecular sieve containing phosphorus and rare earth provided by the invention has higher relative crystal retention after being aged under the harsh conditions of 800 ℃ and 17 hours in the exposed state of the molecular sieve sample, which indicates that the modified Y-type molecular sieve provided by the invention has high hydrothermal stability.

TABLE 3

TABLE 4ACE evaluation of raw oil Properties

TABLE 5

Example numbering	Example 7	Example 8	Example 9	Comparative example 7	Comparative example 8	Comparative example 9
							Sample numbering	SC1	SC2	SC3	DC1	DC2	DC3
The molecular sieve used	SZ1	SZ2	SZ3	DZ1	DZ2	DZ3
							Ratio of agent to oil	5	5	5	9	8	5
Product distribution/weight%
							Dry gas	1.31	1.39	1.34	1.55	1.48	1.45
Liquefied gas	16.98	16.75	17.31	16.86	15.33	16.25
							Coke	4.35	4.51	4.25	8.33	7.61	6.16
Gasoline (gasoline)	53.36	54.19	52.31	38.55	43.91	51.12
							Diesel oil	16.82	16.72	17.22	20.17	19.25	16.81
Heavy oil	7.18	6.44	7.57	14.54	12.42	8.21
							Total up to	100	100	100	100	100	100
Conversion/weight%	76	76.84	75.21	65.29	68.33	74.98
							Coke selectivity/weight%	5.72	5.87	5.65	12.76	11.14	8.22
Yield of light oil/weight%	70.18	70.91	69.53	58.72	63.16	67.93
							Total liquid/weight%	87.16	87.66	86.84	75.58	78.49	84.18

As can be seen from tables 3 and 5, the catalyst provided by the present invention has higher hydrothermal stability, significantly lower coke selectivity, significantly higher liquid yield, significantly higher light oil yield, improved gasoline yield, and higher heavy oil conversion activity.

Claims

1. A catalytic cracking catalyst contains modified Y-type molecular sieve containing P and RE (RE) in 10-50 wt% on dry basis, alumina adhesive in 10-40 wt% on alumina basis, and clay in 10-80 wt% on dry basis₂O₃The content of the rare earth oxide is 4 to 11 weight percent in terms of P₂O₅The phosphorus content is 0.05-10 wt%, the sodium oxide content is 0.1-0.7 wt%, the total pore volume is 0.33-0.39 mL/g, the pore volume of secondary pores with the pore diameter of 2-100 nm of the modified Y-type molecular sieve containing phosphorus and rare earth accounts for 15-30% of the total pore volume, the unit cell constant is 2.440-2.455 nm, the non-framework aluminum content of the modified Y-type molecular sieve containing phosphorus and rare earth accounts for not more than 20% of the total aluminum content, the lattice collapse temperature is not lower than 1050 ℃, and the ratio of the B acid amount to the L acid amount in the total acid amount of the modified Y-type molecular sieve containing phosphorus and rare earth, which is measured by a pyridine adsorption infrared method at 200 ℃, is not lower than 2.50.

2. The catalytic cracking catalyst of claim 1, wherein the pore volume of the secondary pores with the pore diameter of 2nm to 100nm of the modified Y-type molecular sieve containing phosphorus and rare earth accounts for 20% to 30% of the total pore volume.

3. The catalytic cracking catalyst of claim 1, wherein the modified Y-type molecular sieve containing phosphorus and rare earth has a non-framework aluminum content of 13-19% of the total aluminum content, and a framework silica-alumina ratio of SiO₂/Al₂O₃The molar ratio is 7-14.

4. The catalytic cracking catalyst of claim 1, wherein the modified Y-type molecular sieve containing phosphorus and rare earth has a lattice collapse temperature of 1055-1080 ℃.

5. The catalytic cracking catalyst of claim 1, wherein the ratio of the amount of B acid to the amount of L acid in the total acid amount of the modified Y-type molecular sieve, measured at 200 ℃ by pyridine adsorption infrared method, is 2.6 to 4.0.

6. The catalytic cracking catalyst of claim 1, wherein the modified Y-type molecular sieve containing phosphorus and rare earth has a relative crystal retention of 35% or more after aging at 800 ℃ under normal pressure in a 100% steam atmosphere for 17 hours.

7. The catalytic cracking catalyst of claim 1, wherein the modified Y-type molecular sieve containing phosphorus and rare earth has a relative crystallinity of 60 to 70%.

8. The catalytic cracking catalyst according to any one of claims 1 to 7, wherein the modified Y-type molecular sieve containing phosphorus and rare earth has a rare earth oxide content of 4.5 to 10 wt%, a sodium oxide content of 0.3 to 0.7 wt%, and a phosphorus content represented by P₂O₅0.1 to 6 wt%, a unit cell constant of 2.440 to 2.453nm, and a framework Si/Al ratio of 8.5 to 12.6.

9. The catalytic cracking catalyst of claim 1, wherein the modified Y-type molecular sieve containing phosphorus and rare earth has a relative crystal retention of 35-45% after aging at 800 ℃ under normal pressure in a 100% steam atmosphere for 17 hours.

10. The preparation method of the catalytic cracking catalyst comprises the steps of preparing the modified Y-shaped molecular sieve containing the phosphorus and the rare earth, forming slurry containing the modified Y-shaped molecular sieve containing the phosphorus and the rare earth, an alumina binder and clay, and spray drying; wherein

The preparation method of the modified Y-type molecular sieve containing phosphorus and rare earth comprises the following steps:

(1) contacting the NaY molecular sieve with a rare earth salt solution to perform an ion exchange reaction, filtering, washing, and optionally drying to obtain a rare earth-containing Y-type molecular sieve with a conventional unit cell size and reduced sodium oxide content;

(2) roasting the rare earth-containing Y-type molecular sieve with the conventional unit cell size and the reduced sodium oxide content for 4.5-7 hours at the temperature of 350-480 ℃ in the atmosphere of 30-90 vol% of water vapor to obtain the Y-type molecular sieve with the reduced unit cell constant;

(3) carrying out phosphorus modification treatment on the Y-type molecular sieve with the reduced unit cell constant obtained in the step (2) by using a phosphorus compound, and drying to obtain the Y-type molecular sieve with the reduced unit cell constant containing phosphorus;

(4) contacting the Y-type molecular sieve with reduced unit cell constant containing phosphorus with silicon tetrachloride gas for reaction, washing and filtering, and obtaining SiCl₄: the weight ratio of the Y-type molecular sieve with the reduced phosphorus-containing unit cell constant on a dry basis is 0.1-0.7: 1. the reaction temperature is 200-650 deg.C, and the reaction time is 10 min-5 h.

11. The process of claim 10, wherein the rare earth-containing Y-type molecular sieve having a conventional unit cell size and a reduced sodium oxide content in step (1) has a unit cell constant of 2.465 to 2.472nm and a sodium oxide content of not more than 9.5 wt.%.

12. The process of claim 10, wherein in step (1), the rare earth-containing Y-type molecular sieve having a reduced sodium oxide content and a conventional unit cell size contains rare earth in an amount of RE₂O₃4.5 to 13 wt%, sodium oxide content 5.5 to 9.5 wt%, and unit cell constant 2.465nm to 2.472 nm.

13. The method of claim 10, wherein the step (1) of contacting the NaY molecular sieve with a rare earth salt solution to perform an ion exchange reaction comprises: according to the NaY molecular sieve: rare earth salt: h₂O is 1: 0.01-0.18: 5-15 weight ratio of NaY molecular sieve to rare earth saltAnd water to form a mixture, and stirring.

14. The method of claim 10 or 13, wherein the step (1) of contacting the NaY molecular sieve with the rare earth solution for ion exchange reaction comprises: mixing NaY molecular sieve with decationized water, stirring, adding rare earth salt and/or rare earth salt solution to perform ion exchange reaction, filtering, and washing; the conditions of the ion exchange reaction are as follows: the exchange temperature is 15-95 ℃, the exchange time is 30-120 minutes, and the rare earth salt solution is a rare earth salt water solution.

15. The method of claim 10, wherein the rare earth salt is a rare earth chloride or a rare earth nitrate and the phosphorus compound is one or more selected from the group consisting of phosphoric acid, ammonium phosphate, ammonium dihydrogen phosphate and diammonium hydrogen phosphate.

16. The method as claimed in claim 10, wherein the roasting temperature in step (2) is 380-460 ℃, the roasting atmosphere is 40-80% water vapor atmosphere, and the roasting time is 5-6 hours.

17. The method of claim 10, wherein the Y-type molecular sieve having a decreased unit cell constant obtained in step (2) has a unit cell constant of 2.450nm to 2.462 nm.

18. The method of claim 10, wherein the phosphorus modification treatment conditions of step (3) are: contacting the Y-type molecular sieve sample with the reduced unit cell constant with an exchange solution containing a phosphorus compound, carrying out exchange reaction for 10-100 minutes at 15-100 ℃, filtering and washing; wherein the weight ratio of water to the molecular sieve in the exchange liquid is 2-5 in terms of P₂O₅The weight ratio of phosphorus to molecular sieve is: 0.0005 to 0.10.

19. The process of claim 10, wherein the water content of the Y-type molecular sieve having a decreased phosphorus-containing unit cell constant of step (3) is not more than 1 wt.%.

20. The method according to claim 10, wherein the washing method in step (4) is washing with water under the following washing conditions: molecular sieve: h₂The weight ratio of O is 1: 6-15, the pH value is 2.5-5.0, and the washing temperature is 30-60 ℃.

21. The method of claim 12, wherein the reduced sodium oxide content rare earth-containing Y-type molecular sieve having a conventional unit cell size has a sodium oxide content of 5.5 to 8.5 wt.%.

22. The method of claim 18, wherein the weight ratio of water to molecular sieve in the exchange liquid is 3 to 4.

23. The method of claim 18, wherein P is₂O₅The weight ratio of the phosphorus to the molecular sieve is 0.001-0.05.