CN108452832B

CN108452832B - Phosphorus-containing and rare earth-containing modified Y-type molecular sieve rich in secondary pores and preparation method thereof

Info

Publication number: CN108452832B
Application number: CN201710093980.8A
Authority: CN
Inventors: 周灵萍; 张蔚琳; 许明德; 陈振宇; 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: 2020-06-16
Anticipated expiration: 2037-02-21
Also published as: CN108452832A

Abstract

A modified Y-type molecular sieve rich in secondary pores and containing phosphorus and rare earth and a preparation method thereof are disclosed, wherein the modified Y-type molecular sieve contains 4-11 wt% of rare earth oxide, 0.05-10 wt% of phosphorus, no more than 0.5 wt% of sodium oxide, 0.4-0.48 mL/g of total pore volume, 20-38% of secondary pore volume, 2.440-2.455 nm of unit cell constant, no more than 10% of non-framework aluminum content, no less than 1060 ℃ of lattice collapse temperature, and no less than 3.50 of ratio of B acid content to L acid content. The preparation method of the molecular sieve comprises the steps of rare earth exchange, hydrothermal roasting treatment, gas phase ultra-stable modification, acid treatment and phosphorus introduction, and the modified Y-type molecular sieve has higher heavy oil conversion activity, lower coke selectivity, higher gasoline yield, liquefied gas yield, light oil yield and total liquid yield.

Description

Phosphorus-containing and rare earth-containing modified Y-type molecular sieve rich in secondary pores and preparation method thereof

Technical Field

The invention relates to a high-stability modified Y-type molecular sieve and a preparation method thereof, and further relates to a high-stability Y-type molecular sieve for catalytic cracking of hydrocarbon oil in the absence of hydrogen and a preparation method thereof.

Background

The Y-type molecular sieve has been the main active component of catalytic cracking (FCC) catalysts since its first use in the last 60 th century. However, as crude oil heavies increase, the content of polycyclic compounds in the FCC feedstock increases significantly, and their ability to diffuse through the zeolite channels decreases significantly. The aperture of the Y-type molecular sieve as the main active component is only 0.74nm, and the Y-type molecular sieve is directly used for processing heavy fractions such as residual oil and the like, and the accessibility of the active center of the catalyst can become a main obstacle for cracking polycyclic compounds contained in the Y-type molecular sieve.

The molecular sieve pore structure has close relation with the cracking reaction performance, especially for a residual oil cracking catalyst, the secondary pores of the molecular sieve can increase the accessibility of residual oil macromolecules and active centers thereof, and further improve the cracking capability of residual oil. The hydrothermal dealumination process is one of the most widely used in industry, and includes the first exchange of NaY zeolite with water solution of ammonium ion to reduce the sodium ion content in zeolite, and the subsequent roasting of the ammonium ion exchanged zeolite at 600-825 deg.c in water vapor atmosphere to stabilize the zeolite. The method has low cost and is easy for industrialized mass production, and the obtained ultrastable Y-type zeolite has rich secondary pores, but has serious loss of crystallinity and poor thermal stability.

At present, the industrial production of the ultrastable Y-type zeolite is generally an improvement on the hydrothermal roasting process, and the method of twice exchanging and twice roasting is adopted, so that the prepared ultrastable Y-type zeolite also has a certain amount of secondary pores, but the proportion of the secondary pores with larger pore diameters in the total secondary pores is lower, and the specific surface and the crystallinity of the ultrastable zeolite are still required to be further improved.

US5,069,890 and US5,087,348 disclose a method for preparing a mesoporous Y-type molecular sieve, which mainly comprises the following steps: commercially available USY was used as a starting material and treated at 760 ℃ for 24 hours in an atmosphere of 100% steam. The mesoporous volume of the Y-type molecular sieve obtained by the method is increased from 0.02mL/g to 0.14mL/g, but the crystallinity is reduced from 100 percent to 70 percent, and the surface area is 683m²The/g is reduced to 456m²The acid density drops sharply from 28.9% to 6% even more.

In the method for preparing the mesoporous-containing Y-shaped molecular sieve disclosed in US5,601,798, HY or USY is taken as a raw material and is put into an autoclave to react with NH₄NO₃Solution or NH₄NO₃With HNO₃The mixed solution is mixed and treated for 2 to 20 hours at the temperature of 115 to 250 ℃ higher than the boiling point, the volume of the mesoporous of the obtained Y-shaped molecular sieve can reach 0.2 to 0.6ml/g, but the crystallinity and the surface area are obviously reduced.

CN201310240740.8 discloses a combined modification method of a rich-mesoporous ultrastable Y molecular sieve, which is characterized in that organic acid and inorganic salt dealuminization reagents are added simultaneously in the modification process to carry out combined modification of organic acid and inorganic salt, and the optimal process conditions of optimal concentration, volume ratio, reaction time, reaction temperature and the like of organic acid and inorganic salt solution are determined through orthogonal experiments. Compared with industrial USY molecular sieve, the USY obtained by the method has obviously improved secondary pore content, and is suitable for high and medium oil type hydrocracking catalyst carriers. CN1388064 discloses a method for preparing high-silicon Y zeolite with a unit cell constant of 2.420-2.440 nanometers, which comprises the steps of carrying out ammonium exchange, hydrothermal treatment and/or chemical dealumination on NaY zeolite or Y-type zeolite subjected to hyperstabilization treatment for one or more times; characterized in that at least the first ammonium exchange in the ammonium exchange before the hydrothermal treatment and/or chemical dealumination is a low-temperature selective ammonium exchange at room temperature to below 60 ℃, and the rest of the ammonium exchanges are either low-temperature selective ammonium exchanges at room temperature to below 60 ℃ or conventional ammonium exchanges at 60-90 ℃. The high-silicon Y zeolite prepared by the patent still has higher crystal retention degree when the unit cell constant is smaller, and simultaneously has more secondary holes, and is suitable for being used as a middle distillate oil hydrocracking catalyst. The ultrastable Y molecular sieve prepared by the method disclosed by the patent contains a certain amount of secondary pores, has a small unit cell constant, is high in silicon-aluminum ratio, does not contain rare earth, and is suitable for hydrogenation catalysts which are difficult to meet the requirement of high catalytic cracking activity required by processing heavy oil.

CN1629258 discloses a preparation method of a cracking catalyst containing a rare earth ultrastable Y-type molecular sieve, which is characterized in that the method comprises the step of contacting a NaY molecular sieve with an ammonium salt aqueous solution containing 6-94 wt% of ammonium salt twice or more according to the weight ratio of ammonium salt to molecular sieve of 0.1-24 under the conditions of normal pressure and the temperature of more than 90 ℃ to no more than the boiling point temperature of the ammonium salt aqueous solution, so that Na in the molecular sieve is obtained₂Reducing the O content to below 1.5 weight percent, and then contacting the molecular sieve with an aqueous solution with the rare earth salt content of 2-10 weight percent at the temperature of 70-95 ℃ to ensure that the rare earth in the molecular sieve is RE₂O₃0.5-18 wt%, and mixing with carrier and drying. The molecular sieve has low superstability, low Si/Al ratio and less secondary pores.

CN1127161 discloses a rare earth-containingA process for preparing silicon-rich ultrastable Y-type molecular sieve from NaY as raw material in solid RECl₃In the presence of SiCl₄And carrying out gas-phase dealuminization and silicon supplementation reaction to complete the ultra-stabilization of NaY and the rare earth ion exchange in one step. The unit cell constant a of the molecular sieve prepared by the method_o2.430-2.460 nm, rare earth content of 0.15-10.0 wt%, and Na₂The O content is less than 1.0 wt%. However, the molecular sieve is prepared only by a gas phase ultrastable method, and although the ultrastable Y molecular sieve containing rare earth can be prepared, the prepared molecular sieve is lack of secondary pores.

The gas-phase chemical method directly generates isomorphous substitution effect on silicon in gas-phase silicon tetrachloride and aluminum in a molecular sieve framework under the gas-phase ultrastable reaction condition, so that dealuminization and silicon supplement are carried out simultaneously, dealuminization is uniform, but the gas-phase ultrastable molecular sieve has no secondary pores. .

CN1031030 discloses a preparation method of an ultrastable Y-type molecular sieve with low rare earth content, which is used for hydrocarbon cracking and is prepared by using a NaY-type molecular sieve as a raw material through the steps of primary mixed exchange of ammonium ions and rare earth ions, stabilization treatment, removal of part of framework aluminum atoms, thermal or hydrothermal treatment and the like. Rare earth content (RE) of the molecular sieve₂O₃) 0.5 to 6 wt% of SiO₂/Al₂O₃Up to 9 to 50, unit cell constant a₀2.425 to 2.440 nm. The ultrastable molecular sieve prepared by the method has high silicon-aluminum ratio, small unit cell constant and a certain amount of rare earth, but the prepared molecular sieve heavy oil has low catalytic cracking activity and poor coke selectivity.

CN1330981A discloses a phosphorus-containing Y-type zeolite and a preparation method thereof. The said P-containing Y-type zeolite contains P, a Si component and rare-earth component, and the Si component is loaded by impregnating zeolite with solution of Si compound and is 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 prepared by mixing rare earth-containing Y-type zeoliteCo-soaking with a solution containing silicon and phosphorus, drying, and then carrying out hydrothermal roasting at 550-850 ℃. However, the heavy oil containing phosphorus Y-type zeolite has low cracking activity and low light oil yield.

CN1353086A discloses a method for preparing Y-type molecular sieve containing phosphorus and rare earth, which comprises the steps of firstly mixing and exchanging NaY molecular sieve with ammonium ions and rare earth ions, carrying out hydrothermal roasting, and then reacting and combining the NaY molecular sieve with phosphorus compounds by 0.2-10 wt% (based on P)₂O₅Calculated), and then carrying out hydrothermal roasting. However, the heavy oil containing phosphorus Y-type zeolite has low cracking activity and low light oil yield.

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 molecular sieve prepared by the method has high rare earth content, large unit cell constant, poor thermal stability and poor selectivity of molecular sieve coke.

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 treatment, wherein RE is 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 modified Y zeolite obtained by the method has poor thermal stability and low heavy oil cracking activity.

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 zeolite has low cracking activity and low heavy oil conversion rate.

Disclosure of Invention

One of the technical problems to be solved by the invention is to provide a high-stability Y-type molecular sieve (Y-type molecular sieve is also called Y-type zeolite) suitable for heavy oil catalytic cracking processing, wherein the modified Y-type molecular sieve has higher heavy oil cracking activity and better coke selectivity. The second technical problem to be solved by the invention is to provide a preparation method of the modified Y-type molecular sieve.

The invention provides a modified Y-type molecular sieve, which has the content of rare earth oxide of 4-11 wt% and the phosphorus content of P₂O₅0.05 to 10 wt%, sodium oxide content (Na)₂O content) of not more than 0.5% by weight, for example, 0.05 to 0.5% by weight, and a total pore volume of 0.36 to 0.48mL/g, the modified Y-type molecular sieve having a secondary pore diameter of 2 to 100nm in a percentage of the total pore volume of 20 to 40%, a unit cell constant of 2.440 to 2.455nm, an amount of non-framework aluminum in the modified Y-type molecular sieve of not more than 10% by weight based on the total aluminum content, a lattice collapse temperature of not less than 1060 ℃, and a ratio of an amount of B acid to an amount of L acid in the total acid amount of the modified Y-type molecular sieve measured at 200 ℃ by a pyridine adsorption infrared method of not less than 3.5.

The modified Y-type molecular sieve provided by the invention has the lattice collapse temperature of not less than 1060 ℃, preferably, the lattice collapse temperature of the molecular sieve is 1065-1085 ℃, for example, 1067-1080 ℃.

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, which is measured at 200 ℃ by using a pyridine adsorption infrared method, is preferably 3.5-6, for example, 3.5-5.5 or 3.5-4.6.

The modified Y-type molecular sieve provided by the invention has a unit cell constant of 2.440-2.455 nm, such as 2.442-2.453 nm or 2.442-2.451 nm.

The modified Y-type molecular sieve provided by the invention is a high-silicon Y-type molecular sieve, and the framework silicon-aluminum ratio (SiO) of the high-silicon Y-type molecular sieve₂/Al₂O₃In a molar ratio) of 7 to 14, for example 8.5 to 12.6 or 9.2 to 11.4 or 7.8 @12.6。

The percentage of non-framework aluminum content in the modified Y-type molecular sieve provided by the invention in the total aluminum content is not higher than 10%, for example, 5-9.5 wt% or 6-9.5 wt%.

The modified Y-type molecular sieve provided by the invention has a crystal retention of 38% or more, for example, 38-60%, or 50-60%, or 46-58% after aging for 17 hours at 800 ℃ under normal pressure and in a 100 vol% steam atmosphere. The normal pressure is 1 atm.

The modified Y-type molecular sieve provided by the invention has a relative crystallinity of not less than 70%, such as 70-80%, and further such as 70-76%.

The invention provides a modified Y-type molecular sieve, and an embodiment of the modified Y-type molecular sieve has a specific surface area of 600-670 m²The number of grams of the additive is, for example, 610 to 670 or 640 to 670 or 646 to 667m²/g。

The total pore volume of the modified Y-type molecular sieve provided by the invention is 0.36-0.48 mL/g, preferably, the total pore volume is 0.38-0.42 or 0.4-0.48 mL/g. The pore volume of the secondary pores of 2.0 to 100nm is 0.08 to 0.18mL/g, for example, 0.1 to 0.16 mL/g.

The modified Y-type molecular sieve provided by the invention has the pore volume of secondary pores with the pore diameter (diameter) of 2.0-100 nm accounting for 20-40% of the total pore volume, preferably 28-38%, for example 25-35%. The ratio of the pore volume of secondary pores with the pore diameter of 8-100 nm (the total volume of the pores with the pore diameter of 2-100 nm)/the pore volume of total secondary pores (the total volume of the pores with the pore diameter of 2-100 nm) in the modified Y-type molecular sieve is 40-80%, for example, 45-75% or 55-77%.

The modified Y-type molecular sieve contains rare earth elements, and RE is used in the modified Y-type molecular sieve₂O₃The rare earth oxide content is preferably 4.5 to 10 wt%, for example 5 to 9 wt%, in the range of 4 to 11 wt%.

The modified Y-type molecular sieve contains phosphorus modified elements, and P in the modified Y-type molecular sieve₂O₅(i.e. with P)₂O₅Phosphorus content) of 0.05 to 10 wt.%, preferably 0.1 to 6 wt.%, for example 1 to 4 wt.%.

The modified Y-type molecular sieve provided by the invention has the sodium oxide content of not more than 0.5%, and can be 0.05-0.5 wt%, such as 0.1-0.4 wt% or 0.05-0.3 wt%.

The invention provides a preparation method of a modified Y-type molecular sieve, which 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 rare earth-containing Y-type molecular sieve with the reduced sodium oxide content and the conventional unit cell size, and optionally drying to obtain a Y-type molecular sieve with a reduced unit cell constant, wherein the modifying is to roast the rare earth-containing Y-type molecular sieve with the reduced sodium oxide content and the conventional unit cell size 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) for 4.5-7 hours;

(3) mixing the Y-type molecular sieve sample with SiCl, wherein the unit cell constant is reduced₄Carrying out gas contact reaction; wherein the preferable contact reaction temperature is 200-650 ℃, SiCl₄: 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 gas-phase ultra-stable modified Y-type molecular sieve. Wherein the water content of the Y-type molecular sieve sample with reduced unit cell constant is preferably not more than 1 wt%; if the water content in the Y-type molecular sieve sample obtained by modification treatment in the step (2) (in the Y-type molecular sieve sample obtained by roasting) is not more than 1 wt%, the Y-type molecular sieve sample can be directly used for contacting silicon tetrachloride to carry out the reaction, and if the water content in the Y-type molecular sieve sample obtained by roasting in the step (2) exceeds 1 wt%, the Y-type molecular sieve sample with the reduced unit cell constant obtained by roasting in the step (2) is dried to enable the water content to be lower than 1 wt%;

(4) contacting the gas-phase ultra-stable modified Y-shaped molecular sieve obtained in the step (3) with an acid solution for modification to obtain an acid-treated modified Y-shaped molecular sieve;

(5) and (4) contacting the acid-treated modified Y-shaped molecular sieve obtained in the step (4) with a phosphorus compound for phosphorus modification treatment.

The modified Y-type molecular sieve provided by the invention has high thermal and hydrothermal stability, high activity and good coke selectivity, is used for heavy oil catalytic cracking, has higher heavy oil conversion activity and lower coke selectivity than the conventional Y-type molecular sieve, and has higher gasoline yield, liquefied gas yield, light oil yield and total liquid yield.

The preparation method of the sex-modified Y-shaped molecular sieve provided by the invention can be used for preparing the high-silicon Y-shaped molecular sieve which is high in crystallinity, high in thermal stability and high in hydrothermal stability and is rich in secondary pores, the molecular sieve has higher crystallinity under the condition that the ultrastable degree is greatly improved, the prepared molecular sieve is uniform in aluminum distribution, low in non-framework aluminum content and smooth in secondary pore channels, 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 modified Y-type molecular sieve provided by the invention can be used as an active component of a catalytic cracking catalyst and used for converting heavy oil or poor oil; the catalytic cracking catalyst with the molecular sieve as the active component has the advantages of strong heavy oil conversion capacity, high stability, good coke selectivity, high light oil yield and high gasoline yield.

Detailed Description

According to one embodiment of the modified Y-type molecular sieve, the content of rare earth oxide is 4-11 wt%, preferably 4.5-10 wt%; 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.%; the sodium oxide content is 0.05 to 0.5 wt.%, for example 0.1 to 0.4 wt.% or 0.05 to 0.3 wt.%, preferably less than 0.2 wt.%; the total pore volume is 0.36-0.48 mL/g, the percentage of the pore volume of the secondary pores with the pore diameter of 2-100 nm in the total pore volume is preferably 28-38%, preferably 25-35%, the unit cell constant is 2.440-2.455 nm, preferably 2.441-2.453 nm or 2.442-2.451 nm,framework silicon to aluminum ratio (SiO)₂/Al₂O₃Molar ratio) is: 7 to 14 is, for example, 8.5 to 12.6 or 9.2 to 11.4, the percentage of non-framework aluminum content in the molecular sieve to the total aluminum content is not higher than 10%, preferably 6 to 9.5%, the relative crystallinity is not lower than 60%, preferably not lower than 70%, for example 70 to 80%, the lattice collapse temperature is 1065 to 1080 ℃, and 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 a pyridine adsorption infrared method is not lower than 3.50, for example 3.5 to 6, preferably 3.5 to 4.6.

The modified Y-type molecular sieve provided by the invention is a phosphorus-containing and rare earth ultrastable Y-type molecular sieve rich in secondary pores, and the secondary pore distribution curve of the zeolite with the pore diameter of 2 nm-100 nm is in double-probable-pore distribution, wherein the probable pore diameter of the secondary pores with smaller pore diameters is 2-5 nm, and the probable pore diameter of the secondary pores with larger pore diameters is 6 nm-20 nm, preferably 8 nm-18 nm. Preferably, the proportion of secondary pores with a pore diameter of 8nm to 100nm to the total secondary pores (2nm to 100nm) is 40% to 80%, preferably 45% to 75%, for example, 45% to 55% or 55% to 77%. SiO of the zeolite₂/Al₂O₃Is 7 to 14, preferably 7.8 to 13, more preferably 8.5 to 12.6, and has a cell constant of 2.440 to 2.455nm, preferably 2.441 to 2.453 nm.

The preparation process of the modified Y-type molecular sieve comprises the step of contacting the Y-type molecular sieve with silicon tetrachloride to carry out dealuminization and silicon supplementation reaction.

In the preparation method of the modified Y-type molecular sieve, the NaY molecular sieve and the rare earth solution are subjected to ion exchange reaction in the step (1) to obtain the Y-type molecular sieve with the normal unit cell size and the reduced sodium oxide content and containing rare earth. 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. Carrying out ion exchange reaction on the NaY molecular sieve and the rare earth solution in the step (1), wherein the exchange temperature is preferably 15-95 ℃, such as 65-95 ℃, and the exchange time is preferably 30-120 minutes, such as45-90 minutes. NaY molecular sieve (dry basis) rare earth salt (RE)₂O₃Meter) H₂O is 1:0.01 to 0.18:5 to 20 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 stirring a mixture of NaY molecular sieve (also called NaY zeolite), rare earth salt and water at a weight ratio of 1:0.01 to 0.18:5 to 15, for example, at room temperature to 60 ℃ or 65 to 95 ℃, preferably for 30 to 120 minutes. In one embodiment, the weight ratio of the NaY molecular sieve to water is 1:6 to 20, preferably 1:7 to 15. The NaY molecular sieve, rare earth salt and water are mixed to form a mixture, the NaY molecular sieve and the water can be formed into slurry, and then rare earth salt and/or aqueous solution of rare earth salt are added into the slurry, wherein the rare earth solution is solution of rare earth salt, and 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%, and sodium oxide content of not more than 9.5 wt%, for example 5.5 to 9.5 wt%, and a cell constant of 2.465nm to 2.472 nm.

In the preparation method of the modified Y-type molecular sieve, the Y-type 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 in step (2), preferably, the roasting temperature in 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. Preferably, the calcined molecular sieve is also dried in step (2) so that the water content in the Y-type molecular sieve having a reduced unit cell constant is preferably not more than 1 wt%. The solid content of the Y-type molecular sieve sample with reduced unit cell constant obtained in the step (2) is preferably not less than 99% by weight.

In the preparation method of the modified Y-type molecular sieve, SiCl is adopted in the step (3)₄: the weight ratio of the Y-type zeolite (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, usually Na in washed molecular sieve samples⁺，Cl^-And Al³⁺The respective contents of ions do not exceed 0.05 wt.%.

In the preparation method of the modified Y-type molecular sieve provided by the invention, in the step (4), the gas-phase ultrastable modified Y-type molecular sieve obtained in the step (3) is contacted with an acid solution for reaction (the method is called as channel cleaning modification, which is called as channel cleaning for short, or called as acid treatment modification). In one embodiment, the gas phase ultrastable modified Y-type molecular sieve obtained in step (3) is contacted with an acid solution for reaction, the gas phase ultrastable modified molecular sieve, that is, the gas phase ultrastable modified Y-type molecular sieve, is mixed with the acid solution and reacted for a period of time, and then the reacted molecular sieve is separated from the acid solution, for example, by filtration, and then optionally washed (the washing is to remove Na remaining in the zeolite)⁺，Cl^-And Al³⁺Etc. soluble by-products, for example the washing conditions may be: of wash water with molecular sievesThe weight ratio 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, the washing temperature is 30-60 ℃), and the modified Y-type molecular sieve provided by the invention is obtained by optional drying. And (3) contacting the gas-phase ultra-stable modified Y-shaped molecular sieve obtained in the step (3) with an acid solution, wherein the weight ratio of the acid to the molecular sieve (calculated on a dry basis) is 0.001-0.15: 1 is, for example, 0.002 to 0.1: 1 or 0.01 to 0.05: 1, the weight ratio of water to the molecular sieve calculated on a dry basis is 5-20: 1 is, for example, 8 to 15: 1, the temperature for the contact reaction is 60-100 ℃, for example 80-99 ℃, preferably 88-98 ℃.

Preferably, the acid in the acid solution (aqueous acid solution) is at least one organic acid and at least one inorganic acid of medium or higher strength. The organic acid can be one or more of oxalic acid, malonic acid, succinic acid (succinic acid), methylsuccinic acid, malic acid, tartaric acid, citric acid and salicylic acid, and the inorganic acid with medium strength or higher can be one or more of phosphoric acid, hydrochloric acid, nitric acid and sulfuric acid. Preferably, the temperature for cleaning and modifying the pore passage is 80-99 ℃, such as 85-98 ℃, and the time for treating and modifying is more than 60 minutes, such as 60-240 minutes or 90-180 minutes. The weight ratio of the organic acid to the molecular sieve is 0.02-0.05: 1; the weight ratio of the inorganic acid with the medium strength to the molecular sieve is 0.01-0.06: 1 is, for example, 0.02 to 0.05: 1, the weight ratio of water to the molecular sieve is preferably 5-20: 1 is, for example, 8 to 15: 1.

preferably, the pore cleaning modification is carried out in two steps, and firstly, inorganic acid with the strength higher than medium is contacted with the molecular sieve, wherein the weight ratio of the inorganic acid with the strength higher than medium to the molecular sieve is 0.01-0.05: 1 is, for example, 0.02 to 0.05: 1, the weight ratio of water to the molecular sieve is preferably 5-20: 1 is, for example, 8 to 15: 1, the temperature of the contact reaction is 80-99 ℃, preferably 90-98 ℃, and the reaction time is 60-120 minutes; and then contacting the treated molecular sieve with organic acid, wherein the weight ratio of the organic acid to the molecular sieve is (0.02-0.10): 1 is, for example, 0.02 to 0.10: 1 or 0.05-0.08: 1, the weight ratio of water to the molecular sieve is preferably 5-20: 1 is, for example, 8 to 15: 1, the temperature of the contact reaction is 80-99 ℃, preferably 90-98 ℃, and the reaction time is 60-120 minutes. Wherein in the weight ratio, the molecular sieve is on a dry basis.

In the preparation method of the modified Y-type molecular sieve, step (5) is to perform phosphorus modification treatment on the acid-treated modified Y-type molecular sieve obtained in step (4) to introduce phosphorus into the molecular sieve, wherein the phosphorus modification treatment generally comprises contacting the acid-treated modified Y-type molecular sieve obtained in step (4) with an exchange liquid, and the exchange liquid contains a phosphorus compound. The contacting is typically at 15 to 100 ℃, preferably 30 to 95 ℃ for 10 to 100 minutes, followed by filtration, and optionally 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 0.06. 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, the phosphorus modification treatment conditions are: adding the acid-treated modified Y-shaped molecular sieve into an exchange solution containing a phosphorus compound, carrying out exchange reaction for 10-100 minutes at 15-100 ℃, filtering and washing; wherein, in the mixture formed by the exchange liquid containing the phosphorus compound and the molecular sieve, the weight ratio of water to the molecular sieve is 2-5, preferably 3-4, phosphorus (expressed as P)₂O₅Calculated) and the weight ratio of the molecular sieve is as follows: 0.0005 to 0.10, preferably 0.001 to 0.06.

The preparation method of the modified Y-type molecular sieve 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) mixing said reduced unit cell constant Y-type molecular sieve sample having a water content of less than 1 wt% with heat vaporized SiCl₄Gas 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 ℃, optionally washing and filtering to obtain a gas-phase ultra-stable modified Y-type molecular sieve;

(4) carrying out acid treatment modification on the gas-phase superstable modified Y-type molecular sieve obtained in the step (3); mixing the gas-phase ultra-stable modified Y-type molecular sieve obtained in the step (3) with inorganic acid with medium strength or higher and water, contacting at 80-99 ℃, preferably 90-98 ℃, for at least 30 minutes, such as 60-120 minutes, then adding organic acid, contacting at 80-99 ℃, preferably 90-98 ℃, for at least 30 minutes, such as 60-120 minutes, filtering, optionally washing and optionally drying to obtain the acid-treated modified Y-type molecular sieve; (ii) a Wherein the preferable weight ratio of the organic acid to the molecular sieve on a dry basis is 0.02-0.10: 1, the weight ratio of the inorganic acid with the medium strength or more to the molecular sieve based on a dry basis is 0.01-0.05: 1, the weight ratio of water to the molecular sieve is 5-20: 1.

(5) adding the acid-treated modified Y-type molecular sieve into an exchange solution containing a phosphorus compound, carrying out exchange reaction for 10-100 minutes at 15-100 ℃, filtering, washing and optionally drying; 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: 0.005 to 0.10, preferably 0.01 to 0.05.

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 zeuginese corporation, petrochemical catalyst ltd, china, and had a sodium oxide content of 13.5 wtWeight percent, framework silicon to aluminum ratio (SiO)₂/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. An experimental instrument: model Bruker IFS113V FT-IR (fourier transform infrared) spectrometer, usa. An experimental method for measuring the amount of B acid and the amount of L acid in total acid at 200 ℃ by using a pyridine adsorption infrared method comprises the following steps: 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

2000Kg (dry basis) of SiO skeleton₂/Al₂O₃4.6 NaY zeolite (sodium oxide content 13.5 wt%, available from the Kikukushi company, China petrochemical catalyst, Qilu division) was charged in a vessel containing 20m³Stirring the mixture evenly at 25 ℃ in a primary exchange tank of water, and then adding 600L of RECl₃Solutions (RECl)₃Rare earth concentration in solution as RE₂O₃319g/L), stirring for 60 minutes, filtering, washing, and continuously feeding a filter cake into a flash evaporation drying furnace for drying; obtaining the rare earth-containing Y-type molecular sieve with the normal unit cell size and the reduced sodium oxide content, wherein the sodium oxide content is 7.0 weight percent, the unit cell constant is 2.471nm, and then sending the molecular sieve into a roasting furnace for modification: controlling the temperature of the material atmosphere at 390 ℃, and roasting for 6 hours under 50% of water vapor (the atmosphere contains 50% of water vapor by volume); then, introducing the molecular sieve material into a roasting furnace for roasting and drying, controlling the temperature of the material atmosphere at 500 ℃, and roasting for 2.5 hours in a dry air atmosphere (the water vapor content is lower than 1 volume percent) to ensure that the water content is lower than 1 weight percent; obtaining a Y-type molecular sieve having a reduced unit cell constant of 2.455nm, thenThen, the Y-type molecular sieve material with the reduced unit cell constant is directly sent into a continuous gas phase hyperstable reactor for gas phase hyperstable reaction, the gas phase hyperstable reaction process of the molecular sieve in the continuous gas phase hyperstable reactor and the subsequent tail gas absorption process are carried out according to the method of embodiment 1 disclosed in the CN103787352A patent, and the process conditions are as follows: SiCl₄: weight ratio of Y-type zeolite 0.5: 1, the feed rate of the molecular sieve is 800 kg/h, and the reaction temperature is 400 ℃. Separating the molecular sieve material after gas phase superstable reaction by a gas-solid separator, and feeding into a secondary exchange tank, wherein 20m is added in advance in the secondary exchange tank³The water (2) was added to the molecular sieve material in the secondary exchange tank in an amount of 2000Kg (dry basis) by weight, stirred well, and then 0.6m hydrochloric acid having a concentration of 10% by weight was slowly added³Heating to 90 ℃, continuing to stir for 60 minutes, then adding 140Kg of citric acid, continuing to stir for 60 minutes at 90 ℃, filtering, washing, and then directly adding the molecular sieve filter cake into an exchange solution containing ammonium phosphate, wherein the adding amount of the molecular sieve is as follows: phosphorus (in P)₂O₅Calculated) and the weight ratio of the molecular sieve is as follows: 0.04, wherein the weight ratio of water to the molecular sieve is 2.5, the exchange reaction is carried out for 60 minutes at the temperature of 50 ℃, the filtration and the washing are carried out, the rare earth and phosphorus-containing modified Y molecular sieve which is rich in secondary pores is obtained, the sampling and the drying are carried out, and the sample is recorded as SZ-1. Table 1 shows the composition of SZ-1, the unit cell constant, the relative crystallinity, the framework Si/Al ratio, the structural collapse temperature, the specific surface area, the percentage of the secondary pores with larger pore diameter (8 nm-100 nm) in the total secondary pores (2-100 nm), and the total secondary pore volume.

After SZ-1 is aged for 17 hours at 800 ℃, 1atm and 100 percent of water vapor in a naked state, the relative crystallinity of the molecular sieve before and after the SZ-1 is aged is analyzed by an XRD method and the relative crystallinity retention after the aging is calculated, and the result is shown in a table 2, wherein:

example 2

2000Kg (dry basis) of SiO skeleton₂/Al₂O₃NaY type zeolite (sodium oxide) at 4.613.5 wt.% of medium petrochemical catalyst from the company Qilu, Ltd.) was charged in a vessel containing 20m of the catalyst³In a primary exchange tank for removing the cationic water, stirring uniformly at 90 ℃, and then adding 800L RECl₃Solutions (RECl)₃Rare earth concentration in solution as RE₂O₃319g/L) is counted, and stirring is carried out for 60 minutes; filtering, washing, and drying the filter cake in a flash drying furnace to obtain the rare earth-containing Y-type molecular sieve with the normal unit cell size and the reduced sodium oxide content, wherein the sodium oxide content is 5.5 weight percent, and the unit cell constant is 2.471 nm; then, the mixture is sent into a roasting furnace and roasted for 5.5 hours at the temperature (atmosphere temperature) of 450 ℃ under the atmosphere of 80 percent of water vapor; then, the molecular sieve material enters a roasting furnace to be roasted and dried, the roasting temperature is controlled to be 500 ℃, the roasting atmosphere is a dry air atmosphere, the roasting time is 2 hours, the water content of the molecular sieve is enabled to be lower than 1 weight percent, and the Y-shaped molecular sieve with the reduced unit cell constant is obtained, wherein the unit cell constant is 2.461 nm; then, the Y-type molecular sieve material with the reduced unit cell constant is directly sent into a continuous gas phase hyperstable reactor for gas phase hyperstable reaction, the gas phase hyperstable reaction process of the molecular sieve in the continuous gas phase hyperstable reactor and the subsequent tail gas absorption process are carried out according to the method of embodiment 1 disclosed in the CN103787352A patent, and the process conditions are as follows: SiCl₄: weight ratio of Y-type zeolite 0.25: 1, the feed rate of the molecular sieve was 800 kg/hour, and the reaction temperature was 490 ℃. Separating the molecular sieve material after gas phase superstable reaction by a gas-solid separator, and feeding into a secondary exchange tank, wherein 20m is added in advance in the secondary exchange tank³Adding the decationized water into a molecular sieve material in a secondary exchange tank, wherein the weight of the molecular sieve material is 2000Kg (dry basis), uniformly stirring, and slowly adding a sulfuric acid solution with the concentration of 7 weight percent, and the concentration of the sulfuric acid solution is 0.9m³Heating to 93 ℃, stirring for 80 minutes, adding 70Kg of citric acid and 50Kg of tartaric acid, stirring for 70 minutes at 93 ℃, filtering, washing, and directly adding the molecular sieve filter cake into an exchange solution containing diammonium hydrogen phosphate, wherein the adding amount of the molecular sieve is as follows: phosphorus (in P)₂O₅Calculated) and the weight ratio of the molecular sieve is as follows: 0.03, and the weight ratio of water to molecular sieve is 3.0, exchange reaction is carried out for 50 minutes at 60 ℃, and filtration and washing are carried out to obtain the product rich in secondary poresAnd (3) sampling and drying the rare earth and phosphorus-containing modified ultrastable Y molecular sieve, and marking a sample as SZ-2. Table 1 shows the composition of SZ-2, the percentage of the total secondary pores (2-100 nm) occupied by the unit cell constant, the relative crystallinity, the framework Si/Al ratio, the structural collapse temperature, the specific surface area and the secondary pores with larger pore diameter (8-100 nm), and the total secondary pore volume.

After aging SZ-2 in a naked state at 800 ℃ for 17 hours by 100% steam, the crystallinity of the zeolite before and after aging of the SZ-2 is analyzed by an XRD method and the relative crystal retention after aging is calculated, and the result is shown in Table 2.

Example 3

2000Kg (dry basis) of SiO skeleton₂/Al₂O₃4.6 NaY zeolite (sodium oxide content 13.5 wt%, available from the Kikukushi company, China petrochemical catalyst, Qilu division) was charged in a vessel containing 20m³Stirring in a first exchange tank for removing cationic water at 95 deg.C, and adding 570L RECl₃Solutions (RECl)₃Rare earth concentration in solution as RE₂O₃319g/L), stirring for 60 minutes, filtering, washing, continuously feeding filter cakes into a flash drying furnace for drying to obtain the rare earth-containing Y-type molecular sieve with the normal unit cell size and the reduced sodium oxide content, wherein the sodium oxide content is 7.5 weight percent, and the unit cell constant is 2.471 nm; then, the mixture is sent into a roasting furnace for hydrothermal modification, and the hydrothermal modification conditions are as follows: roasting at 470 ℃ for 5 hours in an atmosphere containing 70 volume percent of water vapor; then, the molecular sieve material enters a roasting furnace to be roasted and dried, the roasting temperature is controlled to be 500 ℃, the roasting atmosphere is a dry air atmosphere, the roasting time is 1.5 hours, the water content is enabled to be lower than 1 weight percent, and the Y-type molecular sieve with the reduced unit cell constant is obtained, wherein the unit cell constant is 2.458 nm; then, the Y-shaped molecular sieve material with the reduced unit cell constant is sent into a continuous gas-phase ultra-stable reactor to carry out gas-phase ultra-stable reaction. The gas phase hyperstable reaction process of the molecular sieve in the continuous gas phase hyperstable reactor and the subsequent tail gas absorption process are carried out according to the method disclosed in embodiment 1 of the CN103787352A patent, and the process conditions are as follows: SiCl₄: weight ratio of Y-type zeolite 0.45: 1, the feed rate of the molecular sieve is 800 kg/h, and the reaction temperature is 400 ℃. Molecules after gas phase superstable reactionThe sieve material is separated by a gas-solid separator and then sent into a secondary exchange tank, and 20m is added in advance in the secondary exchange tank³Adding the decationized water into a molecular sieve material in a secondary exchange tank, wherein the weight of the molecular sieve material is 2000Kg (dry basis weight), uniformly stirring, and slowly adding a nitric acid solution with the concentration of 5 weight percent, namely 1.2m³Heating to 95 ℃, stirring for 90 minutes, then adding 90Kg of citric acid and 40Kg of oxalic acid, stirring for 70 minutes at 93 ℃, filtering, washing, and directly adding the molecular sieve filter cake into an exchange solution containing ammonium phosphate, wherein the adding amount of the molecular sieve is as follows: phosphorus (in P)₂O₅Calculated) and the weight ratio of the molecular sieve is as follows: 0.015, the weight ratio of water to the molecular sieve is 2.8, the exchange reaction is carried out for 30 minutes at the temperature of 70 ℃, the filtration and the washing are carried out, the ultrastable Y molecular sieve which is rich in secondary pores and contains rare earth and phosphorus modification is obtained, the sampling and the drying are carried out, and the sample is marked as SZ-3. Table 1 shows the composition of SZ-3, the percentage of the total secondary pores (2-100 nm) occupied by the unit cell constant, the relative crystallinity, the framework Si/Al ratio, the structural collapse temperature, the specific surface area and the secondary pores with larger pore diameter (80-100 nm), and the total secondary pore volume. After aging SZ-3 in a naked state at 800 ℃ for 17 hours by 100% steam, the crystallinity of the zeolite before and after aging of SZ-3 is analyzed by an XRD method and the relative crystal retention after aging is calculated, and the result is shown in Table 2.

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, performing hydrothermal modification treatment (at 650 deg.C, roasting with 100% water vapor for 5 hr), adding into 20L of decationized water 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 ℃, and then carrying out second hydrothermal modification treatment (roasting at 650 ℃ under 100% of water vapor for 5 hours) to obtain the rare earth-free hydrothermal ultrastable Y-type molecular sieve which is subjected to twice ion exchange and twice hydrothermal ultrastable, and is marked as DZ-1. Table 1 shows DZ-1The composition comprises the percentage of a unit cell constant, relative crystallinity, framework silicon-aluminum ratio, structure collapse temperature, specific surface area and secondary pores with larger pore diameter (the pore diameter is 8-100 nm) in total secondary pores (2-100 nm), and total secondary pore volume. After aging DZ-1 in the bare state at 800 ℃ for 17 hours with 100% steam, the crystallinity of the zeolite before and after aging DZ-1 was analyzed by XRD and the relative crystal retention after aging was calculated, the results are shown in Table 2.

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 ℃, keeping for 1 hour, then filtering, washing, drying a filter cake at 120 ℃, and then carrying out hydrothermal modification treatment, wherein the conditions of the hydrothermal modification treatment are as follows: roasting at 650 deg.C under 100% steam for 5 hr, adding into 20L decationized water solution, stirring, mixing, adding 200ml 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 ℃, keeping for 1 hour, then filtering, washing, drying a filter cake at 120 ℃, and then carrying out second hydrothermal modification treatment (roasting at 650 ℃ under 100% of water vapor for 5 hours) to obtain the rare earth-containing hydrothermal ultrastable Y-type molecular sieve which is subjected to twice ion exchange and twice hydrothermal ultrastable, and is marked as DZ-2. Table 1 shows the composition of DZ-2, the percentage of the total secondary pores (2-100 nm) occupied by the unit cell constant, the relative crystallinity, the framework Si/Al ratio, the structural collapse temperature, the specific surface area, and the secondary pores with larger pore diameters (8-100 nm), and the total secondary pore volume. After aging DZ-2 in the bare state at 800 ℃ for 17 hours with 100% steam, the crystallinity of the zeolite before and after aging DZ-2 was analyzed by XRD and the relative crystal retention after aging was calculated, the results are shown in Table 2.

Comparative example 3

2000kg of NaY molecular sieve (dry basis) was added to 20m³Stirring in water to mix well, adding 650L RE (NO)₃)₃Stirring the solution (319g/L), heating to 90-95 ℃ for 1 hour, and thenFiltering, washing, continuously feeding the filter cake into a flash evaporation and roasting furnace for roasting and drying, controlling the roasting temperature to be 500 ℃, the roasting atmosphere to be a dry air atmosphere, roasting for 2 hours, and then feeding the dried molecular sieve material into a continuous gas phase ultra-stable reactor for gas phase ultra-stable reaction. The gas phase hyperstable reaction process of the molecular sieve in the continuous gas phase hyperstable reactor and the subsequent tail gas absorption process are carried out according to the method disclosed in embodiment 1 of the CN103787352A patent, and the process conditions are as follows: SiCl₄: weight ratio of Y-type zeolite 0.4: 1, the feed rate of the molecular sieve is 800 kg/h, and the reaction temperature is 580 ℃. Separating the molecular sieve material after gas phase superstable reaction by a gas-solid separator, and feeding into a secondary exchange tank, wherein 20m is added in advance in the secondary exchange tank³The water (2) is added into a molecular sieve material in a secondary exchange tank, the weight of the molecular sieve material is 2000Kg (dry basis), the mixture is stirred evenly, and then 5 weight percent of nitric acid with the weight of 1.2m is slowly added³Heating to 95 ℃, continuing to stir for 90 minutes, then adding 90Kg of citric acid and 40Kg of oxalic acid, continuing to stir for 70 minutes at 93 ℃, filtering, washing, and then directly adding the molecular sieve filter cake into an exchange solution containing ammonium phosphate, wherein the adding amount of the molecular sieve is as follows: phosphorus (in P)₂O₅Calculated) and the weight ratio of the molecular sieve is as follows: 0.015, the weight ratio of water to molecular sieve is 2.8, exchange reaction is carried out for 30 minutes under the condition of 70 ℃, filtration, washing, sampling and drying are carried out, and the sample is marked as DZ-3. Table 1 shows the composition of DZ-3, the percentage of the total secondary pores (2-100 nm) occupied by the unit cell constant, the relative crystallinity, the framework Si/Al ratio, the structural collapse temperature, the specific surface area, and the secondary pores with larger pore diameters (8-100 nm), and the total secondary pore volume. After aging DZ-3 in the bare state at 800 ℃ for 17 hours with 100% steam, the crystallinity of the zeolite before and after aging DZ-3 was analyzed by XRD and the relative crystal retention after aging was calculated, the results are shown in Table 2.

Examples 4 to 6

Examples 4-6 illustrate the catalytic cracking activity and stability of the modified Y-type molecular sieve provided by the invention.

The modified Y-type molecular sieves SZ-1, SZ-2 and SZ-3 prepared in the embodiments 1-3 are respectively prepared into catalysts, and the serial numbers of the catalysts are as follows: SC-1, SC-2 and SC-3. The light oil micro-reactivity of the catalyst was evaluated after aging the catalyst with 100% steam at 800 ℃ for 4 hours or 17 hours, and the evaluation results are shown in Table 3.

The preparation method of the catalyst comprises the following steps:

the modified Y-type molecular sieve, kaolin, water, pseudo-boehmite adhesive and alumina sol are formed into slurry according to a conventional preparation method of a catalytic cracking catalyst, and the slurry is sprayed and dried to prepare the microspherical catalyst, wherein the obtained catalyst contains 30 wt% of the modified Y-type molecular sieve, 42 wt% of the kaolin, 25 wt% of the pseudo-boehmite and 3 wt% of the alumina sol on a dry basis.

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

Comparative examples 4-6 illustrate the catalytic cracking activity and stability of the ultrastable Y-type molecular sieves prepared by the methods provided in comparative examples 1-3.

The ultrastable Y-type molecular sieves DZ-1, DZ-2 and DZ-3 prepared in comparative examples 1 to 3 were mixed with pseudo-boehmite, kaolin, water and alumina sol according to the preparation method of the catalyst of example 4, and the microspherical catalyst was prepared by spray drying, wherein the composition of each catalyst was the same as that of example 4, and the content of the ultrastable Y-type molecular sieve in the catalyst was 30 wt%. The serial numbers of the catalysts are as follows: DC-1, DC-2 and DC-3. The light oil micro-reactivity of the catalyst was evaluated after aging the catalyst at 800 ℃ for 4 hours or 17 hours with 100% steam. See example 6 for evaluation, and the results are shown in Table 3.

Examples 7 to 9

Examples 7-9 illustrate the catalytic cracking reaction performance of the modified Y-type molecular sieve provided by the invention.

After the SC-1, SC-2 and SC-3 catalysts are aged by 100 percent of water vapor at the temperature of 800 ℃ and 17 ℃, the catalytic cracking reaction performance of the catalysts is evaluated on a small-sized fixed fluidized bed reactor (ACE), and cracked gas and product oil are respectively collected 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 ultrastable Y-type zeolite prepared by the methods provided in comparative examples 1-3.

After aging of DC-1, DC-2 and DC-3 catalysts at 800 ℃ for 17 hours with 100% steam, the catalytic cracking reaction performance of the catalysts was evaluated in a small fixed fluidized bed reactor (ACE), the evaluation method was the same as in example 7, the properties of the raw materials for the ACE experiment are shown in Table 4, and the evaluation results are shown in Table 5.

TABLE 1

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

TABLE 2

As can be seen from Table 2, the modified Y-type molecular sieve 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 catalyst microreactivity

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	SC-1	SC-2	SC-3	DC-1	DC-2	DC-3
The molecular sieve used	SZ-1	SZ-2	SZ-3	DZ-1	DZ-2	DZ-3
							Ratio of agent to oil	5	5	5	9	8	5
Product distribution/weight%
							Dry gas	1.27	1.35	1.29	1.55	1.48	1.41
Liquefied gas	17.05	16.65	16.68	16.86	15.33	16.43
							Coke	3.45	3.59	3.61	8.33	7.61	5.94
Gasoline (gasoline)	55.82	56.47	55.57	38.55	43.91	51.81
							Diesel oil	15.98	15.93	16.27	20.17	19.25	16.46
Heavy oil	6.43	6.01	6.58	14.54	12.42	7.95
							Total up to	100	100	100	100	100	100
Conversion/weight%	77.59	78.06	77.15	65.29	68.33	75.59
							Coke selectivity/weight%	4.45	4.60	4.68	12.76	11.14	7.86
Yield of light oil/weight%	71.8	72.4	71.84	58.72	63.16	68.27
							Total liquid/weight%	88.85	89.05	88.52	75.58	78.49	84.7

As can be seen from the results shown in tables 3 and 5, the catalytic cracking catalyst prepared by using the molecular sieve provided by the present invention as an active component has high 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. The modified Y-type molecular sieve is characterized in that the content of rare earth oxide of the modified Y-type molecular sieve is 4-11 wt%, and the phosphorus content is P₂O₅The modified Y-type molecular sieve comprises, by weight, 0.5-10%, sodium oxide with a content of not more than 0.5%, and a total pore volume of 0.36-0.48 mL/g, wherein the pore volume of secondary pores with a pore diameter of 2-100 nm accounts for 20-40% of the total pore volume, the unit cell constant is 2.440-2.455 nm, the non-framework aluminum content in the modified Y-type molecular sieve accounts for not more than 10% of the total aluminum content, the lattice collapse temperature is not lower than 1060 ℃, and the ratio of the B acid content to the L acid content in the total acid content of the modified Y-type molecular sieve measured at 200 ℃ by a pyridine adsorption infrared method is not lower than 3.5.

2. The modified Y-type molecular sieve of claim 1, wherein the modified Y-type molecular sieve has a secondary pore volume of from 28% to 38% of the total pore volume, with a pore diameter of from 2nm to 100 nm.

3. The modified Y-type molecular sieve of claim 1, wherein the non-framework aluminum content of the modified Y-type molecular sieve is 5-9.5 wt% of the total aluminum content, and the framework silica-alumina ratio is SiO₂/Al₂O₃The molar ratio is 7-14.

4. The modified Y-type molecular sieve of claim 1, wherein the modified Y-type molecular sieve has a lattice collapse temperature of 1065-1085 ℃.

5. The modified Y-type molecular sieve 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 is 3.5 to 6.

6. The modified Y-type molecular sieve of claim 1, having a relative crystal retention of 38% or more after aging at 800 ℃ under atmospheric pressure in a 100% steam atmosphere for 17 hours.

7. The modified Y-type molecular sieve of claim 1, wherein the modified Y-type molecular sieve has a relative crystallinity of 70-80%.

8. The modified Y-type molecular sieve of any one of claims 1 to 7, wherein the modified Y-type molecular sieve has a rare earth oxide content of 4.5 to 10 wt% and a phosphorus content expressed as P₂O₅0.1 to 6 wt%, 0.05 to 0.3 wt% of sodium oxide, 2.442 to 2.451nm of unit cell constant, and 8.5 to 12.6 of framework Si/Al ratio.

9. The modified Y-type molecular sieve of claim 1, wherein the ratio of the pore volume of secondary pores with a pore diameter of 8-100 nm to the pore volume of total secondary pores in the modified Y-type molecular sieve is 40-80%, and the total secondary pores are pores with a pore diameter of 2-100 nm.

10. The modified Y-type molecular sieve of claim 1, wherein the modified Y-type molecular sieve has a relative crystal retention of 38-60% after aging at 800 ℃ under normal pressure in a 100% steam atmosphere for 17 hours.

11. The modified Y-type molecular sieve of claim 1, wherein the modified Y-type molecular sieve has a relative crystal retention of 50-60% after aging at 800 ℃ under normal pressure in a 100% steam atmosphere for 17 hours.

12. A process for the preparation of a modified Y-type molecular sieve as claimed in any one of claims 1 to 11, which process comprises the steps of:

(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, and optionally drying to obtain the Y-type molecular sieve with the reduced unit cell constant;

(3) according to SiCl₄: the Y-type molecular sieve with reduced unit cell constant is 0.1-0.7: 1, carrying out contact reaction on the Y-type molecular sieve with the reduced unit cell constant and silicon tetrachloride gas at the reaction temperature of 200-650 ℃ for 10 minutes to 5 hours, and optionally washing and filtering to obtain a gas-phase ultrastable modified Y-type molecular sieve;

(4) contacting the gas-phase ultra-stable modified Y-shaped molecular sieve obtained in the step (3) with an acid solution;

(5) and (4) contacting the molecular sieve obtained in the step (4) and the acid solution with a phosphorus compound for phosphorus modification treatment.

13. The process of claim 12, 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 9.0 wt.%.

14. The method of claim 12, wherein in step (1), the sodium oxide content is reduced for conventional rare earth-containing cellsIn the size Y-type molecular sieve, the rare earth content is RE₂O₃4.5 to 13 wt%, sodium oxide content 4.5 to 9.5 wt%, and unit cell constant 2.465nm to 2.472 nm.

15. The method of claim 12, wherein the step (1) of contacting the NaY molecular sieve with the rare earth salt solution to perform the ion exchange reaction is performed according to the following formula: rare earth salt: h₂O is 1: 0.01-0.18: 5-20, mixing NaY molecular sieve, rare earth salt and water, and stirring.

16. The method of claim 12 or 15, wherein the step (1) of contacting the NaY molecular sieve with the rare earth solution for an 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.

17. The method of claim 12, 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.

18. The method of claim 12, wherein the roasting temperature in the step (2) is 380-460 ℃, the roasting atmosphere is 40-80% water vapor atmosphere, and the roasting time is 5-6 hours.

19. The method of claim 12, wherein the unit cell constant of the Y-type molecular sieve with reduced unit cell constant obtained in step (2) is 2.450nm to 2.462nm, and the water content of the Y-type molecular sieve with reduced unit cell constant is not more than 1 wt%.

20. The method according to claim 12, wherein the washing method in the step (3) is washing with water under the washing conditions that the molecular sieve: h₂O is 1: 6-15, the pH value is 2.5-5.0, and the washing temperature is 30-60 ℃.

21. The method according to claim 12, wherein the gas phase ultrastable modified Y-type molecular sieve obtained in step (3) is contacted with an acid solution, wherein the weight ratio of the acid to the molecular sieve is 0.001-0.15: 1, the weight ratio of water to the molecular sieve is 5-20: 1, the acid is one or more of organic acid and inorganic acid, the contact time is more than 60 minutes, and the contact temperature is 80-99 ℃.

22. The method according to claim 12, wherein the step (4) is carried out by contacting with an acid solution, wherein the acid solution contains an organic acid and an inorganic acid with a medium strength or higher, and the weight ratio of the inorganic acid with a medium strength or higher to the molecular sieve is 0.01-0.05: 1, the weight ratio of the organic acid to the molecular sieve is 0.02-0.10: 1, the weight ratio of water to the molecular sieve is 5-20: 1, the contact temperature is 80-99 ℃, and the contact time is 1-4 hours.

23. The method according to claim 12, wherein the contacting with the acid solution in step (4) comprises contacting with a medium-strength or higher inorganic acid, and then contacting with an organic acid, under the conditions of: the weight ratio of the inorganic acid with the medium strength to the molecular sieve is 0.01-0.05: 1, the weight ratio of water to the molecular sieve is 5-20: 1, the contact time is: the contact temperature is 90-98 ℃ for 60-120 minutes; the contact conditions with the organic acid are as follows: the weight ratio of the organic acid to the molecular sieve is 0.02-0.10: 1, the weight ratio of water to the molecular sieve is 5-20: 1, the contact time is: the contact temperature is 90-98 ℃ for 60-120 minutes.

24. The method of claim 22 or 23, wherein the organic acid is one or more of oxalic acid, malonic acid, succinic acid, methylsuccinic acid, malic acid, tartaric acid, citric acid, salicylic acid; the inorganic acid with the medium strength or more is one or more of phosphoric acid, hydrochloric acid, nitric acid and sulfuric acid.

25. The method of claim 12, wherein the phosphorus modification treatment conditions of step (5) are: contacting the molecular sieve obtained in the step (4) after contacting with the acid solution with an exchange solution containing a phosphorus compound, carrying out exchange reaction for 10-100 minutes at 15-100 ℃, filtering and washing; wherein in a mixture formed by contacting the exchange liquid with the molecular sieve, the weight ratio of water to the molecular sieve is 2-5, and P is used₂O₅The weight ratio of phosphorus to molecular sieve is 0.0005-0.10, preferably 0.001-0.06.

26. The method of claim 21, wherein the contacting of step (4) is for a contact time of 1 to 4 hours.

27. The method of claim 25, wherein the phosphorus modification treatment conditions of step (5) are such that the weight ratio of water to molecular sieve is 3 to 4.

28. The method of claim 25, wherein the phosphorus modification treatment conditions of step (5) are selected from the group consisting of P₂O₅The weight ratio of the phosphorus to the molecular sieve is 0.001-0.06.