CN114100671A

CN114100671A - Catalytic cracking catalyst, preparation method and application thereof

Info

Publication number: CN114100671A
Application number: CN202010874337.0A
Authority: CN
Inventors: 王久江; 刘宏海; 高雄厚; 刘超伟; 刘涛; 赵红娟; 张莉; 王宝杰; 熊晓云; 申宝剑
Original assignee: China University of Petroleum Beijing; Petrochina Co Ltd
Current assignee: China University of Petroleum Beijing; Petrochina Co Ltd
Priority date: 2020-08-26
Filing date: 2020-08-26
Publication date: 2022-03-01
Anticipated expiration: 2040-08-26

Abstract

The invention provides a catalytic cracking catalyst and a preparation method and application thereof, the catalytic cracking catalyst takes a modified faujasite molecular sieve as an active component, and the modification method of the faujasite molecular sieve comprises the following steps: the method comprises the following steps of carrying out contact reaction on a faujasite molecular sieve and gaseous silicon tetrachloride, wherein the contact reaction time is not more than 5 seconds, the space of the contact reaction is more than 2 times of the bulk volume of the faujasite molecular sieve in a reaction area, and the temperature of the contact reaction is 250-600 ℃. The catalyst prepared by the invention is used for heavy oil catalytic cracking treatment, and has stronger heavy oil conversion activity, higher gasoline yield, light oil yield and total liquid yield, and lower coke yield.

Description

Catalytic cracking catalyst, preparation method and application thereof

Technical Field

The invention relates to the field of catalysts, in particular to a catalytic cracking catalyst, a preparation method of the catalytic cracking catalyst and application of the catalytic cracking catalyst.

Background

Catalytic Cracking (FCC) is the main means of heavy oil processing in our country, catalysts play an extremely important role as the core of the technology, and Y-type molecular sieves have been used as active components in Fluid Catalytic Cracking (FCC) catalysts for 50 years, because Y-type molecular sieves have many important properties: (1) large specific surface area and pore size (pore diameter about 0.74 nm); (2) strong acidity; (3) good thermal stability and hydrothermal stability; (4) relatively low synthesis cost. However, since the silica-alumina ratio of the Y-type molecular sieve is relatively low, the structure is very easy to collapse under high-temperature hydrothermal conditions, and therefore, the Y-type molecular sieve has to be subjected to ultra-stabilization treatment.

Patent CN101284243A discloses a cracking catalyst, mixing a hydrothermal ultrastable Y-type molecular sieve and an acid solution with equivalent concentration of 0.01N-2N according to the liquid-solid weight ratio of 4-20 at the temperature range of 20-100 ℃, stirring for 10-300 minutes, washing, filtering, adding a rare earth salt solution for rare earth ion exchange, washing, filtering and drying after exchange. Patent CN101767029A discloses a heavy oil cracking catalyst, which is obtained by mixing, pulping and spray drying a hydrothermal ultrastable Y-type molecular sieve containing abundant secondary pores and modified rectorite. The hydrothermal superstable method is a method generally adopted in the industry at present, but the molecular sieve has the phenomena of non-uniform dealumination, untimely silicon supplement and the like, the structure is easy to collapse, the cost for obtaining the superstable Y-type molecular sieve with high silica-alumina ratio is that more crystallinity is lost, which inevitably causes the loss of the active center of the molecular sieve, and meanwhile, the hydrothermal superstable method has the defects of high energy consumption, high water consumption, serious pollution and the like through multiple times of exchange and roasting.

First reported in 1980 by Beyer and Mankui a gas phase dealumination silicon supplementation method, which generally uses SiC1 under nitrogen protection₄Reacting with anhydrous Y-shaped molecular sieve at a certain temperature, and fully utilizing SiC1₄The provided foreign Si source completes two reactions of dealuminization and silicon supplement at one time through isomorphous substitution. Therefore, hydroxyl cavities generated during dealuminization and silicon supplementation of the Y-shaped molecular sieve under hydrothermal conditions can be effectively avoided, and lattice collapse and structural defects are avoided, so that the molecular sieve with high crystal retention and high thermal stability is prepared.

CN106276961A discloses a method for preparing a catalytic cracking catalyst by using a small-crystal-grain gas-phase ultrastable high-silicon rare earth Y-type molecular sieve, the molecular sieve provided by the invention is prepared by sequentially carrying out gas-phase ultrastable treatment, washing and rare earth ion exchange, and the catalytic cracking catalyst containing the molecular sieve has good stability, good coke selectivity, high gasoline octane number and good quality. CN108452826A discloses a preparation method of a catalytic cracking catalyst, the catalyst is prepared from a magnesium-containing modified high-silicon gas-phase ultrastable Y-type molecular sieve, an alumina binder and clay, and the magnesium-containing modified high-silicon gas-phase ultrastable Y-type molecular sieve has higher heavy oil conversion activity and lower coke selectivity. CN108452829A discloses a preparation method of a catalytic cracking catalyst, which is prepared from a modified Y-type molecular sieve, an alumina binder and clay, wherein the content of rare earth oxide of the modified Y-type molecular sieve is 5-12 wt%, the content of sodium oxide is 0.1-0.7 wt%, the total pore volume is 0.33-0.39 mL/g, the pore volume of a secondary pore of the modified Y-type molecular sieve with the pore diameter of 2-100 nm accounts for 10-25% of the total pore volume, the unit cell constant is 2.440-2.455 nm, the content of non-framework aluminum in the modified Y-type molecular sieve accounts for not more than 20% of the total aluminum content, the lattice collapse temperature is not lower than 1050 ℃, and the ratio of B acid amount to L acid amount is not lower than 2.50. The catalytic cracking catalyst has higher heavy oil conversion activity, lower coke selectivity, higher gasoline yield, liquefied gas yield, light oil yield and total liquid yield.

Therefore, the catalytic cracking catalyst prepared from the gas-phase ultrastable molecular sieve has good performance, but the gas SiCl reported at present₄And in the continuous production of the solid NaY molecular sieve, the reaction time of the solid NaY molecular sieve and the solid NaY molecular sieve is long, and the framework structure of the molecular sieve is easy to collapse. Therefore, further improvements in the art relating to catalytic cracking catalysts are still needed.

Disclosure of Invention

The catalyst obtained by the invention is used for heavy oil catalytic cracking, and has stronger heavy oil conversion activity, higher gasoline yield, light oil yield, total liquid yield and lower coke yield.

In order to achieve the above object, the present invention provides a method for preparing a catalytic cracking catalyst, the catalytic cracking catalyst comprising a modified faujasite molecular sieve as an active component, the method for modifying the faujasite molecular sieve comprising: the method comprises the following steps of carrying out contact reaction on a faujasite molecular sieve and gaseous silicon tetrachloride, wherein the contact reaction time is not more than 5 seconds, the space of the contact reaction is more than 2 times of the bulk volume of the faujasite molecular sieve in a reaction area, and the temperature of the contact reaction is 250-600 ℃.

The preparation method of the catalytic cracking catalyst comprises the following steps: mixing and pulping the modified faujasite molecular sieve, clay, a binder and water, and drying the obtained slurry to obtain a catalytic cracking catalyst; the total weight of the catalytic cracking catalyst is 100%, the content of the modified faujasite molecular sieve is 5-50 wt%, the content of the clay is 10-70 wt%, and the content of the binder is 5-40 wt%.

The preparation method of the catalytic cracking catalyst comprises the step of carrying out countercurrent contact on the faujasite molecular sieve and the gaseous silicon tetrachloride for reaction.

The preparation method of the catalytic cracking catalyst comprises the following steps of (1) preparing a faujasite molecular sieve, wherein the faujasite molecular sieve is a NaY type zeolite molecular sieve; the framework Si/Al molar ratio of the faujasite molecular sieve is SiO₂And Al₂O₃The molar ratio is 3.2-10; and/or, the faujasite molecular sieve is in a powder form, and 90% of particles have a diameter of not more than 500 microns.

The preparation method of the catalytic cracking catalyst comprises the step of adding Na as a sodium element into the faujasite molecular sieve₂The content of O is not more than 15 wt%, and the rare earth element is RE₂O₃The calculated content is not higher than 23 wt%; the rare earth elements comprise one or more of lanthanum, cerium, praseodymium, neodymium and ytterbium.

The preparation method of the catalytic cracking catalyst comprises the step of drying the faujasite molecular sieve before the faujasite molecular sieve and the gaseous silicon tetrachloride are subjected to contact reaction, so that the water content of the faujasite molecular sieve is not more than 5% by mass; and/or after the faujasite molecular sieve and the gaseous silicon tetrachloride are subjected to contact reaction, one or more treatment steps of degassing, washing and drying are further carried out on the faujasite molecular sieve after the reaction.

The preparation method of the catalytic cracking catalyst comprises the following steps of performing degassing in one or more modes of flash evaporation, vacuumizing and heating volatilization; the washing liquid is water or aqueous solution containing one or more of hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, oxalic acid, tartaric acid, citric acid, ammonium chloride, ammonium sulfate, ammonium nitrate and ammonium phosphate; the washing temperature is normal temperature to 120 ℃, the washing time is 5min to 4h, and the solid-liquid mass ratio during washing is 1: 5 to 30.

The preparation method of the catalytic cracking catalyst comprises the following steps of carrying out contact reaction between the faujasite molecular sieve and gaseous silicon tetrachloride in a reactor, feeding the faujasite molecular sieve from the top of the reactor, feeding the gaseous silicon tetrachloride from the lower part of the reactor, carrying out countercurrent contact between the faujasite molecular sieve and the gaseous silicon tetrachloride in the reactor, carrying out reaction, and outputting the reacted materials from the bottom of the reactor; and/or the faujasite molecular sieve and gaseous silicon tetrachloride form a mixed state of complete mixed flow or partial complete mixed flow in the reactor.

The preparation method of the catalytic cracking catalyst comprises the following steps of (1) enabling a reactor to be a gas-phase ultra-stable reactor, enabling a contact reaction space to be the volume of the reactor, and enabling the volume of the reactor to be more than 10 times of the volume of a faujasite molecular sieve loose pile entering the reactor within the contact reaction time; and/or the ratio of the longitudinal height to the transverse internal diameter of the reactor is not less than 2:1 and not more than 15: 1.

The preparation method of the catalytic cracking catalyst comprises the step of spraying gaseous silicon tetrachloride into a reactor through a nozzle, wherein the spray area of the nozzle is 1-10% of the transverse inner sectional area of the reactor.

The preparation method of the catalytic cracking catalyst provided by the invention is characterized in that the temperature of the contact reaction of the faujasite molecular sieve and the gas-phase silicon tetrachloride is 300-550 ℃, and the time of the contact reaction is not more than 1 second.

The preparation method of the catalytic cracking catalyst comprises the following steps of conveying the faujasite molecular sieve by taking inert gas as carrier gas, wherein the inert gas comprises one or more of air, nitrogen, argon and helium, and the using amount of the inert gas is 0-20% of the mass of the faujasite molecular sieve; and/or the mass ratio of the faujasite molecular sieve to the gas-phase silicon tetrachloride in the reactor is 1: 0.05 to 0.5.

The preparation method of the catalytic cracking catalyst comprises the following steps of (1) preparing a catalyst, wherein the clay is one or more of kaolin, halloysite, montmorillonite and bentonite; the binder is one or more of acidified pseudo-boehmite, aluminum chlorohydrol, aluminum trichloride, aluminum sulfate, aluminum hydroxide, aluminum sol and silica sol; the obtained slurry is dried by spraying, and the step of ion exchange is also included after drying, so that the catalytic cracking catalyst is obtained.

The preparation method of the catalytic cracking catalyst comprises the following steps of (1) spray drying, wherein the temperature of a hearth of a spray tower is 450-600 ℃, and the temperature of tail gas is 150-300 ℃; the ion exchange is acid exchange, the exchange temperature is 60-95 ℃, the pH value is 2.5-4.0, and the exchange time is 0.5-2 h.

In order to achieve the purpose, the invention also provides a catalytic cracking catalyst, which takes the total weight of the catalytic cracking catalyst as 100%, wherein the catalytic cracking catalyst comprises 5-50 wt% of modified faujasite molecular sieve, 10-70 wt% of clay and 5-40 wt% of binder; wherein the modified faujasite molecular sieve has a crystal retention of not less than 85% and a unit cell constant of less than 24.55 angstrom.

In order to achieve the above object, the present invention further provides the use of the above catalytic cracking catalyst in heavy oil processing.

The invention has the beneficial effects that:

the method optimizes the structure of the faujasite molecular sieve by modifying the raw material faujasite molecular sieve, highly retains the crystallinity, increases the silicon-aluminum ratio and reduces the unit cell constant. The catalytic cracking catalyst prepared by using the modified faujasite molecular sieve as an active component has high thermal stability, hydrothermal stability and cracking activity.

The modified faujasite molecular sieve obtained by the invention has the crystal retention degree not less than 85 percent, reaches 100 percent under the optimized condition, and has the unit cell constant less than 24.60 angstrom

(preferably less than 24.50 angstroms under optimal conditions

Further optimized condition is lower than 24.40 angstroms

) And has strong applicability.

Drawings

FIG. 1 is a schematic view of the modification process of faujasite molecular sieve of the present invention.

Wherein, the reference numbers:

10 gas phase ultra-stable reactor

11 reactor body

12 zeolite distributor

13 first conveyor

14 second conveyor

15 spray nozzle

16 silicon tetrachloride inlet

20 gasification device

30 degassing device

40 washing device

Detailed Description

The following detailed description of the present invention is provided in connection with the accompanying drawings for the purpose of facilitating understanding and understanding of the present invention. The present invention is not so limited. The test methods in the following examples are all conventional methods unless otherwise specified; the reagents are commercially available, unless otherwise specified.

The invention provides a preparation method of a catalytic cracking catalyst, wherein the catalytic cracking catalyst takes a modified faujasite molecular sieve as an active component, and the modification method of the faujasite molecular sieve comprises the following steps: the method comprises the following steps of carrying out contact reaction on a faujasite molecular sieve and gaseous silicon tetrachloride, wherein the contact reaction time is not more than 5 seconds, the space of the contact reaction is more than 2 times of the bulk volume of the faujasite molecular sieve in a reaction area, and the temperature of the contact reaction is 250-600 ℃.

In the process of silicon tetrachloride gas phase ultrastable research, researchers of the invention find that the isomorphous replacement dealuminization and silicon supplementation reaction of silicon tetrachloride and the faujasite molecular sieve is a fast reaction which is instantly completed through a large amount of basic researches, which is an important experimental phenomenon which is not reported in the prior art. Meanwhile, researchers also find that silicon tetrachloride which is not reacted at the moment of contact does not react or does not react obviously even if the contact time of the silicon tetrachloride and the faujasite molecular sieve is further increased, and the silicon tetrachloride exists in the faujasite molecular sieve in an adsorption state. Further, researchers have found that adsorption of silicon tetrachloride to faujasite molecular sieves for extended periods of time reduces the crystallinity of the faujasite molecular sieve. Moreover, the mixing contact and diffusion of the silicon tetrachloride and the faujasite molecular sieve not only influence the distribution of silicon and aluminum of the modified faujasite molecular sieve, but also influence the reaction efficiency and the silicon-aluminum ratio and the crystallinity of the modified faujasite molecular sieve.

Therefore, the preparation method of the modified faujasite molecular sieve used in the catalytic cracking catalyst comprehensively controls two factors of the contact reaction time and the mixed contact reaction space of the faujasite molecular sieve and the gaseous silicon tetrachloride, strengthens the diffusion and reaction efficiency and reduces the loss of crystallinity through the synergistic effect of the two factors, in particular the synergistic effect of shorter contact reaction time and larger contact reaction space, thereby realizing the purpose of continuously preparing the faujasite molecular sieve (especially the Y zeolite molecular sieve) with high crystallinity and low unit cell constant (high silicon-aluminum ratio) with higher efficiency.

Compared with a method for preparing high-silicon Y-type zeolite by hydrothermal ultrastable modification, the modification method of the faujasite molecular sieve has the advantages of short reaction time, short process flow, no need of an ammonium exchange step, and higher relative crystallinity or crystallization retention of the obtained product while improving the silicon-aluminum ratio; compared with the ammonium fluosilicate liquid phase superstable modification method, the modification method has the advantages of short reaction time and no consideration of the discharge of processing environment-sensitive fluorine compounds and ammonia nitrogen; compared with the prior art of silicon tetrachloride gas phase ultrastable method, the modification method has the advantages of short modification time, high modification efficiency, high relative crystallinity (or high crystal retention) of the modified product and low unit cell constant, and in addition, the modification process has stable operation and high efficiency and is easy to realize industrial scale-up production.

The catalytic cracking catalyst prepared by using the modified faujasite molecular sieve as an active component has higher thermal stability, hydrothermal stability and cracking activity. The catalyst obtained by the invention is used for heavy oil catalytic cracking, and has stronger heavy oil conversion activity, higher gasoline yield, light oil yield and total liquid yield, and lower coke yield.

In one embodiment, the faujasite molecular sieve of the present invention is a sodium faujasite molecular sieve. In another embodiment, the faujasite molecular sieve of the present invention is a NaY type zeolite molecular sieve having a framework silica to alumina molar ratio (as SiO)₂And Al₂O₃Molar ratio) of 3.2 to 10, preferably 4.5 to 5.5.

In one embodiment, the faujasite molecular sieve of the present invention contains sodium in the form of Na₂The content of O is not more than 15 wt%, preferably not more than 14 wt%. In another embodiment, the faujasite molecular sieve of the present invention contains rare earth elements in the form of RE₂O₃The content is not more than 23 wt%, preferably not more than 20 wt%. The rare earth elements include but are not limited to one, two or more of lanthanum, cerium, praseodymium, neodymium and ytterbium. The faujasite molecular sieve may contain one or more of, but not limited to, sodium, ammonium, hydrogen, etc., in addition to the framework elements of zeolite, such as silicon, aluminum, and oxygen.

In one embodiment, the faujasite molecular sieve of the present invention has a laser scattering particle size such that 90% of the particles have a diameter (Dv 0.9) of no greater than 500 microns, preferably no greater than 100 microns, and more preferably no greater than 30 microns.

In one embodiment, the faujasite molecular sieve further comprises a drying step prior to contact reaction with gaseous silicon tetrachloride. The drying standard is to control the water content of the faujasite molecular sieve to be lower than 5 wt%, and the optimized water content is lower than 4 wt%. The drying method includes, but is not limited to, roasting, spray drying, conveying bed drying and the like, and the drying temperature is, for example, 250-600 ℃.

In one embodiment, the faujasite molecular sieve is reacted in countercurrent contact with gaseous silicon tetrachloride. In another embodiment, the contact reaction of the faujasite molecular sieve and the silicon tetrachloride is carried out in a reactor, the faujasite molecular sieve enters from the top of the reactor, the gaseous silicon tetrachloride enters from the lower part of the reactor, the faujasite molecular sieve and the gaseous silicon tetrachloride are in countercurrent contact in the reactor for reaction, and the reacted material is output from the bottom of the reactor.

In another embodiment, the reaction of faujasite molecular sieve with gaseous silicon tetrachloride is carried out in a gaseous hyperstable reactor of figure 1. As shown in fig. 1, the gaseous hyperstable reactor 10 includes a reactor main body 11, a first conveyor 13, a second conveyor 14, and a silicon tetrachloride inlet 16. The reactor body 11 is, for example, a vertical reactor body, the longitudinal axis of which forms an angle of 90 ° with the horizontal. In one embodiment, the reactor body 11 is cylindrical, provided with cones at the top and bottom, the cylindrical cross-section of which is circular, the reactor body 11 having a ratio of longitudinal height to internal diameter of not less than 2:1, preferably not less than 3: 1. Wherein the longitudinal height is, for example, the height from the upper bottom surface to the lower bottom surface of the columnar body of the reactor main body 11, and the inner diameter is the diameter of a circle formed by the inner wall of the reactor main body 11 in the cross section.

A first conveyor 13 is disposed at the top of the reactor body 11, for example, connected to a cone on the reactor body 11, for conveying the faujasite molecular sieve to the reactor; a second conveyor 14 is disposed at the bottom of the reactor body 11, for example, in connection with a cone below the reactor body 11, for conveying the modified faujasite molecular sieve out of the reactor. The silicon tetrachloride inlet 16 is arranged at the lower part of the reactor main body 11, gaseous silicon tetrachloride enters the reactor main body 11 through the silicon tetrachloride inlet 16, flows upwards, is in countercurrent contact with the downward faujasite molecular sieve and reacts, and the modified faujasite molecular sieve is conveyed out of the reactor through the second conveyor 14.

The first conveyor 13 and the second conveyor 14 in the present invention are, for example, one or more of an auger conveyor, a screw conveyor, a belt conveyor, an air flow conveyor, a piston conveyor, or a pipe chain conveyor. According to the control requirement of the reaction temperature, the conveying device can be additionally provided with a heat tracing device. In the invention, the silicon tetrachloride inlet 16 is communicated with the gasification device 20 through a pipeline, for example, so that the silicon tetrachloride is conveyed to the reactor through the silicon tetrachloride inlet 16 after being introduced into the gasification device 20 for gasification. In one embodiment, one end of the pipeline is disposed in the reactor body 11, and the end is provided with a silicon tetrachloride nozzle 15, so that silicon tetrachloride is uniformly sprayed into the reactor body 11. The nozzle 15 is, for example, a fan nozzle, a cone nozzle, a flat nozzle, etc., and the present invention is not particularly limited as long as gaseous silicon tetrachloride can be uniformly injected into the reactor. In one embodiment, the direction of the silicon tetrachloride injected by the nozzle 15 is opposite to the flow direction of the faujasite molecular sieve.

In one embodiment, a zeolite distributor 12 is disposed between the reactor body 11 and the cone on the reactor body 11, so that the faujasite molecular sieve can be uniformly delivered into the reactor body 11, thereby ensuring the dispersivity of the faujasite molecular sieve distribution inside the reactor body 11. The structure of the zeolite distributor 12 is not particularly limited in the present invention, and for example, the zeolite distributor 12 is provided with uniform holes. In one embodiment, the total area of the holes in the zeolite distributor 12 comprises 25% to 95% of the total area of the holes in the zeolite distributor 12. In another embodiment, the zeolite distributor 12 is one or more of a rotating disc distributor, an orifice plate distributor, a vibrating screen distributor, and a venturi nozzle, and the faujasite molecular sieve forms a downward uniform flow field through the zeolite distributor 12.

Thus, the faujasite molecular sieve is input from the top of the gas phase hyperstable reactor through the first conveyor 13, the gaseous silicon tetrachloride is input from the lower part of the gas phase hyperstable reactor through the silicon tetrachloride inlet 16, the faujasite molecular sieve moves downwards, and the silicon tetrachloride gas moves upwards, so that the two reactants realize reverse rapid contact reaction in the reactor within 5 seconds, and the temperature of the contact reaction is 250-600 ℃. The space for the contact reaction of the two reactants is more than 2 times of the bulk volume of the faujasite molecular sieve in the reaction area. The reacted material is discharged from the bottom of the gas phase ultra-stable reactor through a second conveyor 14, for example, to a subsequent degassing and washing device.

In one embodiment, the faujasite molecular sieve and the silicon tetrachloride gas form a fully mixed flow or partially fully mixed flow state in the reactor, so that the faujasite molecular sieve is fully subjected to modification reaction.

In one embodiment, the faujasite molecular sieve and silicon tetrachloride gas are transported to the reactor and/or in the reactor in a downward or upward direction, and may also be transported by dry inert gas to facilitate the transport of the reaction material (faujasite molecular sieve or silicon tetrachloride), but the invention is not limited thereto. The inert gas comprises one or more of air, nitrogen, argon and helium, the dosage of the inert gas is 0-20% of the mass of the faujasite molecular sieve, and the water content of the inert gas is generally lower than 2 v%. The inert gas inlet is provided, for example, on the first conveyor 13 or the zeolite distributor 12 of the gas phase ultra-stable reactor 10.

In one embodiment, the contact reaction time is the residence time of the faujasite molecular sieve in the reactor, i.e., the time from the entry of the faujasite molecular sieve into the reactor body 11 to the exit of the reactor body 11; the time from the entry of the faujasite molecular sieve into the reactor body 11 to the exit of the reactor body 11 is not more than 5 seconds; the space for the contact reaction is the volume of the reactor, the volume of the reactor is more than 2 times of the volume of the faujasite molecular sieve loose pile in the reactor, in other words, the volume of the reactor is more than 2 times of the volume of the faujasite molecular sieve loose pile entering the reactor in the reaction time, and the space for the contact reaction is more than 2 times, preferably more than 10 times of the volume of the faujasite molecular sieve loose pile entering the reactor in the contact reaction time. The larger contact reaction space provides conditions for mixing and diffusion of the two reactants and diffusion of the byproduct aluminum trichloride.

In another embodiment, the volume of the reactor is the volume of the reactor body 11.

In one embodiment, the faujasite molecular sieve and the gas phase silicon tetrachloride are contacted and reacted for a time of no more than 3 seconds, preferably no more than 1 second. Short reaction times can reduce loss of crystallinity of the faujasite molecular sieve.

In one embodiment, the temperature for the contact reaction of the faujasite molecular sieve and the gaseous silicon tetrachloride is 300-550 ℃. The temperature of the contact reaction is controlled by the temperature of the raw material of the faujasite molecular sieve and the feeding speed, and can also be adjusted by arranging a heating or refrigerating mechanism in the reactor. The temperature of the raw material is controlled by the drying and/or heating process of the raw material or by the drying and/or heating process of the raw material and the heat tracing device of the conveying process in a combined manner.

In one embodiment, the mass ratio of faujasite molecular sieve to gas phase silicon tetrachloride in the reactor of the present invention is 1: 0.05 to 0.5. The mass ratio refers to the ratio of the mass of the faujasite molecular sieve entering the reactor to the mass of the silicon tetrachloride entering the reactor during the reaction time (i.e., during the residence time of the faujasite molecular sieve in the reactor).

In one embodiment, after the faujasite molecular sieve of the present invention is subjected to a contact reaction with silicon tetrachloride gas, the modified faujasite molecular sieve is subjected to a degassing treatment step including one or more of flash evaporation, vacuum pumping and heating volatilization to remove a small amount of unreacted adsorbed silicon tetrachloride. The removed small amount of unreacted adsorption-state silicon tetrachloride can enter the reactor for recycling through the silicon tetrachloride inlet after being metered.

In one embodiment, the degassed faujasite molecular sieve may be further washed with water or an aqueous solution containing one or more of hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, oxalic acid, tartaric acid, citric acid, ammonium chloride, ammonium sulfate, ammonium nitrate, and ammonium phosphate; the washing temperature is normal temperature to 120 ℃, the washing time is 5min to 4h, and the solid-liquid mass ratio during washing is 1: 5 to 30. Preferably, the washing temperature is normal temperature to 95 ℃, the washing time is 10min to 1h, and the solid-liquid mass ratio during washing is 1: 5 to 20. The washed faujasite molecular sieve may then be subjected to a drying step, but the invention is not limited thereto.

In one embodiment, as shown in fig. 1, the mixture discharged from the second conveyor 14 comprises modified faujasite molecular sieve and unreacted silicon tetrachloride. The mixture is introduced into a degassing device 30 for degassing treatment, and the removed silicon tetrachloride enters a gasification device 20 and is mixed with freshly gasified silicon tetrachloride and then introduced into a reactor to continuously participate in the reaction. And introducing the reaction crude product subjected to gas removal into a washing device 40 for washing treatment, and introducing the washed crude product into the subsequent working procedures.

Thus, the invention provides a method for continuously and efficiently preparing modified Y-type zeolite with high crystallinity and low unit cell constant by using conventional faujasite as a raw material, preferably conventional NaY zeolite or/and rare earth-containing NaY zeolite as a raw material. In the modification method, gaseous SiCl₄Compared with a parallel flow contact mode, the method can ensure SiCl in a short time₄And the reaction with the NaY molecular sieve is fully carried out, and the reaction heat can be taken away in time, so that the molecular sieve structure is prevented from collapsing. By the modification method, the modified faujasite molecular sieve with high crystallinity and low unit cell constant, in particular the modified Y-type zeolite molecular sieve, can be obtained. Compared with the molecular sieve raw material, the modified molecular sieve has the crystallization retention degree not less than 85 percent and the unit cell constant less than 24.55 angstrom

Preferably, the modified molecular sieve has a crystal retention of not less than 90% and a unit cell constant of less than 24.50 angstroms as compared to the molecular sieve starting material

Further, the modified molecular sieve has a crystal retention of not less than 100% and a unit cell constant of less than 24.40 angstrom as compared with the molecular sieve raw material

In one embodiment, the method for preparing a catalytic cracking catalyst of the present invention comprises: mixing and pulping the modified faujasite molecular sieve, clay, a binder and water, and drying the obtained slurry to obtain a catalytic cracking catalyst; the total weight of the catalytic cracking catalyst is 100%, the content of the modified faujasite molecular sieve is 5-50 wt%, the content of the clay is 10-70 wt%, and the content of the binder is 5-40 wt%.

In another embodiment, the method for preparing a catalytic cracking catalyst of the present invention comprises: mixing clay, binder and water, pulping, and aging; and mixing and pulping the modified faujasite molecular sieve and water, adding the mixture into the aged mixture, and drying to obtain the catalytic cracking catalyst. Wherein the aging temperature is 30-90 ℃ and the aging time is 0.5-2 h.

Wherein the clay can be one or more of kaolin, halloysite, montmorillonite and bentonite; the binder can be one or more of acidified pseudo-boehmite, aluminum chlorohydrol, aluminum trichloride, aluminum sulfate, aluminum hydroxide, aluminum sol and silica sol.

In another embodiment, the drying of the slurry is carried out by spray drying, and the drying further comprises an ion exchange step to obtain the catalytic cracking catalyst. The temperature of a hearth of a spray tower is 450-600 ℃ and the temperature of tail gas is 150-300 ℃ during spray drying; and (3) ion exchange is acid exchange, the exchange temperature is 60-95 ℃, the pH value is 2.5-4.0, and the exchange time is 0.5-2 h.

The technical solution of the present invention is further illustrated by the following specific examples.

(1) Main raw materials

The molecular sieves were supplied by catalyst factories of landlocked petrochemical company, and the relative crystallinity and framework silica-alumina ratio are shown in table 3. Hydrochloric acid: the chemical purity is 1.19g/L, and the mass concentration is 36%; rare earth chloride solution: RE₂O₃300g/L, provided by catalyst works of petrochemical company, Lanzhou; ammonium chloride: chemical purity, 500g, national pharmaceutical group chemical reagents ltd; SiCl₄: chemically pure, 500g, alatin chemicals ltd; the pseudoboehmite is an industrial product produced by Shanxi aluminum factories, and has the solid content of 62 percent by weight; kaolin is an industrial product produced by Suzhou China kaolin company, and the solid content is 75 percent by weight; the alumina sol was supplied from catalyst factories of landlocked petrochemical company, in which the alumina content was 21 wt%.

(2) Analytical method

The crystalline phase, relative crystallinity or crystal retention, and framework silicon-to-aluminum ratio of the sample were analyzed by a PANALYtic X' PERT POWER model X-ray powder diffractometer manufactured by the Netherlands, and the specific determination methods were as follows:

and (3) testing conditions are as follows: Cu-Kalpha radiation is used, the working voltage is 40kV, the working current is 40mA, the 2 theta angle is between 5 and 50 degrees (the scanning speed is 2 degrees/min) when the relative crystallinity is tested, and the 2 theta angle is between 28 and 32 degrees (the scanning speed is 0.5 degrees/min) when the framework silicon-aluminum ratio is tested.

1) Relative crystallinity determination methods: about 0.3g of a sample to be analyzed was sufficiently ground in an agate mortar for 10 minutes, dried in an oven at 120 ℃ for 2 hours, and then lightly pressed into a flat-surfaced uniform-thickness sheet, followed by measurement. The calculation method of the relative crystallinity comprises the following steps: and (3) multiplying the product of the ratio of the sum of the peak areas of the eight characteristic peaks corresponding to the (331), (511, 333), (440), (533), (642), (822, 660), (555, 751) and (664) crystal planes to the sum of the corresponding peak areas of the standard sample and the crystallinity of the standard sample.

2) Crystal retention determination method: about 0.3g of a sample to be analyzed was sufficiently ground in an agate mortar for 10 minutes, dried in an oven at 120 ℃ for 2 hours, and then lightly pressed into a flat-surfaced uniform-thickness sheet, followed by measuring its relative crystallinity. The degree of crystal retention is calculated as the ratio (expressed as a percentage) of the relative crystallinity of the product or product sample to the relative crystallinity of the starting material or starting powder.

Wherein:

3) cell constant determination method: accurately weighing a proper amount of sample and silicon powder according to the mass ratio of the sample to the silicon powder of 20:1, grinding the sample and the silicon powder in a mortar until the mixture is uniformly mixed (at least for 10min), drying the mixture for 2h at 120 ℃, and then putting the mixture in a humidistat (filled with CaCl)₂Supersaturated aqueous solution) for more than 16h, then slightly pressing the supersaturated aqueous solution into a sheet with a flat surface for measurement, and calculating a unit cell constant according to the following formula:

in the formula: lambda is u-K alpha₁Wavelength of light

(h²+k²+l²) Is the X-ray diffraction index sum of squares.

(3) Catalyst evaluation

The micro-reaction activity evaluation adopts a micro-reaction evaluation device produced by Beijing Huayang company, the raw oil adopts Hongkong light diesel oil, and the evaluation conditions are as follows: the catalyst is aged for 17 hours by 100 percent of water vapor at the temperature of 800 ℃, the reaction temperature is 460 ℃, and the oil inlet time is 70 seconds. The properties of the feed oil are shown in Table 1.

TABLE 1 Properties of the Hongkong light diesel

The reaction performance is evaluated by a small fixed fluidized bed, the used raw oil is Xinjiang vacuum wide-cut wax oil and Xinjiang vacuum residual oil, and the slag mixing ratio is 30%. The properties of the feed oil are shown in Table 2.

TABLE 2 evaluation of the Properties of the raw oils used for the catalyst Selectivity evaluation

Example 1:

the structure of the reactor: the height and inner diameter ratio of the vertical reactor main body is 5:1, and the bottom of the reactor is a cone. The area of the circular through holes on the pore plate distributor accounts for 55% of the total area of the pore plate. Introduction of SiCl₄The total number of the fan-shaped nozzles connected to the end of the line (2) was 3, and the sum of the cross-sectional areas of the fan-shaped nozzles was 6% of the cross-sectional area of the reactor. The feed rate of the molecular sieve was controlled to achieve a reactor volume of 10 times the bulk volume of the molecular sieve entering the reactor during the reaction time, with a molecular sieve residence time of 1 second in the reactor.

Preparation of gas phase super stable molecular sieve: NaY molecular sieve (water content 0.9 wt%, D (v, 0.9) 15.0 μm) with temperature 350 ℃ is transported by an auger onto a perforated plate distributor at the top of the vertical reactor, moves downwards through the NaY molecular sieve of the perforated plate distributor, and is mixed with SiCl introduced from the side line of the reactor₄And (4) reacting. SiCl₄Is sprayed into the space of the vertical reactor through a fan-shaped nozzle. The fan nozzle was installed at a height of about 40% of the entire reactor height from the bottom of the reactor. SiCl in the reaction process₄The feed mass ratio per molecular sieve dry basis was 1: 10. The Y molecular sieve after the reaction falls to the conical body part of the vertical reactor and is led out by a screw conveyer. And degassing the output molecular sieve, and then feeding the molecular sieve into a pulping tank, wherein the mass ratio of the molecular sieve to water in the pulping tank is 6, the pH value of the water is 4.5, the system temperature is controlled at 94 ℃, and after washing and filtering, the gas-phase ultra-stable Y molecular sieve product A is obtained.

Preparation of the catalyst: 714.3g of alumina sol, 1600g of kaolin and 3141g of deionized water are mixed and pulped in a pulping tank, then 1210g of pseudo-boehmite is added, stirred for 1 hour, 139ml of hydrochloric acid with the mass concentration of 36 percent is added, stirred for 1 hour and homogenized, and the mixture is aged for 2 hours at 65 ℃. Mixing 900g (dry basis) of gas phase ultrastable Y molecular sieve A and 1644g of deionized water, pulping for 2 hours, adding into a pulping tank, homogenizing for 2 hours, and then carrying out spray drying at the tail gas temperature of 180-210 ℃. The catalyst obtained by spray drying is exchanged and washed for 1h at 85 ℃ in an acidic aqueous solution with the pH value of 3.2, filtered and dried for 4h at 120 ℃ to obtain the catalyst CAT-1. Wherein, calculated by dry basis, the kaolin accounts for 40 weight percent, the pseudo-boehmite accounts for 25 weight percent, the alumina sol accounts for 5 weight percent, and the gas phase ultra-stable Y molecular sieve A accounts for 30 weight percent.

Example 2:

the structure of the reactor: the height and inner diameter ratio of the vertical reactor main body is 13:1, and the bottom of the reactor is a cone. The area of the through holes on the rotating disc type distributor accounts for 25% of the total area of the pore plates. Introduction of SiCl₄The total number of the circular nozzles connected to the end of the line (2) is 12, and the sum of the cross-sectional areas of the fan-shaped nozzles accounts for 10% of the cross-sectional area of the reactor. The feed rate of the molecular sieve was controlled so that the reactor volume was 10 times the bulk volume of the molecular sieve entering the reactor during the reaction time, the molecular sieve being reactedThe residence time in the vessel was 1 second.

Preparing a gas-phase ultra-stable molecular sieve: NaReY molecular sieve (water content 2.8 wt%, D (v, 0.9)) at 500 deg.C of 20.55 μm, Re₂O₃Content 10 wt.%) was conveyed by a gas stream to a rotating disc distributor at the top of the vertical reactor, while dry air at 3% of the mass of the molecular sieve was fed at the top of the reactor. The Y molecular sieve moving downwards through the distributor and SiCl introduced from the side of the reactor₄And (4) reacting. SiCl₄Is sprayed into the space of the vertical reactor through a circular nozzle. The nozzles were installed at a height of about 25% of the entire reactor height from the bottom of the reactor. SiCl in the reaction process₄The feed mass ratio per dry basis of molecular sieve was 2.5: 10. The Y molecular sieve after the reaction falls to the conical body part of the vertical reactor and is led out by a screw conveyer. And degassing the output molecular sieve, and then feeding the molecular sieve into a pulping tank, wherein the mass ratio of the molecular sieve to water is 18, the pH value of the water is 3.5, the system temperature is controlled at 94 ℃, and washing and filtering the molecular sieve to obtain a gas-phase ultrastable Y molecular sieve product B.

Preparation of the catalyst: 714.3g of alumina sol, 1600g of kaolin and 3141g of deionized water are mixed and pulped in a pulping tank, then 1210g of pseudo-boehmite is added, stirred for 1 hour, 139ml of hydrochloric acid with the mass concentration of 36 percent is added, stirred for 1 hour and homogenized, and the mixture is aged for 2 hours at 65 ℃. Mixing 900g (dry basis) of gas phase ultrastable Y molecular sieve B and 1644g of deionized water, pulping for 2 hours, adding into a pulping tank, homogenizing for 2 hours, and then carrying out spray drying at the tail gas temperature of 180-210 ℃. The catalyst obtained by spray drying is exchanged and washed for 1h at 90 ℃ in an acidic aqueous solution with the pH value of 3.2, filtered and dried for 4h at 120 ℃ to obtain the catalyst CAT-2. Wherein, calculated by dry basis, the kaolin accounts for 40 weight percent, the pseudo-boehmite accounts for 25 weight percent, the alumina sol accounts for 5 weight percent, and the gas phase ultra-stable Y molecular sieve B accounts for 30 weight percent.

Example 3:

the structure of the reactor: the height and inner diameter ratio of the vertical reactor main body is 3:1, and the bottom of the reactor is a cone. The area of the through holes on the vibrating screen distributor positioned at the top of the reactor accounts for 95 percent of the total area of the pore plate. Introduction of SiCl₄The total number of the flat nozzles connected to the end of the pipeline of (1) is 3, flatThe sum of the cross-sectional areas of the flat nozzles accounts for 10% of the cross-sectional area of the reactor. The feed rate of the molecular sieve was controlled so that the reactor volume was 10 times the bulk volume of the molecular sieve entering the reactor during the reaction time and the residence time of the molecular sieve in the reactor was 1 second.

Preparing a gas-phase ultra-stable molecular sieve: NaReY molecular sieve (water content 1.5 wt%, D (v, 0.9)) at 470 deg.C 25.33 μm, Re₂O₃Content 18 wt%) was conveyed by a screw conveyor onto a vibrating sieve distributor at the top of the vertical reactor, while dry nitrogen gas in an amount of 2% by mass of the molecular sieve was fed into the top of the reactor. The NaReY molecular sieve moves downwards through the distributor and SiCl introduced from the side line of the reactor₄And (4) reacting. SiCl₄Is sprayed into the space of the vertical reactor through a circular nozzle. The nozzle was installed at a height of about 50% of the entire height of the reactor from the bottom of the reactor. SiCl in the reaction process₄The feed mass ratio per dry basis of molecular sieve was 2.3: 10. The Y molecular sieve after the reaction falls to the conical body part of the vertical reactor and is led out by a screw conveyer. And degassing the output molecular sieve, and then feeding the molecular sieve into a pulping tank, wherein the mass ratio of the molecular sieve to water is 12, the pH value of the water is 5.5, the system temperature is controlled at 94 ℃, and washing and filtering the molecular sieve to obtain a gas-phase ultrastable Y molecular sieve product C.

Preparation of the catalyst: 714.3g of alumina sol, 1600g of kaolin and 3141g of deionized water are mixed and pulped in a pulping tank, then 1210g of pseudo-boehmite is added, stirred for 1 hour, 139ml of hydrochloric acid with the mass concentration of 36 percent is added, stirred for 1 hour and homogenized, and the mixture is aged for 2 hours at 65 ℃. Mixing 900g (dry basis) of gas phase ultrastable Y molecular sieve C and 1644g of deionized water, pulping for 2 hours, adding into a pulping tank, homogenizing for 2 hours, and then carrying out spray drying at the tail gas temperature of 180-210 ℃. The catalyst obtained by spray drying is exchanged and washed for 1h at 85 ℃ in an acidic aqueous solution with the pH value of 3.2, filtered and dried for 4h at 120 ℃ to obtain the catalyst CAT-3. Wherein, calculated by dry basis, the kaolin accounts for 40 weight percent, the pseudo-boehmite accounts for 25 weight percent, the alumina sol accounts for 5 weight percent, and the gas phase ultra-stable Y molecular sieve C accounts for 30 weight percent.

Example 4:

the structure of the reactor: height and interior of vertical reactor bodyThe diameter ratio was 9: 1. A venturi nozzle was used to inject silicon tetrachloride. Introduction of SiCl₄The end of the line (2) was connected to 3 flat nozzles, the sum of the cross-sectional areas of the nozzles amounted to 3.5% of the cross-sectional area of the reactor. The feed rate of the molecular sieve was controlled so that the reactor volume was 10 times the bulk volume of the molecular sieve entering the reactor during the reaction time and the residence time of the molecular sieve in the reactor was 1 second.

Preparing a gas-phase ultra-stable molecular sieve: a NaY molecular sieve (water content 1.5 wt%, D (v, 0.9) 15.5 μm) at a temperature of 420 ℃ was conveyed into the reactor by means of a screw conveyor. The Y molecular sieve after being distributed through the Venturi nozzle moves downwards and is mixed with SiCl introduced from the side line of the reactor₄And (4) reacting. SiCl₄Is sprayed into the vertical reactor space through a nozzle. The nozzle was installed at a height of about 30% of the entire height of the reactor from the bottom of the reactor. SiCl in the reaction process₄The feed mass ratio/dry basis of the molecular sieve was 3.5: 10. The Y molecular sieve after the reaction falls to the conical body part of the vertical reactor and is led out by a piston conveyor. And degassing the output molecular sieve, and then feeding the molecular sieve into a pulping tank, wherein the mass ratio of the molecular sieve to water is 20, the pH value of the water is 3.0, the system temperature is controlled at 94 ℃, and washing and filtering the molecular sieve to obtain a gas-phase ultrastable Y molecular sieve product D.

Preparation of the catalyst: 714.3g of alumina sol, 1800g of kaolin and 3351g of deionized water are mixed and pulped in a pulping tank, then 1210g of pseudo-boehmite is added, stirred for 1 hour, 139ml of hydrochloric acid with the mass concentration of 36 percent is added, stirred for 1 hour and homogenized, and the mixture is aged for 2 hours at 65 ℃. 750g (dry basis) of gas phase ultrastable Y molecular sieve D and 1456g of deionized water are mixed and pulped for 2 hours, added into a pulping tank, homogenized for 2 hours, and then spray-dried at the temperature of tail gas of 180-210 ℃. The catalyst obtained by spray drying is exchanged and washed for 1h at 85 ℃ in an acidic aqueous solution with the pH value of 3.2, filtered and dried for 4h at 120 ℃ to obtain the catalyst CAT-4. Wherein, calculated by dry basis, the kaolin accounts for 45 weight percent, the pseudo-boehmite accounts for 25 weight percent, the alumina sol accounts for 5 weight percent, and the gas phase ultra-stable Y molecular sieve D accounts for 25 weight percent.

Example 5:

the structure of the reactor: the height and inner diameter ratio of the vertical reactor main body is 71, the cone angle of the cone at the bottom of the reactor is 30 degrees. The area of the through holes on the rotary disc distributor accounts for 45 percent of the total area of the pore plate. Introduction of SiCl₄The number of flat nozzles connected to the end of the line of (2) was 3, and the sum of the cross-sectional areas of the nozzles was 2.3% of the cross-sectional area of the reactor. The feed rate of the molecular sieve was controlled so that the reactor volume was 10 times the bulk volume of the molecular sieve entering the reactor during the reaction time and the residence time of the molecular sieve in the reactor was 1 second.

Preparing a gas-phase ultra-stable molecular sieve: NaReY molecular sieve (water content 0.3 wt%, D (v, 0.5)) at 310 ℃ of 14.3 μm, Re₂O₃Content 2.4%) was transported into the reactor via a flood dragon conveyor. The Y molecular sieve distributed by the rotary distributor moves downwards and is mixed with SiCl introduced from the side line of the reactor₄And (4) reacting. SiCl₄Is sprayed into the vertical reactor space through a conical nozzle. The nozzle was installed at a height of about 50% of the entire height of the reactor from the bottom of the reactor. SiCl in the reaction process₄The feed mass ratio/dry basis of the molecular sieve was 4: 10. And the cone part of the vertical reactor, from which the Y molecular sieve falls after the reaction is finished, is led out by a flood dragon conveyor. And degassing the output molecular sieve, and then feeding the molecular sieve into a pulping tank, wherein the mass ratio of the molecular sieve to water is 20, the pH value of the water is 8.0, the system temperature is controlled at 94 ℃, and washing and filtering the molecular sieve to obtain a gas-phase ultrastable Y molecular sieve product E.

Preparation of the catalyst: 714.3g of alumina sol, 1600g of kaolin and 3141g of deionized water are mixed and pulped in a pulping tank, then 1210g of pseudo-boehmite is added, stirred for 1 hour, 139ml of hydrochloric acid with the mass concentration of 36 percent is added, stirred for 1 hour and homogenized, and the mixture is aged for 2 hours at 65 ℃. Mixing 900g (dry basis) of gas phase ultrastable Y molecular sieve E and 1644g of deionized water, pulping for 2 hours, adding into a pulping tank, homogenizing for 2 hours, and then carrying out spray drying at the tail gas temperature of 180-210 ℃. The catalyst obtained by spray drying is exchanged and washed for 1h at 75 ℃ in an acidic aqueous solution with the pH value of 3.2, filtered and dried for 4h at 120 ℃ to obtain the catalyst CAT-5. Wherein, calculated by dry basis, the kaolin accounts for 40 weight percent, the pseudo-boehmite accounts for 25 weight percent, the alumina sol accounts for 5 weight percent, and the gas phase ultra-stable Y molecular sieve E accounts for 30 weight percent.

Comparative example 1:

the structure of the reactor: the height and inner diameter ratio of the vertical reactor main body is 5:1, and the bottom of the reactor is a cone. The molecular sieve is transported directly from the slide valve to the vertical reactor. Introduction of SiCl₄The total number of the fan-shaped nozzles connected to the end of the line (2) was 3, and the sum of the cross-sectional areas of the fan-shaped nozzles was 6% of the cross-sectional area of the reactor. The feed rate of the molecular sieve was controlled so that the reactor volume was 10 times the bulk volume of the molecular sieve entering the reactor during the reaction time and the residence time of the molecular sieve in the reactor was 1 second.

Preparing a gas-phase ultra-stable molecular sieve: NaY molecular sieve (water content 0.9 wt%, D (v, 0.9) 15.0 μm) at 350 deg.C is transported by slide valve to the top of vertical reactor, moves downwards, and is introduced with SiCl from the side line of reactor₄And (4) reacting. SiCl₄Is sprayed into the space of the vertical reactor through a fan-shaped nozzle. The fan nozzle was installed at a height of about 40% of the entire reactor height from the bottom of the reactor. SiCl in the reaction process₄The feed mass ratio per molecular sieve dry basis was 1: 10. The Y molecular sieve after the reaction falls to the conical body part of the vertical reactor and is led out by a screw conveyer. And degassing the output molecular sieve, and then feeding the molecular sieve into a pulping tank, wherein the mass ratio of the molecular sieve to water in the pulping tank is 6, the pH value of the water is 4.5, the system temperature is controlled at 94 ℃, and after washing and filtering, the gas-phase ultrastable Y molecular sieve product F is obtained.

Preparation of the catalyst: 714.3g of alumina sol, 1600g of kaolin and 3141g of deionized water are mixed and pulped in a pulping tank, then 1210g of pseudo-boehmite is added, stirred for 1 hour, 139ml of hydrochloric acid with the mass concentration of 36 percent is added, stirred for 1 hour and homogenized, and the mixture is aged for 2 hours at 65 ℃. Mixing 900g (dry basis) of gas phase ultrastable Y molecular sieve F and 1644g of deionized water, pulping for 2 hours, adding into a pulping tank, homogenizing for 2 hours, and then carrying out spray drying at the tail gas temperature of 180-210 ℃. The catalyst obtained by spray drying is exchanged and washed for 1h at 85 ℃ in an acidic aqueous solution with the pH value of 3.2, filtered and dried for 4h at 120 ℃ to obtain the catalyst CAT-6. Wherein, calculated by dry basis, the kaolin accounts for 40 weight percent, the pseudo-boehmite accounts for 25 weight percent, the alumina sol accounts for 5 weight percent, and the gas phase ultra-stable Y molecular sieve F accounts for 30 weight percent.

Comparative example 2:

the structure of the reactor: the height and inner diameter ratio of the vertical reactor main body is 13:1, and the bottom part of the reactor is a cone. The area of the through holes on the rotating disc type distributor accounts for 25% of the total area of the pore plates. Introduction of SiCl₄The total number of the circular nozzles connected to the end of the line (2) is 12, and the sum of the cross-sectional areas of the fan-shaped nozzles accounts for 10% of the cross-sectional area of the reactor. The feed rate of the molecular sieve was controlled so that the reactor volume was 10 times the bulk volume of the molecular sieve entering the reactor during the reaction time and the residence time of the molecular sieve in the reactor was 1 second.

Preparing a gas-phase ultra-stable molecular sieve: NaReY molecular sieve (water content 2.8 wt%, D (v, 0.9)) at 500 deg.C of 20.55 μm, Re₂O₃Content 10 wt.%) was conveyed by a gas stream to a rotating disc distributor at the top of the vertical reactor, while dry air at 3% of the mass of the molecular sieve was fed at the top of the reactor. The Y molecular sieve moving downwards through the distributor and SiCl introduced from the side of the reactor₄And (4) reacting. SiCl₄Is sprayed into the space of the vertical reactor through a circular nozzle. The nozzles were installed at a height of about 25% of the entire reactor height from the bottom of the reactor. Nozzle spraying SiCl₄The direction of (A) is consistent with the movement direction of the molecular sieve. SiCl in the reaction process₄The feed mass ratio per dry basis of molecular sieve was 2.5: 10. The Y molecular sieve after the reaction falls to the conical body part of the vertical reactor and is led out by a screw conveyer. And degassing the output molecular sieve, and then feeding the molecular sieve into a pulping tank, wherein the mass ratio of the molecular sieve to water is 18, the pH value of the water is 3.5, the system temperature is controlled at 94 ℃, and washing and filtering the molecular sieve to obtain a gas-phase ultrastable Y molecular sieve product G.

Preparation of the catalyst: 714.3g of alumina sol, 1600g of kaolin and 3141g of deionized water are mixed and pulped in a pulping tank, then 1210g of pseudo-boehmite is added, stirred for 1 hour, 139ml of hydrochloric acid with the mass concentration of 36 percent is added, stirred for 1 hour and homogenized, and the mixture is aged for 2 hours at 65 ℃. Mixing 900G (dry basis) of gas phase ultrastable Y molecular sieve G and 1644G of deionized water, pulping for 2 hours, adding into a pulping tank, homogenizing for 2 hours, and then carrying out spray drying at the tail gas temperature of 180-210 ℃. The catalyst obtained by spray drying is exchanged and washed for 1h at 85 ℃ in an acidic aqueous solution with the pH value of 3.2, filtered and dried for 4h at 120 ℃ to obtain the catalyst CAT-7. Wherein, calculated by dry basis, the kaolin accounts for 40 weight percent, the pseudo-boehmite accounts for 25 weight percent, the alumina sol accounts for 5 weight percent, and the gas phase ultra-stable Y molecular sieve G accounts for 30 weight percent.

Comparative example 3:

the structure of the reactor: a horizontal reactor is adopted, and the included angle between the axis of the reactor and the horizontal plane is 55 degrees. The ratio of the height of the reactor body in the axial direction to the inner diameter of the reactor body is 3:1, and the reactor rotates at the speed of 10 r/min. The bottom of the reactor is connected with a cone body through an elbow. The feed rate of the molecular sieve was controlled so that the reactor volume was 75% of the bulk volume of the molecular sieve entering the reactor during the reaction time and the residence time of the molecular sieve in the reactor was 30 minutes.

Preparing a gas-phase ultra-stable molecular sieve: a NaY molecular sieve (water content 1.5 wt%, D (v, 0.9) 15.5 μm) at a temperature of 420 ℃ was transported by a screw conveyor to the top of the horizontal reactor, while dry nitrogen gas in an amount of 2% by mass of the molecular sieve was fed to the top of the reactor. The NaY molecular sieve moves in an oblique downward direction and SiCl introduced from the side line of the reactor₄And (4) reacting. The nozzle is mounted at a distance from the centerline of the reactor. SiCl in the reaction process₄The feed mass ratio per dry basis of molecular sieve was 2.3: 10. The Y molecular sieve after the reaction falls to the conical body part of the vertical reactor and is led out by a screw conveyer. And degassing the output molecular sieve, and then feeding the molecular sieve into a pulping tank, wherein the mass ratio of the molecular sieve to water is 12, the pH value of the water is 5.5, the system temperature is controlled at 94 ℃, and washing and filtering the molecular sieve to obtain a gas-phase ultrastable Y molecular sieve product H.

Preparation of the catalyst: 714.3g of alumina sol, 1600g of kaolin and 3141g of deionized water are mixed and pulped in a pulping tank, then 1210g of pseudo-boehmite is added, stirred for 1 hour, 139ml of hydrochloric acid with the mass concentration of 36 percent is added, stirred for 1 hour and homogenized, and the mixture is aged for 2 hours at 65 ℃. Mixing 900g (dry basis) of gas phase ultrastable Y molecular sieve H and 1644g of deionized water, pulping for 2 hours, adding into a pulping tank, homogenizing for 2 hours, and then carrying out spray drying at the tail gas temperature of 180-210 ℃. The catalyst obtained by spray drying is exchanged and washed for 1h at 85 ℃ in an acidic aqueous solution with the pH value of 3.2, filtered and dried for 4h at 120 ℃ to obtain the catalyst CAT-8. Wherein, calculated by dry basis, the kaolin accounts for 40 weight percent, the pseudo-boehmite accounts for 25 weight percent, the alumina sol accounts for 5 weight percent, and the gas phase ultra-stable Y molecular sieve H accounts for 30 weight percent.

Comparative example 4:

preparing a hydrothermal ultrastable molecular sieve: NaY molecular sieve (water content 1.5 wt%, D (v, 0.9) 15.5 μm), ammonium chloride and deionized water, the ammonium chloride: NaY molecular sieve 0.4:1, exchange at pH 3.8 and 90 ℃ for 1h, filter to remove filtrate, and wash the filter cake with deionized water to obtain a first batch; roasting the primary cross-linked material for 2 hours at 600 ℃ under the condition of 100 percent of water vapor to obtain a primary roasted material; exchanging the primary baked material once with ammonium chloride at a pH of 3.8 at 90 deg.C for 1 hr, filtering, and washing to obtain secondary material; roasting the secondary cross-linked material for 2 hours at the temperature of 600 ℃ and under the condition of 100 percent of water vapor to obtain a hydrothermal ultrastable Y molecular sieve product I.

Preparation of the catalyst: 714.3g of alumina sol, 1600g of kaolin and 3141g of deionized water are mixed and pulped in a pulping tank, then 1210g of pseudo-boehmite is added, stirred for 1 hour, 139ml of hydrochloric acid with the mass concentration of 36 percent is added, stirred for 1 hour and homogenized, and the mixture is aged for 2 hours at 65 ℃. Mixing 900g (dry basis) of the hydrothermal ultrastable Y molecular sieve product I and 1644g of deionized water, pulping for 2 hours, adding into a pulping tank, homogenizing for 2 hours, and then carrying out spray drying at the tail gas temperature of 180-210 ℃. The catalyst obtained by spray drying is exchanged and washed for 1h at 85 ℃ in an acidic aqueous solution with the pH value of 3.2, filtered and dried for 4h at 120 ℃ to obtain the catalyst CAT-9. Wherein, calculated by dry basis, the kaolin accounts for 40 weight percent, the pseudo-boehmite accounts for 25 weight percent, the alumina sol accounts for 5 weight percent, and the hydrothermal ultrastable Y molecular sieve I accounts for 30 weight percent.

The following table shows the results of comparing the performance of various molecular sieves obtained in examples and comparative examples.

TABLE 3 comparison of the properties of the faujasite molecular sieves obtained in the examples and comparative examples

As can be seen from table 3, the modified faujasite molecular sieve obtained in the examples of the present invention has higher crystal retention and lower unit cell constant than that before modification. Compared with the hydrothermal ultrastable modified molecular sieve of comparative example 4, the modified faujasite molecular sieve of the embodiment of the invention has equivalent unit cell constants, but the crystal retention of the modified faujasite molecular sieve of the embodiment of the invention is far greater than that of the modified molecular sieve of comparative example 4. The modified molecular sieve obtained in the comparative example 3 has slightly reduced unit cell constant compared with the modified molecular sieve obtained in the inventive example, but the crystallinity retention of the modified molecular sieve obtained in the comparative example 3 is far lower than that of the modified molecular sieve obtained in the inventive example although higher than that of the comparative example 4. Comparative example 2 in the modification process, the reaction time and reaction space are equivalent to those of the inventive example, but the faujasite molecular sieve and the gaseous silicon tetrachloride are mixed in the same direction, so that the modified molecular sieve of comparative example 2 is still far lower than that of the inventive example. Comparative example 1 no zeolite distributor was used and the modified molecular sieve had a slightly higher crystal retention than comparative examples 2 and 3, but still lower than the examples of the present application.

The physical and chemical properties of the catalysts CAT-1 to CAT-5 prepared in examples 1 to 5 and the catalysts CAT-6 to CAT-9 prepared in comparative examples 1 to 4 are shown in Table 4.

TABLE 4 comparison of microreflective activities of CAT-1 to CAT-5 and CAT-6 to CAT-9

800 ℃ and 17 hours, 100% water vapor aging.

As can be seen from the comparison of the data in table 4, the catalyst prepared by the present invention has significantly higher micro-reverse activity for 17 hours than the catalyst prepared by the comparative example, in the case of equivalent amount of the modified Y molecular sieve.

The catalysts CAT-1 to CAT-5 prepared in examples 1 to 5 and the catalysts CAT-6 to CAT-9 prepared in comparative examples 1 to 4 were subjected to performance evaluation, and the results are shown in Table 5.

TABLE 5 evaluation of the reactivity of the different catalysts

800 ℃ for 10 hours, 100% moisture aging.

The content of the modified Y molecular sieve in the catalyst of example 4 is less than that in the catalysts of comparative examples 1-4, but the data in Table 5 show that the light oil yield and the total liquid yield of the catalyst of example 4 are still slightly higher than those of the catalysts of comparative examples 1-4 when the catalyst is used for heavy oil processing. Comparative example 3 the modified faujasite molecular sieve of comparative example 3 has a longer modification time and a smaller reaction space, and compared with the catalyst of example 1 of the present invention, when the modified faujasite molecular sieve of comparative example 3 is used in a catalytic cracking catalyst, the heavy oil conversion rate, the total liquid yield and the light oil yield of the catalyst of comparative example 3 are all lower than those of the catalyst of example 1.

The present invention is capable of other embodiments, and various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A preparation method of a catalytic cracking catalyst is characterized in that the catalytic cracking catalyst takes a modified faujasite molecular sieve as an active component, and the modification method of the faujasite molecular sieve comprises the following steps: the method comprises the following steps of carrying out contact reaction on a faujasite molecular sieve and gaseous silicon tetrachloride, wherein the contact reaction time is not more than 5 seconds, the space of the contact reaction is more than 2 times of the bulk volume of the faujasite molecular sieve in a reaction area, and the temperature of the contact reaction is 250-600 ℃.

2. The method of preparing a catalytic cracking catalyst according to claim 1, comprising: mixing and pulping the modified faujasite molecular sieve, clay, a binder and water, and drying the obtained slurry to obtain a catalytic cracking catalyst; the total weight of the catalytic cracking catalyst is 100%, the content of the modified faujasite molecular sieve is 5-50 wt%, the content of the clay is 10-70 wt%, and the content of the binder is 5-40 wt%.

3. The method of preparing the catalytic cracking catalyst of claim 1, wherein the faujasite molecular sieve is contacted with the gaseous silicon tetrachloride in a counter-current manner to react.

4. The process for preparing a catalytic cracking catalyst according to claim 1, wherein the faujasite molecular sieve is a NaY type zeolite molecular sieve; the framework Si/Al molar ratio of the faujasite molecular sieve is SiO₂And Al₂O₃The molar ratio is 3.2-10; and/or, the faujasite molecular sieve is in a powder form, and 90% of particles have a diameter of not more than 500 microns.

5. The method of claim 4, wherein the faujasite molecular sieve is prepared by reacting Na as the Na element₂The content of O is not more than 15 wt%, and the rare earth element is RE₂O₃The calculated content is not higher than 23 wt%; the rare earth elements comprise one or more of lanthanum, cerium, praseodymium, neodymium and ytterbium.

6. The method for preparing the catalytic cracking catalyst according to claim 1, wherein the faujasite molecular sieve is dried before being subjected to contact reaction with the gaseous silicon tetrachloride, so that the water content percentage of the faujasite molecular sieve is not more than 5%; and/or after the faujasite molecular sieve and the gaseous silicon tetrachloride are subjected to contact reaction, one or more treatment steps of degassing, washing and drying are further carried out on the faujasite molecular sieve after the reaction.

7. The method of claim 6, wherein the degassing comprises one or more of flash evaporation, vacuum pumping, and heat volatilization; the washing liquid is water or aqueous solution containing one or more of hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, oxalic acid, tartaric acid, citric acid, ammonium chloride, ammonium sulfate, ammonium nitrate and ammonium phosphate; the washing temperature is normal temperature to 120 ℃, the washing time is 5min to 4h, and the solid-liquid mass ratio during washing is 1: 5 to 30.

8. The preparation method of the catalytic cracking catalyst according to claim 1, wherein the contact reaction of the faujasite molecular sieve and gaseous silicon tetrachloride is carried out in a reactor, the faujasite molecular sieve enters from the top of the reactor, the gaseous silicon tetrachloride enters from the lower part of the reactor, the faujasite molecular sieve and the gaseous silicon tetrachloride are in countercurrent contact in the reactor to carry out the reaction, and the reacted material is output from the bottom of the reactor; and/or the faujasite molecular sieve and gaseous silicon tetrachloride form a mixed state of complete mixed flow or partial complete mixed flow in the reactor.

9. The method for preparing a catalytic cracking catalyst according to claim 8, wherein the reactor is a gas phase ultra-stable reactor, the space for the contact reaction is the volume of the reactor, and the volume of the reactor is more than 10 times of the volume of the faujasite molecular sieve bulk volume entering the reactor in the contact reaction time; and/or the ratio of the longitudinal height to the transverse internal diameter of the reactor is not less than 2:1 and not more than 15: 1.

10. The method for preparing the catalytic cracking catalyst according to claim 9, wherein the gaseous silicon tetrachloride is sprayed into the reactor through a nozzle, and the spraying area of the nozzle is 1-10% of the transverse inner cross-sectional area of the reactor.

11. The method for preparing a catalytic cracking catalyst according to claim 1, wherein the temperature of the contact reaction between the faujasite molecular sieve and the gas-phase silicon tetrachloride is 300-550 ℃, and the time of the contact reaction is not more than 1 second.

12. The method for preparing the catalytic cracking catalyst of claim 8, wherein the faujasite molecular sieve is transported by taking inert gas as carrier gas, the inert gas comprises one or more of air, nitrogen, argon and helium, and the amount of the inert gas is 0-20% of the mass of the faujasite molecular sieve; and/or the mass ratio of the faujasite molecular sieve to the gas-phase silicon tetrachloride in the reactor is 1: 0.05 to 0.5.

13. The method for preparing a catalytic cracking catalyst according to claim 2, wherein the clay is one or more of kaolin, halloysite, montmorillonite and bentonite; the binder is one or more of acidified pseudo-boehmite, aluminum chlorohydrol, aluminum trichloride, aluminum sulfate, aluminum hydroxide, aluminum sol and silica sol; the obtained slurry is dried by spraying, and the step of ion exchange is also included after drying, so that the catalytic cracking catalyst is obtained.

14. The method for preparing the catalytic cracking catalyst according to claim 13, wherein the spray drying is performed at a temperature of 450-600 ℃ in a hearth of a spray tower and at a temperature of 150-300 ℃ in a tail gas; the ion exchange is acid exchange, the exchange temperature is 60-95 ℃, the pH value is 2.5-4.0, and the exchange time is 0.5-2 h.

15. The catalytic cracking catalyst is characterized by comprising, by taking the total weight of the catalytic cracking catalyst as 100%, 5-50 wt% of a modified faujasite molecular sieve, 10-70 wt% of clay and 5-40 wt% of a binder; wherein the modified faujasite molecular sieve has a crystal retention of not less than 85% and a unit cell constant of less than 24.55 angstrom.

16. Use of the catalytic cracking catalyst of claim 15 in heavy oil processing.