CN112745945A

CN112745945A - Method and system for treating catalytic pyrolysis gasoline, catalytic pyrolysis process and device for producing more dimethylbenzene

Info

Publication number: CN112745945A
Application number: CN201911048195.6A
Authority: CN
Inventors: 王迪; 魏晓丽; 龚剑洪; 于敬川; 张久顺
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: 2019-10-30
Filing date: 2019-10-30
Publication date: 2021-05-04

Abstract

The invention relates to a method and a system for treating catalytic pyrolysis gasoline, and a catalytic pyrolysis process and a device for producing more dimethylbenzene. The method and the system provided by the invention can efficiently convert the catalytic pyrolysis gasoline into low-carbon olefin and light aromatic hydrocarbon, produce more dimethylbenzene, have the advantages of continuous reaction and continuous regeneration, good heat transfer and mass transfer effects, uniform temperature distribution when the temperature is increased and decreased, low investment and the like, can maintain the constant property of the catalyst, and ensure the long-period stable operation.

Description

Method and system for treating catalytic pyrolysis gasoline, catalytic pyrolysis process and device for producing more dimethylbenzene

Technical Field

The invention relates to a method and a system for treating catalytic pyrolysis gasoline, and a catalytic pyrolysis process and a device for producing more dimethylbenzene.

Background

BTX (benzene, toluene and xylene) is an important petrochemical basic product, is an important raw material of various chemical products such as synthetic rubber, synthetic fiber and synthetic resin, and the toluene and the xylene can also be used as a gasoline octane number additive. The growth of the global aromatic hydrocarbon industrial chain is concentrated in northeast Asia regions under the continuous pulling of the industries of Chinese terylene, polyester and PTA, and the demand of triphenyl is continuously increased. However, the aromatic hydrocarbon production process is accompanied with the production of C9+ heavy aromatic hydrocarbon, the C9+ heavy aromatic hydrocarbon has large yield, low value and limited utilization path, which causes resource waste, and the method converts the C9+ heavy aromatic hydrocarbon in the catalytic pyrolysis gasoline into BTX, and simultaneously produces more xylene, which is undoubtedly an effective method for fully utilizing resources and improving quality and efficiency of enterprises.

CN97106718.X discloses a heavy aromatics hydrodealkylation and transalkylation process, which comprises using C10 or/and C11 aromatics as raw materials, in a fixed bed reactor, using hydrogen-type mordenite loaded with bismuth and at least one metal or oxide selected from iron, cobalt, nickel or molybdenum as a catalyst, and reacting at 600 ℃ and 1.5-4.0 MPa to generate C6-C9 aromatics and C1-C4 paraffin. The process is especially suitable for hydrodealkylation and transalkylation of heavy aromatics of C10 and/or C10, and can be used in industrial production.

CN200410066625.4 discloses a method for hydrodealkylation and transalkylation of heavy aromatics, which mainly solves the problems in the prior art that the content of heavy aromatics in raw materials is allowed to be lower and the utilization rate of the heavy aromatics is low. The technical scheme that C10 or/and C11 aromatic hydrocarbon is/are used as raw materials, and the macroporous zeolite loaded with metal or oxide of bismuth and molybdenum is used as a catalyst in a fixed bed reactor to react at the temperature of 300-600 ℃ and the pressure of 1.0-4.0 MPa to generate mixed xylene is adopted, so that the problem is solved well. The method has the characteristics of simple flow, high yield of mixed xylene, low hydrogen-hydrocarbon ratio and the like, and can be used for industrial production of mixed xylene from heavy aromatic hydrocarbon.

CN101362669A discloses a catalytic conversion method for preparing ethylene, propylene and aromatic hydrocarbon, which comprises contacting hydrocarbon raw materials with different cracking performances with a catalytic cracking catalyst, carrying out cracking reaction in a fluidized bed reactor, separating spent catalyst and reaction oil gas, regenerating spent catalyst, returning to the reactor, separating the reaction oil gas, separating to obtain target products, namely low-carbon olefin and aromatic hydrocarbon, wherein 160-plus-260 ℃ fraction is used as a circulating material to return to the catalytic cracking, and ethane, propane and butane enter steam cracking to further produce ethylene and propylene. The method produces low-carbon olefins such as ethylene, propylene and the like from heavy raw materials to the maximum extent, the yield of the ethylene and the propylene is over 20 percent by weight, and aromatic hydrocarbons such as toluene, xylene and the like are co-produced.

CN200710043941.3 discloses a method for producing light aromatics and light alkanes from hydrocarbon raw materials, which comprises the steps of reacting the hydrocarbon raw materials with the boiling point of 30-250 ℃ in the presence of a Pt or Pd-containing zeolite catalyst, carrying out hydrodealkylation on heavy aromatics in the hydrocarbon raw materials and carrying out transalkylation reaction with the light aromatics, carrying out isomerization reaction on the light aromatics to convert the light aromatics into components rich in BTX (B is benzene, T is toluene and X is xylene) light aromatics, carrying out hydrocracking reaction on non-aromatics to generate light alkanes, separating liquid phase products into benzene, toluene, xylene and C9+ aromatics respectively according to different boiling points in a distillation tower, and separating the light alkanes from gas phase products. The method solves the technical problems that the traditional separation process of the hydrocarbon raw materials needs solvent extraction, the process is complex, the cost is high, and the heavy aromatic hydrocarbon and the non-aromatic hydrocarbon after separation have low utilization value.

CN200810043966.8 discloses a method for hydrocracking and producing more benzene and xylene by using pyrolysis gasoline. The method comprises the steps of reacting a C7+ pyrolysis gasoline raw material in the presence of a catalyst, carrying out hydrodealkylation on heavy aromatic hydrocarbons and carrying out transalkylation with light aromatic hydrocarbons, carrying out isomerization reaction on the light aromatic hydrocarbons to convert the light aromatic hydrocarbons into components rich in BTX light aromatic hydrocarbons, and separating liquid-phase products into benzene, toluene, xylene and C9+ fractions according to different boiling points, wherein the toluene and the C9+ fractions can be returned as feed materials to be continuously treated, and the light alkanes can be separated from gas-phase products. The method solves the problems that only BTX (B is benzene, T is toluene and X is xylene) aromatic hydrocarbon is simply separated in the traditional process of pyrolysis gasoline, a light aromatic hydrocarbon product contains a large amount of toluene, and the utilization value of the separated heavy aromatic hydrocarbon and non-aromatic hydrocarbon is low.

CN201280055636.5 discloses a process for converting biomass into products by contacting the biomass with hydrogen in the presence of a hydropyrolysis catalyst in a fluidized bed reaction vessel under hydropyrolysis conditions; the product and char are removed from the reaction vessel and the char and catalyst are separated according to the settling rate.

It can be seen from the techniques disclosed in the above patent applications that the existing heavy aromatics upgrading techniques mostly adopt fixed bed hydrodealkylation, and have harsh reaction conditions, complex operation and high catalyst requirements.

Disclosure of Invention

The invention aims to provide a method and a system for treating catalytic pyrolysis gasoline, and a catalytic pyrolysis process and a device for producing more dimethylbenzene. The method and the process can efficiently convert the catalytic pyrolysis gasoline into the low-carbon olefin and the light aromatic hydrocarbon and realize the long-period stable operation.

In order to achieve the above object, a first aspect of the present invention provides a method for treating catalytically cracked gasoline, the method comprising:

fractionating catalytically cracked gasoline and/or catalytically cracked reaction oil gas from the catalytic cracking reaction unit to obtain light gasoline, middle gasoline fraction, heavy gasoline fraction and optional other products; the middle gasoline fraction contains light aromatic hydrocarbons of C6-C8, and the heavy gasoline fraction contains heavy aromatic hydrocarbons of C9 or above;

performing aromatic extraction on the gasoline middle distillate to obtain BTX aromatic hydrocarbon and aromatic raffinate oil;

the heavy fraction of the gasoline enters a catalytic cracking reactor to contact with a third catalyst for catalytic cracking reaction, and the obtained product enters a fluidized reactor to contact with a second catalyst for hydrodealkylation reaction to obtain a dealkylated liquid product and a second spent catalyst; the second fractionation is carried out after mixing the dealkylated liquid product with the heavy gasoline.

The second aspect of the invention provides a catalytic cracking process for producing more xylene, which comprises the steps of enabling a raw material to be in contact with a first catalyst in a catalytic cracking reactor to carry out catalytic cracking reaction to obtain catalytic cracking reaction oil gas, and treating the catalytic cracking reaction oil gas by adopting the method of the first aspect of the invention.

The third aspect of the invention provides a system for treating catalytically cracked gasoline, which comprises a catalytically cracked gasoline inlet, a separation unit, an aromatic extraction unit, a catalytic cracking unit and a dealkylation reaction unit;

the separation unit comprises separation equipment, and the separation equipment is provided with a first oil gas inlet, a light gasoline outlet, a gasoline middle fraction outlet, a gasoline heavy fraction outlet and optional other product outlets; the first oil gas inlet is communicated with the catalytic pyrolysis gasoline inlet; the light gasoline outlet is optionally used for communicating with the inlet of the catalytic cracking reactor;

the aromatic hydrocarbon extraction unit comprises aromatic hydrocarbon extraction and separation equipment, and the aromatic hydrocarbon extraction and separation equipment is provided with a third oil gas inlet, a BTX aromatic hydrocarbon outlet and an aromatic hydrocarbon raffinate oil outlet; the third oil gas inlet is communicated with a gasoline middle distillate outlet of the separation unit; the aromatic raffinate oil outlet is optionally used for communicating with an inlet of a catalytic cracking reactor;

the catalytic cracking unit comprises a catalytic cracking reactor, and the catalytic cracking reactor is provided with a second oil gas inlet and a catalytic cracking reaction oil gas outlet; the second oil gas inlet is communicated with a gasoline heavy fraction outlet of the separation unit;

the dealkylation reaction unit comprises a fluidization reactor, the fluidization reactor comprises a fourth oil gas inlet and a dealkylation oil gas outlet, the fourth oil gas inlet is communicated with the catalytic cracking reaction oil gas outlet, and the dealkylation oil gas outlet is communicated with the catalytic pyrolysis gasoline inlet.

The fourth aspect of the invention provides a catalytic cracking device, which comprises a catalytic cracking reactor and the system of the third aspect of the invention, wherein a reaction oil gas outlet of the catalytic cracking reactor is communicated with a catalytic cracking reaction oil gas inlet of the system, a raw material inlet of the catalytic cracking reactor is communicated with the light gasoline outlet, and a raw material inlet of the catalytic cracking reactor is communicated with the aromatic raffinate oil outlet.

The method and the system provided by the invention adopt a fluidized bed reaction system to carry out catalytic cracking and hydrodealkylation treatment on heavy aromatics in the catalytic pyrolysis gasoline, can efficiently convert the catalytic pyrolysis gasoline into low-carbon olefin and light aromatics, and can produce more dimethylbenzene; meanwhile, a fluidized bed reaction system is adopted, so that the heat and mass transfer effect is good, the temperature distribution is uniform when the temperature is increased and decreased, the investment is low, and the problems that the content of aromatic hydrocarbon in the pyrolysis gasoline of the catalytic cracking device is high, but the low-value heavy aromatic hydrocarbon is more and difficult to utilize are solved.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is a process flow diagram of one embodiment of the method of treating catalytically cracked gasoline of the present invention;

FIG. 2 is a schematic view of a catalytic cracking reaction unit of one embodiment of the catalytic cracking unit of the present invention;

FIG. 3 is a schematic view of a catalytic cracking reaction unit of one embodiment of the catalytic cracking unit of the present invention;

fig. 4 is a schematic view of a second catalyst regenerator in an embodiment of the method for treating catalytically cracked gasoline of the present invention.

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

The invention provides a method for treating catalytic pyrolysis gasoline, which comprises the following steps:

The method provided by the invention can efficiently convert the catalytic cracking gasoline and/or the catalytic cracking reaction oil gas into the low-carbon olefin and the light aromatic hydrocarbon, can improve the yield of the low-carbon olefin, and can ensure the long-period stable operation.

According to the present invention, the light gasoline obtained by fractionation contains olefins with carbon atoms of 5 to 8, and in order to further improve the yield of the low carbon olefins, in a specific embodiment, as shown in fig. 1, the light gasoline obtained by fractionation may be returned to a catalytic cracking reaction unit to continue the catalytic cracking reaction, the catalytic cracking reactor may include a catalytic cracking reactor, the reactor may include a riser reactor and a fluidized bed reactor, and the position of the light gasoline returned to the catalytic cracking reactor is not limited, and the light gasoline may be returned to the riser reactor or the fluidized bed reactor.

According to the invention, the catalytic pyrolysis gasoline is from a catalytic pyrolysis reaction unit and can be a component obtained by separating reaction oil gas generated by catalytic pyrolysis reaction. In the method of the present invention, the catalytically cracked gasoline to be treated may be fed alone as the raw material or in the form of catalytically cracked reaction oil gas containing catalytically cracked gasoline.

The apparatus and operating conditions for fractionating catalytically cracked gasoline according to the present invention are not particularly limited, and the apparatus for fractionating may be, for example, a fractionating tower, and the conditions for fractionating may be conventional in the art.

Preferably, the condition for carrying out fractionation can be that the initial boiling point of the light gasoline is 20-40 ℃, and the final boiling point is 80-100 ℃; the initial boiling point of the gasoline intermediate fraction is 80-100 ℃, and the final boiling point is 120-150 ℃; the initial boiling point of the gasoline heavy fraction is 120-150 ℃, and the final boiling point is 200-250 ℃. Other products can comprise low-carbon olefin, aromatic hydrocarbon above C12 and non-aromatic hydrocarbon components, wherein the low-carbon olefin mainly contains olefin with 2-4 carbon atoms.

According to the present invention, the gasoline middle distillate obtained by fractionation mainly contains BTX aromatic hydrocarbons and non-aromatic hydrocarbon components, the gasoline middle distillate can be subjected to aromatic hydrocarbon extraction to further separate light aromatic hydrocarbon products such as benzene, toluene, xylene, etc., the apparatus and reaction conditions for aromatic hydrocarbon extraction are not particularly limited, the apparatus for aromatic hydrocarbon extraction includes, for example, an extraction column, a solvent recovery column and an aromatic hydrocarbon separation column, the extraction agent can be conventional in the art, for example, sulfolane, tetraethylene glycol ether, diethylene glycol ether, N-methylpyrrolidone, and the types and operating conditions of the extraction column, the solvent recovery column and the aromatic hydrocarbon separation column can be conventional in the art, and will not be described herein again.

According to the invention, the aromatic raffinate oil obtained by aromatic extraction contains non-aromatic components, and in order to further improve the yield of the low-carbon olefin, in a specific implementation mode, the aromatic raffinate oil can be returned to a catalytic cracking reactor for continuous catalytic cracking reaction.

According to the invention, the gasoline heavy fraction obtained by fractionation mainly contains C9+ aromatics and also contains non-aromatic components such as naphthenes and paraffins, the fraction containing C9+ heavy aromatics can be subjected to catalytic cracking reaction firstly, the non-aromatics, the C9+ heavy aromatics containing long side chains and the like are cracked under relatively mild conditions,

the device and reaction conditions for carrying out catalytic cracking can be changed in a large range, preferably, the catalytic cracking reactor is a riser reactor, the reaction temperature of catalytic cracking can be 550-720 ℃, preferably 580-650 ℃, the reaction time is 1-10 s, preferably 2-8 s, the reaction pressure is 130-450kPa, preferably 170-350 kPa, and the ratio of catalyst to oil is (1-100): 1, preferably (3-70): 1.

according to the present invention, the third catalyst may be a catalytic cracking catalyst of the kind conventional in the art, and in a preferred embodiment, the third catalyst comprises, based on the total weight of the catalyst: 1-60 wt% of zeolite, 5-99 wt% of inorganic oxide and 0-70 wt% of clay; further preferably, the third catalyst comprises: 10-50 wt% of zeolite, 10-80 wt% of inorganic oxide and 20-50 wt% of clay, wherein the zeolite is selected from medium pore zeolite, large pore zeolite or combination thereof; the medium pore zeolite is ZSM zeolite and/or ZRP zeolite, and the large pore zeolite is selected from one or more of beta zeolite, rare earth Y, rare earth hydrogen Y, ultra-stable Y and high silicon Y; the inorganic oxide may be at least one selected from the group consisting of silica, alumina, zirconia, titania and amorphous silica-alumina; the clay is at least one selected from kaolin, halloysite, montmorillonite, diatomaceous earth, attapulgite, sepiolite, halloysite, hydrotalcite, bentonite and rectorite.

According to the invention, a product mixture obtained by catalytic cracking reaction can enter a fluidized reactor to contact with a second catalyst under the hydrogen condition for hydrodealkylation reaction, so that C9+ aromatic hydrocarbon is further cracked and dealkylated to generate dealkylated product, the dealkylated product can be continuously subjected to gas-liquid separation to obtain dealkylated liquid product and hydrogen, and the dealkylated liquid product rich in light aromatic hydrocarbon can be returned to the fractionation step to be fractionated together with heavy fraction of gasoline so as to separate middle fraction of gasoline rich in light aromatic hydrocarbon. The conditions for the hydrodealkylation reaction of the gasoline heavy fraction in the fluidized reactor can be changed within a wide range, and in one embodiment, the reaction temperature can be 260-720 ℃, and is preferably 33 DEG C0 to 580 ℃, more preferably 360 to 560 ℃, the pressure can be 0 to 5.6MPa, preferably 0.1 to 4.8MPa, more preferably 1 to 4MPa, and the weight hourly space velocity can be 0.2 to 6.5h^-1Preferably 0.5 to 5.8 hours^-1More preferably 1.5 to 4.2 hours^-1The hydrogen/hydrocarbon molar ratio may be 1 to 13, preferably 2 to 10, and more preferably 3.5 to 6.5.

According to the present invention, the second catalyst for the hydrodealkylation reaction may include a carrier and an active metal component supported on the carrier, and the composition and content of the second catalyst may vary within a wide range, and preferably, the content of the carrier in the second catalyst may be 50 to 99.99 wt%, preferably 55 to 85 wt%, based on the total weight of the second catalyst; the content of the active metal component may be 0.01 to 50% by weight, preferably 0.01 to 45% by weight.

The active metal component is preferably one or a combination of more than two of rare earth metals and transition metals, such as one or more of Fe, Ni, Pt, Pd, Co and Mo, preferably Ni, Pt and Pd.

The composition and amount of the support may also vary widely, and in a preferred embodiment, the support may contain 1 to 60 wt% zeolite, 5 to 99 wt% inorganic oxide, and 0 to 70 wt% clay, based on the dry weight of the support; more preferably, the carrier may contain 10 to 50 wt% of zeolite, 10 to 90 wt% of inorganic oxide and 1 to 60 wt% of clay. Further, the zeolite may comprise a medium pore zeolite and/or a large pore zeolite, preferably selected from medium pore zeolite and optionally large pore zeolite, preferably the weight of the medium pore zeolite is 50 to 100 wt% of the total weight of the zeolite, more preferably the weight of the medium pore zeolite is 70 to 90 wt% of the total weight of the zeolite; the large-pore zeolite accounts for 0-50 wt% of the total weight of the zeolite, and preferably the large-pore zeolite accounts for 10-30 wt% of the total weight of the zeolite.

In the support of the second catalyst according to the present invention, the medium-and large-pore zeolites may be of the type conventional in the art, for example ZSM zeolites and/or ZRP zeolites, the large-pore zeolites being preferably selected from one or more of beta zeolites, rare earth Y zeolites, rare earth hydrogen Y zeolites, ultrastable Y zeolites and high-silicon Y zeolites; in the carrier of the second catalyst, the inorganic oxide and the clay may each be of a kind conventional in the art, and the inorganic oxide may be at least one of silica, alumina, zirconia, titania and amorphous silica-alumina, preferably silica and/or alumina; the clay may be selected from at least one of kaolin, montmorillonite, diatomaceous earth, attapulgite, sepiolite, halloysite, hydrotalcite, bentonite and rectorite, and is preferably kaolin and/or halloysite.

According to the present invention, the second catalyst for the hydrodealkylation reaction may be prepared by a method conventional in the art, for example, by supporting the active metal component on the above-mentioned carrier by a pore saturation impregnation method.

The second spent catalyst may be separated from the product of the hydrodealkylation reaction according to the present invention by means of a cyclone separator, which is well known to those skilled in the art, or by means of a filter, which is well known to those skilled in the art. The separated second spent catalyst can be sent to a second catalyst regenerator for regeneration and then recycled. The second catalyst regenerator may be of a type conventional in the art, and in one embodiment, the second spent catalyst may be introduced into a fluidized bed regenerator for regeneration and the resulting second regenerated catalyst recycled to the fluidized reactor. The regeneration of the second spent catalyst is well known to those skilled in the art, all or at least part of the second spent catalyst can come from the second regenerated catalyst, during the regeneration process, an oxygen-containing gas is generally introduced from the bottom of the regenerator, the oxygen-containing gas can be air, for example, and after being introduced into the regenerator, the second spent catalyst is contacted with oxygen for coke burning regeneration, the flue gas generated after the catalyst is burned and regenerated is subjected to gas-solid separation at the upper part of the regenerator, and the flue gas enters a subsequent energy recovery system. According to the property of active metal component of catalyst it can increase the regeneration process of catalyst, such as reduction and sulfurization.

In order to avoid contacting the hydrogen-containing gas stream with the oxygen-containing gas stream during catalyst regeneration, and to improve plant safety, in one embodiment, the fluidized bed regenerator may include a lock hopper, and the method of regeneration may include: and (3) enabling the second spent catalyst to enter the fluidized bed regenerator for regeneration through a lock hopper, and recycling the second regenerated catalyst to the fluidized reactor through the lock hopper. In this embodiment, the lock hopper allows for safe and efficient transfer of the second catalyst from the high pressure hydrocarbon or hydrogen environment of the reactor to the low pressure oxygen environment of the regenerator, and from the low pressure oxygen environment of the regenerator to the high pressure hydrocarbon or hydrogen environment of the reactor. By using the lock hopper, the reducing atmosphere (hydrogen atmosphere) of the reactor and the regenerated second catalyst feeding tank can be well isolated from the oxygen-containing atmosphere of the regenerator for coke burning regeneration, the safety of the process method is ensured, the operating pressure of the reactor and the regenerator can be flexibly regulated and controlled, and particularly the operating pressure of the reactor can be increased under the condition of not increasing the operating pressure of the regenerator, so that the treatment capacity of the device is increased. The lock hopper of the present invention is a device that allows the same material stream to be switched between different atmospheres (e.g., oxidizing and reducing atmospheres) and/or between different pressure environments (e.g., from high to low pressure, or vice versa), the construction and operation of which are well known to those skilled in the relevant art.

In a further embodiment, as shown in fig. 4, the fluidized bed regenerator may further comprise a reactor receiver 32, a regenerator receiver 35, a regeneration feed tank 29 and an optional reducer 36, and the second spent catalyst withdrawn from the fluidized bed reactor may be transferred to the reactor receiver 32, then transferred to the regeneration feed tank 29 through a lock hopper 33, then transferred from the regeneration feed tank 29 to the fluidized bed regenerator 30, and subjected to a coke-burning regeneration in the regenerator under an oxygen-containing atmosphere to obtain a second regenerated catalyst; the second regenerated catalyst is continuously withdrawn from the fluidized bed regenerator 30, passed through the regenerator receiver 35, and then introduced into the reducer 36 for reduction, and then returned to the fluidized bed hydrodealkylation reactor for recycling.

In the method provided by the present invention, the fluidized reactor is a reactor which makes solid catalyst particles in a suspended motion state by using a reaction material gas and performs a gas-solid phase reaction process, and the type of the fluidized reactor is, for example, a dilute phase transport bed reactor, a fluidized bed reactor, a composite reactor composed of a dilute phase transport bed reactor and a fluidized bed reactor, a composite reactor composed of two or more dilute phase transport bed reactors, or a composite reactor composed of two or more fluidized bed reactors; wherein the dilute phase transport bed reactor is preferably a riser reactor; the fluidized bed reactor is, for example, a bubbling bed reactor, a turbulent bed reactor or a fast bed reactor. In a preferred embodiment, the fluidized reactor according to the invention is preferably a fluidized bed reactor, which may comprise an upper expanded diameter section, in which a cyclone or a catalyst filter may be arranged for recovering catalyst entrained by the gas. In the case of a fluidized bed reactor or a riser reactor, the feeding and operation methods are the same as those of the conventional fluidized bed reactor or riser reactor in the prior art, and the present invention is not limited thereto.

The second aspect of the invention provides a catalytic cracking process, which comprises the steps of enabling raw oil to contact with a first catalyst in a catalytic cracking reactor to carry out catalytic cracking reaction to obtain catalytic cracking reaction oil gas containing catalytic cracking gasoline, and treating the catalytic cracking reaction oil gas by adopting the method of the first aspect of the invention.

According to the present invention, the type of the feedstock oil is not particularly limited, and is, for example, at least one of gasoline, diesel oil, vacuum wax oil, atmospheric wax oil, coker wax oil, deasphalted oil, vacuum residue, atmospheric residue, raffinate oil, and low-grade recycle oil, coal liquefied oil, oil sand oil, and shale oil.

According to the present invention, the catalytic cracking reactor may be of a kind conventional in the art, and in one embodiment, the catalytic cracking reactor includes a fluidized bed reactor and a riser reactor disposed one above another. In the embodiment of returning the light gasoline to the catalytic cracking reaction unit, the returning position of the light gasoline can be a fluidized bed reactor or a riser reactor. In embodiments where the aromatic raffinate is returned to the catalytic cracking unit, the return location for the aromatic raffinate may be a fluidized bed reactor or a riser reactor.

According to the present invention, the conditions of the catalytic cracking reaction may vary within wide ranges, and preferably, the reaction conditions of the riser reactor include: the reaction temperature is 550-720 ℃, the reaction time is 1-10 seconds, the reaction pressure is 130-450kPa, the catalyst-oil ratio is 1-100: 1; the reaction conditions of the fluidized bed reactor include: the reaction temperature is 530 ℃ and 730 ℃, and the reaction time is 1-20 seconds.

According to the present invention, the first catalyst used for the catalytic cracking reaction may be a conventional catalytic cracking catalyst, and the kinds of the first catalyst and the third catalyst may be the same or different; in one embodiment, the first catalyst comprises, based on the total weight of the catalyst: 1-60 wt% of zeolite, 5-99 wt% of inorganic oxide and 0-70 wt% of clay, wherein the zeolite can comprise medium-pore zeolite and/or large-pore zeolite, preferably selected from medium-pore zeolite and optional large-pore zeolite, the medium-pore zeolite accounts for 50-100 wt%, preferably 70-100 wt% of the total weight of the zeolite, and the large-pore zeolite accounts for 0-50 wt%, preferably 0-30 wt% of the total weight of the zeolite. The medium pore zeolite is ZSM zeolite and/or ZRP zeolite, and the large pore zeolite is selected from one or more of beta zeolite, rare earth Y-type zeolite, rare earth hydrogen Y-type zeolite, ultrastable Y-type zeolite and high-silicon Y-type zeolite; the inorganic oxide may be at least one selected from the group consisting of silica, alumina, zirconia, titania and amorphous silica-alumina; the clay is at least one selected from kaolin, montmorillonite, diatomaceous earth, attapulgite, sepiolite, halloysite, hydrotalcite, bentonite and rectorite.

The third aspect of the invention provides a system for treating catalytically cracked gasoline, which comprises a catalytically cracked gasoline inlet, a separation unit, a catalytic cracking unit, an aromatic extraction unit and a dealkylation reaction unit;

According to the invention, the light gasoline outlet is optionally used for communicating with the inlet of the catalytic cracking reactor, so that the light gasoline returns to the catalytic cracking reactor for continuous reaction.

According to the invention, the aromatic raffinate outlet is optionally used for communicating with the inlet of the catalytic cracking reactor so as to return the aromatic raffinate to the catalytic cracking reactor for continuous reaction.

According to the invention, the separation unit and the separation equipment are used for separating light gasoline, gasoline middle distillate and gasoline heavy distillate in catalytic pyrolysis gasoline and/or catalytic pyrolysis reaction oil gas, and optionally separating other products, such as low-carbon olefin, aromatic hydrocarbon above C12 and non-aromatic hydrocarbon components. The separation apparatus may be conventional in the art, for example a fractionation column. The first oil-gas inlet of the separation device is used for feeding catalytic cracking gasoline and/or catalytic cracking reaction oil-gas.

According to the invention, an aromatic hydrocarbon extraction unit and an aromatic hydrocarbon extraction and separation device are used for separating BTX aromatic hydrocarbon in gasoline middle distillate obtained by the separation unit, the aromatic hydrocarbon extraction and separation device can be a conventional type in the field, in one embodiment, the aromatic hydrocarbon extraction and separation device can comprise an aromatic hydrocarbon extraction device, an aromatic hydrocarbon separation tower and a solvent recovery device, and the aromatic hydrocarbon extraction device is provided with a third oil gas inlet, a solvent inlet, an aromatic hydrocarbon-solvent mixed liquid outlet and an aromatic hydrocarbon raffinate oil outlet; the solvent recovery equipment is provided with an aromatic hydrocarbon-solvent mixed liquid inlet, an aromatic hydrocarbon outlet and a solvent outlet, and the aromatic hydrocarbon-solvent mixed liquid inlet is communicated with the aromatic hydrocarbon-solvent mixed liquid outlet of the aromatic hydrocarbon extraction equipment; the aromatic hydrocarbon separation tower is provided with a fifth oil gas inlet and a BTX aromatic hydrocarbon outlet, the fifth oil gas inlet is communicated with the aromatic hydrocarbon outlet of the solvent recovery equipment, and the BTX aromatic hydrocarbon outlet comprises a benzene outlet, a toluene outlet and a xylene outlet.

According to the invention, the catalytic cracking unit is used for carrying out catalytic cracking reaction on the separated gasoline heavy fraction, and cracking long aromatic hydrocarbon side chains and non-aromatic hydrocarbons in the gasoline heavy fraction to realize primary lightening. The apparatus of the catalytic cracking unit may comprise a catalytic cracking reactor, which may be of a kind conventional in the art, for example a riser reactor.

In a further embodiment, the catalytic cracking unit may further include a third catalyst regenerator, which may be of a type conventional in the art and will not be described herein again.

The dealkylation unit is used for further dealkylating the gasoline heavy fraction cracking product obtained by catalytic cracking to convert the C9+ aromatics into light aromatics, and the fluidized reactor used for dealkylation is not particularly limited, and may be of a type conventional in the art, for example, a dilute phase transport bed reactor, a fluidized bed reactor, a composite reactor composed of a dilute phase transport bed reactor and a fluidized bed reactor, a composite reactor composed of two or more dilute phase transport bed reactors, or a composite reactor composed of two or more fluidized bed reactors; wherein the dilute phase transport bed reactor is preferably a riser reactor; the fluidized bed reactor can be a bubbling bed reactor, a turbulent bed reactor or a fast bed reactor; the fluidized reactor may be an upflow reactor or a downflow reactor.

The dealkylation unit may further comprise a second catalyst regenerator, which may be of a type conventional in the art, preferably a fluidized bed regenerator, for regenerating the second spent catalyst, and in a further embodiment, preferably a fluidized bed regenerator with lock hoppers for further improving the safety of the system in order to prevent the oxygen-containing gas stream from contacting the hydrogen-containing gas stream during the regeneration process. In other embodiments of the invention, the catalyst transfer between the second catalyst regenerator and the fluidized reactor of the dealkylation reaction unit can be a conventional regeneration chute and a spent chute.

The fourth aspect of the invention provides a catalytic cracking device, which comprises a catalytic cracking reaction unit and the system of the third aspect of the invention, wherein a reaction oil gas outlet of the catalytic cracking reaction unit is communicated with a catalytic cracking reaction oil gas inlet of the system.

In one embodiment, the light gasoline outlet is communicated with the raw material inlet of the catalytic cracking reaction unit, so that the light gasoline is returned to the catalytic cracking reaction unit for recycling, and the yield of the low-carbon olefin is increased.

In one embodiment, the aromatic raffinate oil outlet is communicated with the raw material inlet of the catalytic cracking reaction unit, so that the aromatic raffinate oil is returned to the catalytic cracking reaction unit for recycling, and the yield of the low-carbon olefin is increased.

In a preferred embodiment, the light gasoline outlet and the aromatic raffinate oil outlet are respectively communicated with the raw material inlet of the catalytic cracking reaction unit.

The catalytic cracking reaction unit may be of a type conventional in the art, and for example, includes a catalytic cracking reactor, and in one embodiment, the catalytic cracking reaction unit includes a fluidized bed reactor and a riser reactor arranged up and down, and further includes a first catalyst regenerator for regenerating the first catalyst, and the first catalyst regenerator may be of a type conventional in the art, and the present invention is not limited thereto.

In a preferred embodiment, the catalytic cracking process of the present invention comprises:

as shown in fig. 1, raw oil 6 enters a catalytic cracking reaction unit 1 for catalytic cracking reaction, obtained reaction oil gas 7 enters a separation unit 2, light gasoline 8, gasoline middle fraction 9, gasoline heavy fraction 10 and optional other products are obtained by separation, the light gasoline 8 returns to the catalytic cracking reaction unit 1 for continuous reaction, the gasoline middle fraction 9 enters an aromatic extraction separation unit 3 for separation to obtain aromatic raffinate oil 13, benzene 14, toluene 15 and xylene 16, and the aromatic raffinate oil 13 returns to the catalytic cracking reaction unit 1 for continuous reaction; the heavy fraction 10 of the gasoline enters a catalytic cracking reaction unit 4, the heavy gasoline cracking product 11 enters a hydrodealkylation reaction unit 5 for hydrodealkylation reaction, and the light liquid product 12 is mixed with the reaction oil gas 7 and then returns to a product separation unit 2.

As shown in fig. 2, the raw oil 6 enters the riser cracking reactor 19 from the raw oil nozzle 17, the mixture of the reaction oil gas and the first catalyst ascends along the riser and reaches the fluidized bed cracking reactor 20, the mixture of the light gasoline 8 and the raffinate oil 13 of the aromatic hydrocarbon enters the fluidized bed cracking reactor 20 from the light gasoline nozzle 18 for reaction, the mixture of the reaction oil is separated in the first gas-solid separation device 21 to obtain the reaction oil gas 7, the first catalyst to be regenerated enters the first regenerator 22 for regeneration, and the first catalyst to be regenerated returns to the bottom of the riser cracking reactor 19 after being degassed by the degassing tank 23 for recycling.

As shown in fig. 3, the gasoline heavy fraction 10 enters a catalytic cracking reactor 25 from a heavy gasoline nozzle 24, a mixture of reaction oil gas and a third catalyst ascends along a riser tube and enters a second gas-solid separation device 26 for separation to obtain a heavy gasoline cracking product 11, and the third spent catalyst enters a third catalyst regenerator 27 for regeneration, is degassed by a degassing tank 28 and then returns to the bottom of the catalytic cracking reactor 25 for recycling.

As shown in fig. 4, the heavy gasoline cracking product 11 and hydrogen enter the fluidized bed hydrodealkylation reactor 30 from the lower part, contact with a second catalyst, and undergo a hydrodealkylation reaction, the reaction product enters the gas-liquid separation tank 31 to undergo gas-liquid separation, so as to obtain a light liquid product 12 and hydrogen, the second catalyst to be regenerated enters the lock hopper 33 through the reactor receiver 32, then enters the regeneration feed tank 29, and then enters the second catalyst regenerator 34 (fluidized bed regenerator), and is subjected to coke-burning regeneration in the regenerator under an oxygen-containing atmosphere, and the obtained regenerated second catalyst is led out to the regenerator receiver 35, then enters the reducer 36 through the lock hopper 33 to be reduced, and then returns to the fluidized bed hydrodealkylation reactor 30 for recycling.

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

The properties of feedstock A used in the examples and comparative examples are shown in tables 1 and 2, wherein feedstock A is vacuum distillate and feedstock B is catalytic pyrolysis gasoline.

The first catalyst C1 used in the catalytic cracking reaction unit is purchased from China petrochemical Changling catalyst division and has the brand number of DMMC-2;

the second catalyst C2 used in the catalytic cracking unit was purchased from catalyst division of China petrochemical ChangLing under the designation CDOS.

Preparation examples 1 to 3 are provided to illustrate the preparation methods of the catalysts H1, H2 and H3.

Preparation of example 1

The preparation method of C4 comprises the following steps: mixing the alumina sol and kaolin, preparing the mixture into slurry with the solid content of 10-50 wt% by using decationized water, uniformly stirring, adjusting the pH value of the slurry to 1-4 by using inorganic salt such as hydrochloric acid, nitric acid, phosphoric acid or sulfuric acid, keeping the pH value, standing and aging at 20-80 ℃ for 0-2 hours, adding the alumina sol, stirring for 0.5-1.5 hours to form colloid, adding a Y-type molecular sieve (produced by a Changling catalyst factory) to form catalyst slurry (with the solid content of 35 wt%), continuously stirring, and performing spray drying to prepare the microspherical catalyst, wherein Y: kaolin: aluminum sol 40: 39: 21. the microspherical catalyst was then calcined at 500 ℃ for 1 hour, washed with ammonium sulfate (where ammonium sulfate: microspherical catalyst: water 0.5:1:10) at 60 ℃ to a sodium oxide content of less than 0.25 wt%, then rinsed with deionized water and filtered, and then dried at 110 ℃, i.e., support C4 of this example.

The catalyst H1 was prepared by loading 0.04 wt% Pd and 0.04 wt% Pt (based on the total weight of the catalyst) on C4 by pore saturation impregnation and calcining at 400 deg.C for 4 hours.

Preparation of example 2

The presulfurized catalyst H2 was prepared by pore saturation impregnation using C4 as the carrier, wherein the weight ratio of NiS was 10% (based on the total weight of the catalyst).

Preparation of example 3

The preparation method of C3 comprises the following steps: mixing the alumina sol and kaolin, preparing the mixture into slurry with the solid content of 10-50 wt% by using decationized water, uniformly stirring, adjusting the pH value of the slurry to 1-4 by using inorganic salt such as hydrochloric acid, nitric acid, phosphoric acid or sulfuric acid, keeping the pH value, standing and aging at 20-80 ℃ for 0-2 hours, adding the alumina sol, stirring for 0.5-1.5 hours to form colloid, adding a ZSM-5 molecular sieve and a Y-type molecular sieve (produced by a Changling catalyst factory) to form catalyst slurry (with the solid content of 35 wt%), continuously stirring, and performing spray drying to prepare the microspherical catalyst, wherein the ZSM-5: y: kaolin: aluminum sol 20: 20: 39: 21. the microspherical catalyst was then calcined at 500 ℃ for 1 hour, washed with ammonium sulfate (where ammonium sulfate: microspherical catalyst: water 0.5:1:10) at 60 ℃ to a sodium oxide content of less than 0.25 wt%, then rinsed with deionized water and filtered, and then dried at 110 ℃, i.e., support C3 of this example.

The catalyst H3 was prepared by loading 0.04% Pd and 0.04% Pt (based on the total weight of the catalyst) on C3 by pore saturation impregnation and calcining at 400 ℃ for 4 hours.

Examples 1 to 6

Illustrating the method for treating catalytic pyrolysis gasoline of the present invention.

The tests were carried out according to the procedures shown in FIGS. 1 to 4, respectively, on a continuously regenerated medium-sized fluidized bed apparatus, using the raw material A in examples 1 to 5 and the raw material B in example 6. The relevant operating conditions and products are listed in table 3.

Comparative example 1

The experiment was conducted according to the method of example 1, except that the gasoline heavy fraction was reacted in the catalytic cracking reactor, and then directly fed into the aromatics extraction and separation unit for separation without being fed into the fluidized bed hydrodealkylation reactor for reaction. The relevant operating conditions and products are listed in table 4.

Comparative example 2

The experiment was carried out according to the method of example 1, except that the light gasoline and the aromatic raffinate oil were not recycled, and the heavy fraction of the gasoline was not reacted in the catalytic cracking reactor, and was directly fed into the aromatic extraction separation unit for separation without undergoing hydrodealkylation reaction. The relevant operating conditions and products are listed in table 4.

Comparative example 3

The experiment was carried out according to the method of example 1, except that the light gasoline and the aromatic raffinate oil were not recycled, and the heavy fraction of the gasoline was directly fed into the aromatic extraction separation unit for separation without hydrodealkylation after entering the catalytic cracking reactor for reaction. The relevant operating conditions and products are listed in table 4.

Comparative example 4

An experiment was conducted in accordance with the method of example 1 except that the reactor of the hydrodealkylation reaction unit was a fixed bed reactor and the catalyst was discontinuously regenerated. The relevant operating conditions and products are listed in table 4.

Comparative example 5

The experiment was conducted according to the method of example 1, except that the heavy gasoline was not reacted in the catalytic cracking reactor, but directly reacted in the hydrodealkylation reaction unit. The relevant operating conditions and products are listed in table 4.

TABLE 1 Properties of the raw materials

Heavy oil feedstock name	A
		Density (20 deg.C), kg/m³	912.1
Carbon residue, by weight%	3.14
		S, wt.%	0.39
N, weight%	0.13
		C, weight%	86.95
H, weight%	12.69
		Metal content, ppm
Ni	3.1
		V	3.2
Fe	0.2
		Four components, by weight%
Saturated hydrocarbons	54.7
		Aromatic hydrocarbons	33.5
Glue	11.6
		Asphaltenes	0.2

TABLE 2

TABLE 3

TABLE 4

As can be seen from the data of the examples and the comparative examples, the method for treating catalytic pyrolysis gasoline of the present invention can reduce the content of heavy aromatics of C9 or more and increase the content of BTX light aromatics. The catalytic cracking process can effectively convert heavy aromatics in the cracked product into light aromatics, improve the BTX aromatic content and reduce the heavy aromatic content above C9. The method and the process of the invention adopt a fluidized bed reaction system, have flexible operation and large elasticity, are easy to regenerate the catalyst and have uniform mass and heat transfer, and can ensure the stable operation in a long period.

The preferred embodiments of the present invention have been described in detail, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.

It should be noted that the various technical features described in the above embodiments can be combined in any suitable manner without contradiction, and the invention is not described in any way for the possible combinations in order to avoid unnecessary repetition.

In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.

Claims

1. A method of treating a catalytic pyrolysis gasoline, the method comprising:

fractionating catalytically cracked gasoline and/or catalytically cracked reaction oil gas from the catalytic cracking reaction unit to obtain light gasoline, middle gasoline fraction, heavy gasoline fraction and optional other products; the middle gasoline fraction contains light aromatic hydrocarbons of C6-C8, and the heavy gasoline fraction contains heavy aromatic hydrocarbons of above C9;

2. The method of claim 1, wherein the light gasoline is returned to the catalytic cracking reaction unit to continue the catalytic cracking reaction.

3. The method according to claim 1 or 2, wherein the light gasoline has an initial boiling point of 20 to 40 ℃ and an end boiling point of 80 to 100 ℃.

4. The method according to claim 1, wherein the gasoline middle distillate has an initial boiling point of 80 to 100 ℃ and an end boiling point of 120 to 150 ℃; the initial boiling point of the gasoline heavy fraction is 120-150 ℃, and the final boiling point is 200-250 ℃.

5. The method of claim 1, wherein the aromatic raffinate is returned to the catalytic cracking reaction unit for continuing the catalytic cracking reaction.

6. The process of claim 1, wherein the third catalyst comprises, based on the total weight of the catalyst: 1-60 wt% of zeolite, 5-99 wt% of inorganic oxide and 0-70 wt% of clay, wherein the zeolite is selected from medium pore zeolite, large pore zeolite or combination thereof; the medium pore zeolite is ZSM zeolite and/or ZRP zeolite, and the large pore zeolite is selected from one or more of beta zeolite, rare earth Y-type zeolite, rare earth hydrogen Y-type zeolite, ultrastable Y-type zeolite and high-silicon Y-type zeolite.

7. The process of claim 1, wherein the catalytic cracking reactor is a riser reactor; the temperature of the catalytic cracking reaction is 550-720 ℃, the reaction time is 1-10 s, the reaction pressure is 130-450kPa, and the catalyst-oil ratio is (1-100): 1.

8. the process of claim 1, wherein the temperature of the hydrodealkylation reaction is 260 to 720 ℃, the pressure is 0 to 5.6MPa, and the weight hourly space velocity is 0.2 to 6.5h^-1The hydrogen/hydrocarbon molar ratio is 1-13; preferably, the temperature of the hydrodealkylation reaction is 330-580 ℃, the pressure is 0.1-4.8 MPa, and the weight hourly space velocity is 0.5-5.8 h^-1The hydrogen/hydrocarbon molar ratio is 2-10; more preferably, the temperature of the lightening reaction is 360-560 ℃, the pressure is 1-4 MPa, and the weight hourly space velocity is 1.5-4.2 h^-1The hydrogen/hydrocarbon molar ratio is 3.5 to 6.5.

9. The method of claim 1, wherein the second catalyst comprises a support and an active metal component supported on the support; the content of the active metal component is 0.01-50 wt% based on the total weight of the second catalyst.

10. The method of claim 9, wherein the carrier comprises, based on the total weight of the carrier: 1 to 60 wt% of zeolite, 5 to 99 wt% of an inorganic oxide and 0 to 70 wt% of clay;

the zeolite comprises a medium pore zeolite and/or a large pore zeolite; the inorganic oxide is at least one of silicon dioxide, aluminum oxide, zirconium oxide, titanium oxide and amorphous silica-alumina; the clay is at least one selected from kaolin, montmorillonite, diatomite, attapulgite, sepiolite, halloysite, hydrotalcite, bentonite and rectorite.

11. The process of claim 10 wherein the intermediate pore zeolite is a ZSM zeolite and/or a ZRP zeolite and the large pore zeolite is selected from one or more of beta zeolite, rare earth Y zeolite, rare earth hydrogen Y zeolite, ultrastable Y zeolite, and high silica Y zeolite.

12. The method of claim 9, wherein the active metal component is one or a combination of two or more of a rare earth metal and a transition metal.

13. The method of claim 1, wherein the method further comprises: and (3) feeding the second spent catalyst into a fluidized bed regenerator for regeneration, and recycling the obtained second regenerated catalyst to the fluidized reactor.

14. The method of claim 13, wherein the fluidized bed regenerator includes a lock hopper, the method of regenerating comprising: and (3) enabling the second spent catalyst to enter the fluidized bed regenerator for regeneration through a lock hopper, and recycling the second regenerated catalyst to the fluidized reactor through the lock hopper.

15. A catalytic cracking process for producing xylene in high yield comprises the steps of enabling a raw material to be in contact with a first catalyst in a catalytic cracking reactor to carry out catalytic cracking reaction to obtain catalytic cracking reaction oil gas, and treating the catalytic cracking reaction oil gas by the method of any one of claims 1-14.

16. A system for processing catalytic pyrolysis gasoline comprises a catalytic pyrolysis gasoline inlet, a separation unit, an aromatic extraction unit, a catalytic cracking unit and a dealkylation reaction unit;

17. The system of claim 16, wherein the aromatics extraction and separation device comprises an aromatics extraction device, an aromatics separation column, and a solvent recovery device, the aromatics extraction device having the third oil gas inlet, a solvent inlet, an aromatics-solvent mixture outlet, and the aromatics raffinate oil outlet; the solvent recovery equipment is provided with an aromatic hydrocarbon-solvent mixed liquid inlet, an aromatic hydrocarbon outlet and a solvent outlet, and the aromatic hydrocarbon-solvent mixed liquid inlet is communicated with the aromatic hydrocarbon-solvent mixed liquid outlet of the aromatic hydrocarbon extraction equipment; the aromatic hydrocarbon separation tower is provided with a fifth oil gas inlet and a BTX aromatic hydrocarbon outlet, the fifth oil gas inlet is communicated with the aromatic hydrocarbon outlet of the solvent recovery equipment, and the BTX aromatic hydrocarbon outlet comprises a benzene outlet, a toluene outlet and a xylene outlet.

18. The system of claim 16, wherein the dealkylation reaction unit further comprises a second catalyst regenerator, the second catalyst regenerator being a fluidized bed regenerator with a lock hopper.

19. The system of claim 16, wherein the fluidized reactor is a dilute phase transport bed reactor, a fluidized bed reactor, a composite reactor composed of a dilute phase transport bed reactor and a fluidized bed reactor, a composite reactor composed of two or more dilute phase transport bed reactors, or a composite reactor composed of two or more fluidized bed reactors; the dilute phase conveying bed reactor is a riser reactor; the fluidized bed reactor is a bubbling bed reactor, a turbulent bed reactor or a fast bed reactor; the fluidized reactor is an upflow reactor or a downflow reactor.

20. The system of claim 16, wherein the catalytic cracking unit further comprises a third catalyst regenerator.

21. A catalytic cracking device, comprising a catalytic cracking reactor and the system of any one of claims 16-20, wherein the reaction oil gas outlet of the catalytic cracking reactor is communicated with the catalytic cracking reaction oil gas inlet of the system, the raw material inlet of the catalytic cracking reactor is communicated with the light gasoline outlet, and the raw material inlet of the catalytic cracking reactor is communicated with the aromatic raffinate oil outlet.