Process and apparatus for co-production of low carbon olefins and aromatic hydrocarbons from fischer-tropsch synthesis products

Abstract

The present invention provides a method for co-production of low carbon olefins and aromatics from Fischer-Tropsch synthesis products and an apparatus for carrying out the method. The method of the present invention is achieved by feeding different Fischer-Tropsch synthesis products into three reactors in series, wherein the first reactor is mainly used for processing Fischer-Tropsch low carbon saturated hydrocarbons for catalytic thermal cracking reaction; the second reactor is mainly used for processing Fischer-Tropsch light oil for catalytic cracking reaction; and the third reactor is mainly used for processing Fischer-Tropsch heavy oil for catalytic cracking and aromatization reaction, so as to achieve the purpose of co-production of low carbon olefins and aromatics with high yield. In particular, the method of the present invention can achieve the production of low carbon olefins with a yield of more than 39% while co-producing aromatics with a yield of more than 30%.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of processing of Fischer-Tropsch synthesis products, and relates to a method for converting Fischer-Tropsch synthesis products and a device for implementing the method, in particular to a method for co-producing low-carbon olefins and aromatic hydrocarbons from Fischer-Tropsch synthesis products and a device for implementing the method. BACKGROUND

[0002] Fischer-Tropsch synthesis is a process for synthesizing liquid fuels mainly composed of saturated linear hydrocarbons from synthesis gas as raw material under the catalysis of catalysts and appropriate reaction conditions. Fischer-Tropsch synthesis technology can obtain very clean Fischer-Tropsch synthesis oil because the sulfur and nitrogen pollutants are removed in the synthesis gas purification unit, and the synthesis gas can be converted from coal, natural gas, coal bed gas and biomass, etc., and is not restricted by natural oil reserves. Low-carbon olefins and aromatic hydrocarbons are both chemical raw materials with high added value, which can bring considerable economic benefits. Therefore, using Fischer-Tropsch synthesis products as raw materials to produce chemical raw materials such as low-carbon olefins and aromatic hydrocarbons can better adapt to market changes.

[0003] From the literature reports in recent years, it can be seen that the processing of Fischer-Tropsch synthesis products mainly adopts catalytic cracking technology, and the target product is mainly clean gasoline. Patent application CN106609154A discloses a method for producing gasoline from Fischer-Tropsch synthesis oil, which adopts two reactors in parallel to process Fischer-Tropsch oil products, wherein the first reactor is a riser reactor, and the active component of the catalyst is a zeolite molecular sieve and a five-membered ring high-silica zeolite, and the processing distillation range of Fischer-Tropsch synthesis products is 200-750℃; the second reactor is a riser reactor, a fluidized bed reactor, a moving bed reactor, and a downflow reactor, and a mixed catalyst of a fresh catalyst and a regenerated catalyst is used as an aromatization catalyst, and the processing is liquefied gas and / or gasoline fraction. The conversion of Fischer-Tropsch synthesis products into aromatic hydrocarbons requires a relatively low oil agent contact temperature and a relatively long oil agent contact time, while the oil agent contact temperature of the method is relatively high and the contact time is relatively short, and the aromatic hydrocarbon yield is not ideal.

[0004] Patents CN105567299B, CN105567307B and CN106609151B disclose a method for producing low-carbon olefins from Fischer-Tropsch synthesis products. However, these methods do not focus on how to obtain aromatic hydrocarbons, and even less on how to co-produce low-carbon olefins and aromatic hydrocarbons.

[0005] From the existing technologies disclosed in the art, the processing of Fischer-Tropsch synthesis products is mainly focused on the process of producing gasoline from Fischer-Tropsch synthesis products or the process of producing low-carbon olefins from Fischer-Tropsch synthesis products, and there are few reports on the process of co-producing low-carbon olefins in the process of producing aromatic hydrocarbons from Fischer-Tropsch synthesis products. SUMMARY

[0006] To solve the above problems, the present inventors provide a method for co-producing low carbon olefins and aromatic hydrocarbons from Fischer-Tropsch synthesis products, and also provide an apparatus for implementing the method. The method of the present application realizes the co-production of low carbon olefins and aromatic hydrocarbons with high yield by feeding different Fischer-Tropsch synthesis products into three reactors in series, wherein the first reactor is mainly used for treating Fischer-Tropsch low carbon saturated hydrocarbons to perform catalytic thermal cracking reaction; the second reactor is mainly used for treating Fischer-Tropsch light oil to perform catalytic cracking reaction; and the third reactor is mainly used for treating Fischer-Tropsch heavy oil to perform catalytic cracking and aromatization reaction. In particular, the method of the present application can realize the production of low carbon olefins with a yield of more than 39% and the production of aromatic hydrocarbons with a yield of more than 30%.

[0007] In one aspect, the present application provides a method for co-producing low carbon olefins and aromatic hydrocarbons from Fischer-Tropsch synthesis products, the method comprising:

[0008] (1) feeding Fischer-Tropsch low carbon saturated hydrocarbons and optional atomizing medium into the first reactor in atomized form, contacting with a first catalyst and performing catalytic thermal cracking reaction to obtain a first reaction stream and feeding the first reaction stream to the second reactor;

[0009] (2) feeding Fischer-Tropsch light oil and optional atomizing medium into the second reactor in atomized form, mixing with the first reaction stream, contacting with a second catalyst and performing catalytic cracking reaction to obtain a second reaction stream and feeding the second reaction stream to the third reactor;

[0010] (3) feeding Fischer-Tropsch heavy oil and optional atomizing medium into the third reactor in atomized form, mixing with the second reaction stream, contacting with a third catalyst and performing catalytic cracking and aromatization reaction to obtain a third reaction stream;

[0011] (4) performing settling separation on the third reaction stream obtained in step (3) to remove spent catalyst from the third reaction stream; performing fractionation on the obtained reaction product to obtain gas phase product, light oil, heavy oil, wherein performing olefin separation on the gas phase product to obtain dry gas, low carbon saturated hydrocarbons, low carbon olefins, performing aromatic hydrocarbon extraction on the light oil to obtain aromatic hydrocarbons and aromatic hydrocarbon raffinate; and performing stripping on the spent catalyst, optionally performing decoking and performing regeneration to obtain regenerated catalyst, wherein the regenerated catalyst is returned to the first reactor, the second reactor and the third reactor respectively for recycling.

[0012] In some embodiments, the method further comprises recycling the low carbon saturated hydrocarbons and the aromatic hydrocarbons raffinate obtained in step (4) to the first reactor and the second reactor, respectively. In some embodiments, the method further comprises recycling the low carbon saturated hydrocarbons obtained in step (4) to the first reactor; recycling the aromatic hydrocarbons raffinate obtained in step (4) to the second reactor.

[0013] In another aspect, the present application provides a co-production apparatus for carrying out the above-mentioned method, i.e., an apparatus for co-producing low carbon olefins and aromatic hydrocarbons from Fischer-Tropsch synthesis products, the apparatus comprising a reaction system, a regeneration system and a product separation system,

[0014] wherein the reaction system comprises:

[0015] a first reactor;

[0016] a second reactor, which is arranged in series with the first reactor;

[0017] a third reactor, which is arranged in series with the second reactor;

[0018] a settling unit, which is connected in fluid communication to the third reactor and the product separation system;

[0019] wherein the regeneration system is for catalyst regeneration, and the regeneration system comprises:

[0020] a stripping section, which is connected in fluid communication to the settling unit; and

[0021] a regenerator, which is connected in fluid communication to the stripping section and the first reactor, the second reactor and the third reactor.

[0022] In some embodiments, the product separation system comprises:

[0023] (a) a fractionation unit,

[0024] (b) an olefin separation unit, and

[0025] (c) an aromatic hydrocarbons extraction unit,

[0026] wherein the fractionation unit is connected in fluid communication to the settling unit, and the olefin separation unit and the aromatic hydrocarbons extraction unit are connected in fluid communication to the fractionation unit, respectively.

[0027] In preferred embodiments, the regeneration system further comprises:

[0028] A coke burning tank is connected in fluid communication to the stripping section and the regenerator.

[0029] In some embodiments, a combustion furnace is also provided in the regeneration system, which is connected in fluid communication to the coke burning tank to provide oxygen-containing high-temperature flue gas into the coke burning tank.

[0030] The method according to the present application can achieve the following beneficial effects:

[0031] (1) The method according to the present application can obtain low-carbon olefins at a yield of more than 39% (e.g. 39%-55%) and aromatics at a yield of more than 30% (e.g. 30%-38%).

[0032] (2) The present application sends Fischer-Tropsch low-carbon saturated hydrocarbons, Fischer-Tropsch light oil and Fischer-Tropsch heavy oil into the first reactor, the second reactor and the third reactor, respectively. The Fischer-Tropsch low-carbon saturated hydrocarbons undergo catalytic thermal cracking reaction by contacting with the catalyst at a higher temperature, the Fischer-Tropsch light oil undergoes catalytic cracking reaction by contacting with the catalyst at a higher temperature, and the Fischer-Tropsch heavy oil undergoes catalytic cracking and aromatization reaction by contacting with the catalyst at a lower temperature. The purpose of co-production of low-carbon olefins and aromatics can be better achieved by flexibly adjusting the feedstock ratio of the three reactors.

[0033] (3) The present application can increase the secondary reaction (e.g. condensation, cyclization and dehydrogenation reaction, etc.) of the olefins, which are the intermediate products of the catalytic cracking of Fischer-Tropsch synthesis products, to facilitate the production of more aromatics. Therefore, the present application utilizes three reactors to process Fischer-Tropsch synthesis products according to their different properties, thereby achieving the co-production of low-carbon olefins and aromatics.

[0034] (4) The prior art has disclosed methods for separately producing aromatics and separately producing low-carbon olefins from Fischer-Tropsch synthesis products. The present application uses different processing methods for feedstocks with different carbon numbers. The shorter the carbon number of the feedstock, the higher the temperature of the contact with the catalyst; the longer the carbon number of the feedstock, the lower the temperature of the contact with the catalyst. By processing multiple feedstocks, the co-production of low-carbon olefins and aromatics can be achieved, thereby achieving good economic benefits. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 A schematic diagram of an exemplary device for co-production of low-carbon olefins and aromatics from Fischer-Tropsch synthesis products according to the present application.

[0036] The explanation of the reference signs is as follows:

[0037] 1, first reactor; 2, second reactor; 3, third reactor; 4, combustion furnace; 5, coking drum; 6, regenerator; 7, reactor settler; 8, regenerator settler; 9, raw gas pipe; 10, stripping section; 11, regeneration pipe I; 12, regeneration pipe II; 13, regeneration pipe III; 14, fractionation unit; 15, olefin separation unit; 16, aromatic extraction unit.

[0038] I, Fischer-Tropsch low carbon saturated hydrocarbon; II, Fischer-Tropsch light oil; III, Fischer-Tropsch heavy oil; IV, atomizing medium; V, stripping steam; VI, flue gas; VII, gas phase product; VIII, light oil; IX, heavy oil; X, dry gas; XI, low carbon saturated hydrocarbon; XII, low carbon olefin; XIII, aromatic; XIV, aromatic raffinate. DETAILED DESCRIPTION

[0039] For better understanding of the present application, further description will be made in connection with specific embodiments, but these embodiments should not be understood as any limitation to the present application.

[0040] In the present application, unless otherwise specified, the term "low carbon olefin" means C2-C4 olefin, for example, including ethylene, propylene, 1-butene, isobutylene, cis-2-butene, trans-2-butene, or a mixture thereof.

[0041] In the present application, unless otherwise specified, the term "aromatic" means C6-C10 aromatic, including benzene, toluene, ethylbenzene, o-xylene, m-xylene, p-xylene, and C9, C10 aromatic, or a mixture thereof.

[0042] In the present application, unless otherwise specified, the term "low carbon saturated hydrocarbon" means C2-C4 alkane, for example, including ethane, propane, butane, isobutane, or a mixture thereof.

[0043] In the present application, unless otherwise specified, the term "gas phase product" means a fraction of the product having a distillation range of 15°C or less.

[0044] In the present application, unless otherwise specified, the term "light oil" means a fraction of the product having a distillation range of 15°C to 220°C.

[0045] In the present application, unless otherwise specified, the term "heavy oil" means a fraction of the product having a distillation range of 220°C or more.

[0046] In the present application, unless otherwise specified, the term "dry gas" means a portion remaining after "olefin (i.e., low carbon olefin)" and low carbon saturated hydrocarbon are separated from "gas phase product". For example, dry gas can include hydrogen, methane, or a mixture thereof.

[0047] In the present application, the term "aromatic raffinate" refers to the portion remaining after the "aromatics" are separated from the "light oil" unless otherwise specified.

[0048] In the present application, the term "spent catalyst" refers to the carbon-containing catalyst after reaction unless otherwise specified. For example, the term "spent catalyst" can refer to the carbon-containing catalyst after reaction but before stripping. In some cases, the term "spent catalyst" includes the carbon-containing catalyst after reaction and stripping, commonly referred to as the spent catalyst after stripping.

[0049] In the present application, the term "carbon deposit" refers to the total carbon mass of the spent catalyst characterized by using a sulfur carbon analyzer or a thermogravimetric analyzer, in combination with the loading calculation of the spent catalyst unless otherwise specified.

[0050] In one aspect, the present application provides a method for co-producing low carbon olefins and aromatics from Fischer-Tropsch synthesis products, the method comprising:

[0051] (1) feeding the Fischer-Tropsch low carbon saturated hydrocarbons and optionally an atomizing medium into a first reactor in an atomized form, contacting with a first catalyst and performing a catalytic thermal cracking reaction to obtain a first reaction stream and feeding the first reaction stream to a second reactor;

[0052] (2) feeding the Fischer-Tropsch light oil and optionally an atomizing medium into the second reactor in an atomized form, mixing with the first reaction stream, contacting with a second catalyst and performing a catalytic cracking reaction to obtain a second reaction stream and feeding the second reaction stream to a third reactor;

[0053] (3) feeding the Fischer-Tropsch heavy oil and optionally an atomizing medium into the third reactor in an atomized form, mixing with the second reaction stream, contacting with a third catalyst and performing a catalytic cracking and aromatization reaction to obtain a third reaction stream;

[0054] (4) performing a settling separation on the third reaction stream obtained in step (3) to remove the spent catalyst from the third reaction stream; performing a fractionation on the reaction products obtained to obtain a gas phase product, a light oil, a heavy oil, wherein performing an olefin separation on the gas phase product to obtain dry gas, low carbon saturated hydrocarbons, low carbon olefins, performing an aromatic extraction on the light oil to obtain aromatics and an aromatic raffinate; performing an optional coke burning on the spent catalyst after stripping and performing a regeneration to obtain a regenerated catalyst, wherein the regenerated catalyst is returned to the first reactor, the second reactor and the third reactor respectively for recycling.

[0055] In some embodiments, the method further comprises recycling the low carbon saturated hydrocarbons and the aromatic hydrocarbons raffinate obtained in step (4) to the first reactor and the second reactor, respectively. In some embodiments, the method further comprises recycling the low carbon saturated hydrocarbons obtained in step (4) to the first reactor; recycling the aromatic hydrocarbons raffinate obtained in step (4) to the second reactor.

[0056] In step (1), the Fischer-Tropsch low carbon saturated hydrocarbons are C2-C4 alkanes obtained from Fischer-Tropsch liquid gas after olefin separation, and specifically can comprise ethane, propane, butane, isobutane or a mixture thereof. Among them, the Fischer-Tropsch liquid gas can be C2-C4 hydrocarbons in Fischer-Tropsch synthesis products. For example, the Fischer-Tropsch liquid gas can comprise ethane, ethylene, propane, propylene, n-butane, isobutane, cis-2-butene, trans-2-butene or a mixture thereof.

[0057] In step (2), the Fischer-Tropsch light oil is selected from Fischer-Tropsch synthesis light components with an initial boiling point of 36-220°C, but is not limited thereto. In some embodiments, the Fischer-Tropsch light oil mainly comprises C5-C12 hydrocarbons in Fischer-Tropsch synthesis products.

[0058] In step (3), the Fischer-Tropsch heavy oil is a Fischer-Tropsch synthesis heavy component with an initial boiling point greater than 220°C, preferably greater than 280°C. In some embodiments, the Fischer-Tropsch heavy oil mainly comprises hydrocarbons above C12 in Fischer-Tropsch synthesis products.

[0059] In the present application, the mass ratio of Fischer-Tropsch low carbon saturated hydrocarbons, Fischer-Tropsch light oil and Fischer-Tropsch heavy oil can be (5-30):(5-40):(30-90).

[0060] In a preferred embodiment, in step (1), step (2) or step (3), the Fischer-Tropsch low carbon saturated hydrocarbons, Fischer-Tropsch light oil or Fischer-Tropsch heavy oil is mixed with optional atomization medium for atomization. Among them, the atomization medium can be selected from one or more of methanol, ethanol, propanol, dry gas, nitrogen or water vapor, for example, a mixture thereof. The dry gas includes one or more of hydrogen, methane, ethane. In some embodiments, the dry gas can be hydrogen, methane, ethane in Fischer-Tropsch products. In the present application, atomization is carried out according to the operating process available in the art.

[0061] In a particular embodiment, the mass ratio of the Fischer-Tropsch low carbon saturated hydrocarbons to the atomizing medium can be 1 : (0-1), preferably 1 : (0.1-1), for example, 1 :0, 1 :0.1, 1 :0.15, 1 :0.18, 1 :0.2, 1 :0.25, 1 :0.3, 1 :0.35, 1 :0.4, 1 :0.45, 1 :0.5, 1 :0.55, 1 :0.6, 1 :0.65, 1 :0.7, 1 :0.75, 1 :0.8, 1 :0.85, 1 :0.9, 1 :0.95, or 1 :1; or, the mass ratio of the Fischer-Tropsch light oil to the atomizing medium can be 1 : (0-1), preferably 1 : (0.1-1), for example, 1 :0, 1 :0.1, 1 :0.15, 1 :0.18, 1 :0.2, 1 :0.25, 1 :0.3, 1 :0.35, 1 :0.4, 1 :0.45, 1 :0.5, 1 :0.55, 1 :0.6, 1 :0.65, 1 :0.7, 1 :0.75, 1 :0.8, 1 :0.85, 1 :0.9, 1 :0.95, or 1 :1; or, the mass ratio of the Fischer-Tropsch heavy oil to the atomizing medium can be 1 : (0-1), preferably 1 : (0.1-1), for example, 1 :0, 1 :0.1, 1 :0.15, 1 :0.18, 1 :0.2, 1 :0.25, 1 :0.3, 1 :0.35, 1 :0.4, 1 :0.45, 1 :0.5, 1 :0.55, 1 :0.6, 1 :0.65, 1 :0.7, 1 :0.75, 1 :0.8, 1 :0.85, 1 :0.9, 1 :0.95, or 1 :1.

[0062] Preferably, in step (1), the weight ratio of the Fischer-Tropsch low carbon saturated hydrocarbons to the atomizing medium is 1 : (0-0.6), preferably 1 : (0.15-0.6). Preferably, in step (2), the weight ratio of the Fischer-Tropsch light oil to the atomizing medium is 1 : (0-0.8), preferably 1 : (0.15-0.5). Preferably, in step (3), the weight ratio of the Fischer-Tropsch heavy oil to the atomizing medium is 1 : (0-0.8), preferably 1 : (0.15-0.5).

[0063] In some preferred embodiments, in step (1), step (2), or step (3), the Fischer-Tropsch low carbon saturated hydrocarbons, Fischer-Tropsch light oil, or Fischer-Tropsch heavy oil is preheated before being atomized. Preferably, the Fischer-Tropsch low carbon saturated hydrocarbons, Fischer-Tropsch light oil, or Fischer-Tropsch heavy oil is preheated to 100°C-400°C. More preferably, in step (1), the Fischer-Tropsch low carbon saturated hydrocarbons is preheated to 100°C-350°C. Preferably, in step (2), the Fischer-Tropsch light oil is preheated to 100°C-350°C. In step (3), the Fischer-Tropsch heavy oil is preheated to 100°C-350°C.

[0064] In some preferred embodiments, the active components of the first catalyst, the second catalyst and the third catalyst of the present application are at least one selected from unmodified or modified eight-membered ring molecular sieve, ten-membered ring molecular sieve, twelve-membered ring molecular sieve or metal oxide. Preferably, the eight-membered ring molecular sieve, ten-membered ring molecular sieve or twelve-membered ring molecular sieve can be selected from SAPO-34, SAPO-18, ITQ-13, IM-5, ZSM-5, ZSM-11, MCM-22, EU-1, beta, mordenite molecular sieve and the like; the metal oxide can be selected from one or several of zinc oxide, lanthanum oxide, magnesium oxide, manganese oxide, cerium oxide, gallium oxide, chromium oxide, nickel oxide, tungsten oxide.

[0065] In some preferred embodiments, the active components of the first catalyst, the second catalyst and the third catalyst of the present application are at least one selected from unmodified or modified eight-membered ring molecular sieve, ten-membered ring molecular sieve, twelve-membered ring molecular sieve or metal oxide. Preferably, the eight-membered ring molecular sieve, ten-membered ring molecular sieve or twelve-membered ring molecular sieve can be selected from SAPO-34, SAPO-18, ITQ-13, IM-5, ZSM-5, ZSM-11, MCM-22, EU-1, beta, mordenite molecular sieve and the like; the metal oxide can be selected from one or several of zinc oxide, lanthanum oxide, magnesium oxide, manganese oxide, cerium oxide, gallium oxide, chromium oxide, nickel oxide, tungsten oxide.

[0066] In some preferred embodiments, the first catalyst can be a mixed catalyst of regenerated catalyst and spent catalyst, wherein the carbon content of the first catalyst can be 0wt%-2.00wt%. In another further preferred embodiment, the second catalyst can be a mixture of regenerated catalyst and spent catalyst, wherein the carbon content of the second catalyst can be 0wt%-2.0wt%. In another further preferred embodiment, the third catalyst can be a mixture of regenerated catalyst and spent catalyst, wherein the carbon content of the third catalyst can be 0wt%-2.0wt%.

[0067] In some preferred embodiments, in step (1), the reaction conditions of the first reactor are: temperature 500-750°C, preferably 580-680°C; pressure 0.01-0.7MPa, preferably 0.1-0.5MPa; weight hourly space velocity 10-300h -1 , preferably 40-200h -1 ; catalyst to oil ratio 0.5-50, preferably 5-30.

[0068] In some preferred embodiments, in step (2), the reaction conditions of the second reactor are: temperature 450-700°C, preferably 530-630°C; pressure 0.01-0.7MPa, preferably 0.1-0.5MPa; weight hourly space velocity 1-150h -1 , preferably 40-120h -1 ; catalyst to oil ratio 1-40, preferably 5-25.

[0069] In some preferred embodiments, in step (3), the reaction conditions of the third reactor are: temperature 400-650°C, preferably 480-580°C; pressure 0.01-0.7 MPa, preferably 0.1-0.5 MPa; weight hourly space velocity 0.5-30 h -1 , preferably 2-20 h -1 ; and oil to catalyst ratio 1-20, preferably 2-15.

[0070] In some preferred embodiments, the first reactor is a transport bed reactor, a fast bed reactor or a turbulent bed reactor, preferably a transport bed reactor or a fast bed reactor. In which the feedstock with shorter carbon chain can be contacted with catalyst at higher temperature to occur catalytic thermal cracking reaction, thereby obtaining more olefins.

[0071] In some preferred embodiments, the second reactor is a fast bed reactor, a turbulent bed reactor or a bubbling bed reactor, preferably a turbulent bed reactor or a fast bed reactor. In which the feedstock with moderate carbon chain length can be contacted with catalyst at higher temperature to occur catalytic cracking reaction, thereby obtaining more olefins.

[0072] In some preferred embodiments, the third reactor is a turbulent bed reactor, a bubbling bed reactor or a dispersed fluidized bed reactor, preferably a turbulent bed reactor or a bubbling bed reactor. In which the feedstock with longer carbon chain can be contacted with catalyst at lower temperature and under lower space velocity to occur more catalytic cracking reaction, condensation reaction, cyclization reaction, hydrogen transfer reaction and aromatization reaction, thereby obtaining more aromatics.

[0073] In some preferred embodiments, in step (4), the operating pressure of the settling separation is 0.01-0.7 MPa, preferably 0.1-0.5 MPa.

[0074] In this context, fractionation, olefin separation, aromatic extraction and stripping are all carried out by conventional operations in the art without particular limitation.

[0075] In some preferred embodiments, 10-90% of the low carbon saturated hydrocarbons obtained in step (4) can be returned to the first reactor for recycling; and 5-95% of the aromatic raffinate obtained in step (4) can be returned to the second reactor for recycling.

[0076] In some preferred embodiments, in step (4), the contact of the spent catalyst with the oxygen-containing gas for the optional coking and regeneration is carried out under the following conditions: pressure 0.01-0.7 MPa, preferably 0.1-0.5 MPa; temperature 550-750°C, preferably 580-700°C. Preferably, the oxygen-containing gas can be air or oxygen-containing high-temperature flue gas.

[0077] In another aspect, the present application provides a co-production apparatus for carrying out the above-mentioned method, i.e., an apparatus for co-producing low carbon olefins and aromatic hydrocarbons from Fischer-Tropsch synthesis products, the apparatus comprising a reaction system, a regeneration system and a product separation system,

[0078] wherein the reaction system comprises:

[0079] a first reactor;

[0080] a second reactor, which is arranged in series with the first reactor;

[0081] a third reactor, which is arranged in series with the second reactor;

[0082] a settling unit, which is connected in fluid communication to the third reactor and the product separation system;

[0083] wherein the regeneration system comprises:

[0084] a stripping section, which is connected in fluid communication to the settling unit;

[0085] a regenerator, which is connected in fluid communication to the stripping section and the first, second and third reactors.

[0086] In a preferred embodiment, the regeneration system further comprises:

[0087] a coking drum, which is connected in fluid communication to the stripping section and the regenerator.

[0088] In some embodiments, a combustion furnace is further provided in the regeneration system, which is connected in fluid communication to the coking drum to provide oxygen-containing high-temperature flue gas (e.g., the flue gas temperature is at 550-750°C) into the coking drum.

[0089] In some embodiments, fuel gas and air are sent into the combustion furnace to be ignited to generate oxygen-containing high-temperature flue gas, and then the oxygen-containing high-temperature flue gas is introduced into the coking drum. In some embodiments, the fuel gas can be selected from liquefied petroleum gas, which has a composition of C3, C4 alkanes.

[0090] In some embodiments, the product separation system comprises:

[0091] a fractionation unit, which is connected in fluid communication to the settling unit;

[0092] an olefin separation unit, which is connected in fluid communication to the fractionation unit; and

[0093] an aromatics extraction unit connected in fluid communication to the fractionation unit.

[0094] In some preferred embodiments, the first reactor is a transport bed reactor, a fast bed reactor or a turbulent bed reactor, preferably a transport bed reactor or a fast bed reactor.

[0095] In some preferred embodiments, the second reactor is a fast bed reactor, a turbulent bed reactor or a bubbling bed reactor. In the present application, the second reactor is preferably a fast bed reactor or a turbulent bed reactor.

[0096] In some preferred embodiments, the third reactor is a turbulent bed reactor, a bubbling bed reactor or a dispersed fluidized bed reactor, preferably a turbulent bed reactor or a bubbling bed reactor.

[0097] In the present application, the first reactor, the second reactor and the third reactor can share one settler.

[0098] The method provided by the present application is further described below in combination with the accompanying drawings.

[0099] The preheated Fischer-Tropsch low-carbon saturated hydrocarbons and optional atomizing medium at 100-400℃ are mixed in a mass ratio of 1:(0-1) and atomized, and then fed into the first reactor; the preheated Fischer-Tropsch light oil and optional atomizing medium at 100-400℃ are mixed in a mass ratio of 1:(0-1) and atomized, and then fed into the second reactor; and the preheated Fischer-Tropsch heavy oil and optional atomizing medium at 100-400℃ are mixed in a mass ratio of 1:(0-1) and atomized, and then fed into the third reactor. -1 The first reaction stream is obtained by contacting the preheated Fischer-Tropsch low-carbon saturated hydrocarbons and optional atomizing medium at 100-400℃ with the first catalyst under the conditions of a reaction temperature of 500-750℃, a reaction pressure of 0.01-0.7 MPa, a catalyst / oil ratio of 0.5-50, and a weight hourly space velocity of 10-300 h-1, and then the first reaction stream carrying the reacted first catalyst goes up into the second reactor.

[0100] The first reaction stream is obtained by contacting the preheated Fischer-Tropsch low-carbon saturated hydrocarbons and optional atomizing medium at 100-400℃ with the first catalyst under the conditions of a reaction temperature of 500-750℃, a reaction pressure of 0.01-0.7 MPa, a catalyst / oil ratio of 0.5-50, and a weight hourly space velocity of 10-300 h-1, and then the first reaction stream carrying the reacted first catalyst goes up into the second reactor. -1 The second reaction stream is obtained by contacting the preheated Fischer-Tropsch light oil and optional atomizing medium at 100-400℃ with the second catalyst under the conditions of a reaction temperature of 450-700℃, a reaction pressure of 0.01-0.7 MPa, a catalyst / oil ratio of 1-40, and a weight hourly space velocity of 1-150 h-1, and then the second reaction stream carrying the reacted second catalyst goes into the third reactor.

[0101] The first reaction stream is obtained by contacting the preheated Fischer-Tropsch low-carbon saturated hydrocarbons and optional atomizing medium at 100-400℃ with the first catalyst under the conditions of a reaction temperature of 500-750℃, a reaction pressure of 0.01-0.7 MPa, a catalyst / oil ratio of 0.5-50, and a weight hourly space velocity of 10-300 h-1, and then the first reaction stream carrying the reacted first catalyst goes up into the second reactor.

[0097] In the present application, the first reactor, the second reactor and the third reactor can share one settler.

[0098] The method provided by the present application is further described below in combination with the accompanying drawings.

[0099] The preheated Fischer-Tropsch low-carbon saturated hydrocarbons and optional atomizing medium at 100-400℃ are mixed in a mass ratio of 1:(0-1) and atomized, and then fed into the first reactor; the preheated Fischer-Tropsch light oil and optional atomizing medium at 100-400℃ are mixed in a mass ratio of 1:(0-1) and atomized, and then fed into the second reactor; and the preheated Fischer-Tropsch heavy oil and optional atomizing medium at 100-400℃ are mixed in a mass ratio of 1:(0-1) and atomized, and then fed into the third reactor. -1 The first reaction stream is obtained by contacting the preheated Fischer-Tropsch low-carbon saturated hydrocarbons and optional atomizing medium at 100-400℃ with the first catalyst under the conditions of a reaction temperature of 500-750℃, a reaction pressure of 0.01-0.7 MPa, a catalyst / oil ratio of 0.5-50, and a weight hourly space velocity of 10-300 h-1, and then the first reaction stream carrying the reacted first catalyst goes up into the second reactor.

[0100] The first reaction stream is obtained by contacting the preheated Fischer-Tropsch low-carbon saturated hydrocarbons and optional atomizing medium at 100-400℃ with the first catalyst under the conditions of a reaction temperature of 500-750℃, a reaction pressure of 0.01-0.7 MPa, a catalyst / oil ratio of 0.5-50, and a weight hourly space velocity of 10-300 h-1, and then the first reaction stream carrying the reacted first catalyst goes up into the second reactor.

[0101] The first reaction stream is obtained by contacting the preheated Fischer-Tropsch low-carbon saturated hydrocarbons and optional atomizing medium at 100-400℃ with the first catalyst under the conditions of a reaction temperature of 500-750℃, a reaction pressure of 0.01-0.7 MPa, a catalyst / oil ratio of 0.5-50, and a weight hourly space velocity of 10-300 h-1, and then the first reaction stream carrying the reacted first catalyst goes up into the second reactor.-1 The third reaction stream is carried upward by the reacted third catalyst, and is separated in a settler under an operating pressure of 0.01-0.7 MPa to obtain a reaction product and spent catalyst.

[0102] The third reaction stream is carried upward by the reacted third catalyst, and is separated in a settler under an operating pressure of 0.01-0.7 MPa to obtain a reaction product and spent catalyst. The reaction product is sent to a fractionation unit for fractionation to obtain a gas phase product, light oil and heavy oil, wherein the gas phase product is sent to an olefin separation unit for olefin separation to obtain dry gas, low-carbon saturated hydrocarbons and low-carbon olefins, and the light oil is sent to an aromatic extraction unit for aromatic extraction to obtain aromatic hydrocarbons and aromatic raffinate. In some preferred embodiments, 10-90% of the obtained low-carbon saturated hydrocarbons and 5-95% of the aromatic raffinate can be returned to the first reactor and the second reactor, respectively, for back-refining.

[0103] The spent catalyst is steam-stripped in a stripping section and is sent through a spent catalyst pipe to an optional coking tank and regenerator for optional coking and regeneration, and is contacted with an oxygen-containing gas (such as air) under conditions of a temperature of 550-750°C and a pressure of 0.1-0.7 MPa to burn off the coke to obtain regenerated catalyst, which is circulated back to the first reactor, the second reactor and the third reactor through a regeneration pipe I, a regeneration pipe II and a regeneration pipe III, respectively, for recycling.

[0104] The exemplary technical solutions of the present application can be illustrated by the following numbered paragraphs, but the scope of protection of the present application is not limited thereto:

[0105] 1. A method for co-producing low-carbon olefins and aromatic hydrocarbons from Fischer-Tropsch synthesis products, the method comprising:

[0106] (1) feeding Fischer-Tropsch low-carbon saturated hydrocarbons and optional atomizing medium into a first reactor in an atomized form, contacting with a first catalyst and performing a catalytic thermal cracking reaction to obtain a first reaction stream and sending the first reaction stream to a second reactor;

[0107] (2) feeding Fischer-Tropsch light oil and optional atomizing medium into the second reactor in an atomized form, mixing with the first reaction stream, contacting with a second catalyst and performing a catalytic cracking reaction to obtain a second reaction stream and sending the second reaction stream to a third reactor;

[0108] (3) feeding Fischer-Tropsch heavy oil and optional atomizing medium into the third reactor in an atomized form, mixing with the second reaction stream, contacting with a third catalyst and performing a catalytic cracking and aromatization reaction to obtain a third reaction stream;

[0109] (4) subjecting the third reaction stream obtained in step (3) to a settling separation to remove spent catalyst from the third reaction stream; subjecting the obtained reaction product to a fractionation to obtain a gas phase product, a light oil, a heavy oil, wherein the gas phase product is subjected to an olefin separation to obtain dry gas, low carbon saturated hydrocarbons, low carbon olefins, the light oil is subjected to an aromatic extraction to obtain aromatic hydrocarbons and an aromatic raffinate; subjecting the spent catalyst to a stripping, then to an optional coke burning and to a regeneration to obtain a regenerated catalyst, wherein the regenerated catalyst is returned to the first reactor, the second reactor and the third reactor respectively for recycling.

[0110] 2. The method of paragraph 1, wherein the method further comprises returning the low carbon saturated hydrocarbons and the aromatic raffinate obtained in step (4) to the first reactor and the second reactor respectively for backfrying.

[0111] 3. The method of paragraph 1, wherein the mass ratio of the Fischer-Tropsch low carbon saturated hydrocarbons, the Fischer-Tropsch light oil and the Fischer-Tropsch heavy oil is (5-30):(5-40):(30-90).

[0112] 4. The method of any one of paragraphs 1-3, wherein in step (1), step (2) or step (3), the atomizing medium is selected from methanol, ethanol, propanol, dry gas, nitrogen or water vapor, or a mixture thereof.

[0113] 5. The method of paragraph 4, wherein the dry gas comprises one or more of hydrogen, methane and ethane.

[0114] 6. The method of paragraph 4, wherein the dry gas is hydrogen, methane and ethane in the Fischer-Tropsch products.

[0115] 7. The method of any one of paragraphs 1-3, wherein in step (1), step (2) or step (3), the mass ratio of the Fischer-Tropsch low carbon saturated hydrocarbons, the Fischer-Tropsch light oil or the Fischer-Tropsch heavy oil to the atomizing medium is 1:(0-1).

[0116] 8. The method of paragraph 7, wherein in step (1), step (2) or step (3), the mass ratio of the Fischer-Tropsch low carbon saturated hydrocarbons, the Fischer-Tropsch light oil or the Fischer-Tropsch heavy oil to the atomizing medium is 1:(0.1-1).

[0117] 9. The method of paragraph 7, wherein the mass ratio of the Fischer-Tropsch light saturates, the Fischer-Tropsch light oil, or the Fischer-Tropsch heavy oil to the atomizing medium in step (1), step (2), or step (3) is 1 :0, 1 :0.1, 1 :0.15, 1 :0.18, 1 :0.2, 1 :0.25, 1 :0.3, 1 :0.35, 1 :0.4, 1 :0.45, 1 :0.5, 1 :0.55, 1 :0.6, 1 :0.65, 1 :0.7, 1 :0.75, 1 :0.8, 1 :0.85, 1 :0.9, 1 :0.95, or 1 :1.

[0118] 10. The method of any one of paragraphs 1-3, wherein the weight ratio of the Fischer-Tropsch light saturates to the atomizing medium in step (1) is 1 :(0-0.6); or wherein the weight ratio of the Fischer-Tropsch light oil to the atomizing medium in step (2) is 1 :(0-0.8); or wherein the weight ratio of the Fischer-Tropsch heavy oil to the atomizing medium in step (3) is 1 :(0-0.8).

[0119] 11. The method of paragraph 10, wherein the weight ratio of the Fischer-Tropsch light saturates to the atomizing medium in step (1) is 1 :(0.15-0.6); or wherein the weight ratio of the Fischer-Tropsch light oil to the atomizing medium in step (2) is 1 :(0.15-0.5); or wherein the weight ratio of the Fischer-Tropsch heavy oil to the atomizing medium in step (3) is 1 :(0.15-0.5).

[0120] 12. The method of any one of paragraphs 1-3, wherein the Fischer-Tropsch light saturates, Fischer-Tropsch light oil, or Fischer-Tropsch heavy oil is preheated prior to atomization in step (1), step (2), or step (3).

[0121] 13. The method of paragraph 12, wherein the Fischer-Tropsch light saturates, Fischer-Tropsch light oil, or Fischer-Tropsch heavy oil is preheated to a temperature of 100 °C to 400 °C.

[0122] 14. The method of paragraph 13, wherein the Fischer-Tropsch light saturates is preheated to a temperature of 100 °C to 350 °C; or wherein the Fischer-Tropsch light oil is preheated to a temperature of 100 °C to 350 °C; or wherein the Fischer-Tropsch heavy oil is preheated to a temperature of 100 °C to 350 °C.

[0123] 15. The method of any one of paragraphs 1-3, wherein the active component of the first catalyst, second catalyst, and third catalyst is at least one selected from the group consisting of unmodified or modified eight-membered ring molecular sieves, ten-membered ring molecular sieves, twelve-membered ring molecular sieves, or metal oxides.

[0124] 16. The process of paragraph 15, wherein the eight-, ten- or twelve-membered ring molecular sieve is selected from the group consisting of SAPO-34, SAPO-18, ITQ-13, IM-5, ZSM-5, ZSM-11, MCM-22, EU-1, beta, mordenite molecular sieve; or, the metal oxide is selected from one or more of zinc oxide, lanthanum oxide, magnesium oxide, manganese oxide, cerium oxide, gallium oxide, chromium oxide, nickel oxide, tungsten oxide.

[0125] 17. The process of paragraph 15, wherein the active component of the first, second and third catalysts is in the range of 20 wt% to 60 wt% of the catalyst weight on a dry basis.

[0126] 18. The process of paragraph 17, wherein the first, second and third catalysts contain, in addition to the active component, a remaining amount of alumina and / or silica as a carrier.

[0127] 19. The process of any one of paragraphs 1-3, wherein the first catalyst is a mixed catalyst of regenerated catalyst and spent catalyst, wherein the carbon content of the first catalyst is in the range of 0 wt% to 2.00 wt%; or, wherein the second catalyst is a mixture of regenerated catalyst and spent catalyst, wherein the carbon content of the second catalyst is in the range of 0 wt% to 2.0 wt%; or, wherein the third catalyst is a mixture of regenerated catalyst and spent catalyst, wherein the carbon content of the third catalyst is in the range of 0 wt% to 2.0 wt%.

[0128] 20. The process of any one of paragraphs 1-3, wherein in step (1), the reaction conditions of the first reactor are: temperature 500°C to 750°C; pressure 0.01 to 0.7 MPa; weight hourly space velocity 10 to 300 h -1 ; catalyst to oil ratio 0.5 to 50.

[0129] 21. The process of paragraph 20, wherein the temperature is 580°C to 680°C; or the pressure is 0.1 to 0.5 MPa; or, the weight hourly space velocity is 40 to 200 h -1 ; or, the catalyst to oil ratio is 5 to 30.

[0130] 22. The process of any one of paragraphs 1-3, wherein in step (2), the reaction conditions of the second reactor are: temperature 450°C to 700°C; pressure 0.01 to 0.7 MPa; weight hourly space velocity 1 to 150 h -1 ; catalyst to oil ratio 1 to 40.

[0131] 23. The process as claimed in paragraph 22, wherein the temperature is 530-630 °C; or the pressure is 0.1-0.5 MPa; or the weight hourly space velocity is 40-120 h -1 ; or the ratio of agent to oil is 5-25.

[0132] 24. The process as claimed in any one of paragraphs 1-3, wherein in step (3), the reaction conditions of the third reactor are: temperature 400-650 °C; pressure 0.01-0.7 MPa; weight hourly space velocity 0.5-30 h -1 ; ratio of agent to oil 1-20.

[0133] 25. The process as claimed in paragraph 24, wherein the temperature is 480-580 °C; or the pressure is 0.1-0.5 MPa; or the weight hourly space velocity is 2-20 h -1 ; or the ratio of agent to oil is 2-15.

[0134] 26. The process as claimed in any one of paragraphs 1-3, wherein the first reactor is a transport bed reactor, a fast bed reactor or a turbulent bed reactor; or the second reactor is a fast bed reactor, a turbulent bed reactor or a bubbling bed reactor; or the third reactor is a turbulent bed reactor, a bubbling bed reactor or a dispersed fluidized bed reactor.

[0135] 27. The process as claimed in paragraph 26, wherein the first reactor is a transport bed reactor or a fast bed reactor; or the second reactor is a fast bed reactor or a turbulent bed reactor; or the third reactor is a bubbling bed reactor or a turbulent bed reactor.

[0136] 28. The process as claimed in any one of paragraphs 1-3, wherein in step (4), the operating pressure of the settling separation is 0.01-0.7 MPa.

[0137] 29. The process as claimed in paragraph 2, wherein 10%-90% of the low-carbon saturated hydrocarbons obtained in step (4) is returned to the first reactor for back- refining; or 5%-95% of the aromatic hydrocarbon raffinate obtained in step (4) is returned to the second reactor for back-refining.

[0138] 30. The process as claimed in any one of paragraphs 1-3, wherein in step (4), the contact of the spent catalyst with the oxygen-containing gas is optionally calcined and regenerated under the following conditions: pressure 0.01-0.7 MPa; temperature 550-750 °C.

[0139] 31. The process as claimed in paragraph 29, wherein the oxygen-containing gas is air or an oxygen-containing high-temperature flue gas.

[0140] 32. An apparatus for co-producing low carbon olefins and aromatic hydrocarbons from Fischer-Tropsch synthesis products, the apparatus comprising a reaction system, a regeneration system, and a product separation system,

[0141] wherein the reaction system comprises:

[0142] a first reactor;

[0143] a second reactor, the second reactor being disposed in series with the first reactor;

[0144] a third reactor, the third reactor being disposed in series with the second reactor;

[0145] a settler unit, the settler unit being connected in fluid communication to the third reactor and the product separation system;

[0146] wherein the regeneration system comprises:

[0147] a stripping section, the stripping section being connected in fluid communication to the settler unit;

[0148] a regenerator, the regenerator being connected in fluid communication to the stripping section and the first, second, and third reactors,

[0149] wherein the product separation system comprises:

[0150] a fractionation unit, the fractionation unit being connected in fluid communication to the settler unit;

[0151] an olefin separation unit, the olefin separation unit being connected in fluid communication to the fractionation unit; and

[0152] an aromatic extraction unit, the aromatic extraction unit being connected in fluid communication to the fractionation unit.

[0153] 33. The apparatus of paragraph 32, wherein the regeneration system further comprises:

[0154] a coking drum, the coking drum being connected in fluid communication to the stripping section and the regenerator.

[0155] 34. The apparatus of paragraph 33, wherein a combustion furnace is further provided in the regeneration system, the combustion furnace being connected in fluid communication to the coking drum to provide oxygen-containing high-temperature flue gas to the coking drum.

[0156] 35. The apparatus of any one of paragraphs 32-34, wherein the first, second, and third reactors share a common settler.

[0157] EMBODIMENTS

[0158] Unless otherwise indicated, the reagents, materials and apparatuses involved in the following examples are commercially available and conventional in the art; the conventional operations involved in the following examples can be found in the published patents, patent applications and publications in the art (for example, HE Yongde, ed., Handbook of Modern Coal Chemical Engineering Technology, Chemical Industry Press, 2003, the entire contents of which are incorporated herein).

[0159] The relevant properties of the Fischer-Tropsch heavy oil, Fischer-Tropsch light oil, Fischer-Tropsch low-carbon saturated hydrocarbon and dry gas used in the following examples are shown in Tables 1, 2 and 3.

[0160] Table 1 Relevant properties of Fischer-Tropsch synthesis products

[0161]

[0162] Note: * is the upper limit of chromatographic detection, 79% at 720°C; / is beyond the upper limit of detection

[0163] Table 2 Composition of Fischer-Tropsch low-carbon saturated hydrocarbon

[0164] Content, wt% Ethane 5％ Propane 40％ Butane 21％ Isobutane 34％

[0165] Table 3 Composition of dry gas

[0166] Content, wt% Hydrogen 36％ Methane 64％

[0167] Table 4 Molecular sieve, modified element type and content, composition, specific surface area and pore volume of catalyst

[0168]

[0169] Example 1

[0170] The mass ratio of Fischer-Tropsch low-carbon saturated hydrocarbon, Fischer-Tropsch light oil and Fischer-Tropsch heavy oil is 10:10:80, and the catalyst is the above-mentioned cat-1 catalyst.

[0171] The preheated Fischer-Tropsch low-carbon saturated hydrocarbon and methanol at 250°C are mixed and sent into the first transport bed reactor using methanol atomization, the mass ratio of Fischer-Tropsch low-carbon saturated hydrocarbon to methanol is 1:0.25; under the conditions of a reaction temperature of 660°C, a catalyst-oil ratio of the first catalyst and Fischer-Tropsch low-carbon saturated hydrocarbon in the first reactor of 10, a weight hourly space velocity of 60 h -1 The first reaction stream is obtained by contacting with the first catalyst and catalytic pyrolysis reaction. The first reaction stream carries the reacted first catalyst upwards and enters the second reactor.

[0172] Preheated Fischer-Tropsch light oil to 200°C was mixed with methanol and atomized into a second fast bed reactor. The mass ratio of Fischer-Tropsch light oil to methanol was 1:0.25. After entering the second reactor, the Fischer-Tropsch light oil was mixed with the first reaction stream. The reaction was carried out at a temperature of 560°C, a catalyst-to-oil ratio of 8 for the second catalyst in the second reactor, and a weight hourly space velocity of 50 h⁻¹. -1 Under certain conditions, the catalyst reacts with a second catalyst to undergo a catalytic cracking reaction, yielding a second reaction stream. This second reaction stream, carrying the reacted second catalyst, is then sent to a third reactor.

[0173] Preheated Fischer-Tropsch heavy oil to 150°C was mixed with methanol and atomized into a third turbulent bed reactor. The mass ratio of Fischer-Tropsch heavy oil to methanol was 1:0.25. After entering the third reactor, the Fischer-Tropsch heavy oil was mixed with the second reaction stream. The reaction temperature was 470°C, the catalyst-to-oil ratio in the third reactor was 2.2, and the weight hourly space velocity was 4 h⁻¹. -1 Under certain conditions, it comes into contact with a third catalyst and undergoes catalytic cracking and aromatization reactions to obtain a third reaction stream.

[0174] The third reactant stream, carrying the reacted third catalyst, rises and undergoes sedimentation separation in a settling tank at an operating pressure of 0.3 MPa, yielding reaction products and the remaining catalyst. The reaction products enter a fractionation unit to obtain gaseous products, light oil, and heavy oil. The gaseous products then pass through an olefin separation unit to obtain dry gas, low-carbon saturated hydrocarbons, and low-carbon olefins. The light oil enters an aromatics extraction unit to obtain aromatics and aromatics raffinate. 10% of the low-carbon saturated hydrocarbons are returned to the first reactor for reprocessing, and 5% of the aromatics raffinate is returned to the second reactor for reprocessing.

[0175] Fuel gas and air enter the combustion furnace and are ignited to produce oxygen-containing high-temperature flue gas, which is then sent into the coking tank.

[0176] The catalyst to be recycled is stripped by steam in the stripping section and then fed into the coking tank through the recycling pipe. There, it comes into contact with high-temperature oxygen-containing flue gas from the combustion furnace for coking. It then ascends to the regenerator to completely burn off the carbon deposits. The coking and regeneration temperatures are 630℃ and the pressure is 0.3 MPa, yielding regenerated catalyst. This regenerated catalyst is recycled back to the first, second, and third reactors via regeneration pipes I, II, and III, respectively. The amount of carbon deposits is calculated by measuring the carbon content in the catalyst to be recycled.

[0177] Comparative Example 1

[0178] Except that the Fischer-Tropsch low-carbon saturated hydrocarbons, Fischer-Tropsch light oil, and Fischer-Tropsch heavy oil were all mixed and fed into the first reactor, the reaction conditions in this comparative example were the same as those in the first reactor of Example 1. The second reactor was used only for catalyst boosting, and the third reactor was used only for catalyst recycling. As can be seen from Comparative Example 1, the reaction of Fischer-Tropsch low-carbon saturated hydrocarbons, Fischer-Tropsch light oil, and Fischer-Tropsch heavy oil in the first reactor yielded a relatively large amount of olefins, but the yield of aromatics was low.

[0179] Comparative Example 2

[0180] Except that the Fischer-Tropsch low-carbon saturated hydrocarbons, Fischer-Tropsch light oil, and Fischer-Tropsch heavy oil were all mixed and fed into the third reactor, the reaction conditions in this comparative example were the same as those in the third reactor of Example 1. The first and second reactors were only used to boost the catalyst. As can be seen from Comparative Example 2, the Fischer-Tropsch low-carbon saturated hydrocarbons, Fischer-Tropsch light oil, and Fischer-Tropsch heavy oil all reacted in the third reactor, producing a large amount of liquid-phase products, while the yields of low-carbon olefins and aromatics were relatively low.

[0181] Example 2

[0182] The mass ratio of Fischer-Tropsch low-carbon saturated hydrocarbons, Fischer-Tropsch light oil, and Fischer-Tropsch heavy oil is 5:15:80, and the catalyst is the aforementioned cat-2 catalyst.

[0183] Preheated Fischer-Tropsch low-carbon saturated hydrocarbons to 280°C were mixed with methanol and atomized into the first fast bed reactor. The mass ratio of Fischer-Tropsch low-carbon saturated hydrocarbons to methanol was 1:0.25. The reaction temperature was 610°C, the catalyst-to-oil ratio of the first catalyst to the Fischer-Tropsch low-carbon saturated hydrocarbons in the first reactor was 15, and the weight hourly space velocity was 45 h⁻¹. -1 Under certain conditions, the catalyst comes into contact with the first catalyst and undergoes a catalytic thermal cracking reaction to obtain the first reaction stream. The first reaction stream carries the reacted first catalyst upwards and enters the second reactor.

[0184] Preheated Fischer-Tropsch light oil to 250°C was mixed with methanol and atomized into a second turbulent bed reactor. The mass ratio of Fischer-Tropsch light oil to methanol was 1:0.25. After entering the second reactor, the Fischer-Tropsch light oil was mixed with the first reaction stream. The reaction temperature was 560°C, the catalyst-to-oil ratio in the second reactor was 10, and the weight hourly space velocity was 60 h⁻¹. -1 Under certain conditions, the catalyst comes into contact with the second catalyst and undergoes a catalytic cracking reaction to obtain a second reaction stream. The second reaction stream, carrying the reacted second catalyst, is then lifted to the third reactor via a riser.

[0185] The F-T heavy oil preheated to 180°C is mixed with methanol and sent into the third bubbling bed reactor by methanol atomization, the mass ratio of F-T heavy oil to methanol is 1:0.25; the F-T heavy oil enters the third reactor and is mixed with the second reactant stream; under the conditions that the reaction temperature is 490°C, the third catalyst in the third reactor and the F-T heavy oil have a catalyst / oil ratio of 3.5, and the weight hourly space velocity is 4h -1 , the F-T heavy oil is contacted with the third catalyst and catalytic cracking and aromatization reactions occur, to obtain the third reaction stream.

[0186] The third reaction stream carries the reacted third catalyst upward, and is separated by sedimentation in a settler under an operating pressure of 0.5 MPa, to obtain a reaction product and spent catalyst; the reaction product is fractionated to obtain a gas phase product, light oil, and heavy oil, wherein the gas phase product is subjected to an olefin separation unit to obtain dry gas, low-carbon saturated hydrocarbon, and low-carbon olefin, and the light oil is subjected to an aromatic extraction unit to obtain aromatic hydrocarbon and aromatic raffinate oil. Among them, 20% of the low-carbon saturated hydrocarbon is returned to the first reactor for reprocessing, and 15% of the aromatic raffinate oil is returned to the second reactor for reprocessing.

[0187] Fuel gas and air are ignited in a combustion furnace to produce high-temperature flue gas containing oxygen, and then the high-temperature flue gas containing oxygen is introduced into a coking tank.

[0188] The spent catalyst is subjected to steam stripping in a stripping section and is sent into the coking tank through a spent catalyst pipe to contact with the high-temperature flue gas containing oxygen from the combustion furnace for coking; and then is upwardly introduced into a regenerator to completely remove coke. The temperature for coking and regeneration is 580°C, and the pressure is 0.5 MPa, to obtain regenerated catalyst, which is circulated back to the first reactor, the second reactor, and the third reactor through a regenerated catalyst pipe I, a regenerated catalyst pipe II, and a regenerated catalyst pipe III, respectively, for recycling. The amount of coke is calculated by measuring the amount of carbon in the spent catalyst.

[0189] Example 3

[0190] The mass ratio of F-T low-carbon saturated hydrocarbon, F-T light oil, and F-T heavy oil is 5:5:90, and the catalyst is the cat-3 catalyst described above.

[0191] The F-T low-carbon saturated hydrocarbon preheated to 250°C is mixed with water vapor and sent into the first turbulent bed reactor by water vapor atomization, the mass ratio of F-T low-carbon saturated hydrocarbon to water vapor is 1:0.35; under the conditions that the reaction temperature is 580°C, the first catalyst in the first reactor and the F-T low-carbon saturated hydrocarbon have a catalyst / oil ratio of 20, and the weight hourly space velocity is 45h -1 , the F-T low-carbon saturated hydrocarbon is contacted with the first catalyst and catalytic thermal cracking reactions occur, to obtain the first reaction stream. The first reaction stream carries the reacted first catalyst upward and enters the second reactor.

[0192] Preheated Fischer-Tropsch light oil to 200°C was mixed with steam and atomized by steam before being fed into the second bubbling bed reactor. The mass ratio of Fischer-Tropsch light oil to steam was 1:0.25. After entering the second reactor, the Fischer-Tropsch light oil was mixed with the first reaction stream. The reaction was carried out at a temperature of 530°C, a catalyst-to-oil ratio of 20 for the second catalyst in the second reactor, and a weight hourly space velocity of 45 h⁻¹. -1 Under certain conditions, the catalyst is brought into contact with a second catalyst and undergoes a catalytic cracking reaction to obtain a second reaction stream. The second reaction stream, carrying the reacted second catalyst, is then sent to a third reactor.

[0193] Preheated Fischer-Tropsch heavy oil to 180°C was mixed with steam and atomized before being fed into a third dispersed fluidized bed reactor. The mass ratio of Fischer-Tropsch heavy oil to steam was 1:0.35. After entering the third reactor, the Fischer-Tropsch heavy oil was mixed with the second reactant stream. The reaction temperature was 490°C, the catalyst-to-oil ratio in the third reactor was 2.4, and the weight hourly space velocity was 4.5 h⁻¹. -1 Under certain conditions, it comes into contact with a third catalyst and undergoes catalytic cracking and aromatization reactions to obtain a third reaction stream.

[0194] The third reactant stream, carrying the third catalyst after the reaction, rises and undergoes sedimentation separation in a settling tank at an operating pressure of 0.3 MPa, yielding reaction products and the catalyst to be produced. The reaction products are fractionated to obtain gaseous products, light oil, and heavy oil. The gaseous products are then processed through an olefin separation unit to obtain dry gas, low-carbon saturated hydrocarbons, and low-carbon olefins. The light oil enters an aromatics extraction unit to obtain aromatics and aromatics raffinate. 30% of the low-carbon saturated hydrocarbons are returned to the first reactor for reprocessing, and 25% of the aromatics raffinate is returned to the second reactor for reprocessing.

[0195] Fuel gas and air enter the combustion furnace and are ignited to produce oxygen-containing high-temperature flue gas, which is then sent into the coking tank.

[0196] The catalyst to be recycled is stripped by steam in the stripping section and then fed into the coking tank through the recycling pipe. There, it comes into contact with high-temperature oxygen-containing flue gas from the combustion furnace for coking. It then ascends to the regenerator to completely burn off the carbon deposits. The coking and regeneration temperatures are 630℃ and the pressure is 0.3 MPa, yielding regenerated catalyst. This regenerated catalyst is recycled back to the first, second, and third reactors via regeneration pipes I, II, and III, respectively. The amount of carbon deposits is calculated by measuring the carbon content in the catalyst to be recycled.

[0197] Example 4

[0198] The mass ratio of Fischer-Tropsch low-carbon saturated hydrocarbons, Fischer-Tropsch light oil, and Fischer-Tropsch heavy oil is 20:20:60, and the catalyst is the aforementioned Cat-4 catalyst.

[0199] Preheated Fischer-Tropsch low-carbon saturated hydrocarbons to 280°C were mixed with dry gas and atomized into the first conveyed bed reactor. The mass ratio of Fischer-Tropsch low-carbon saturated hydrocarbons to dry gas was 1:0.25. The reaction temperature was 530°C, the catalyst-to-oil ratio of the first catalyst in the first reactor was 6, and the weight hourly space velocity was 100 h⁻¹. -1 Under certain conditions, the catalyst comes into contact with the first catalyst and undergoes catalytic thermal decomposition to obtain the first reaction stream. The first reaction stream carries the reacted first catalyst upwards and enters the second reactor.

[0200] Preheated Fischer-Tropsch light oil to 250°C was mixed with dry gas and atomized before being fed into the second fast bed reactor. The mass ratio of Fischer-Tropsch light oil to dry gas was 1:0.18. After entering the second reactor, the Fischer-Tropsch light oil was mixed with the first reaction stream. The reaction temperature was 530°C, the catalyst-to-oil ratio in the second reactor was 25, and the weight hourly space velocity was 75 h⁻¹. -1 Under certain conditions, the catalyst is brought into contact with a second catalyst and undergoes a catalytic cracking reaction to obtain a second reaction stream. The second reaction stream, carrying the reacted second catalyst, is then sent to a third reactor.

[0201] Preheated Fischer-Tropsch heavy oil to 180°C was mixed with dry gas and atomized before being fed into the third turbulent bed reactor. The mass ratio of Fischer-Tropsch heavy oil to dry gas was 1:0.3. After entering the third reactor, the Fischer-Tropsch heavy oil was mixed with the second reaction stream. The reaction temperature was 430°C, the catalyst-to-oil ratio in the third reactor was 5.5, and the weight hourly space velocity was 10 h⁻¹. -1 Under certain conditions, it comes into contact with a third catalyst and undergoes catalytic cracking and aromatization reactions to obtain a third reaction stream.

[0202] The third reactant stream, carrying the reacted third catalyst, rises and undergoes sedimentation separation in a settler at an operating pressure of 0.3 MPa, yielding reaction products and the catalyst to be produced. The reaction products are fractionated to obtain gaseous products, light oil, and heavy oil. The gaseous products are then processed through an olefin separation unit to obtain dry gas, low-carbon saturated hydrocarbons, and low-carbon olefins. The light oil enters an aromatics extraction unit to obtain aromatics and aromatics raffinate. Of this, 40% of the low-carbon saturated hydrocarbons are returned to the first reactor for reprocessing, and 35% of the aromatics raffinate is returned to the second reactor for reprocessing.

[0203] Fuel gas and air enter the combustion furnace and are ignited to produce oxygen-containing high-temperature flue gas, which is then sent into the coking tank.

[0204] The catalyst to be recycled is stripped by steam in the stripping section and then fed into the coking tank through the recycling pipe. There, it comes into contact with high-temperature oxygen-containing flue gas from the combustion furnace for coking. It then ascends to the regenerator to completely burn off the carbon deposits. The coking and regeneration temperatures are 680℃ and the pressure is 0.3 MPa, yielding regenerated catalyst. This regenerated catalyst is recycled back to the first, second, and third reactors via regeneration pipes I, II, and III, respectively. The amount of carbon deposits is calculated by measuring the carbon content in the catalyst to be recycled.

[0205] Example 5

[0206] The mass ratio of Fischer-Tropsch low-carbon saturated hydrocarbons, Fischer-Tropsch light oil, and Fischer-Tropsch heavy oil is 25:30:45, and the catalyst is the aforementioned Cat-5 catalyst.

[0207] Preheated Fischer-Tropsch low-carbon saturated hydrocarbons to 250°C were mixed with dry gas and atomized into the first fast bed reactor. The mass ratio of Fischer-Tropsch low-carbon saturated hydrocarbons to dry gas was 1:0.6. The reaction temperature was 670°C, the catalyst-to-oil ratio of the first catalyst to the Fischer-Tropsch low-carbon saturated hydrocarbons in the first reactor was 15, and the weight hourly space velocity was 120 h⁻¹. -1 Under certain conditions, the catalyst comes into contact with the first catalyst and undergoes a catalytic thermal cracking reaction to obtain the first reaction stream. The first reaction stream carries the reacted first catalyst upwards and enters the second reactor.

[0208] Preheated Fischer-Tropsch light oil to 200°C was mixed with dry gas and atomized before being fed into the second turbulent bed reactor. The mass ratio of Fischer-Tropsch light oil to dry gas was 1:0.3. After entering the second reactor, the Fischer-Tropsch light oil was mixed with the first reaction stream. The reaction was carried out at a temperature of 610°C, a catalyst-to-oil ratio of 8 for the second catalyst in the second reactor, and a weight hourly space velocity of 100 h⁻¹. -1 Under certain conditions, the catalyst is brought into contact with a second catalyst and undergoes a catalytic cracking reaction to obtain a second reaction stream. The second reaction stream, carrying the reacted second catalyst, is then sent to a third reactor.

[0209] Preheated Fischer-Tropsch heavy oil to 150°C was mixed with dry gas and atomized before being fed into the third bubbling bed reactor. The mass ratio of Fischer-Tropsch heavy oil to dry gas was 1:0.18. After entering the third reactor, the Fischer-Tropsch heavy oil was mixed with the second reaction stream. The reaction temperature was 530°C, the catalyst-to-oil ratio in the third reactor was 6.2, and the weight hourly space velocity was 8 h⁻¹. -1 Under certain conditions, it comes into contact with a third catalyst and undergoes catalytic cracking and aromatization reactions to obtain a third reaction stream.

[0210] The third reaction stream carrying the reacted third catalyst ascends, and is separated by sedimentation in the settler at an operating pressure of 0.5 MPa to obtain a reaction product and spent catalyst; the reaction product is fractionated to obtain a gas phase product, light oil, and heavy oil, wherein the gas phase product is subjected to an olefin separation unit to obtain dry gas, low-carbon saturated hydrocarbon, and low-carbon olefin, and the light oil is subjected to an aromatic extraction unit to obtain aromatic hydrocarbon and aromatic raffinate oil. Among them, 50% of the low-carbon saturated hydrocarbon is returned to the first reactor for recycling, and 45% of the aromatic raffinate oil is returned to the second reactor for recycling.

[0211] The fuel gas and air are ignited in the combustion furnace to generate high-temperature flue gas containing oxygen, and then the high-temperature flue gas containing oxygen is introduced into the coking tank.

[0212] The spent catalyst is introduced into the coking tank through the spent catalyst pipe after steam stripping in the stripping section, and is contacted with the high-temperature flue gas containing oxygen from the combustion furnace to perform coking; and then ascends to the regenerator to completely remove the coke. The temperature of coking and regeneration is 630°C, and the pressure is 0.5 MPa, to obtain regenerated catalyst. The regenerated catalyst is circulated back to the first reactor, the second reactor, and the third reactor through the regeneration pipe I, the regeneration pipe II, and the regeneration pipe III, respectively, for recycling. The amount of coke is calculated by measuring the amount of carbon in the spent catalyst.

[0213] Example 6

[0214] The mass ratio of Fischer-Tropsch low-carbon saturated hydrocarbon, Fischer-Tropsch light oil, and Fischer-Tropsch heavy oil is 30:40:30, and the catalyst is the cat-6 catalyst described above.

[0215] The Fischer-Tropsch low-carbon saturated hydrocarbon preheated to 280°C is mixed with steam and sent into the first turbulent bed reactor by steam atomization, and the mass ratio of the Fischer-Tropsch low-carbon saturated hydrocarbon to steam is 1:0.3; the Fischer-Tropsch low-carbon saturated hydrocarbon is contacted with the first catalyst at a reaction temperature of 680°C, a reaction pressure of 0.2 MPa, a catalyst-oil ratio of the first catalyst to the Fischer-Tropsch low-carbon saturated hydrocarbon of 10, and a weight hourly space velocity of 180 h -1 The first reaction stream carrying the reacted first catalyst ascends and enters the second reactor.

[0216] The Fischer-Tropsch light oil preheated to 250°C is mixed with steam and sent into the second bubbling bed reactor by steam atomization, and the mass ratio of the Fischer-Tropsch light oil to steam is 1:0.25; the Fischer-Tropsch light oil is mixed with the first reaction stream after entering the second reactor; the Fischer-Tropsch light oil is contacted with the second catalyst at a reaction temperature of 630°C, a reaction pressure of 0.2 MPa, a catalyst-oil ratio of the second catalyst to the Fischer-Tropsch light oil of 5, and a weight hourly space velocity of 120 h -1 The second reaction stream carrying the reacted second catalyst is sent to the third reactor.

[0217] The F-T heavy oil preheated to 180°C and steam are mixed and sent into the third dispersed fluidized bed reactor by steam atomization, the mass ratio of F-T heavy oil to steam is 1:0.2; the F-T heavy oil is mixed with the second reactant stream after entering the third reactor; under the conditions of reaction temperature of 460°C, reaction pressure of 0.2 MPa, the third catalyst in the third reactor and the ratio of F-T heavy oil to catalyst of 13, the weight hourly space velocity of 16 h -1 The third reactant stream carries the third catalyst after reaction and goes up in the settler, and the settling separation is carried out under the operating pressure of 0.2 MPa, to obtain the reaction product and the spent catalyst; the reaction product is subjected to fractionation to obtain the gas phase product, light oil and heavy oil, wherein the gas phase product is subjected to olefin separation unit to obtain dry gas, low carbon saturated hydrocarbon and low carbon olefin, the light oil enters the aromatic hydrocarbon extraction unit to obtain aromatic hydrocarbon and aromatic hydrocarbon raffinate oil. Among them, 60% of the low carbon saturated hydrocarbon returns to the first reactor for reprocessing, and 55% of the aromatic hydrocarbon raffinate oil returns to the second reactor for reprocessing.

[0218] The third reactant stream carries the third catalyst after reaction and goes up in the settler, and the settling separation is carried out under the operating pressure of 0.2 MPa, to obtain the reaction product and the spent catalyst; the reaction product is subjected to fractionation to obtain the gas phase product, light oil and heavy oil, wherein the gas phase product is subjected to olefin separation unit to obtain dry gas, low carbon saturated hydrocarbon and low carbon olefin, the light oil enters the aromatic hydrocarbon extraction unit to obtain aromatic hydrocarbon and aromatic hydrocarbon raffinate oil. Among them, 60% of the low carbon saturated hydrocarbon returns to the first reactor for reprocessing, and 55% of the aromatic hydrocarbon raffinate oil returns to the second reactor for reprocessing.

[0219] The fuel gas and air enter the combustion furnace to ignite, to produce high-temperature flue gas containing oxygen, and then the high-temperature flue gas containing oxygen enters the coking tank.

[0220] The spent catalyst is sent into the coking tank through the spent catalyst pipe after steam stripping in the stripping section, and is contacted with the high-temperature flue gas containing oxygen from the combustion furnace to carry out coking; and then goes up to the regenerator to completely remove the coke. The temperature of coking and regeneration is 700°C, and the pressure is 0.2 MPa, to obtain the regenerated catalyst, which is circulated back to the first reactor, the second reactor and the third reactor through the regeneration pipe I, the regeneration pipe II and the regeneration pipe III respectively for recycling. The amount of coke is calculated by measuring the amount of carbon in the spent catalyst.

[0221] The product distribution of the example is shown in Table 5.

[0222] Table 5 Product distribution of examples and comparative examples

[0223]

[0224] The gas phase product, light oil, heavy oil, coke, olefin and aromatic hydrocarbon yield in the above examples and comparative examples are calculated based on the total hydrocarbon content in the feed.

[0225] As can be seen from Table 5, the gaseous product of Comparative Example 1 is higher than that of Example 1, the light oil is lower than that of Example 1, the heavy oil is higher than that of Example 1, and the low carbon olefin yield and the aromatic yield are lower than those of Example 1, in which the aromatic yield is only 6.5%. This indicates that it is not good for obtaining more target products if all the raw materials are reacted in the first reactor. The gaseous product of Comparative Example 2 is lower than that of Example 1, the light oil and the heavy oil are substantially the same as those of Example 1, and the low carbon olefin and the aromatic yield are both less than those of Example 1. This indicates that it is not good for obtaining more target products if all the raw materials are reacted in the third reactor.

[0226] As can be seen from the rest of the examples, if the reaction temperature is increased, more gaseous product can be obtained. If the reaction temperature is decreased, more liquid product (the light oil and the heavy oil obtained are collectively referred to as "liquid product") can be obtained. For example, the reaction temperature of Example 1 is higher than that of Example 3, the gaseous product yield of Example 1 is higher than that of Example 3, and the liquid product of Example 1 is lower than that of Example 3. If the proportion of Fischer-Tropsch heavy oil in the raw materials is increased, the liquid product and the aromatic yield can be increased. If the proportion of low carbon saturated hydrocarbon and Fischer-Tropsch light oil in the raw materials is increased, more gaseous product and low carbon olefin yield can be obtained. For example, the Fischer-Tropsch heavy oil in Example 3 accounts for 90% of the raw materials, the Fischer-Tropsch heavy oil in Example 6 accounts for only 30% of the raw materials, the liquid product yield and the aromatic yield of Example 3 are both higher than those of Example 6, and the gaseous product yield and the low carbon olefin yield of Example 3 are lower than those of Example 6. Under different reaction conditions, the aromatic yield in each example is more than 30% (between 30.4-37.4%), and the olefin yield is more than 39% (between 39.1-55.1%).

[0227] The embodiments of the present application have been described in detail above, and it will be obvious to those skilled in the art that many improvements and modifications can be made without departing from the basic spirit of the present application, and all such improvements and modifications are included in the scope of the present application.

Claims

1. A process for co-production of low carbon olefins and aromatics from Fischer-Tropsch synthesis products, the process comprising: (1) feeding the Fischer-Tropsch low-carbon saturated hydrocarbons and an atomizing medium into a first reactor in an atomized form, contacting with a first catalyst and carrying out a catalytic thermal cracking reaction to obtain a first reaction stream and feeding the first reaction stream to a second reactor, wherein in step (1), the reaction conditions of the first reactor are: temperature 500-750°C; pressure 0.01-0.7 MPa; weight hourly space velocity 10-300 h -1 ; catalyst / oil ratio 0.5-50; (2) feeding the Fischer-Tropsch light oil and atomizing medium into the second reactor in atomized form, mixing with the first reaction stream, contacting with the second catalyst and carrying out catalytic cracking reaction to obtain a second reaction stream and feeding the second reaction stream to the third reactor, wherein in step (2), the reaction conditions of the second reactor are: temperature 450-700°C; pressure 0.01-0.7 MPa; weight hourly space velocity 1-150 h -1 ; catalyst / oil ratio 1-40; (3) feeding the Fischer-Tropsch heavy oil and an atomizing medium into a third reactor in an atomized form, mixing with the second reaction stream, contacting with a third catalyst and carrying out catalytic cracking and aromatization reaction to obtain a third reaction stream, wherein in step (3), the reaction conditions of the third reactor are: temperature 400-650°C; pressure 0.01-0.7 MPa; weight hourly space velocity 0.5-30 h -1 ; catalyst / oil ratio 1-20; (4) subjecting the third reaction stream obtained in step (3) to a settling separation to remove spent catalyst from the third reaction stream; subjecting the obtained reaction products to fractionation to obtain a gas phase product, a light oil, a heavy oil, wherein the gas phase product is subjected to olefin separation to obtain dry gas, low carbon saturated hydrocarbons, low carbon olefins, the light oil is subjected to aromatic extraction to obtain aromatics and aromatic raffinate; subjecting the spent catalyst to stripping, optionally to coking and to regeneration to obtain regenerated catalyst, wherein the regenerated catalyst is returned to the first reactor, the second reactor and the third reactor respectively for recycle use, wherein the mass ratio of Fischer-Tropsch low carbon saturated hydrocarbons, Fischer-Tropsch light oil and Fischer-Tropsch heavy oil is (5-30):(5-40):(30-90).

2. The method of claim 1, wherein, The process further comprises returning the low carbon saturated hydrocarbons and the aromatic raffinate obtained in step (4) to the first reactor and the second reactor respectively for backfrying.

3. The method of claim 1, wherein, In step (1), step (2) or step (3), the atomization medium is selected from methanol, ethanol, propanol, dry gas, nitrogen or water vapor, or a mixture thereof.

4. The method of claim 3, wherein, The dry gas comprises one or more of hydrogen, methane and ethane.

5. The method of any one of claims 1-4, wherein, In step (1), step (2) or step (3), the mass ratio of the Fischer-Tropsch low carbon saturated hydrocarbons, the Fischer-Tropsch light oil or the Fischer-Tropsch heavy oil to the atomization medium is 1:(0.1-1).

6. The method of any one of claims 1-4, wherein, In step (1), step (2) or step (3), the mass ratio of the Fischer-Tropsch low carbon saturated hydrocarbons, the Fischer-Tropsch light oil or the Fischer-Tropsch heavy oil to the atomization medium is 1:0.1, 1:0.15, 1:0.18, 1:0.2, 1:0.25, 1:0.3, 1:0.35, 1:0.4, 1:0.45, 1:0.5, 1:0.55, 1:0.6, 1:0.65, 1:0.7, 1:0.75, 1:0.8, 1:0.85, 1:0.9, 1:0.95 or 1:

1.

7. The method of any one of claims 1-4, wherein, In step (1), the weight ratio of the Fischer-Tropsch low carbon saturated hydrocarbons to the atomization medium is 1:(0.1-0.6); or wherein, in step (2), the weight ratio of the Fischer-Tropsch light oil to the atomization medium is 1:(0.1-0.8); or wherein, in step (3), the weight ratio of the Fischer-Tropsch heavy oil to the atomization medium is 1:(0.1-0.8).

8. The method of claim 7, wherein, In step (1), the weight ratio of the Fischer-Tropsch low carbon saturated hydrocarbons to the atomization medium is 1:(0.15-0.6); or wherein, in step (2), the weight ratio of the Fischer-Tropsch light oil to the atomization medium is 1:(0.15-0.5); or wherein, in step (3), the weight ratio of the Fischer-Tropsch heavy oil to the atomization medium is 1:(0.15-0.5).

9. The method of any one of claims 1-3, wherein, In step (1), step (2) or step (3), the Fischer-Tropsch low carbon saturated hydrocarbons, the Fischer-Tropsch light oil or the Fischer-Tropsch heavy oil is preheated before being atomized.

10. The method of claim 9, wherein, The Fischer-Tropsch low carbon saturated hydrocarbons, the Fischer-Tropsch light oil or the Fischer-Tropsch heavy oil is preheated to 100℃-400℃.

11. The method of claim 10, wherein, The Fischer-Tropsch low-carbon saturated hydrocarbon is preheated to 100-350℃; or, wherein the Fischer-Tropsch light oil is preheated to 100-350℃; or, wherein the Fischer-Tropsch heavy oil is preheated to 100-350℃.

12. The method of any one of claims 1-3, wherein, The active component of the first catalyst, the second catalyst and the third catalyst is at least one of unmodified or modified eight-membered ring molecular sieve, ten-membered ring molecular sieve, twelve-membered ring molecular sieve or metal oxide.

13. The method of claim 12, wherein, The eight-membered ring molecular sieve, ten-membered ring molecular sieve or twelve-membered ring molecular sieve is selected from SAPO-34, SAPO-18, ITQ-13, IM-5, ZSM-5, ZSM-11, MCM-22, EU-1, beta, mordenite molecular sieve; or, the metal oxide is one or several of zinc oxide, lanthanum oxide, magnesium oxide, manganese oxide, cerium oxide, gallium oxide, chromium oxide, nickel oxide, tungsten oxide.

14. The method of claim 12, wherein, The active component of the first catalyst, the second catalyst and the third catalyst accounts for 20wt%-60wt% of the weight of the catalysts on a dry basis.

15. The method of claim 14, wherein, In addition to the active component, the first catalyst, the second catalyst and the third catalyst further contain the remaining amount of alumina and / or silica as a carrier.

16. The method of any one of claims 1-3, wherein, The first catalyst is a mixed catalyst of regenerated catalyst and spent catalyst, wherein the carbon content of the first catalyst is 0wt%-2.00wt%; or, wherein the second catalyst is a mixture of regenerated catalyst and spent catalyst, wherein the carbon content of the second catalyst is 0wt%-2.0wt%; or, wherein the third catalyst is a mixture of regenerated catalyst and spent catalyst, wherein the carbon content of the third catalyst is 0wt%-2.0wt%.

17. The method of claim 1, wherein, In step (1), the temperature is 580-680℃; or the pressure is 0.1-0.5 MPa; or, the weight hourly space velocity is 40-200 h -1 ; or, the agent to oil ratio is 5-30.

18. The method of claim 1, wherein, In step (2), the temperature is 530-630 DEG C; or, the pressure is 0.1-0.5 MPa; or, the weight hourly space velocity is 40-120 h -1 ; or, the agent to oil ratio is 5-25.

19. The method of claim 1, wherein, In step (3), the temperature is 480-580℃; or, the pressure is 0.1-0.5MPa; or, the weight hourly space velocity is 2-20h -1 ; or, the agent to oil ratio is 2-15.

20. The method of any one of claims 1-3, wherein, The first reactor is a transport bed reactor, a fast bed reactor or a turbulent bed reactor; or, the second reactor is a fast bed reactor, a turbulent bed reactor or a bubbling bed reactor; Or, the third reactor is a turbulent bed reactor, a bubbling bed reactor or a dispersed fluidized bed reactor.

21. The method of claim 20, wherein, The first reactor is a transport bed reactor or a fast bed reactor; or, the second reactor is a fast bed reactor or a turbulent bed reactor; or, the third reactor is a bubbling bed reactor or a turbulent bed reactor.

22. The method of any one of claims 1-3, wherein, In step (4), the operating pressure of the settling separation is 0.01-0.7MPa.

23. The method of claim 2, wherein, 10%-90% of the low-carbon saturated hydrocarbon obtained in step (4) is returned to the first reactor for back-fining; or, 5%-95% of the aromatic hydrocarbon raffinate obtained in step (4) is returned to the second reactor for back-fining.

24. The method of any one of claims 1-3, wherein, In step (4), the contact of the spent catalyst with the oxygen-containing gas is optionally decoking and regeneration under the conditions of pressure 0.01-0.7MPa and temperature 550-750℃.

25. The method of claim 24, wherein, The oxygen-containing gas is air or oxygen-containing high-temperature flue gas.

26. An apparatus for implementing the method for co-production of low-carbon olefins and aromatic hydrocarbons from Fischer-Tropsch synthesis products according to any one of claims 1-25, the apparatus comprising a reaction system, a regeneration system and a product separation system, wherein The reaction system comprises: a first reactor; a second reactor; and a third reactor. a second reactor, the second reactor being arranged in series with the first reactor; a third reactor, the third reactor being arranged in series with the second reactor; a settling unit, the settling unit being connected in fluid communication to the third reactor and to the product separation system; wherein the regeneration system comprises: a stripping section, the stripping section being connected in fluid communication to the settling unit; a regenerator, the regenerator being connected in fluid communication to the stripping section and to the first reactor, second reactor and third reactor, wherein the product separation system comprises: a fractionation unit, the fractionation unit being connected in fluid communication to the settling unit; an olefin separation unit, the olefin separation unit being connected in fluid communication to the fractionation unit; and an aromatics extraction unit, the aromatics extraction unit being connected in fluid communication to the fractionation unit.

27. The apparatus of claim 26, wherein, the regeneration system further comprises: a coke burning tank, the coke burning tank being connected in fluid communication to the stripping section and to the regenerator.

28. The apparatus of claim 27, wherein, a combustion furnace is further provided in the regeneration system, the combustion furnace being connected in fluid communication to the coke burning tank to provide oxygen-containing high-temperature flue gas to the coke burning tank.

29. The apparatus of any one of claims 26-28, wherein, the first reactor, second reactor and third reactor share a common settler.

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