System and method for one-step preparation of green aromatic hydrocarbon and high yield of benzene and p-xylene through COx hydrogenation

Abstract

The invention provides a system and method for one-step preparation of green aromatic hydrocarbon and high yield of benzene and p-xylene through COx hydrogenation, the system comprises a high-pressure fluidized bed reaction device, a gas-liquid separation device and a cracking reaction device, and the method comprises the steps of fluidization aromatization reaction, gas-liquid separation, cracking reaction and the like. According to the method disclosed by the invention, green aromatic hydrocarbon and high-yield benzene and p-xylene are prepared by adopting a high-pressure fluidization one-step method, and efficient aromatization reaction and cracking reaction are realized through optimized reaction conditions and the designed and synthesized bifunctional catalyst and the Ni / Mg supported catalyst; and the yield and selectivity of the target product benzene and p-xylene and the effective circulation conversion rate of the carbon source are greatly improved. Meanwhile, the technological process is simple and convenient, less by-products and pollutants are discharged, and the production efficiency, the economic benefit and the environmental friendliness are improved.

Description

Technical Field The present invention relates to the technical field of using COx to prepare high-value chemicals, and in particular to a system and method for preparing green aromatics by hydrogenating COx in one step and producing high yields of benzene and para-xylene. Background Art As basic chemical raw materials, benzene and paraxylene (PX) play an important strategic role in China's chemical industry. They are widely used in the production of downstream products such as plastics, synthetic fibers, rubber and coatings, and directly support the stable development of multiple industries such as plastics, textiles, and packaging. At present, benzene and PX are mainly derived from petroleum and produced through petroleum cracking and reforming units. However, due to limited petroleum resources and high dependence on imported petroleum raw materials, the supply of raw materials is vulnerable to fluctuations in the international market, affecting the cost and supply stability of chemical products. Therefore, developing new preparation schemes for benzene and PX to alleviate the high dependence on petroleum is of great significance to improving energy security and reducing the risks brought by external market fluctuations. With the increasing global attention to environmental protection and sustainable energy, the use of carbon dioxide (CO2) and carbon monoxide (CO) as raw materials to produce high-value-added chemicals, especially high-value chemicals, has become an important research direction in the field of petroleum alternative energy. In particular, the application of high-pressure fluidized bed technology not only improves the utilization rate and reaction efficiency of catalysts in reactors, but also effectively solves the mass transfer and heat transfer problems in traditional reactors, providing a new technical approach for high-value chemicals. CN116459754A discloses a system and method for producing aromatics by hydrogenation of carbon dioxide driven by renewable energy, the system comprising a renewable energy power generation device, a renewable energy storage device, a carbon dioxide capture device, a water electrolysis hydrogen production device, a moving bed reaction device and a product separation device, etc. Although the energy of the system all comes from renewable energy, achieving zero emission of the entire system, the system and method are relatively complex, the process flow is cumbersome, and the conversion rate of carbon dioxide is low, only 40.1% at most, and the yield of xylene is also low, only 42.6% at most. At present, existing technologies face many challenges. First, the activity and stability of the catalyst are the main factors restricting its industrial application, especially under high pressure and high temperature environment, the catalyst is susceptible to poisoning and thermal deactivation. Secondly, the control and optimization of reaction conditions are crucial to the conversion rate of CO2 or CO, the selectivity and yield of aromatization reaction, and it is necessary to comprehensively consider parameters such as temperature, pressure, and gas composition. In addition, the maturity and economy of waste gas treatment and product separation technology are also difficult problems that need to be overcome in the process of technology commercialization. Summary of the invention Problem that the invention aims to solve In view of the multiple challenges faced by the existing technology, such as the activity and stability of the catalyst, the optimization of reaction conditions, the waste gas treatment and the separation of products and other technical issues, the present invention aims to provide a system and method for preparing green aromatics in one step by COx hydrogenation using high-pressure fluidization technology and producing high yields of benzene and para-xylene. In particular, a bifunctional catalyst and a Ni / Mg supported catalyst are selected to further improve the conversion rate of the raw material, the selectivity and yield of para-xylene and benzene. Solutions for solving problems In order to solve the above problems, the present invention provides the following technical solutions:

[0001] A system for preparing green aromatics by hydrogenating COx in one step and producing high yields of benzene and p-xylene, comprising: A high-pressure fluidized bed reaction device (1) is used for the contact reaction of a raw gas with a bifunctional catalyst in a fluidized state to obtain reaction products C1-C3 hydrocarbons, benzene and mixed green aromatics; wherein the raw gas comprises COx and hydrogen, x is 1 or 2; the mixed green aromatics comprises toluene, xylene, trimethylbenzene, tetramethylbenzene, pentamethylbenzene and hexamethylbenzene; The gas-liquid separation device (3) is used to cool the gas output from the high-pressure fluidized bed reaction device (1), perform gas-liquid separation to form gas phase products and liquid phase products, separate benzene and mixed green aromatics in the liquid phase products, and output the product benzene; The cracking reaction device (2) is used to carry out a cracking reaction on the mixed green aromatics output from the gas-liquid separation device (3), so as to convert the mixed green aromatics into products of benzene and paraxylene, and generate a gas phase product containing methane.

[0002] The system according to [1], wherein: The system further comprises a gas separation device (4) for separating the gas phase product containing methane outputted from the cracking reaction device (2) to obtain dry gas, and inputting the remaining gas phase product into the high pressure fluidized bed reaction device (1) for recycling; The gas phase product in the gas-liquid separation device (3) is input into the high-pressure fluidized bed reaction device (1) for recycling; The gas-liquid separation device (3) comprises a functional module for separating benzene and mixed green aromatics.

[0003] A method for preparing green aromatics by hydrogenating COx in one step and producing high yields of benzene and p-xylene, which is carried out in the system described in [1] or [2], and comprises the following steps: S1, fluidized aromatization reaction: the feed gas is introduced into a high-pressure fluidized bed reaction device, and is contacted with a bifunctional catalyst in a fluidized state, and an aromatization reaction occurs to obtain products C1-C3 hydrocarbons, benzene and mixed green aromatics; wherein the feed gas comprises COx and hydrogen, and x is 1 or 2; the mixed green aromatics comprise toluene, xylene, trimethylbenzene, tetramethylbenzene, pentamethylbenzene and hexamethylbenzene; the bifunctional catalyst comprises a metal oxide and a molecular sieve carrier; S2, gas-liquid separation: in a gas-liquid separation device, the gas generated in step S1 is cooled, the gas and liquid are separated to form a gas phase product and a liquid phase product, and the liquid phase product is purified to separate benzene and mixed green aromatics; S3, cracking reaction: the mixed green aromatics obtained in step S2 are cracked in a cracking reaction device to convert them into benzene and p-xylene, and generate a gas phase product containing methane.

[0004] The method according to [3], wherein: The pressure of the aromatization reaction is 2-6 MPa; The temperature of the aromatization reaction is 250-550°C, preferably 250-400°C; The pressure of the cracking reaction is 2-6 MPa; The temperature of the cracking reaction is 180-250°C.

[0005] The method according to [3] or [4], wherein: In the bifunctional catalyst, the metal oxide is selected from a combination of one or more of ZnCr2O4, ZnFe2O4 and LaFeO3, and the molecular sieve carrier is selected from a combination of one or more of zeolite, alumina and nano H-ZSM-5; Preferably, when x is 2, the metal oxide is a combination of one or more of ZnCr2O4 and LaFeO3, and the molecular sieve carrier is nano H-ZSM-5; when x is 1, the metal oxide is ZnCr2O4, and the molecular sieve carrier is nano H-ZSM-5; Preferably, the mass ratio of the metal oxide to the molecular sieve is 1:3 to 3:1, preferably 1:1 to 1.5:1; Preferably, the average particle size of the bifunctional catalyst is not less than 30 μm, preferably 30 to 130 μm.

[0006] The method according to any one of [3] to [5], wherein: In step S3, the cracking reaction is carried out in the presence of a Ni / Mg supported catalyst; Preferably, the Ni / Mg supported catalyst comprises metal oxide Al2O3, metal Ni and metal Mg, with the metal oxide Al2O3 serving as a carrier; Preferably, in the Ni / Mg supported catalyst, the sum of the mass fractions of the Ni element and the Mg element is 0.1% to 1.5%; Preferably, in the Ni / Mg supported catalyst, the mass ratio of the Ni element to the Mg element is 1-10.

[0007] The method according to any one of [3] to [6], wherein: In the raw gas, the volume flow ratio of COx and H2 is 5:1 to 1:5, preferably 1:1 to 1:2; Preferably, the raw gas is introduced into the high-pressure fluidized bed reaction device after pretreatment; further, the pretreatment is to process the raw gas through compression, cooling and dehydration steps to remove impurity gases.

[0008] The method according to any one of [3] to [7], wherein: The method further comprises the following steps: S4, tail gas circulation: the gas phase product containing methane generated by the cracking reaction in step S3 is transported to a gas separation device, the dry gas is separated and discharged, and the remaining gas phase product is combined with the gas phase product in step S2 as a recycled raw gas and transported to a high-pressure fluidized bed reaction device; Preferably, the raw gas in the method comprises fresh raw gas and recycled raw gas in step S4; further, the volume flow ratio of the recycled raw gas to the fresh raw gas is 2 to 8:1, preferably 2 to 4:1.

[0009] The method according to any one of [3] to [8], wherein: The high-pressure fluidized bed reaction device is provided with a gas distributor, a heat exchange tube bundle and a cyclone separator; Preferably, the gas distributor is provided with a gas nozzle; Preferably, the heat exchange tube bundle is arranged vertically or horizontally, and the internal heat exchange medium is water or water vapor; further, when the heat exchange tube bundle is arranged horizontally, the shape of the heat exchange tube bundle is drop-shaped and / or cylindrical.

[0010] The method according to any one of [3] to [9], wherein: The loading amount of the bifunctional catalyst is 3 to 10 times the height-to-diameter ratio of the high-pressure fluidized bed reaction device, and the unit of the loading amount is ton. Effects of the Invention Compared with the prior art, the beneficial effects of the present invention mainly include the following aspects: (1) The high-pressure fluidized bed method is used to prepare green aromatics in one step and produce high yields of benzene and p-xylene, which can complete the efficient conversion from feed gas to target products in a single reactor. Through optimized reaction conditions and designed and synthesized bifunctional catalysts and Ni / Mg supported catalysts, efficient aromatization and cracking reactions are achieved, greatly improving the yield and selectivity of the target products benzene and p-xylene, and the effective circulation conversion rate of carbon sources. (2) The present invention is applicable to the use of CO2 and / or biomass-derived synthesis gas (including components such as CO and H2), or directly using raw gas of CO and H2, effectively promoting the comprehensive utilization of energy resources. By converting waste gas or biomass into valuable aromatic products, it helps to reduce the consumption of fossil energy and reduce greenhouse gas emissions. (3) The bifunctional catalyst designed in the present invention has good stability and durability, and can maintain efficient catalytic activity under high pressure and high temperature conditions, thereby extending the service life of the catalyst and reducing production costs and catalyst replacement frequency. (4) Compared with the traditional multi-step process for preparing aromatics, the present invention adopts a one-step fluidized reaction, which simplifies the process flow, reduces the complexity of intermediate processing steps and equipment, and improves production efficiency and economic benefits. (5) By optimizing the reaction conditions and catalyst design, the present invention can reduce the generation of by-products during the reaction, improve the selectivity of aromatics, reduce the emission of environmental pollutants, and meet the environmental protection requirements of sustainable development. (6) The present invention can economically and efficiently treat the reaction waste gas, especially discharge or convert methane in the waste gas, thereby improving the overall economy and environmental friendliness. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 A schematic diagram of the system structure of a high-pressure fluidized one-step method for preparing green aromatics and high-yield benzene and para-xylene provided in an embodiment of the present invention is shown; wherein: 1. a high-pressure fluidized bed reaction device; 2. a cracking reaction device; 3. a gas-liquid separation device; 4. a gas separation device; 5. a raw gas inlet; 6. a reaction product delivery pipeline; 7. a benzene product outlet; 8. para-xylene and benzene product outlets; 9. a liquid phase transmission pipeline; 10. a dry gas output pipeline; 11. a gas phase output pipeline; 12. a circulating gas circulation pipeline of a gas separation device; and 13. a total circulating gas pipeline. Figure 2 The schematic diagram of the structure of the high-pressure fluidized bed of the present invention is shown. Figure 3 The schematic diagram of the structure of the horizontal heat exchange tube bundle inside the high-pressure fluidized bed of the present invention is shown. DETAILED DESCRIPTION Various exemplary embodiments, features and aspects of the present invention will be described in detail below. The word "exemplary" used here means "used as an example, embodiment or illustrative". Any embodiment described here as "exemplary" is not necessarily interpreted as being superior or better than other embodiments. In addition, in order to better illustrate the present invention, numerous specific details are provided in the following specific embodiments. It should be understood by those skilled in the art that the present invention can be implemented without certain specific details. In other examples, methods, means, equipment and steps well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present invention. Unless otherwise stated, the units used in this specification are all international standard units, and the numerical values ​​and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production. In this specification, the word "may" means both performing a certain process and not performing a certain process. In this specification, the references to "some specific / preferred embodiments", "other specific / preferred embodiments", "embodiments", etc., mean that the specific elements (e.g., features, structures, properties and / or characteristics) described in connection with the embodiments are included in at least one embodiment described herein, and may or may not exist in other embodiments. In addition, it should be understood that the elements may be combined in various embodiments in any suitable manner. In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints numerical values ​​A and B. First, the present invention provides a system for preparing green aromatics and producing high yields of benzene and p-xylene in one step by hydrogenating COx using high-pressure fluidization technology. Figure 1 The schematic diagram of the structure of the circulation system provided by the embodiment of the present invention is shown, and the system comprises: A high-pressure fluidized bed reaction device (1) is used for the contact reaction of a raw gas with a bifunctional catalyst in a fluidized state to obtain reaction products C1-C3 hydrocarbons, benzene and mixed green aromatics; wherein the raw gas comprises COx and hydrogen, x is 1 or 2; the mixed green aromatics comprises toluene, xylene, trimethylbenzene, tetramethylbenzene, pentamethylbenzene and hexamethylbenzene; The gas-liquid separation device (3) is used to cool the gas (including C1-C3 hydrocarbons, benzene and mixed green aromatic hydrocarbons, and unreacted raw gas) output from the high-pressure fluidized bed reaction device (1), perform gas-liquid separation to form gas phase products and liquid phase products, separate benzene and mixed green aromatic hydrocarbons in the liquid phase products, and output the product benzene; The cracking reaction device (2) is used to carry out a cracking reaction (for example, under the action of a Ni / Mg supported catalyst) on the mixed green aromatics output from the gas-liquid separation device (3), so as to convert the mixed green aromatics into product benzene and paraxylene, and generate a gas phase product containing methane. In some embodiments, such as Figure 1 As shown, the system of the present invention also includes a gas separation device (4) for separating the gas phase product containing methane output from the cracking reaction device (2) to obtain dry gas, and the remaining gas phase product is input into the high-pressure fluidized bed reaction device (1) for recycling. In some embodiments, the gas phase product in the gas-liquid separation device (3) is input into the high-pressure fluidized bed reaction device (1) for recycling. In some embodiments, the gas-liquid separation device (3) includes a functional module for separating benzene and mixed green aromatics. In some embodiments, such as Figure 1 As shown, the system of the present invention also includes the following features: The high-pressure fluidized bed reaction device (1) comprises a raw gas inlet (5); A reaction product delivery pipeline (6) is arranged between the high-pressure fluidized bed reaction device (1) and the gas-liquid separation device (3); The gas-liquid separation device (3) is provided with a benzene product outlet (7); A liquid phase transmission pipeline (9) is provided between the gas-liquid separation device (3) and the cracking reaction device (2) for transporting mixed green aromatics; A total circulating gas pipeline (13) is provided between the gas-liquid separation device (3) and the high-pressure fluidized bed reaction device (1); The cracking reaction device (2) comprises a para-xylene and benzene product outlet (8); A gas phase output pipeline (11) is arranged between the cracking reaction device (2) and the gas separation device (4); A gas separation device circulating gas circulation pipeline (12) and a total circulating gas pipeline (13) are provided between the gas separation device (4) and the high-pressure fluidized bed reaction device (1); The gas separation device (4) comprises a dry gas output pipeline (10). In addition, the present invention also provides a method for preparing green aromatics with high yield of benzene and p-xylene by hydrogenation of COx in one step. Optionally, the preparation method can be carried out in the above system. Specifically, the method for preparing green aromatics with high yield of benzene and p-xylene by hydrogenation of COx in one step comprises the following steps: S1, fluidized aromatization reaction: the feed gas is introduced into a high-pressure fluidized bed reaction device, and is contacted with a bifunctional catalyst in a fluidized state, and an aromatization reaction occurs to obtain products C1-C3 hydrocarbons, benzene and mixed green aromatics; wherein the feed gas comprises COx and hydrogen, and x is 1 or 2; the mixed green aromatics comprise toluene, xylene, trimethylbenzene, tetramethylbenzene, pentamethylbenzene and hexamethylbenzene; the bifunctional catalyst comprises a metal oxide and a molecular sieve carrier; S2, gas-liquid separation: In the gas-liquid separation device, the gas output from the high-pressure fluidized bed reaction device (including C1-C3 hydrocarbons, benzene and mixed green aromatics, and unreacted raw gas) is cooled, the gas and liquid are separated to form gas phase products and liquid phase products, and the liquid phase products are purified to separate benzene and mixed green aromatics; S3, cracking reaction: the mixed green aromatics obtained in step S2 are cracked in a cracking reaction device to convert them into p-xylene and benzene, and generate a gas phase product containing methane. In the present invention, the main components of "mixed green aromatics" are aromatics such as toluene, xylene, trimethylbenzene, tetramethylbenzene, pentamethylbenzene and hexamethylbenzene, wherein the position of the methyl group in xylene, trimethylbenzene and tetramethylbenzene is not particularly limited, for example, xylene includes o-xylene, p-xylene and m-xylene, trimethylbenzene includes 1,2,3-trimethylbenzene, 1,2,4-trimethylbenzene and 1,3,5-trimethylbenzene, and tetramethylbenzene includes 1,2,4,5-tetramethylbenzene, 1,2,3,4-tetramethylbenzene and 1,2,3,5-tetramethylbenzene, and the proportion of each component is not particularly limited. In the cracking reaction, toluene, xylene, trimethylbenzene, tetramethylbenzene, pentamethylbenzene and hexamethylbenzene can all be cracked to produce benzene and methane, etc., and trimethylbenzene, tetramethylbenzene, pentamethylbenzene and hexamethylbenzene can all be cracked to produce benzene, methane and p-xylene, etc. In some embodiments, the reaction pressure of the aromatization reaction is 2-6 MPa, such as 2 MPa, 3 MPa, 4 MPa, 5 MPa, 6 MPa, etc. Pressures outside this range will significantly increase the cost of equipment. In some embodiments, the reaction temperature of the aromatization reaction is 250-550°C, preferably 250-400°C, such as 280°C, 300°C, 330°C, 350°C, 380°C, etc. In some embodiments, the reaction temperature of the cleavage reaction is 180-250°C, such as 200°C, 220°C, 240°C, etc. In some embodiments, the reaction pressure of the cracking reaction is 2 to 6 MPa, for example, 2 MPa, 3 MPa, 4 MPa, 5 MPa, 6 MPa, etc. In the present invention, the "metal oxide" is a high-performance metal oxide, which refers to a metal oxide having a single-pass conversion rate of 30% or more for the catalytic reaction of raw materials during the COx hydrogenation reaction. In some embodiments, the metal oxide of the present invention is a bimetallic oxide. In some specific embodiments, the metal is selected from a combination of any two of Zn, Cr, Fe and La. In some embodiments, in the bifunctional catalyst, the metal oxide is selected from a combination of one or more of ZnCr2O4, ZnFe2O4 and LaFeO3. It should be noted that the metal ratio in the metal oxides ZnCr2O4, ZnFe2O4 and LaFeO3 is not fixed, and is within a certain range near the stoichiometric ratio. For example, the metal oxide ZnCr2O4 contains a certain ratio of ZnO and Cr2O3, and the Zn / Cr molar ratio is not a fixed ratio of 1:2. In some specific embodiments, the Zn / Cr molar ratio in ZnCr2O4 is 0.45 to 0.65, such as 0.5, 0.55, 0.6, etc. In some embodiments, ZnCr2O4 or ZnFe2O4 is synthesized by any one of an impregnation method and a co-precipitation method. In some specific embodiments, the synthesis steps of the co-precipitation method are: mixing a salt substance containing a metal element in the metal oxide to be prepared (optionally, the salt is chloride, nitrate, sulfate, etc.) with water to obtain a first metal salt solution (optionally, the concentration of the first metal salt is 0.1-3 mol / L); mixing the first metal salt solution with a precipitant having a pH of not less than 8.5 (optionally, the precipitant is ammonium carbonate, sodium hydroxide, potassium hydroxide, etc.) under continuous stirring to obtain a second mixed solution, and maintaining the temperature of the second mixed solution at 70-100°C and the pH at 5.5-8.5 during the mixing process. After the mixing is completed, the second mixed solution is placed in a nitrogen atmosphere and continuously stirred for crystallization for 6-48 hours to obtain a third mixed solution. After stirring for 4-26 hours, it is filtered and roasted (optionally, the roasting temperature is 350-550°C and the time is 2-12 hours) to obtain the metal oxide of the present invention. In some embodiments, LaFeO3 is synthesized by any one of a sol-gel method, a microemulsion method, an impregnation method, and a hydrothermal method. In some specific embodiments, the synthesis steps of the sol-gel method are: weighing a nitrate containing the metal element in the metal oxide to be prepared and dissolving it in deionized water to form a nitrate solution (optionally, the concentration of the nitrate solution is 0.2 to 3 mol / L), and then adding EDTA and citric acid to the nitrate solution (optionally, the molar ratio of EDTA to nitrate is 1:1 to 1:1.5, and the molar ratio of citric acid to nitrate is 0.5:1 to 1:1.5) to form a mixed system, and using ammonium carbonate solution to adjust the pH of the mixed system to alkaline (optionally, the pH is 7 to 10), and finally heating and stirring the mixed system (optionally, the heating temperature is 30 to 90°C, and the time is 4 to 24 hours) to form a sol, and the sol is dried and calcined (optionally, the calcination temperature is 350 to 750°C, and the time is 4 to 8 hours) to obtain the metal oxide of the present invention. In some embodiments, in the bifunctional catalyst, the molecular sieve support is selected from a combination of one or more of zeolite, alumina and nano H-ZSM-5. In some embodiments, the molar ratio of silicon to aluminum in the molecular sieve carrier is not less than 30, preferably 30 to 120, such as 40, 50, 80, 100, etc. In some specific embodiments, the preparation steps of nano H-ZSM-5 molecular sieve are: adding commercial silica-alumina molecular sieve to a 50-90°C alkaline solution (optionally, the alkaline solution is an ammonium carbonate solution, such as an ammonium carbonate solution with a pH of 9-11; optionally, the concentration of ammonium carbonate is 0.5-1 mol / mL; optionally, the mass ratio of the molecular sieve to the ammonium carbonate solution is 1:10-1:20), stirring for 0.5-12 hours, filtering, and adding the obtained solid to a 50-90°C alkaline solution (optionally, the alkaline solution is a KOH solution with a pH of 8-11) again, stirring for 0.5-12 hours, filtering, collecting the filter residue and washing it to neutrality, drying, and calcining (optionally, the calcination temperature is 300-650°C for 2-48 hours) to obtain a nano H-ZSM-5 molecular sieve. In some specific embodiments, when x is 2 (ie, the raw gas contains CO2 and H2), the metal oxide is a combination of one or more of ZnCr2O4 and LaFeO3, and the molecular sieve carrier is nano H-ZSM-5. In some specific embodiments, when x is 1 (ie, the raw gas contains CO and H2), the metal oxide is ZnCr2O4, and the molecular sieve carrier is nano H-ZSM-5. In some specific embodiments, the average particle size of the bifunctional catalyst is not less than 30 μm, preferably 30-130 μm, for example 40 μm, 50 μm, 60 μm, 65 μm, 70 μm, 80 μm, 90 μm, 100 μm, 120 μm, etc. In some embodiments, the bifunctional catalyst is prepared by the following method: the metal oxide and the molecular sieve carrier are uniformly mixed by physical means or wet mixing. In some specific embodiments, the mass ratio of the metal oxide to the molecular sieve is 1:3 to 3:1, preferably 1:1 to 1.5:1, for example 1:2, 1:1, 2:1, etc. In some specific embodiments, the physical method is mechanical stirring or ball milling. In some specific embodiments, the wet mixing method includes the steps of impregnating, drying and calcining the precursor and the molecular sieve carrier; the precursor is a solid substance before the metal oxide is calcined, such as a substance generated by coprecipitation, sol-gel or other methods of salts of corresponding metal elements in the metal oxide. In some specific embodiments, the metal oxide and the molecular sieve support are mixed evenly by physical means or coprecipitation, and then calcined. The purpose of the calcination is to form a stable catalyst structure and active sites. In some preferred embodiments, the calcination temperature is 300 to 700° C., preferably 500 to 600° C., such as 520° C., 550° C., 580° C., etc. In the present invention, the bifunctional catalyst has high stability. When the system for preparing green aromatics by one-step hydrogenation of COx and high yield of paraxylene and benzene runs for more than 100 hours, or more than 120 hours, or more than 150 hours, the catalyst can still maintain a high catalytic activity. In some embodiments, in step S3, the cleavage reaction is performed in the presence of a Ni / Mg supported catalyst. In some embodiments, the Ni / Mg supported catalyst comprises metal oxide Al2O3, metal Ni and metal Mg, with the metal oxide Al2O3 serving as a support. In some specific embodiments, in the Ni / Mg supported catalyst, the sum of the mass fractions of the Ni element and the Mg element is 0.1% to 1.5%, for example, 0.2%, 0.5%, 1%, 1.2%, and the like. In some specific embodiments, in the Ni / Mg supported catalyst, the mass ratio of Ni element to Mg element is 1 to 10, for example, 1, 2, 3, 5, 8, etc. In some embodiments, the volume flow ratio of COx and H2 in the raw gas is 5:1 to 1:5, preferably 1:1 to 1:2, for example, 1:1.2, 1:1.5, 1:1.8, 1:3, etc. In some embodiments, the raw gas is pre-treated before being introduced into the high pressure fluidized bed reaction device. In some preferred embodiments, the pre-treatment may be to treat the raw gas through compression, cooling and dehydration steps to remove impurity gases. In some embodiments, the method of the present invention further comprises the following steps: S4, tail gas circulation: the gaseous product containing methane generated by the cracking reaction in step S3 is transported to a gas separation device, the dry gas is separated and discharged, and the remaining gaseous product is combined with the gaseous product in step S2 as a recycled raw gas and transported to a high-pressure fluidized bed reaction device. In some embodiments, the feed gas comprises fresh feed gas and recycled feed gas in step S4. In some specific embodiments, the volume flow ratio of the recycled feed gas to the fresh feed gas is 2 to 8:1, preferably 2 to 4:1, for example, 2:1, 3:1, 4:1, 6:1, etc. In some embodiments, the dry gas (gas containing methane) in the reaction tail gas in step S4 can be removed or converted by adsorption, separation or other appropriate methods, preferably low-temperature condensation separation. In some embodiments, the high pressure fluidized bed reaction device is as follows Figure 2 As shown, a gas distributor, a heat exchange tube bundle and a cyclone separator are arranged inside to optimize the gas distribution and the control of the reaction conditions. In some specific embodiments, the gas distributor is provided with a gas nozzle. In the present invention, the linear velocity of the gas ejected from the gas nozzle is not particularly limited, and it can be adaptively adjusted according to the size of the reaction space velocity. In the present invention, the linear velocity of the gas is not less than 10 m / s. In some specific embodiments, the heat exchange tube bundle is arranged vertically or horizontally, and the heat exchange medium inside is water or water vapor. In some preferred embodiments, when the heat exchange tube bundle is arranged horizontally, Figure 3 As shown, the heat exchange tube bundle has a water drop shape and / or a cylindrical shape. In some specific embodiments, the inlet linear velocity of the cyclone separator is not particularly limited and can be adaptively adjusted according to the reaction space velocity. In the present invention, the linear velocity of the gas is not less than 18 m / s. In the present invention, the superficial gas velocity U of the feed gas entering the high-pressure fluidized bed reaction device is gis the ratio of the flow rate of the raw gas to the cross-sectional area of ​​the high-pressure fluidized bed reactor. In the present invention, the superficial gas velocity U g There is no particular limitation, and it can be adaptively adjusted according to the size of the reaction space velocity. In the present invention, the superficial gas velocity U g Not less than the minimum fluidization velocity U of the bifunctional catalyst under reaction conditions mf 1.5 times of . The minimum fluidization velocity in fluidization refers to the minimum gas velocity at which the medium (usually solid particles) begins to flow and remains in the bed in a given fluidized bed system. When the gas velocity reaches the minimum fluidization velocity, the particles in the bed begin to move in a liquid-like manner, forming a fluidized state. The methods for testing the minimum fluidization velocity include observation method, pressure drop method, bed oscillation method and resistance measurement method. In some embodiments, the present invention uses a pressure drop method to test the minimum fluidization velocity, that is, during the experiment, the gas flow rate can be gradually increased according to the height and density of the bifunctional catalyst. The data of the gas pressure drop in the bed changing with the flow rate are recorded. When the gas flow rate reaches a certain value, the gas pressure drop in the bed begins to stabilize, and this flow rate usually corresponds to the minimum fluidization velocity. In some embodiments, the loading amount of the bifunctional catalyst is 3 to 10 times (eg, 4 times, 5 times, 6 times, 8 times, etc.) the height-to-diameter ratio of the high-pressure fluidized bed reactor, and the unit of the loading amount is tons. In the present invention, the loading amount of the Ni / Mg supported catalyst is not particularly limited. In actual production, the loading amount of the catalyst can be adaptively adjusted according to the space velocity of the catalyst's treatment amount of mixed green aromatics. In the present invention, a method for preparing green aromatics and producing high yields of benzene and p-xylene in one step by COx hydrogenation using high-pressure fluidization technology can achieve efficient conversion of carbon sources. In some embodiments, the conversion rate of the carbon source (e.g., effective cycle conversion rate) can reach more than 80%, or more than 85%, or more than 90%, or more than 95%. In the present invention, "carbon source conversion rate" or "effective cycle conversion rate of carbon source" refers to the efficiency of converting carbon in the raw gas COx into carbon in the total hydrocarbon products, that is, the ratio of carbon in the total hydrocarbon products to carbon in COx. In the present invention, a method for preparing green aromatics and producing high-yield benzene and p-xylene in one step by COx hydrogenation using high-pressure fluidization technology can improve the yield and selectivity of p-xylene and benzene. In some embodiments, based on the total hydrocarbon products, the selectivity of benzene can reach more than 25%, or more than 30%, or more than 35%, or more than 40%; the selectivity of p-xylene can reach more than 45%, or more than 50%, or more than 55%, or more than 60%. In the present invention, "total hydrocarbon products" refers to the sum of hydrocarbons obtained in the method of the present invention, including C1-C3 hydrocarbons and benzene obtained in step S1, and benzene, p-xylene, methane, etc. obtained in step S3. Example The embodiments of the present invention will be described in detail below in conjunction with the examples, but those skilled in the art will appreciate that the following examples are only used to illustrate the present invention and should not be considered to limit the scope of the present invention. If no specific conditions are specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be obtained commercially. In an embodiment of the present invention, the ZnCr2O4 spinel used is prepared by a co-precipitation method, and the specific steps are: mixing zinc nitrate and chromium nitrate (molar ratio of 1:2) with deionized water to obtain a first metal salt solution (the concentration of the zinc nitrate solution is 0.5 mol / L, and the concentration of the chromium nitrate solution is 1 mol / L); slowly mixing the first metal salt solution with an ammonium carbonate solution with a pH of 10 under continuous stirring to obtain a second mixed solution, and maintaining the temperature of the second mixed solution at 75°C and the pH at 7.5 during the mixing process. After the mixing is completed, the second mixed solution is placed in a nitrogen atmosphere and continuously stirred for crystallization for 12 hours to obtain a third mixed solution; after stirring for 12 hours, filtering and roasting (the roasting temperature is 350°C and the time is 4 hours) are performed to obtain the metal oxide ZnCr2O4. In the embodiment of the present invention, the molar ratio of Zn / Cr in the ZnCr2O4 spinel used is 1:2. In an embodiment of the present invention, the LaFeO3 perovskite used is prepared by a sol-gel method, and the specific steps are: weighing nitrate (i.e., ferric nitrate and lanthanum nitrate, in a molar ratio of 1:1) and dissolving them in deionized water to form a nitrate solution (wherein the concentration of ferric nitrate is 1 mol / L, and the concentration of lanthanum nitrate solution is 1 mol / L), and then adding appropriate amounts of EDTA and citric acid to the nitrate solution (wherein the molar ratio of EDTA to nitrate is 1:1, and the molar ratio of citric acid to nitrate is 0.5:1) to form a mixed system, and adjusting the pH of the mixed system to 7.5 with ammonium carbonate solution, and finally heating and stirring the mixed system (heating temperature is 85°C, time is 12h) to form a sol, and the sol is dried and calcined (calcination temperature is 450°C, time is 6h) to obtain LaFeO3 perovskite. In the embodiments of the present invention, the Fe2O3 crystals used are purchased. In an embodiment of the present invention, the H-ZSM-5 molecular sieve used has a silicon-aluminum molar ratio of 120, and the specific preparation steps are: commercial silicon-aluminum molecular sieve is added to an ammonium carbonate solution (concentration of 1 mol / L) at 60°C and pH 10, and the mass ratio of silicon-aluminum molecular sieve to ammonium carbonate solution is 1:10, and the mixture is stirred for 24 hours, filtered, and the obtained solid is added to a KOH solution at 45°C and pH 12 again, stirred for 4 hours, filtered, the filter residue is collected and washed to neutrality, dried, and calcined at 580°C for 6 hours to obtain an H-ZSM-5 molecular sieve. Example 1 This embodiment provides a system and method for preparing green aromatics with high yield of benzene and p-xylene by one-step high-pressure fluidization. Figure 1 As shown, it specifically includes: a high-pressure fluidized bed reaction device 1, a gas-liquid separation device 3, a cracking reaction device 2, and a gas separation device 4. The bifunctional catalyst is loaded into the high-pressure fluidized bed reaction device 1 , and the Ni / Mg supported catalyst is loaded into the cracking reaction device 2 . The bifunctional catalyst is a mixture obtained by mechanically stirring ZnCr2O4 spinel and H-ZSM-5 molecular sieve in a mass ratio of 1:1. The average particle size of the bifunctional catalyst is 60 μm. The Ni / Mg supported catalyst uses metal oxide Al2O3 as a carrier, the sum of the mass fractions of Ni and Mg in the catalyst is 0.8%, and the mass ratio of Ni to Mg is 1:1. The loading capacity of the Ni / Mg supported catalyst is 1 cubic meter, and the mass is 0.8 tons. The high pressure fluidized bed reaction device 1 is provided with a gas distributor, a heat exchange tube bundle and a cyclone separator. Figure 2As shown. The heat exchange tube bundle is arranged horizontally and is cylindrical in shape. The heat exchange medium inside is water. The gas distributor is equipped with a gas nozzle, and the linear velocity of the gas is 15m / s. The inlet linear velocity of the cyclone separator is 25m / s. The height-to-diameter ratio of the high-pressure fluidized bed reaction device 1 is 5. The loading height of the bifunctional catalyst in the high-pressure fluidized bed reaction device 1 is 5 m, and the loading amount is 30 t. The raw gas is a synthesis gas with a volume flow ratio of CO:H2=1:1.2, and the flow rate of the synthesis gas is 5250Nm 3 / hr, wherein the volume flow ratio of the recycled raw gas separated from the tail gas to the fresh raw gas in the raw gas is 4:1. After the pretreatment steps of dust removal, water removal, compression and cooling, the raw gas enters the high-pressure fluidized bed reaction device 1 to contact with the bifunctional catalyst for reaction. The reaction temperature is 350°C and the reaction pressure is 4MPa. The product output from the high-pressure fluidized bed reaction device 1 is condensed and separated in the device 3 to form gas phase products and liquid phase products. The liquid phase products are further separated, and the benzene product is collected. The remaining mixed green aromatics enter the device 2 for cracking reaction. The temperature of the cracking reaction is 180°C. Benzene exits the device 3 through the outlet 7, and the cracked p-xylene and benzene products exit the device 2 through the outlet 8. The gas after the reaction in the device 2 enters the device 4 through the pipeline 11. The device 4 performs low-temperature condensation and separation on the gas and outputs dry gas. The gas phase product in the device 3 is combined with the remaining gas in the device 4 and circulates into the device 1 through the pipeline 13. The above steps are repeated to make the reaction process continuous. After testing, after 100 hours of stable operation, based on the total hydrocarbon products, the selectivity of benzene was 35%, the selectivity of paraxylene was 55%, and the effective circulation conversion rate of the carbon source was 90.5%. Example 2 This embodiment provides a high-pressure fluidized one-step method for preparing green aromatics and producing high yields of benzene and para-xylene. Compared with Example 1, the only difference is that the raw gas is carbon dioxide and hydrogen, and the volume flow ratio CO2:H2=1:1.2; the bifunctional catalyst is a mixture obtained by mechanically stirring LaFeO3 perovskite and H-ZSM-5 molecular sieve in a mass ratio of 1:1, and the average particle size of the bifunctional catalyst is 65μm. The rest is the same as Example 1. After testing, after 100 hours of stable operation, based on the total hydrocarbon products, the selectivity of benzene was 30%, the selectivity of paraxylene was 60%, and the effective circulation conversion rate of the carbon source was 98.2%. Example 3 This embodiment provides a high-pressure fluidized bed one-step method for preparing green aromatics and producing high yields of benzene and p-xylene. Compared with Example 1, the only difference is that the volume flow ratio of the recycled raw gas obtained by separating the tail gas and the fresh raw gas in the raw gas is 3:1; the heat exchange tube bundle in the high-pressure fluidized bed reaction device 1 is horizontally arranged and has a water drop shape, such as Figure 3 As shown; the aromatization reaction temperature in the high-pressure fluidized bed reaction device 1 is 350°C, the reaction pressure is 6MPa, and the others are the same as in Example 1. After testing, after 100 hours of stable operation, based on the total hydrocarbon products, the selectivity of benzene was 35%, the selectivity of paraxylene was 60%, and the effective circulation conversion rate of the carbon source was 92.1%. Example 4 This embodiment provides a high-pressure fluidized one-step method for preparing green aromatics and producing high yields of benzene and p-xylene. Compared with Example 1, the only difference is that the flow rate of the synthesis gas selected as the raw gas is 4880 Nm 3 / hr, carbon dioxide and hydrogen are selected, and the volume flow ratio CO2:H2=1:1.2; the bifunctional catalyst is a mixture obtained by mechanically stirring ZnCr2O4 spinel and H-ZSM-5 molecular sieve in a mass ratio of 1:1, and calcined at 550°C for 2h to form a bifunctional catalyst with an average particle size of 55μm. Others are the same as in Example 1. After testing, after 100 hours of stable operation, based on the total hydrocarbon products, the selectivity of benzene was 30%, the selectivity of paraxylene was 65%, and the effective circulation conversion rate of the carbon source was 93.7%. Example 5 This embodiment provides a high-pressure fluidized one-step method for preparing green aromatics and producing high yields of benzene and para-xylene. Compared with Example 1, the only difference is that the aromatization reaction temperature in the high-pressure fluidized bed reaction device 1 is 300°C and the reaction pressure is 3MPa. The rest is the same as Example 1. After testing, after 100 hours of stable operation, based on the total hydrocarbon products, the selectivity of benzene was 40%, the selectivity of paraxylene was 45%, and the effective circulation conversion rate of the carbon source was 87.6%. Example 6 This embodiment provides a high-pressure fluidized one-step method for preparing green aromatics and producing high yields of benzene and para-xylene. Compared with Example 2, the only difference is that: the bifunctional catalyst is a mixture obtained by mechanically stirring LaFeO3 perovskite and H-ZSM-5 molecular sieve in a mass ratio of 1.5:1; the aromatization reaction temperature in the high-pressure fluidized bed reactor 1 is 330°C, and the reaction pressure is 2MPa. The rest is the same as Example 1. After testing, after 100 hours of stable operation, based on the total hydrocarbon products, the selectivity of benzene was 35%, the selectivity of paraxylene was 55%, and the effective circulation conversion rate of the carbon source was 91.5%. Example 7 The embodiment of the present invention provides a high-pressure fluidized one-step method for preparing green aromatics and producing high yields of benzene and para-xylene. Compared with Example 2, the only difference is that: the bifunctional catalyst is a mixture obtained by mechanically stirring LaFeO3 perovskite and H-ZSM-5 molecular sieve in a mass ratio of 1:1, the average particle size of the bifunctional catalyst is 60 μm, the volume flow ratio of the recycled raw gas obtained by separating the tail gas from the raw gas and the fresh raw gas is 2:1, and the rest is the same as Example 1. After testing, after 100 hours of stable operation, based on the total hydrocarbon products, the selectivity of benzene was 25%, the selectivity of paraxylene was 50%, and the effective circulation conversion rate of the carbon source was 96.1%. Comparative Example 1 The only difference between this comparative example and Example 1 is that the reactor used in Device 1 is a fixed bed with a diameter of 1 m, rather than a fluidized bed, the filling height of the bifunctional catalyst in the fixed bed reactor is 3 m, and the filling amount is 30 t. The rest is the same as Example 1. After testing, after 100 hours of stable operation, based on the total hydrocarbon products, the selectivity of benzene was 20%, the selectivity of paraxylene was 45%, and the effective circulation conversion rate of the carbon source was 58.8%. Comparative Example 2 The only difference between this comparative example and Example 1 is that the bifunctional catalyst is a mixture obtained by mechanically stirring Fe2O3 crystals and H-ZSM-5 molecular sieves in a mass ratio of 1:1, the average particle size of the bifunctional catalyst is 62 μm, and the rest is the same as Example 1. After testing, after 100 hours of stable operation, based on the total hydrocarbon products, the selectivity of benzene was 15%, the selectivity of paraxylene was 30%, and the effective circulation conversion rate of the carbon source was 54.9%. Comparative Example 3 The only difference between this comparative example and Example 2 is that the volume flow ratio of the recycled raw gas obtained by separating the tail gas and the fresh raw gas in the raw gas is 3:1, and the aromatization reaction temperature in the high-pressure fluidized bed reaction device 1 is 600° C., and the rest is the same as Example 2. After testing, after 100 hours of stable operation, based on the total hydrocarbon products, the selectivity of benzene was 10%, the selectivity of paraxylene was 30%, and the effective circulation conversion rate of the carbon source was 60.5%. From the above test results, it can be seen that the one-step method for preparing green aromatics and producing benzene and p-xylene in high yields by using the embodiments 1 to 7 provided by the present invention has significantly higher selectivity of benzene and p-xylene products and a higher recycling conversion rate of carbon sources than the comparative examples 1 to 3 that do not adopt the technical solution of the present invention. Therefore, the one-step method for preparing green aromatics and producing benzene and p-xylene in high yields by high-pressure fluidization provided by the present invention has obvious technical advantages and significant economic efficiency. It should be noted that, although the technical solution of the present invention is introduced with specific examples, those skilled in the art will appreciate that the present invention should not be limited thereto. The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A system for preparing green aromatics by hydrogenating COx in one step and producing high yields of benzene and p-xylene, comprising: A high-pressure fluidized bed reaction device (1) is used for the contact reaction of a raw gas with a bifunctional catalyst in a fluidized state to obtain reaction products C1-C3 hydrocarbons, benzene and mixed green aromatics; wherein the raw gas comprises COx and hydrogen, x is 1 or 2; the mixed green aromatics comprises toluene, xylene, trimethylbenzene, tetramethylbenzene, pentamethylbenzene and hexamethylbenzene; The gas-liquid separation device (3) is used to cool the gas output from the high-pressure fluidized bed reaction device (1), perform gas-liquid separation to form gas phase products and liquid phase products, separate benzene and mixed green aromatics in the liquid phase products, and output the product benzene; The cracking reaction device (2) is used to carry out a cracking reaction on the mixed green aromatics output from the gas-liquid separation device (3), so as to convert the mixed green aromatics into products of benzene and paraxylene, and generate a gas phase product containing methane.

2. The system according to claim 1, characterized in that The system further comprises a gas separation device (4) for separating the gas phase product containing methane outputted from the cracking reaction device (2) to obtain dry gas, and inputting the remaining gas phase product into the high pressure fluidized bed reaction device (1) for recycling; The gas phase product in the gas-liquid separation device (3) is input into the high-pressure fluidized bed reaction device (1) for recycling; The gas-liquid separation device (3) comprises a functional module for separating benzene and mixed green aromatics.

3. A method for preparing green aromatics by hydrogenating COx in one step and producing high yields of benzene and p-xylene, which is carried out in the system according to claim 1 or 2, and the method comprises the following steps: S1, fluidized aromatization reaction: the feed gas is introduced into a high-pressure fluidized bed reaction device, and is contacted with a bifunctional catalyst in a fluidized state, and an aromatization reaction occurs to obtain products C1-C3 hydrocarbons, benzene and mixed green aromatics; wherein the feed gas comprises COx and hydrogen, and x is 1 or 2; the mixed green aromatics comprise toluene, xylene, trimethylbenzene, tetramethylbenzene, pentamethylbenzene and hexamethylbenzene; the bifunctional catalyst comprises a metal oxide and a molecular sieve carrier; S2, gas-liquid separation: in a gas-liquid separation device, the gas generated in step S1 is cooled, the gas and liquid are separated to form a gas phase product and a liquid phase product, and the liquid phase product is purified to separate benzene and mixed green aromatics; S3, cracking reaction: the mixed green aromatics obtained in step S2 are cracked in a cracking reaction device to convert them into benzene and p-xylene, and generate a gas phase product containing methane.

4. The method according to claim 3, characterized in that: The pressure of the aromatization reaction is 2-6 MPa; The temperature of the aromatization reaction is 250-550°C, preferably 250-400°C; The pressure of the cracking reaction is 2-6 MPa; The temperature of the cracking reaction is 180-250°C.

5. The method according to claim 3 or 4, characterized in that: In the bifunctional catalyst, the metal oxide is selected from a combination of one or more of ZnCr2O4, ZnFe2O4 and LaFeO3, and the molecular sieve carrier is selected from a combination of one or more of zeolite, alumina and nano H-ZSM-5; Preferably, when x is 2, the metal oxide is a combination of one or more of ZnCr2O4 and LaFeO3, and the molecular sieve carrier is nano H-ZSM-5; when x is 1, the metal oxide is ZnCr2O4, and the molecular sieve carrier is nano H-ZSM-5; Preferably, the mass ratio of the metal oxide to the molecular sieve is 1:3 to 3:1, preferably 1:1 to 1.5:1; Preferably, the average particle size of the bifunctional catalyst is not less than 30 μm, preferably 30 to 130 μm.

6. The method according to any one of claims 3 to 5, characterized in that: In step S3, the cracking reaction is carried out in the presence of a Ni / Mg supported catalyst; Preferably, the Ni / Mg supported catalyst comprises metal oxide Al2O3, metal Ni and metal Mg, with the metal oxide Al2O3 serving as a carrier; Preferably, in the Ni / Mg supported catalyst, the sum of the mass fractions of the Ni element and the Mg element is 0.1% to 1.5%; Preferably, in the Ni / Mg supported catalyst, the mass ratio of the Ni element to the Mg element is 1-10.

7. The method according to any one of claims 3 to 6, characterized in that: In the raw gas, the volume flow ratio of COx and H2 is 5:1 to 1:5, preferably 1:1 to 1:2; Preferably, the raw gas is introduced into the high-pressure fluidized bed reaction device after pretreatment; further, the pretreatment is to process the raw gas through compression, cooling and dehydration steps to remove impurity gases.

8. The method according to any one of claims 3 to 7, characterized in that: The method further comprises the following steps: S4, tail gas circulation: the gas phase product containing methane generated by the cracking reaction in step S3 is transported to a gas separation device, the dry gas is separated and discharged, and the remaining gas phase product is combined with the gas phase product in step S2 as a recycled raw gas and transported to a high-pressure fluidized bed reaction device; Preferably, the raw gas in the method comprises fresh raw gas and recycled raw gas in step S4; further, the volume flow ratio of the recycled raw gas to the fresh raw gas is 2 to 8:1, preferably 2 to 4:

1.

9. The method according to any one of claims 3 to 8, characterized in that: The high-pressure fluidized bed reaction device is provided with a gas distributor, a heat exchange tube bundle and a cyclone separator; Preferably, the gas distributor is provided with a gas nozzle; Preferably, the heat exchange tube bundle is arranged vertically or horizontally, and the internal heat exchange medium is water or water vapor; further, when the heat exchange tube bundle is arranged horizontally, the shape of the heat exchange tube bundle is drop-shaped and / or cylindrical.

10. The method according to any one of claims 3 to 9, characterized in that: The loading amount of the bifunctional catalyst is 3 to 10 times the height-to-diameter ratio of the high-pressure fluidized bed reaction device, and the unit of the loading amount is ton.

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