Method for preparing full-fraction aviation kerosene from synthesis gas

Abstract

The invention discloses a method for preparing full-fraction aviation kerosene from synthesis gas, and belongs to the technical field of synthetic fuels, and the method comprises the following steps: S1, decomposing wood and crop residues into synthesis gas through biomass gasification; s2, coupling the cobalt base and the molecular sieve to obtain a first catalyst, inputting the synthesis gas into a first Fischer-Tropsch reactor, and promoting the reaction by the first catalyst to obtain alkane; s3, coupling the composite oxide and the molecular sieve to obtain a second catalyst, inputting the synthesis gas into a second Fischer-Tropsch reactor, and promoting the reaction by the second catalyst to obtain aromatic hydrocarbon; and S4, after heat exchange of the alkane and the aromatic hydrocarbon in the process flow, carrying out isomerization refining and rectification to collect hydrocarbon products, and blending to form petroleum fractions, thereby obtaining the full-fraction aviation kerosene. The invention is rooted on leading-edge exploration of sustainable development energy, and aims to integrate renewable resource technologies such as biomass gasification and green electric driven H2 manufacturing so as to construct a low-carbon and environment-friendly aviation kerosene production system, thereby providing a scientific and feasible technical path for green transformation of the global aviation fuel industry.

Description

Technical Field

[0001] The invention belongs to the technical field of synthetic fuels, and in particular relates to a method for preparing full-fraction aviation kerosene from synthetic gas. Background Art

[0002] Currently, the production of biofuels mainly relies on the direct combustion of biomass resources or their conversion into valuable chemicals and energy through complex chemical conversion processes. Although these methods have reduced dependence on fossil fuels to a certain extent, there are still some challenges in terms of economics and environmental sustainability. For example, the existing process of converting biomass syngas (CO2 / CO / H2) into jet fuel often requires high temperature and high pressure conditions, resulting in high energy consumption and large equipment investment. In addition, these processes can usually only produce a single type of fuel and cannot meet the demand for full-fraction jet fuel, that is, compounds containing a variety of different boiling point ranges.

[0003] The current process of producing jet fuel from syngas usually uses the Fischer-Tropsch process, which is a chemical reaction that converts CO and H2 into liquid hydrocarbons. However, this process is usually accompanied by the production of by-products, such as light alkanes and olefins, which reduces the quality of the final product and increases the separation cost. In addition, the traditional Fischer-Tropsch catalyst has low activity at low temperatures, making it difficult to achieve the production of full-fraction jet fuel at lower temperatures.

[0004] To overcome these problems, researchers have been seeking new catalysts and process strategies to improve the efficiency and selectivity of syngas to jet fuel conversion. However, existing solutions either fail to significantly improve conversion or require the use of expensive metal catalysts, limiting their large-scale application. Summary of the invention

[0005] In view of this, the object of the present invention is to provide a method for preparing full-fraction aviation kerosene from synthesis gas to solve the above problems.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A method for preparing full-fraction aviation kerosene from synthesis gas comprises the following steps:

[0008] S1, decomposing wood and crop residues into synthesis gas through biomass gasification, wherein the synthesis gas is composed of CO, H2 and CO2;

[0009] S2, a cobalt-based catalyst is coupled with a molecular sieve to obtain a first catalyst, and the synthesis gas is input into a first Fischer-Tropsch reactor, and the first catalyst promotes the reaction to obtain alkanes;

[0010] S3, the composite oxide and the molecular sieve are coupled to obtain a second catalyst, the synthesis gas is input into a second Fischer-Tropsch reactor, and the second catalyst promotes the reaction to obtain aromatics;

[0011] S4. The process flow of synthesizing alkanes is heat exchanged with the process flow of synthesizing aromatics, and then distilled. After distillation, hydrocarbon products are collected and blended to form a complete petroleum fraction, that is, full-fraction aviation kerosene.

[0012] Furthermore, in step S2, the reaction temperature when the first catalyst is used to promote the production of alkanes is less than 260°C, and the reaction temperature when the second catalyst is used to promote the production of aromatics is greater than 280°C.

[0013] Furthermore, in step S3, the composite oxide is ZnZrOx.

[0014] Furthermore, when the first catalyst is used to promote the reaction, the molar ratio of H2 to CO in the introduced synthesis gas is 1.5-2.5:1, and the content of CO2 in the synthesis gas does not exceed 10% of the total volume.

[0015] Further, when the first catalyst is used, the pressure in the first Fischer-Tropsch reactor is 1.0-5.0 MPa.

[0016] Furthermore, when the second catalyst is used to promote the reaction, the molar ratio of H2 to CO2 does not exceed 2.5-3.5:1, and the CO content in the synthesis gas does not exceed 10% of the total volume.

[0017] Further, when the second catalyst is used, the pressure in the second Fischer-Tropsch reactor is 2.5-3.5 MPa.

[0018] Furthermore, in the step S1, wood and crop residues can be decomposed into synthesis gas after steam reforming; the cobalt base in the step S2 can be replaced by a ruthenium base.

[0019] Furthermore, in step S2, the molecular sieve coupled with the first catalyst is ZSM-5; and in step S3, the molecular sieve coupled with the second catalyst is HZSM-5.

[0020] Furthermore, steps S2 and S3 may be performed simultaneously.

[0021] The beneficial effects of the present invention are:

[0022] 1. The present invention is rooted in the frontier exploration of sustainable energy, and aims to integrate renewable resource technologies such as biomass gasification and green electricity-driven H2 production, in order to build a low-carbon and environmentally friendly aviation kerosene production system, and provide a scientific and feasible technical path for the green transformation of the global aviation fuel industry. Based on the existing process of converting syngas to alkanes, the present invention introduces a second technical route, that is, the directional preparation of heavy aromatic components through the syngas Fischer-Tropsch synthesis process, so as to achieve the expansion of syngas utilization pathways and the diversification of product spectrum. The present invention effectively integrates the above two conversion pathways, works in coordination, and then produces aviation kerosene products covering the full range of fractions. The product meets the technical specifications and performance requirements of the national standard GB6537-2018 "No. 3 Jet Fuel", ensuring its compatibility and safety in aviation turbine engine applications. This comprehensive technical solution not only marks a major progress in the field of commercial production of green aviation fuel, but also provides strong technical support and practical guidance for alleviating the pressure of carbon emissions in aviation transportation and accelerating the green upgrade of the global energy structure.

[0023] 2. The first catalyst of the present invention exhibits excellent performance, including high conversion rate (CO single-pass conversion rate 70-90%), low methane selectivity (about 6-10%), and highly targeted product selectivity (C8-C 16 The selectivity of aviation kerosene is 50-75%). The products are mainly normal hydrocarbons and iso-hydrocarbons, which are beneficial to the synthesis of aviation fuel, while significantly reducing the generation of heavy by-products and reducing subsequent processing costs.

[0024] 3. The second catalyst in the present invention focuses on the efficient generation of aromatics, with a CO2 single-pass conversion rate of >20%, C8-C 12 The selectivity of heavy aromatics in aviation fraction is >80%.

[0025] 4. The present invention uses a hydroisomerization refining process to optimize the molecular structure of the product. Unsaturated hydrocarbons (such as olefins) are converted into more stable saturated hydrocarbons through selective hydrogenation reactions, and straight-chain alkanes are converted into branched alkanes through isomerization reactions. The increase in branched structures can significantly improve the low-temperature fluidity of the fuel, lower the freezing point, and ensure that the aircraft can operate safely in low-temperature environments. At the same time, through the synergistic effect of the distillation process and thermal coupling technology, the energy utilization efficiency is further optimized, energy consumption is reduced, and the high quality of the product is maintained.

[0026] 5. The system of the present invention is designed as an independent module for the synthesis of aromatics and alkanes. When the green hydrogen supply is unstable, the crude reactants can be pre-synthesized and stored to ensure the continuous operation of the distillation section. The intelligent ratio adjustment technology is used in the mixing stage to dynamically adjust the mixing ratio of aromatics and alkanes according to the GB6537-2018 standard to ensure that the volume fraction of aromatics in the final product does not exceed 20%. The integrated real-time monitoring and feedback mechanism automatically adjusts the module operating parameters to adapt to the fluctuation of green hydrogen supply and ensure production continuity and product quality.

[0027] 6. The present invention is a technical method for preparing full-fraction aviation kerosene from syngas, which uses two process routes and then connects them in parallel to achieve its purpose. The products of each process route are different. One route is C8-C 16 The main fractions are alkanes and olefins, and the other line is C8-C 12 Mainly heavy aromatics.

[0028] 7. The present invention optimizes the molecular structure of the alkane product and improves the low-temperature fluidity of the product aviation kerosene through the hydroisomerization refining process.

[0029] Other advantages, objectives and features of the present invention will be described in the following description and will be apparent to those skilled in the art to some extent, or those skilled in the art may be taught from the practice of the present invention. The objectives and other advantages of the present invention may be realized and obtained through the following description.

[0030] Other advantages, objectives and features of the present invention will be described in the following description and will be apparent to those skilled in the art to some extent, or those skilled in the art may be taught from the practice of the present invention. The objectives and other advantages of the present invention may be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to make the purpose, technical solution and beneficial effects of the invention clearer, the present invention provides the following drawings for illustration:

[0032] Figure 1 is a process flow chart of the present invention;

[0033] Figure 2 This is a heat coupling flow chart of the hydroisomerization heat exchange network distillation of the present invention;

[0034] Figure 3 The usage of the utility works before thermal coupling of the present invention;

[0035] Figure 4 This is the usage of public works after heat recovery by thermal coupling of the present invention. DETAILED DESCRIPTION

[0036] A method for preparing full-fraction aviation kerosene from synthesis gas comprises the following steps:

[0037] Example 1

[0038] S1, decomposing wood and crop residues into synthesis gas through biomass gasification, wherein the synthesis gas is composed of CO, H2 and CO2;

[0039] S2, using cobalt-based and ZSM-5 coupling to obtain a first catalyst; and inputting H2 and CO at a molar ratio of 2:1, and CO2 not exceeding 10% in the synthesis gas, into a first Fischer-Tropsch reactor; and then promoting the reaction by the first catalyst at a temperature of 255°C and a pressure of 3MPa to obtain alkanes;

[0040] S3, using ZnZrOx and HZSM-5 to couple to obtain a second catalyst; and inputting H2 and CO2 with a molar ratio of no more than 3:1 and no more than 10% of CO in the synthesis gas into a second Fischer-Tropsch reactor; and then promoting the reaction with the second catalyst at a temperature of 280° C. and a pressure of 3 MPa to obtain aromatics;

[0041] S4. The process flow of synthesizing alkanes is heat exchanged with the process flow of synthesizing aromatics, and then distilled. After distillation, hydrocarbon products are collected and blended to form a complete petroleum fraction, that is, full-fraction aviation kerosene.

[0042] Example 2

[0043] S1, fully burning wood and crop residues to decompose into synthesis gas, wherein the synthesis gas is composed of CO, H2 and CO2;

[0044] S2, using ruthenium base and ZSM-5 to couple to obtain a first catalyst; and inputting H2 and CO at a molar ratio of 2:1, and CO2 not exceeding 10% in the synthesis gas into a first Fischer-Tropsch reactor; and then promoting the reaction by the first catalyst at a temperature of 260°C and a pressure of 3MPa to obtain alkanes;

[0045] S3, using ZnZrOx and HZSM-5 to couple to obtain a second catalyst; and inputting H2 and CO2 with a molar ratio of no more than 2:1 and no more than 10% of CO in the synthesis gas into a second Fischer-Tropsch reactor; and then promoting the reaction with the second catalyst at a temperature of 280° C. and a pressure of 3 MPa to obtain aromatics;

[0046] S4. The process flow of synthesizing alkanes is heat exchanged with the process flow of synthesizing aromatics, and then distilled. After distillation, hydrocarbon products are collected and blended to form a complete petroleum fraction, that is, full-fraction aviation kerosene.

[0047] In order to demonstrate the influence of heating mode on heat recovery, different heating modes are set here:

[0048] Method 1: It includes the following steps: Figure 2 As shown:

[0049] S1. Aromatic production reactions are carried out at relatively high temperatures (>280°C), and the generated reaction heat can be recovered by heat exchangers; the gas flowing out of the high temperature reaction is first preheated by a heat exchanger to the cold synthesis gas or circulating gas entering the reaction system to recover a large amount of heat energy;

[0050] S2, transferring the waste heat of the high temperature reaction of the aviation kerosene aromatic fraction from the synthesis gas to the preheating feed of the fractionation tower reboiler of the alkane fraction and the hydrogenation reactor system;

[0051] S3, the multi-stage heat exchange network constructed enables the high-temperature reaction effluent to exchange heat with multiple subsequent cooling stages in sequence, gradually cool down, and preheat other fluids step by step to maximize thermal efficiency;

[0052] S4. The amount of public works saved is as follows: Figure 4 shown.

[0053] Method 2: includes the following steps:

[0054] S1. The production reaction of aviation kerosene aromatic fraction from syngas is carried out at a relatively high temperature (>280°C), and the outlet hot stream is directly cooled and heat-exchanged through the cold utility in the cooler;

[0055] S2, the preheated feed of the fractionation tower reboiler and hydrogenation reactor system for the syngas to jet fuel alkane fraction is directly heated by the thermal utility in the heater;

[0056] S3. Required utility quantities such as Figure 3 shown.

[0057] The difference between method 1 and method 2 is that method 2 adopts the method of direct heat exchange of public works without constructing a heat exchange network, resulting in a low energy utilization rate and being unfavorable for heat recovery.

[0058] The ZnZrOx material in the present invention helps to activate and convert CO2, which is a key step in converting CO2 into more valuable chemicals. At the same time, ZnZrOx has a certain acidity and alkalinity, which can provide necessary acid sites to help CO2 hydrogenate to generate CO and H2 intermediates, promote the formation of cyclic precursors, and then convert them into aromatics, which is crucial to the reaction steps of the Fischer-Tropsch synthesis process. In addition, the electronic properties of ZnZrOx are conducive to the adsorption and activation of reactants, including hydrogen transfer and carbon chain growth. And the stability and heat resistance of the ZnZrOx material itself help the catalyst to remain active during long-term operation. By coupling with the HZSM-5 molecular sieve, ZnZrOx can also help adjust the selectivity of the product, especially for the selectivity of aromatics.

[0059] When the first catalyst is used in the present invention, the molar ratio of H2 to CO is 1.5-2.5:1, and the supply of H2 is relatively sufficient, which is beneficial for the production of light olefins and alkanes. A higher H2 concentration helps to form longer carbon chains, thereby obtaining more liquid fuel. In addition, the presence of CO2 will reduce the reaction rate because it will compete for adsorption sites and consume a portion of H2. Therefore, controlling the CO2 content in the synthesis gas can allow more H2 to participate in the reaction, thereby increasing the yield.

[0060] When the second catalyst is used in the present invention, the aromatics synthesis catalyst is usually sensitive to the ratio of H2 to CO2. Maintaining an appropriate ratio can maximize the use of the active sites of the catalyst, improve the reaction efficiency and the service life of the catalyst, and limiting the content of CO can reduce the occurrence of side reactions. When the CO content is high, more methanation reactions will occur, which will lead to changes in product distribution and a decrease in catalyst performance.

[0061] Reaction principle of the present invention:

[0062] 1. Molecular sieve and cobalt-based or ruthenium-based coupling first catalyst

[0063] In the reaction of CO plus H2 to produce alkanes, when a cobalt-based / ruthenium-based + molecular sieve is used as the first catalyst for coupling, the reaction mechanism is described by the following basic reaction formula.

[0064] Alkane formation reaction:

[0065] CO+2H2→(CH2)+H2OΔHR(227℃)=-165kJ

[0066] Water Gas Shift Reaction:

[0067] CO+H2O→H2+COΔHR(227℃)=-39.8kJ

[0068] From the above two equations, the general formula of CO+H2 synthesis reaction can be obtained:

[0069] 2CO+H2→(CH2)+CO2ΔHR(227℃)=-204.7kJ

[0070] From the above two formulas, the general stoichiometric formula for alkane generation can be deduced as follows:

[0071] Alkane formation reaction:

[0072] nCO+(2n+1)H2→CnH 2n+2 +nH2O

[0073] 2nCO+(n+1)H2→CnH 2n+2 +nCO2

[0074] 3nCO+(n+1)H2O→CnH 2n+2 +(2n+1)CO2

[0075] nCO2+(3n+1)H2→CnH 2n+2 +2nH2O

[0076] Due to the different factors of reaction operating conditions, in addition to the above main reaction, the following side reactions also occur in the FT (Fischer-Tropsch) synthesis reaction: methane generation reaction, alcohol generation reaction, aldehyde generation reaction, surface carbide generation reaction, catalyst oxidation-reduction reaction (M is the catalyst metal component), catalyst body carbide generation reaction. In the present invention, the optimization of FT synthesis process conditions can reduce the occurrence of these side reactions as much as possible.

[0077] The molecular sieve coupled with the cobalt-based or ruthenium-based first catalyst has the following advantages:

[0078] ① High CO conversion rate: Under the temperature range of less than 260°C and the pressure conditions of 1.0-5.0MPa, the cobalt-based catalyst can increase the single-pass conversion rate of CO to 70-90%, significantly improving the utilization rate of synthesis gas.

[0079] ② Low methane selectivity: Compared with traditional iron-based catalysts, cobalt-based catalysts can reduce the selectivity of methane to about 6-10%, significantly reducing the generation of light by-products and increasing the yield of the target product.

[0080] ③ Highly targeted product selectivity: Cobalt-based catalysts have a high selectivity for C8-C 16 The key components of aviation kerosene show a high selectivity of 50-75%, which directly responds to the needs of the aviation fuel market and reduces the complexity of subsequent processing.

[0081] ④ Confined catalytic effect: By constructing a confined catalytic system, the spatial limitation of the catalyst active sites effectively controls the product distribution, promotes the formation of normal hydrocarbons and isohydrocarbons, reduces the generation of heavy by-products, and further reduces production costs.

[0082] ⑤Flexibility of operating conditions: Cobalt-based catalysts maintain stable activity over a wide range of temperature and pressure, providing a larger operating window and higher safety for industrial production.

[0083] 2. Molecular sieve coupled with highly active nano ZnZrOx as the second catalyst

[0084] In the reaction of CO2 plus H2 to produce aromatics, when molecular sieves are used to couple the second catalyst with highly active nano ZnZrOx, the reaction mechanism can be summarized into several main steps:

[0085] Activation of CO2 and reaction with H2: CO2 is first activated on the surface of ZnZrOx and then reacts with H2 to form formate or formic acid intermediate HCOO ZnZrOx (Indicating that the formate intermediate is adsorbed on the surface of the ZnZrOx catalyst).

[0086] CO2+H2→HCOO ZnZrOx

[0087] Dehydration of formate or formic acid: Under the action of ZnZrOx catalyst, formate or formic acid is further dehydrated to form methanol or formaldehyde.

[0088] HCOO ZnZrOx →CH3OH+CO2

[0089] or

[0090] HCOO ZnZrOx →HCHO+H2O

[0091] Conversion of methanol or formaldehyde: The formed methanol or formaldehyde undergoes methanol cracking MTO (methanol to olefins) reaction under the action of the acidic sites of HZSM-5 molecular sieve to produce light olefins (such as ethylene and propylene).

[0092] CH3OH→C2H4+H2O

[0093] or

[0094] CH3OH→C2H6+H2O

[0095] Polymerization and aromatization of olefins: The generated low-carbon olefins are further polymerized and cyclized in the mesoporous structure of HZSM-5 molecular sieve to eventually form aromatics.

[0096] nC m H 2m →C6H6+(n -1 )C m H2M

[0097] Among them, C6H6 represents the benzene ring, which is the basic unit of aromatic hydrocarbons.

[0098] The molecular sieve coupled with highly active nano ZnZrOx as the second catalyst has the following advantages:

[0099] ① Selective control of aromatics: By adjusting the structural parameters of HZSM-5 molecular sieve (such as b-axis length) and reaction conditions (such as contact time), the selectivity of aromatics, especially the selectivity for PX (paraxylene), can be optimized.

[0100] ② Retention of active sites: Compared with traditional surface acid modification methods, the second catalyst combines the redox ability of metal oxides (ZnZrOx) and the acid catalytic activity of molecular sieves (HZSM-5). This bifunctional property enables the second catalyst to simultaneously carry out redox reactions and acid-catalyzed reactions in a single reaction system, promoting the formation of specific products, thereby improving reaction efficiency and selectivity.

[0101] ③ Suppression of by-products: By optimizing the second catalyst structure and reaction conditions, the generation of CO and other non-aromatic by-products can be reduced, and the yield and selectivity of aromatics can be increased.

[0102] ④High CO2 conversion rate: The composite oxide series catalysts synthesize the heavy aromatic fraction required for aviation kerosene. Through the development of the second catalyst coupled with ZnZrOx / HZSM-5, the CO2 single-pass conversion rate is >20% and the fraction selectivity is >80%.

[0103] ⑤ Extended service life of the catalyst: HZSM-5 molecular sieve is known for its excellent thermal stability and hydrothermal stability. The catalyst can maintain its structure and catalytic activity, extending the service life of the catalyst.

[0104] ⑥Flexible adjustment: The acidity strength and type of HZSM-5 molecular sieve can be adjusted through different synthesis conditions and post-treatment methods, and the catalyst can be optimized for specific reactions.

[0105] ⑦Simple preparation method: ZnZrOx / HZSM-5 catalyst can be prepared by a one-step solid-phase reaction. The preparation method is relatively simple, and the performance of the catalyst can be adjusted by changing the calcination temperature and other preparation parameters.

[0106] 3. Hydrogenation isomerization heat exchange network distillation thermal coupling

[0107] ① Heat recovery after high temperature reaction: Aromatics production reaction is carried out at a relatively high temperature (>280°C), and the generated reaction heat can be recovered through a heat exchanger. The gas flowing out of the high temperature reaction is first preheated through a heat exchanger to enter the cold synthesis gas or circulating gas of the system, and then cooled to recover a large amount of heat energy.

[0108] ②Intermediate medium heat exchange: Use heat carrier or hot oil circulation system as an intermediary to transfer the waste heat of high-temperature reaction to the low-temperature system or use it for other factory needs, such as preheating feed or heating auxiliary facilities.

[0109] ③ Multi-stage heat exchange network: Build a heat exchange network so that the high-temperature reaction effluent flow exchanges heat with multiple subsequent cooling sections in sequence, gradually cools down, and preheats other fluids step by step to maximize thermal efficiency.

[0110] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A method for preparing full-fraction aviation kerosene from synthesis gas, characterized in that: The following steps are included: S1, decomposing wood and crop residues into synthesis gas through biomass gasification, wherein the synthesis gas is composed of CO, H2 and CO2; S2, a cobalt-based catalyst is coupled with a molecular sieve to obtain a first catalyst, and the synthesis gas is input into a first Fischer-Tropsch reactor, and the first catalyst promotes the reaction to obtain alkanes; S3, the composite oxide and the molecular sieve are coupled to obtain a second catalyst, the synthesis gas is input into a second Fischer-Tropsch reactor, and the second catalyst promotes the reaction to obtain aromatics; S4. The process flow of synthesizing alkanes is heat exchanged with the process flow of synthesizing aromatics, and then distilled. After distillation, hydrocarbon products are collected and blended to form a complete petroleum fraction, that is, full-fraction aviation kerosene.

2. The method for preparing full-fraction aviation kerosene from synthesis gas according to claim 1, characterized in that: In the step S2, the reaction temperature when the first catalyst is used to promote the production of alkanes is less than 260°C, and the reaction temperature when the second catalyst is used to promote the production of aromatics is greater than 280°C.

3. The method for preparing full-fraction aviation kerosene from synthesis gas according to claim 1, characterized in that: In the step S3, the composite oxide is ZnZrOx.

4. The method for preparing full-fraction aviation kerosene from synthesis gas according to claim 2, characterized in that: When the first catalyst is used to promote the reaction, the molar ratio of H2 to CO in the introduced synthesis gas is 1.5-2.5:1, and the content of CO2 in the synthesis gas does not exceed 10% of the total volume.

5. The method for preparing full-fraction aviation kerosene from synthesis gas according to claim 4, characterized in that: When the first catalyst is used, the pressure in the first Fischer-Tropsch reactor is 1.0-5.0 MPa.

6. The method for preparing full-fraction aviation kerosene from synthesis gas according to claim 1, characterized in that: When the second catalyst is used to promote the reaction, the molar ratio of H2 to CO2 does not exceed 2.5-3.5:1, and the CO content in the synthesis gas does not exceed 10% of the total volume.

7. The method for preparing full-fraction aviation kerosene from synthesis gas according to claim 6, characterized in that: When the second catalyst is used, the pressure in the second Fischer-Tropsch reactor is 2.5-3.5 MPa.

8. The method for preparing full-fraction aviation kerosene from synthesis gas according to claim 1, characterized in that: The cobalt group in step S2 can be replaced by a ruthenium group.

9. The method for preparing full-fraction aviation kerosene from synthesis gas according to claim 1, characterized in that: In the step S2, the molecular sieve coupled with the first catalyst is ZSM-5; in the step S3, the molecular sieve coupled with the second catalyst is HZSM-5.

10. The method for preparing full-fraction aviation kerosene from synthesis gas according to claim 1, characterized in that: The steps S2 and S3 can be performed simultaneously.

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