A method for synthesizing aviation kerosene

Abstract

The application discloses a synthesis method of aviation kerosene and belongs to the technical field of fuel preparation. S1, natural gas, CO2 and water vapor are proportionally introduced into a reforming reactor to perform a reforming reaction, and a catalyst is added to prepare synthetic gas I; in the components of the natural gas, the content of methane is > 95%, and the content of ethane, propane, ethylene and other hydrocarbons is ≤ 5%; S2, the prepared synthetic gas I is introduced into a Fischer-Tropsch reactor to react with H2 and CO to prepare mixed oil C 8+ ; S3, the mixed oil is subjected to rectification separation to obtain C 8+ fraction, the C 8+ fraction is reacted with H2 again to obtain a crude aviation kerosene fraction, the crude aviation kerosene fraction is separated and purified by using a catalyst to obtain an aviation kerosene fraction. The aviation kerosene fraction is prepared by using natural gas and CO2 as raw materials, combining three technologies of reforming, Fischer-Tropsch synthesis and hydrogenation isomerization, without purifying the natural gas raw material and without separating and purifying the intermediate product, so that the energy consumption and production cost are effectively reduced, and an overall technical solution of aviation kerosene synthesis is provided.

Description

Technical Field

[0001] This invention belongs to the field of fuel preparation technology, specifically relating to a method for synthesizing jet fuel. Background Technology

[0002] Aviation kerosene, also known as jet fuel, is a light petroleum product specifically designed for aviation gas turbine engines (including turbojet, turbofan, and turboprop engines). It is the "blood" of modern civil airliners and military aircraft, generating thrust through the combustion of fuel to power the aircraft.

[0003] The special operating environment of aviation kerosene (high altitude, low temperature, high speed) dictates that it must meet a series of extremely stringent physical and chemical performance indicators. It needs to have a high calorific value to ensure the aircraft's endurance; it must also burn stably and completely with minimal carbon buildup, and continue burning even in high-speed airflow without easily extinguishing; the extremely low air temperature at high altitudes necessitates that the fuel have good low-temperature fluidity, i.e., a low freezing point; aviation kerosene must be highly clean, free of mechanical impurities and moisture, and possess good thermal and storage stability, meaning it should not easily form gums or deposits during long-term storage or exposure to high temperatures; modern jet engine components such as fuel pumps rely on aviation kerosene itself for lubrication; and the sulfur content (especially mercaptan sulfur) must be strictly controlled to reduce corrosion of engine parts and combustion chamber flame tubes.

[0004] Although the production and use of traditional aviation kerosene are highly mature technologies, the sector faces severe technological and market challenges in the context of global energy transition and the recovery of the aviation industry. Currently, approximately 99% of the aviation industry's carbon emissions come from aviation fuel consumption, resulting in immense pressure to reduce emissions. The International Air Transport Association (IATA) has committed to achieving net-zero emissions by 2050, and regions such as the EU have mandated the blending of sustainable aviation fuels. However, the promotion of sustainable aviation fuels faces multiple obstacles: 1. Raw material supply bottleneck: Current mainstream oil-based hydrogenation processes rely on waste oils, making it difficult to meet the demands of large-scale production; 2. High production costs: The production cost of sustainable aviation fuels is far higher than that of traditional aviation kerosene, and raw material prices remain high. The EU's incentives for biofuels made from waste oils have led to a large-scale export of domestic waste oils, further driving up domestic raw material prices and squeezing production profits; 3. Technology and process compatibility: Impurities in waste oil raw materials can easily lead to catalyst poisoning and equipment corrosion, affecting the continuity and stability of production. Existing pretreatment processes have not yet fundamentally solved these problems. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a method for synthesizing jet fuel to solve the current problem of insufficient jet fuel supply.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for synthesizing jet fuel, comprising the following steps: S1. Natural gas, CO2, and steam are introduced into a reforming reactor in a specific ratio to carry out a reforming reaction. After adding a first catalyst, syngas 1 is obtained. The natural gas contains >95% methane and ≤5% ethane, propane, ethylene, and other hydrocarbons. S2. The synthesized gas is simultaneously passed into a Fischer-Tropsch reactor along with H2 and CO to produce a mixed oil product C. 8+ ; S3. Separate the mixed oils by distillation to obtain C. 8+ fraction, C 8+ The fraction was reacted with H2 again to obtain crude aviation kerosene fraction. The crude aviation kerosene fraction was then separated and purified using a second catalyst to obtain aviation kerosene fraction.

[0007] Further, in step S1, the conditions for the methane and CO2 reforming reaction are: a temperature of 750-900℃, a pressure of 0.1-3.0 MPa, and a space velocity of 1000-12000 h⁻¹ for the mixture of natural gas and CO2. -1 The molar ratio of natural gas / CO2 / water vapor is 1:(1-2.5):(0.1-0.8).

[0008] Further, in step S2, the methane selectivity is less than 6%; in step S3, the C8 content in the mixed oil is... + The mass fraction is higher than 65%, and the positive-negative ratio is 0.5-1.0.

[0009] Furthermore, in step S2, the molar ratio of H2 to CO is 1.5-2.3; the CO conversion rate of Fischer-Tropsch synthesis is higher than 85%, and the H2 conversion rate is higher than 75%.

[0010] Furthermore, in step S2, a third catalyst is used to accelerate the Fischer-Tropsch reaction. This third catalyst is a Co / Mn / Si / Al catalyst, and the reaction conditions in the Fischer-Tropsch reactor are: temperature 220-280℃, pressure 1.5-3 MPa, and space velocity 500-6000 h⁻¹. -1 .

[0011] Further, in step S3, the active metal in the second catalyst is Pt, and the auxiliary metal is one or more of Pd, La, Ce, Al, Ca, Mg, Si, Fe, Co, and Mo. Both the active metal and the auxiliary metal salt are nitrates. The support used is generally one or more of ZSM-5, ZSM-48, SAPO-11, ZSM-22, β molecular sieve, etc. The catalyst used for separating crude aviation kerosene fraction is a hydrogenation catalyst, and the reaction conditions are: temperature 280-360℃, pressure 3.0-7.0 MPa, and space velocity 0.5-2.0 h⁻¹. -1 The hydrogen-to-oil ratio is 300-2000 Nm³ / m³; the concentration of the crude aviation coal fraction is higher than 85%.

[0012] Further, in step S1, the active metal in the first catalyst is Ni, and the auxiliary metal is one or more of La, Ce, Al, Ca, Mg, Zr, Mn, Fe, and Co. The active metal and auxiliary metal salts are both nitrates, and the precipitant used is one or more of NaOH, KOH, triethylamine, NaCO3, K2CO3, and ammonia water.

[0013] Further, in step S1, the first catalyst is prepared as follows: P1. Dissolve the active metal, auxiliary metal and nitrate in deionized water, and gradually add the precipitant under constant temperature and stirring conditions. After stirring for 24 hours, wash and filter out the catalyst precursor. P2. After washing and filtering the catalyst precursor, the pH of the filtrate is controlled to obtain a washed filter cake, which is then placed in a muffle furnace and calcined at a certain temperature to obtain the reforming catalyst.

[0014] Furthermore, in P1, the ratio of the active metal to the auxiliary metal is 20-100:1, the ratio of the metal ion to the precipitant is 5-20:1, and the constant temperature condition is 60-90℃; in P2, the pH control range is 7.5-8.5, the calcination temperature is 350-550℃, and the calcination time is 4-12h.

[0015] In step S3, the second catalyst is prepared as follows: P1. Prepare a solution containing an active metal precursor, mix the solution with the support and stir for 24 hours, then wash and filter out the catalyst precursor; P2. The impregnated wet catalyst is dried to remove the solvent, and then calcined in air to obtain the hydroisomerization catalyst.

[0016] The beneficial effects of this invention are as follows: 1. This invention utilizes natural gas and CO2 as raw materials, combining three technologies: reforming, Fischer-Tropsch synthesis, and hydroisomerization. It eliminates the need to purify natural gas raw materials and separate and purify intermediate products to obtain jet fuel fractions, effectively reducing energy consumption and production costs, and providing a comprehensive technical solution for jet fuel synthesis.

[0017] 2. This invention provides a systematic carbon neutrality solution that effectively solves the problem of carbon dioxide emissions while efficiently utilizing natural gas, ultimately producing high-value-added aviation kerosene. This technical solution helps address the current shortage of domestic aviation kerosene production and has significant social and economic benefits.

[0018] Other advantages, objectives, and features of the invention will be set forth in the following description and will be apparent to those skilled in the art in some respects, or may be learned by practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0019] To make the purpose, technical solution, and beneficial effects of the invention clearer, the following figures are provided for illustration: Figure 1 This is a schematic diagram of the process of the present invention. Detailed Implementation

[0020] like Figure 1 As shown, this invention provides a method for synthesizing aviation kerosene.

[0021] Example 1 S1. Natural gas, CO2, and water vapor are introduced into the reforming reactor at a molar ratio of 1:1.5:0.4, and the mixture is subjected to a reaction at 850℃ and 0.5MPa for 6000 h⁻¹. -1 The reforming reaction was carried out at a space velocity of 100 h. Ni / Al / Ce / Ca and nitrate were precipitated under the action of triethylamine at a constant temperature of 65 °C. The pH of the filtrate was controlled to be 8. After washing three times, the catalyst precursor was obtained. Then, the catalyst was calcined at 500 °C for 8 h to obtain the reforming catalyst (first catalyst). The first catalyst was used to promote the reforming reaction to obtain syngas 1. S2. Synthesis gas 1, H2, and CO are simultaneously introduced into the Fischer-Tropsch reactor. After mixing synthesis gas 1 with H2 and CO, the H2 / CO molar ratio is controlled to be 2.0. The reaction is carried out under the action of a Co / Mn / Si / Al catalyst (the third catalyst) to obtain a mixed oil product. The mixed oil product contains C8-C 16 The effective component of the jet fuel is 68% by mass. The reaction temperature is controlled at 230℃, the reaction pressure at 2.0 MPa, and the reaction space velocity (GHSV) at 1200 h⁻¹. -1 The unreacted syngas is returned to the Fischer-Tropsch reactor after the reaction is complete. S3. Pt(NO3)2 and Pd(NO3)2 are dissolved in water at a ratio of 1:2, and mixed with SAPO-11 using an equal-volume impregnation method. The amount of active metal Pt impregnated is 1.5%, and the impregnation time is 24 hours. After that, it is dried and calcined in air at 400°C for 16 hours to obtain the hydrogenation catalyst (second catalyst). The mixed oil is then separated by distillation to obtain C. 8+ fraction, C 8+ The fraction was reacted with hydrogen in the presence of a hydrogenation catalyst to obtain crude aviation coal fraction. The reaction temperature was controlled at 280℃, the reaction pressure at 4.0 MPa, and the low-space velocity (LHSV) at 1.0 h⁻¹. -1 The hydrogen-to-oil ratio is 1000 Nm³ / m³; unreacted hydrogen is recycled back to the hydrogenation reactor, and the crude jet fuel fraction is separated and purified to obtain jet fuel fraction with a concentration of 89%.

[0022] Example 2 S1. Natural gas, CO2, and water vapor are introduced into the reforming reactor at a molar ratio of 1:2.0:0.6, and the mixture is subjected to a reaction at 900℃ and 1.5MPa for 9000 h⁻¹. -1 The reforming reaction was carried out at a space velocity of 100 h. At the same time, Ni / Al / Mg / La and nitrates were precipitated under the action of NaOH at a constant temperature of 70 °C. The pH of the filtrate was controlled at 7.5. After washing three times, the catalyst precursor was obtained and then calcined at 450 °C for 6 h to obtain the reforming catalyst (first catalyst). The reforming reaction was carried out using the catalyst to produce syngas 1. S2. Synthesis gas 1, H2, and CO are simultaneously introduced into the Fischer-Tropsch reactor. The H2 / CO molar ratio is controlled to be 1.85 after mixing the synthesis gas 1 with H2 and CO. The mixture reacts under the action of a Co / Mn / Si / Al catalyst (the third catalyst) to obtain a mixed oil product. The mixed oil product contains C8~C6... 16 The effective component of the jet fuel is 70% by mass. The reaction temperature is controlled at 235℃, the reaction pressure at 2.2MPa, and the reaction space velocity (GHSV) at 1800h. -1 After the reaction is complete, the unreacted syngas is returned to the Fischer-Tropsch reactor. S3. Pt(NO3)2:Pd(NO3)2:La(NO3)2 were dissolved in water in a ratio of 1:1:5, and mixed with ZSM-48 using an equal-volume impregnation method. The impregnation amount of active metal Pt was 1%, and the impregnation time was 36 h. After that, it was dried and calcined in air at 450℃ for 20 h to obtain the hydrogenation catalyst (second catalyst). The mixed oil was separated by distillation to obtain C. 8+ fraction, C 8+The fraction was reacted with hydrogen in the presence of a Pt / Pd / SAPO-11 catalyst to obtain crude aviation coal fraction. The reaction temperature was controlled at 300℃, the reaction pressure at 4.5 MPa, and the low-space velocity (LHSV) at 1.2 h⁻¹. -1 The hydrogen-to-oil ratio is 1200 Nm³ / m³; unreacted hydrogen is recycled back to the hydrogenation reactor, and the crude jet fuel fraction is separated and purified to obtain jet fuel fraction with a concentration of 92%.

[0023] This invention employs natural gas and CO2 reforming technology to produce syngas under the action of a Ni-based reforming catalyst. The H2 / CO ratio in the syngas is adjusted to be maintained at 1.0-2.5. The syngas is then catalyzed by a Co-based Fischer-Tropsch catalyst to produce a mixed oil product. Finally, the mixed oil product is catalytically hydrogenated by a Pt-based hydrogenation catalyst and then separated by multi-stage distillation to obtain a jet fuel product that meets international standards.

[0024] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended 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 to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. A method for synthesizing aviation kerosene, characterized in that: Includes the following steps, S1. Natural gas, CO2, and steam are introduced into a reforming reactor in a specific ratio to carry out a reforming reaction. After adding a first catalyst, syngas 1 is obtained. The natural gas contains >95% methane and ≤5% ethane, propane, ethylene, and other hydrocarbons. S2. The synthesized gas is simultaneously passed into a Fischer-Tropsch reactor along with H2 and CO to produce a mixed oil product C. 8+ ; S3. Separate the mixed oils by distillation to obtain C. 8+ fraction, C 8+ The fraction was reacted with H2 again to obtain crude aviation kerosene fraction. The crude aviation kerosene fraction was then separated and purified using a second catalyst to obtain aviation kerosene fraction.

2. The method for synthesizing aviation kerosene according to claim 1, characterized in that: In step S1, the reforming reaction conditions of methane and CO2 are: temperature of 750-900℃, pressure of 0.1-3.0 MPa, and space velocity of the mixture formed by natural gas and CO2 of 1000-12000 h⁻¹. -1 The molar ratio of natural gas / CO2 / water vapor is 1:(1-2.5):(0.1-0.8).

3. The method for synthesizing aviation kerosene according to claim 2, characterized in that: In step S2, the methane selectivity is less than 6%; in step S3, the C8 content in the mixed oil is... + The mass fraction is higher than 65%, and the positive-negative ratio is 0.5-1.

0.

4. The method for synthesizing aviation kerosene according to claim 3, characterized in that: In step S2, the molar ratio of H2 to CO is 1.5-2.3; the CO conversion rate of Fischer-Tropsch synthesis is higher than 85%, and the H2 conversion rate is higher than 75%.

5. The method for synthesizing aviation kerosene according to claim 3, characterized in that: In step S2, a third catalyst is used to accelerate the Fischer-Tropsch reaction. The third catalyst is a Co / Mn / Si / Al catalyst. The reaction conditions in the Fischer-Tropsch reactor are: temperature 220-280℃, pressure 1.5-3 MPa, and space velocity 500-6000 h⁻¹. -1 .

6. The method for synthesizing aviation kerosene according to claim 5, characterized in that: In step S3, the active metal in the second catalyst is Pt, and the auxiliary metal is one or more of Pd, La, Ce, Al, Ca, Mg, Si, Fe, Co, and Mo. Both the active metal and the auxiliary metal salt are nitrates. The support used is generally one or more of ZSM-5, ZSM-48, SAPO-11, ZSM-22, β molecular sieve, etc. The catalyst used for separating crude aviation kerosene fraction is a hydrogenation catalyst, and the reaction conditions are: temperature 280-360℃, pressure 3.0-7.0 MPa, and space velocity 0.5-2.0 h⁻¹. -1 The hydrogen-to-oil ratio is 300-2000 Nm³ / m³; the concentration of the crude aviation coal fraction is higher than 85%.

7. The method for synthesizing aviation kerosene according to claim 1, characterized in that: In step S1, the active metal in the first catalyst is Ni, and the auxiliary metal is one or more of La, Ce, Al, Ca, Mg, Zr, Mn, Fe, and Co. The active metal and auxiliary metal salts are both nitrates, and the precipitant used is one or more of NaOH, KOH, triethylamine, NaCO3, K2CO3, and ammonia.

8. The method for synthesizing aviation kerosene according to claim 7, characterized in that: In step S1, the first catalyst is prepared as follows: P1. Dissolve the active metal, auxiliary metal and nitrate in deionized water, and gradually add the precipitant under constant temperature and stirring conditions. After stirring for 24 hours, wash and filter out the catalyst precursor. P2. After washing and filtering the catalyst precursor, the pH of the filtrate is controlled to obtain a washed filter cake, which is then placed in a muffle furnace and calcined at a certain temperature to obtain the reforming catalyst.

9. The method for synthesizing aviation kerosene according to claim 8, characterized in that: In P1, the ratio of active metal to auxiliary metal is 20-100:1, the ratio of metal ions to precipitant is 5-20:1, and the constant temperature is 60-90℃; in P2, the pH control range is 7.5-8.5, the calcination temperature is 350-550℃, and the calcination time is 4-12h.

10. The method for synthesizing aviation kerosene according to claim 1, characterized in that: In step S3, the second catalyst is prepared as follows: P1. Prepare a solution containing an active metal precursor, mix the solution with the support and stir for 24 hours, then wash and filter out the catalyst precursor; P2. The impregnated wet catalyst is dried to remove the solvent, and then calcined in air to obtain the hydroisomerization catalyst.

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