Method for preparing aviation fuel

Abstract

The invention provides a method for preparing an aviation fuel. The method for preparing the aviation fuel comprises the following steps: preparing a feeding material; a step of introducing the feedstock into a Fischer-Tropsch (FT) reaction to prepare FT synthetic oil wherein the FT synthetic oil comprises a first fraction and a kerosene fraction, the first fraction being a fraction having a boiling point lower than the boiling point range of kerosene, the total content of the first fraction and the kerosene fraction in the FT synthetic oil being 85% by weight or more; a high boiling step of converting the first fraction into a second fraction, the boiling point of which is higher than the boiling point of the first fraction; and a step of recovering aviation fuel from the kerosene fraction and the second fraction.

Description

Technical Field

[0001] This invention relates to a method for preparing aviation fuel. Background Technology

[0002] Synthetic fuels (or synfuels) are generally defined as hydrocarbons produced from syngas, a mixture of carbon monoxide and hydrogen, through a series of chemical reactions, as a synthesis of fuels. This differs from hydrocarbons distilled from crude oil and selected for their production. The Fischer-Tropsch (FT) reaction is a representative example of a reaction that utilizes catalytic reactions to synthesize liquid hydrocarbons from syngas.

[0003] Aviation fuel is used in aircraft engines. Its composition is not significantly different from kerosene; it is typically prepared by mixing various additives into kerosene fractions. Specifically, aviation fuel is produced by processing kerosene, which has lower volatility.

[0004] Sustainable aviation fuel (SAF) refers to aviation fuel made from sustainable and renewable raw materials. These raw materials can be biologically derived materials such as algae, plants and animals, and edible oils, or synthetic raw materials prepared using carbon dioxide from the air, hydrogen derived from water, etc.

[0005] SAF can replace traditional aviation fuels without requiring modifications to existing aircraft. Compared to traditional aviation fuels based on fossil resources such as oil and coal, SAF offers the advantage of reducing carbon emissions by up to 80%. SAF has garnered attention not only for the depletion of existing fossil resources and rising crude oil prices, but also for preventing global warming and reducing carbon dioxide emissions.

[0006] [Existing Technical Documents]

[0007] [Patent Literature]

[0008] (Patent Document 1) US2010 / 0108568A1 Summary of the Invention

[0009] (a) Technical problems to be solved

[0010] According to one aspect of the present invention, a method for preparing aviation fuel that can improve the production yield of aviation fuel can be provided.

[0011] The method of this invention can also be applied to the preparation technology of sustainable aviation fuel (SAF), thus contributing to the prevention of global warming by reducing carbon emissions.

[0012] (II) Technical Solution

[0013] One aspect of the present invention is a method for preparing aviation fuel, the method comprising: a step of preparing a feedstock; a step of introducing the feedstock into a Fischer-Tropsch (FT) reaction to prepare FT syncrude, wherein the FT syncrude comprises a first fraction and a kerosene fraction, the first fraction being a fraction with a boiling point lower than that of kerosene, the total content of the first fraction and the kerosene fraction in the FT syncrude being 85% by weight or more; a step of converting the first fraction into a second fraction with a higher boiling point, wherein the second fraction has a boiling point higher than that of the first fraction; and a step of recovering aviation fuel from the kerosene fraction and the second fraction.

[0014] According to one embodiment, the feed is syngas.

[0015] According to one embodiment, the syngas is derived from waste, biomass, animal fats, vegetable oils, waste cooking oil, or a combination thereof, or contains CO derived from captured carbon dioxide and green hydrogen.

[0016] According to one embodiment, the FT reaction is carried out in the presence of a catalyst at a temperature of 180-400°C, a pressure of 10-100 bar, and an H2 / CO molar ratio of 1 to 10.

[0017] According to one embodiment, the catalyst comprises Co, Fe, Ni, Ru, or a combination thereof.

[0018] According to one embodiment, the catalyst further comprises Y, Ce, La, W, Mo, or combinations thereof as a co-catalyst.

[0019] According to one implementation scheme, the first fraction is a naphtha fraction.

[0020] According to one embodiment, the olefin content in the first fraction is 40% by weight or more.

[0021] According to one embodiment, the high-boiling-point conversion step is carried out in the presence of a catalyst at a temperature of 100-300°C, a pressure of 1-100 bar, and a duration of 0.01-2.0 h. -1 The procedure was performed at a liquid hourly space velocity (LHSV).

[0022] According to one embodiment, the catalyst is an acid catalyst.

[0023] According to one embodiment, the acid catalyst comprises a solid acid catalyst, a liquid acid catalyst, or a combination thereof, wherein the solid acid catalyst comprises zeolite, clay, solid phosphate, ion exchange resin, amorphous silica-alumina, mesoporous alumina, mesoporous silicate, or a combination thereof, and the liquid acid catalyst comprises sulfuric acid, hydrofluoric acid, ionic liquid, or a combination thereof.

[0024] According to one embodiment, the method includes the step of introducing at least a portion of a second fraction, at least a portion of a kerosene fraction, or a combination thereof into a hydrogenation reaction to generate hydrogenation reaction products (upgrading step), the recovery step including the step of recovering aviation fuel from the hydrogenation reaction products.

[0025] According to one embodiment, the hydrogenation reaction includes at least one of a hydro-isomerization reaction and a hydro-cracking reaction.

[0026] According to one embodiment, the FT synthetic oil further comprises diesel fuel + fraction, and the method further comprises the step of introducing at least a portion of the diesel fuel + fraction into a hydrogenation reaction.

[0027] (III) Beneficial Effects

[0028] According to one implementation plan, the production efficiency of aviation fuel can be improved. According to one implementation plan, the production efficiency of SAF (Satellite Air Fuel) can be improved. Attached Figure Description

[0029] Figure 1 This is a schematic process flow diagram of an aviation fuel preparation method according to one implementation plan.

[0030] Figure 2 This is a diagram illustrating the composition of the steps involved in the production of FT synthetic oil according to one embodiment.

[0031] Explanation of reference numerals in the attached figures:

[0032] 1: Feed; 2: First fraction

[0033] 3: Kerosene fraction; 4: Diesel + fraction

[0034] 5: Second fraction; 6: Naphtha

[0035] 7: Aviation fuel; 10: FT reaction

[0036] 20: High boiling point; 30: Upgrade Detailed Implementation

[0037] The present invention will now be described in detail with reference to the accompanying drawings. However, this is merely exemplary, and the present invention is not limited to the specific embodiments described herein.

[0038] One aspect of the present invention provides a method for preparing aviation fuel. In this invention, aviation fuel can be used interchangeably with aviation fuel, jet fuel, and jet fuel oil. The method includes: a step of preparing a feedstock; a step of introducing the feedstock into a Fischer-Tropsch (FT) reaction to prepare an FT synthetic oil, wherein the FT synthetic oil comprises a first fraction and a kerosene fraction, the first fraction being a fraction with a boiling point lower than that of kerosene, and the total content of the first fraction and the kerosene fraction in the FT synthetic oil being 85% by weight or more; a step of converting the first fraction into a second fraction with a higher boiling point, wherein the second fraction has a boiling point higher than that of the first fraction; and a step of recovering aviation fuel from the kerosene fraction and the second fraction.

[0039] The feedstock may be syngas containing CO and H2. In this invention, the source of the syngas is not particularly limited. Exemplarily, the syngas may be derived from fossil fuels. Alternatively, the syngas may be derived from waste, biomass, animal fats, vegetable oils, waste cooking oil, or combinations thereof. The composition of CO and H2 in the syngas may vary depending on the intended use. According to one embodiment, the volume ratio of CO to H2 in the syngas may be from 1:1 to 1:4.

[0040] According to one embodiment, the aviation fuel can be sustainable aviation fuel (SAF). In this case, the syngas can contain, for example, hydrogen derived from water. Specifically, the hydrogen can be green hydrogen obtained by electrolyzing water using renewable energy sources. Here, "renewable energy sources" refers to energy harvested from renewable and sustainable resources that can be naturally replenished over time, such as sunlight, wind, rain, tides, waves, geothermal energy, etc. Furthermore, the syngas can contain CO derived from captured carbon dioxide. The carbon dioxide can be carbon dioxide captured from the atmosphere or carbon dioxide captured from exhaust gases.

[0041] like Figure 1As shown, FT synthetic oil can be prepared using the feed 1. To this end, the method of the present invention includes the step of introducing the feed into FT reaction 10. In the present invention, "FT synthetic oil" refers to a liquid hydrocarbon generated by the FT reaction. Regarding the synthetic oil, the present invention uses the terms naphtha fraction, kerosene fraction, and diesel + fraction. Naphtha fraction refers to a fraction within the boiling point range of naphtha or a fraction within the hydrocarbon range of naphtha; these terms are used interchangeably. The same applies to kerosene fraction and diesel + fraction. In the present invention, naphtha fraction contains hydrocarbons having 5-8 carbon atoms (C5-C8), and kerosene fraction contains hydrocarbons having 9-15 carbon atoms (C9-C6). 15 Diesel fuel fraction contains hydrocarbons with more than 16 carbon atoms (C6N). 16+ ).

[0042] From the perspective of improving aviation fuel production efficiency, the FT synthetic oil of the present invention contains at least 85% by weight of a fraction with a boiling point equal to or lower than that of kerosene. Specifically, the FT synthetic oil contains a first fraction and a kerosene fraction, wherein the boiling point of the first fraction is lower than that of kerosene. According to one embodiment, the first fraction may be a naphtha fraction. The total content of the first fraction and the kerosene fraction in the FT synthetic oil is at least 85% by weight. According to one embodiment, the total content of the first fraction and the kerosene fraction in the FT synthetic oil may be 85-100% by weight, specifically 85-97% by weight, and more specifically 85-95% by weight. Increasing the content of diesel + fraction in the FT synthetic oil is accompanied by an increase in the catalyst and operating costs for the hydrocracking reaction of the diesel + fraction, and byproducts other than aviation fuel fractions are generated through this hydrocracking reaction. From the perspective of improving aviation fuel yield, the content of diesel + fraction in the FT synthetic oil can be minimized.

[0043] Furthermore, from the perspective of improving the efficiency of the high-boiling point conversion step described below, the olefin content in the first fraction can be higher than the alkanes content. According to some embodiments, the olefin content in the first fraction can be 40% by weight or more. Specifically, the olefin content in the first fraction can be 40-80% by weight, more specifically, 40-70% by weight, and even more specifically, 50-70% by weight. When the olefin content is lower than the above range, the effect of increasing aviation fuel production through the high-boiling point conversion step of the first fraction may be reduced. Additionally, according to one embodiment, the isoparaffin content in the first fraction can be higher than the n-paraffin content.

[0044] The FT reaction of the present invention is controlled to achieve the FT synthetic oil composition as described above. According to one embodiment, the FT reaction can be carried out in the presence of a catalyst at a temperature of 180-400°C, a pressure of 10-100 bar, and an H2 / CO molar ratio of 1 to 10. Specifically, the temperature can be 190-380°C, more specifically, 200-350°C. Additionally, specifically, the pressure can be 10-70 bar, more specifically, 10-50 bar. Furthermore, specifically, the H2 / CO molar ratio can be 1 to 7, more specifically, 1 to 4.

[0045] The catalyst used in the FT reaction can comprise Fe, Co, Ni, Ru, or combinations thereof. Specifically, the catalyst can be Fe, Co, or combinations thereof. Additionally, the catalyst can be supported on a support. Exemplarily, the support can comprise alumina, magnesium oxide, silica, titanium dioxide, zirconium oxide, or combinations thereof. Furthermore, according to one embodiment, the catalyst can further comprise a co-catalyst. The co-catalyst can comprise Y, Ce, La, W, Mo, or combinations thereof.

[0046] In addition to FT synthetic oil, the FT reaction products may also contain tail gas and water. The water can be separated from other products and recovered for other uses. The step of preparing the FT synthetic oil may further include a step of separating water from the FT reaction products, which can be carried out using known oil-water separation methods.

[0047] The FT reaction products, after water removal, can be separated into tail gas and FT synthetic oil by fractionation. According to one embodiment, the FT synthetic oil can be separated into a first fraction 2, a kerosene fraction 3, and a diesel + fraction 4 by fractionation. According to another embodiment, the diesel + fraction can be further separated into a diesel fraction (C... 16 -C 20 ) and fractions with boiling points exceeding the boiling point range of diesel (C 21+ In this invention, the tail gas may contain hydrocarbons (C1-C4) that are gases at room temperature, unreacted syngas, and carbon dioxide. The tail gas can be recovered and reintroduced into the FT reaction.

[0048] like Figure 1As shown, the first fraction in the FT synthetic oil is converted into a heavier second fraction 5 with a higher boiling point to have a boiling point that meets aviation fuel specifications. In other words, the method of the present invention includes a step 20 of converting the first fraction into a higher boiling point second fraction, wherein the boiling point of the second fraction is higher than that of the first fraction. According to one embodiment, the second fraction may be a fraction with a boiling point equal to or higher than the boiling point range of kerosene (so-called kerosene+ fraction). Specifically, the second fraction may be a fraction within the boiling point range of kerosene.

[0049] The high-boiling-point treatment step may include at least one of polymerization, alkylation, and aromatization reactions in the first fraction. The polymerization refers to the polymerization reaction between olefins present in the first fraction. The polymerization may include dimerization, trimerization, and oligomerization, etc.

[0050] Alkylation refers to the reaction between olefins and alkanes present in naphtha fractions, specifically the reaction between olefins and isoalkanes. Alkylation may include acid-catalyzed alkylation.

[0051] As mentioned above, the presence of olefins is essential in the high-boiling point conversion step, and as mentioned above, the olefin content in the first fraction is higher than the alkanes content, thus allowing for efficient conversion to the second fraction.

[0052] In the high-boiling-point oxidation step, polymerization, alkylation, and aromatization reactions can occur simultaneously. These reactions can be carried out separately under known reaction conditions. Exemplarily, the high-boiling-point oxidation step can be performed in the presence of a catalyst at a temperature of 100-300°C, a pressure of 1-100 bar, and for 0.01-2.0 h. -1 The process is carried out at a liquid hourly space velocity (LHSV). LHSV refers to the volumetric flow rate of liquid supplied per unit time relative to the volume of catalyst in the reactor. In the high-boiling point step, the liquid may contain a first fraction. Specifically, the temperature can be 150-280°C, more specifically, 150-250°C. Furthermore, the pressure can be 10-50 bar, more specifically, 30-50 bar. Additionally, the LHSV can be 0.05-1.0 h⁻¹. -1 More specifically, it can be 0.1-1.0h. -1 .

[0053] The catalyst used in the high-boiling-point conversion step can be an acid catalyst. Specifically, the acid catalyst can include solid acid catalysts, liquid acid catalysts, or combinations thereof.

[0054] The solid acid catalyst may comprise zeolite, clay, solid phosphate, ion exchange resin, amorphous silica-alumina, mesoporous alumina, mesoporous silicate, etc. The zeolite may comprise zeolite with structures such as MFI, BEA, FAU, MRE, etc. Furthermore, the clay may comprise montmorillonite, illite, vermiculite, saponite, kaolin, or mixtures thereof. Furthermore, the mesoporous silicate may comprise MCM, SBA, etc. According to some embodiments, the solid acid catalyst may be a catalyst impregnated with a metal. The metal may be Pt.

[0055] The liquid acid catalyst may include sulfuric acid, hydrofluoric acid, ionic liquids, etc.

[0056] Through the high-boiling-point conversion step, the first fraction can be converted into the second fraction. However, in actual processes, unconverted fractions may remain during the high-boiling-point conversion step. Therefore, according to one embodiment, the high-boiling-point conversion step may further include a step of separating the second fraction and the unconverted first fraction. The unconverted first fraction can be recycled back to the high-boiling-point conversion step to help improve the conversion rate. Alternatively, the unconverted first fraction can be recovered and processed further to be used as naphtha 6, naphtha being a known feedstock for the preparation of petrochemical products.

[0057] The second fraction obtained through the high-boiling point step can undergo an upgrading step to meet the specifications required for use as aviation fuel. In this invention, the term "upgrading step" is used interchangeably with "hydrogenation reaction step." In other words, the method may include the step of introducing at least a portion of the second fraction into a hydrogenation reaction to generate hydrogenation reaction products.

[0058] Upgrade step 30 is the productization step of aviation fuel 7, referring to the process of producing an oil fraction into a product that meets the physical properties of aviation fuel. The hydrogenation reaction may include at least one of hydroisomerization and hydrocracking. Hydrocracking converts heavy fractions into lighter fractions. Hydroisomerization is a reaction that removes wax components such as n-alkanes by isomerizing them into isoalkanes. Hydroisomerization can improve the freezing point of the oil fraction, thereby controlling the low-temperature performance of the product. For aviation fuels used by aircraft that primarily fly at high altitudes, a low freezing point is one of the important requirements.

[0059] The hydrogenation reaction can be carried out under known reaction conditions. Exemplarily, the hydrogenation reaction can be carried out in the presence of hydrogen and a catalyst at a reaction temperature of 200-500°C and a concentration of 20-300 kg / cm³. 2 Reaction pressure, 0.1-5.0h -1 LHSV and 100-3000Nm 3 / m 3 The reaction is carried out under H2 / oil ratio conditions. Specifically, the reaction temperature can be 200-450℃, more specifically, 250-410℃. Additionally, the reaction pressure can be 20-250 kg / cm². 2 More specifically, it can be 30-200 kg / cm². 2 Additionally, the LHSV can be 0.1-4.0h. -1 More specifically, it can be 0.1-3.0h. -1 Additionally, the H2 / oil ratio can be 150-2500 Nm. 3 / m 3 More specifically, it can be 150-2000 Nm 3 / m 3 .

[0060] Furthermore, the catalyst that can be used in the hydrogenation reaction process comprises a support and a metal, wherein the support is a support with acid sites selected from molecular sieves, alumina, and silica-alumina, and the metal is one or more metals with hydrogenation function selected from elements of Group 2, Group 6, Group 9, and Group 10 of the periodic table. In particular, the Group 9 and Group 10 (i.e., Group VIII) metals can be Co, Ni, Pt, or Pd, and the Group 6 (i.e., Group VIB) metals can be Mo or W. The types of carriers with acid sites include molecular sieves, alumina, silica-alumina, etc. Among them, molecular sieves refer to crystalline aluminosilicates (zeolite), SAPO, ALPO, etc. Mesoporous molecular sieves with 10-membered oxygen rings (e.g., SAPO-11, SAPO-41, ZSM-11, ZSM-22, ZSM-23, ZSM-35, ZSM-48, etc.) and macroporous molecular sieves with 12-membered oxygen rings can be used.

[0061] Additionally, the kerosene fraction separated from the first fraction in the FT synthetic oil can also be processed via hydrogenation to meet the specifications required for use as aviation fuel. In other words, the method may include the step of introducing at least a portion of the kerosene fraction into a hydrogenation reaction to generate hydrogenation products. The details of the hydrogenation reaction described above can also be applied to the details of the hydrogenation reaction involving the introduction of the kerosene fraction. Depending on the requirements, the hydrogenation reaction of the kerosene fraction can be carried out simultaneously with the hydrogenation reaction of the second fraction, or it can be carried out separately.

[0062] According to one embodiment, the diesel + fraction (specifically, the diesel fraction) in FT synthetic oil can also be introduced into the hydrogenation reaction. In other words, the method may further include the step of introducing at least a portion of the diesel + fraction into the hydrogenation reaction. The content of the above-described hydrogenation reaction can also be applied to the hydrogenation reaction of the diesel + fraction. Furthermore, the boiling point of the diesel + fraction is higher than that of aviation fuel, therefore the hydrogenation reaction includes a hydrocracking reaction.

[0063] The products of the hydrogenation reaction may include a fraction lighter than aviation fuel (e.g., naphtha) as a byproduct. This lighter fraction may also be recovered, as with the unconverted first fraction described above, and used as a feedstock for the preparation of petrochemical products after further processing.

[0064] The method of the present invention includes the step of recovering aviation fuel from a kerosene fraction and a second fraction of FT synthetic oil. When at least a portion of the kerosene fraction and / or at least a portion of the second fraction is introduced into a hydrotreating reaction, the recovery step may further include the step of recovering aviation fuel from the hydrotreating reaction products. Similarly, according to one embodiment, when a diesel+ fraction is introduced into a hydrotreating reaction, the method may further include the step of recovering aviation fuel from the hydrotreating reaction products.

[0065] Through the aforementioned recycling step, aviation fuel of the desired specifications can be separated and recovered. This separation and recovery can be carried out using known methods such as fractionation. Figure 1 As shown, according to one embodiment, the fraction of the hydrogenation reaction product with a boiling point lower than that of aviation fuel can be recovered as naphtha along with the unconverted first fraction.

[0066] From a product stability perspective, the recovery step may further include introducing at least a portion of the hydrogenation reaction products into a hydro-finishing (HDF) reaction. In the HDF reaction, hydrogen is added to at least a portion of the hydrogenation reaction products to saturate the aromatics and olefins in the products, thereby improving the stability of the aviation fuel product under oxidation, heat, and ultraviolet (UV) radiation. The HDF reaction can be carried out under known reaction conditions.

[0067] For example, the HDF reaction can be carried out in the presence of hydrogen and a catalyst. The catalyst used in the HDF reaction contains one or more metals with hydrogenation capabilities selected from Group 6, Group 8, Group 9, Group 10, and Group 11 elements. Specifically, metal sulfide series such as Ni-Mo, Co-Mo, and Ni-W, or noble metals such as Pt and Pd can be used.

[0068] In addition, the carrier can be silica, alumina, silica-alumina, titanium dioxide, zirconium oxide, or zeolite with a large surface area. Specifically, alumina or silica-alumina can be used.

[0069] Aviation fuel can be prepared from the same amount of feed at a higher yield using the preparation method of the present invention as described above.

[0070] The embodiments of the present invention will be further described below with reference to specific experimental examples. The embodiments and comparative examples included in the experimental examples are only for illustrating the present invention and are not intended to limit the scope of the claims. Various changes and modifications can be made to the embodiments within the scope of the present invention and its technical concept, which is obvious to those skilled in the art, and these variations and modifications naturally fall within the scope of the claims.

[0071] Experimental Example

[0072] 1. Example 1 and Comparative Example 1: Preparation of aviation fuel from FT synthetic oil

[0073] (1) Preparation of Co(10 wt%) / Al2O3 catalyst

[0074] First, prepare 50g of Al2O3 extrudate. Dissolve 27.435g of Co(NO3)2·6H2O in 100g of distilled water to prepare a Co-solution. Pour the Co-solution into the Al2O3 extrudate and place it in a rotary evaporator. Evaporate the distilled water in the rotary evaporator to prepare a Co-loaded wet extrudate (pink) (water bath temperature 80-95℃; pressure 100-200mmHg; 40-100rpm). Dry the Co-loaded wet extrudate in an oven (80℃, overnight). Then, heat-treat the dried extrudate (12 hours at 120℃, then 5 hours at 500℃, heating rate 5℃ / min). After heat treatment, the catalyst color changed from pink to black.

[0075] (2) Preparation of aviation fuel from kerosene fraction derived from FT synthetic oil

[0076] 1 g of catalyst and 10 g of SiC were mixed and placed in a fixed-bed reactor. As a pretreatment process, hydrogen was introduced at atmospheric pressure at a flow rate of 20 mL / min, while the temperature was increased to 420 °C at a rate of 2 °C / min. The catalyst metal was then reduced and activated for 12 hours, followed by cooling to room temperature. The hydrogen was replaced with the reaction gas (syngas, 60% H2 + 30% CO + 10% Ar), the reaction pressure was adjusted to 20 bar, and the reaction gas was introduced at a flow rate of 50 mL / min, while the temperature was increased to 250 °C at a rate of 2 °C / min to initiate the reaction. The reaction was carried out for 100 hours, followed by cooling to room temperature. The liquid reaction products were recovered using a hot trap and a cold trap.

[0077] The recovered liquid product was analyzed by two-dimensional gas chromatography (2D-GC) to separate and quantify it according to the number of carbon atoms into n-alkanes, isoalkanes, alkenes, cycloalkanes, and aromatics. Specifically, an Agilent 7890A instrument equipped with two columns (DB-5, DB-Wax) and a modulator was used. The liquid product was mixed with methylene chloride solvent at a concentration of 10% and injected in 1 μL (split ratio of 100:1). The GC oven was heated from 40°C to 250°C at a rate of 2°C / min.

[0078] The composition of the prepared FT synthetic oil was determined to be approximately 35% by weight naphtha fraction, approximately 50% by weight kerosene fraction, and approximately 15% by weight diesel + fraction. The kerosene fraction in the FT synthetic oil was separated and subjected to a hydrogenation reaction. 15g of kerosene fraction and 1g of catalyst were injected into an autoclave-type reactor, and then hydrogen was supplied to the reactor until the hydrogen partial pressure reached 30 bar. A Pt / EU-2 zeolite catalyst was used. Subsequently, the reactor temperature was raised to 200°C, and then stirred at 500 rpm while the temperature was raised to 320°C and maintained for 2 hours. The product obtained after the reaction had a freezing point of -50°C, meeting aviation fuel product specifications.

[0079] Aviation fuel was obtained in 50% yield of FT synthetic oil using the method described above (Comparative Example 1).

[0080] (3) Confirmation of the composition of naphtha fraction

[0081] FT synthetic oil with a composition of approximately 35 wt% naphtha fraction, approximately 50 wt% kerosene fraction, and approximately 15 wt% diesel + fraction was prepared using the same method as described above. The naphtha fraction was then separated and its composition analyzed. 2D-GC analysis of the naphtha fraction confirmed a content of 83.1 wt% alkanes, 15.3 wt% olefins, and 1.6 wt% aromatics.

[0082] (4) Preparation of high-boiling-point catalysts

[0083] The high-boiling-point catalyst was prepared by the following steps.

[0084] 7 g of MFI zeolite (SiO2 / Al2O3=30) and 3 g of Pseudo-Boehmite were mixed in a roller for at least 12 hours. A 1M nitric acid (HNO3) solution was prepared and added to the zeolite and Pseudo-Boehmite mixture while mixing to form a composite carrier paste. The paste was extruded using an extruder and cut into pieces with a diameter of 2 mm and a length of 10 mm. The extrudate was calcined in air at 120°C for 5 hours and then at 550°C for 5 hours. The heating rate was 2°C / min.

[0085] (5) High-boiling point reaction of naphtha fraction

[0086] High-boiling-point reaction experiments were conducted in a continuous fixed-bed reactor using the aforementioned catalyst and naphtha fraction. Nitrogen was first supplied to the continuous fixed-bed reactor loaded with the catalyst, followed by the supply of naphtha fraction (LHSV of 0.37 h⁻¹). -1 (N240 bar, reaction temperature 240℃). The analytical results of the composition of the naphtha fraction before and after the reaction are shown in Table 1 below.

[0087] [Table 1]

[0088]

[0089] Referring to Table 1, it can be confirmed that the olefin content in the fraction after the reaction decreases, and the proportion of C9+ fraction (kerosene: diesel +=85:15) that was not present before the reaction increases.

[0090] (6) Hydrogenation reaction

[0091] The C9+ fraction (6.23 wt% (=35 × 17.8 / 100) based on total synthetic oil) was mixed with 50 wt% kerosene fraction and 15 wt% diesel+ fraction of the previously prepared FT synthetic oil and subjected to a hydrogenation reaction. The hydrogenation reaction was carried out using the same method as that used in the preparation of Comparative Example 1 above. The content of each fraction of the reaction product was analyzed using the Simulated Distillation Analysis (SIMDIS) method according to ASTM D7500. After the hydrogenation reaction, a fraction with a boiling point within the boiling point range of aviation fuel relative to the total synthetic oil was obtained (Example 1). The freezing point of the fraction was below -50°C, meeting the aviation fuel product specifications.

[0092] As can be seen, by obtaining aviation fuel by the method described above, the yield of aviation fuel is increased by 15% compared with Comparative Example 1.

[0093] 2. Example 2: Preparation of aviation fuel from FT synthetic oil containing high olefin content

[0094] (1) Preparation of FT Synthetic Oil

[0095] Prepare 16.1 g of MFI zeolite (SiO2 / Al2O3=30). Mix the zeolite and 7.9 g of pseudoboehmite in a drum for more than 12 hours to prepare a composite carrier mixture.

[0096] Cobalt nitrate and nitrate of the co-catalyst metal were dissolved in a 1M nitric acid (HNO3) solution to prepare a catalyst precursor mixture. This catalyst precursor mixture was then added to and mixed with the zeolite and pseudoboehmite composite support mixture to prepare a paste. The paste was extruded using an extruder, and the extrudate was cut into pieces with a diameter of 2 mm and a length of 10 mm. The extrudate was calcined in air at 120°C for 5 hours and then at 550°C for 5 hours. The heating rate was 2°C / min. The calcined extrudate was then pulverized and meshed to prepare the catalyst (particles with a diameter of 0.4-1.2 mm).

[0097] In addition to using the catalyst described above, FT synthetic oil was prepared by the same method as described in Example 1 (2). The content of each fraction of the prepared FT synthetic oil was confirmed by SIMDIS analysis. The results are as follows: Figure 2 As shown.

[0098] (2) High boiling point reaction

[0099] 20 g of the previously obtained FT synthetic oil and 5 g of catalyst were injected into a high-pressure autoclave reactor, and nitrogen was then supplied to the reactor until the nitrogen partial pressure reached 20 bar. The catalyst used was the catalyst prepared in Example 1 (4). The reactor temperature was then raised to 200°C, and the mixture was stirred at 300 rpm while the reaction temperature was raised to 220°C and maintained for 6 hours. The product was then collected, and the content of each fraction was confirmed by SIMDIS analysis. The results are as follows: Figure 2 As shown.

[0100] (3) Hydrogenation reaction

[0101] The high-boiling-point reaction product was subjected to hydrogenation. The hydrogenation reaction was carried out under the same catalyst and conditions as in Example 1. Afterwards, the product was collected, and the content of each fraction was confirmed by SIMDIS analysis. The results are as follows: Figure 2 As shown.

[0102] Reference Figure 2 It is known that a naphtha fraction with an olefin content of over 40% by weight was generated through the FT reaction. Furthermore, it is known that through a high-boiling-point conversion reaction, 66.2% by weight of the naphtha fraction of the FT synthetic oil was converted into a kerosene+ fraction. Additionally, it is known that through a hydrogenation reaction, 73.5% by weight of the total FT synthetic oil fraction with boiling points within the boiling point range of aviation fuel was finally obtained (Example 2).

[0103] The kerosene fraction in the FT synthetic oil was 49.5% by weight, and the aviation fuel fraction prepared by the method of the present invention was 73.5% by weight. Compared with the aviation fuel fraction obtained by means of the kerosene fraction alone, the method of the present invention achieved a 24% yield improvement.

[0104] The amounts of aviation fuel fractions relative to FT synthetic oil obtained in each experiment are summarized in Table 2 below.

[0105] [Table 2]

[0106]

[0107] As can be seen from Table 2, the method of the present invention can significantly improve the efficiency of producing aviation fuel from FT synthetic oil, and thus significantly improve the efficiency of producing SAF.

[0108] The above description is merely an example of applying the principles of this invention, and other configurations may be included without departing from the scope of this invention.

Claims

1. A method for preparing aviation fuel, wherein, The method for preparing aviation fuel includes: The steps for preparing the feed material; The step of introducing the feed into the Fischer-Tropsch (FT) reaction to prepare FT synthetic oil, wherein the FT synthetic oil comprises a first fraction and a kerosene fraction, the first fraction being a fraction with a boiling point lower than that of kerosene, and the total content of the first fraction and the kerosene fraction in the FT synthetic oil is more than 85% by weight. The step of converting the first fraction into a high-boiling-point second fraction, wherein the boiling point of the second fraction is higher than that of the first fraction; and The step of recovering aviation fuel from the kerosene fraction and the second fraction.

2. The method for preparing aviation fuel according to claim 1, wherein, The feed is syngas.

3. The method for preparing aviation fuel according to claim 2, wherein, The syngas is derived from waste, biomass, animal fats, vegetable oils, waste cooking oil, or a combination thereof, or contains CO derived from captured carbon dioxide and green hydrogen.

4. The method for preparing aviation fuel according to claim 1, wherein, The Fischer-Tropsch (FT) reaction is carried out in the presence of a catalyst at a temperature of 180-400°C, a pressure of 10-100 bar, and an H2 / CO molar ratio of 1 to 10.

5. The method for preparing aviation fuel according to claim 4, wherein, The catalyst contains Co, Fe, Ni, Ru, or a combination thereof.

6. The method for preparing aviation fuel according to claim 5, wherein, The catalyst further comprises Y, Ce, La, W, Mo, or combinations thereof as a co-catalyst.

7. The method for preparing aviation fuel according to claim 1, wherein, The first fraction is the naphtha fraction.

8. The method for preparing aviation fuel according to claim 1, wherein, The olefin content in the first fraction is 40% by weight or more.

9. The method for preparing aviation fuel according to claim 1, wherein, The high-boiling-point conversion step is carried out in the presence of a catalyst at a temperature of 100-300°C, a pressure of 1-100 bar, and a duration of 0.01-2.0 h. -1 The procedure was performed at a liquid hourly space velocity (LHSV).

10. The method for preparing aviation fuel according to claim 9, wherein, The catalyst is an acid catalyst.

11. The method for preparing aviation fuel according to claim 10, wherein, The acid catalyst comprises a solid acid catalyst, a liquid acid catalyst, or a combination thereof. The solid acid catalyst comprises zeolite, clay, solid phosphate, ion exchange resin, amorphous silica-alumina, mesoporous alumina, mesoporous silicate, or a combination thereof. The liquid acid catalyst comprises sulfuric acid, hydrofluoric acid, ionic liquid, or a combination thereof.

12. The method for preparing aviation fuel according to claim 1, wherein, The method includes the step of introducing at least a portion of a second fraction, at least a portion of a kerosene fraction, or a combination thereof into a hydrogenation reaction to generate hydrogenation reaction products. The recycling step includes the step of recovering aviation fuel from the hydrogenation reaction products.

13. The method for preparing aviation fuel according to claim 12, wherein, The hydrogenation reaction includes at least one of the hydrogenation isomerization reaction and the hydrogenation cracking reaction.

14. The method for preparing aviation fuel according to claim 1, wherein, The FT synthetic oil further comprises diesel fuel and distillate fractions. The method further includes the step of introducing at least a portion of the diesel fuel fraction into the hydrogenation reaction.

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