A feedstock desulfurization process and device for producing sustainable aviation fuel

Abstract

The application discloses a raw material desulfurization process and device for producing sustainable aviation fuel, and relates to the technical field of aviation fuel manufacturing. The desulfurization process comprises the following steps: mixing sulfur-containing raw material oil with an oxidizing agent aqueous solution, performing oxidation pretreatment, and obtaining a pretreatment mixed solution; performing oil-water separation on the pretreatment mixed solution to obtain an oil phase; performing hydrogenation desulfurization treatment on the oil phase to obtain desulfurized raw material oil; wherein the hydrogenation desulfurization reaction adopts a molybdenum-based hydrogenation treatment catalyst and is performed under the condition of 150-250 DEG C and 0.5-1.5 MPa; and the desulfurized raw material oil is subjected to multi-stage adsorption desulfurization to obtain the sustainable aviation fuel. The application realizes rapid and efficient degradation of sulfur content through chemical oxidation pretreatment, low-temperature catalytic efficient cracking and multi-stage adsorption, the whole process condition is more moderate, energy consumption and equipment investment are significantly reduced, and high-temperature side reactions are avoided.

Description

Technical Field

[0001] This invention relates to the field of aviation fuel manufacturing technology, and in particular to a process and apparatus for reducing sulfur content in raw materials for producing sustainable aviation fuel. Background Technology

[0002] Sustainable aviation fuel (SAF), as an environmentally friendly alternative to traditional aviation kerosene, has become a research hotspot in the aviation field due to its ability to reduce carbon emissions and alleviate energy shortages. The raw materials for sustainable aviation fuel are widely available, mainly including biomass energy sources such as waste plastic pyrolysis oil, waste tire pyrolysis oil, and high-sulfur waste oils. These raw materials have the advantages of abundant sources, low costs, and the ability to realize the resource utilization of waste, making them the preferred raw materials for current sustainable aviation fuel production.

[0003] However, the raw materials for sustainable aviation fuel often contain impurities such as sulfur, chlorine, and metals. Among these, sulfur is one of the most destructive impurities, with common forms including sulfides, thiols, thioethers, thiophenols, and thioaldehydes. The traditional and effective method for sulfur reduction is hydrodesulfurization (HDS), which requires temperatures above 300°C and pressures above 3 MPa. The reaction conditions are harsh, the energy consumption per unit is extremely high, and the equipment investment is substantial. Summary of the Invention

[0004] To address the problems of harsh reaction conditions, high unit energy consumption, and large equipment investment in the prior art of treating raw materials for sustainable aviation fuel using hydrodesulfurization methods described above, this invention proposes a process and apparatus for desulfurizing raw materials for producing sustainable aviation fuel.

[0005] In a first aspect, the present invention provides a desulfurization process for the production of sustainable aviation fuel, comprising the following steps:

[0006] Sulfur-containing feedstock oil is mixed with an aqueous oxidant solution for oxidation pretreatment to obtain a pretreated mixture.

[0007] The pretreated mixture is subjected to oil-water separation to obtain an oil phase;

[0008] The oil phase is subjected to hydrodesulfurization treatment to obtain desulfurized feedstock oil; wherein the hydrodesulfurization reaction is carried out using a molybdenum-based hydrotreating catalyst at 150-250℃ and 0.5-1.5MPa.

[0009] The desulfurized feedstock oil is subjected to multi-stage adsorption to remove sulfur, thereby obtaining the sustainable aviation fuel.

[0010] This invention achieves rapid and efficient degradation of sulfur content through chemical oxidation pretreatment to soften sulfur impurities, low-temperature catalytic high-efficiency cracking, and multi-stage adsorption. Compared with traditional high-pressure hydrodesulfurization, the entire process is more temperate, significantly reducing energy consumption and equipment investment while avoiding high-temperature side reactions and inhibiting the formation of harmful byproducts such as dioxins. The final product meets the ASTM D7566 aviation fuel standard.

[0011] The oxidant aqueous solution can be a hydrogen peroxide aqueous solution or a persulfate mixed aqueous solution.

[0012] Multi-stage adsorption desulfurization involves using zinc oxide to adsorb residual hydrogen sulfide or low-boiling-point sulfides, and using activated carbon / zeolite adsorption towers to further remove high-boiling-point sulfides such as alkyl mercaptans, ensuring that the sulfur content meets aviation fuel standards.

[0013] When sulfur-containing feedstock oil is mixed with an aqueous oxidant solution for oxidation pretreatment, mechanical stirring, static mixers, high-shear emulsification, ultrasonic emulsification, phase transfer catalysts, and microchannel reactors can be used to improve the mass transfer efficiency between the two phases.

[0014] The support for molybdenum-based hydrotreating catalysts is generally γ-Al₂O₃, which has a high specific surface area of ​​150-350 m² / g. Through the L-acid sites within the mesopores of γ-Al₂O₃, oxide precursors of molybdenum, tungsten, and nickel can be dispersed on its surface, forming Mo-O-Al or WO-Al interfacial bonds. After sulfidation, a highly active type II Co(Ni)-Mo-S phase is generated, with its edge active sites fully exposed.

[0015] This invention optimizes the traditional high-pressure hydrodesulfurization into a multi-step coupled treatment method of chemical oxidation pretreatment to soften sulfur impurities, low-temperature catalytic high-efficiency cracking, and multi-stage adsorption. Inevitably, this introduces an aqueous phase into the feedstock oil, which means that sufficient oil-water separation must be carried out before low-temperature catalytic high-efficiency cracking to avoid water participating in low-temperature catalytic high-efficiency cracking and causing hydrothermal deactivation of γ-Al2O3.

[0016] On the other hand, the feedstock for sustainable aviation fuel includes waste plastic-derived oil, biomass oil, and other raw materials, which are extremely complex in composition and contain a large number of olefins, aromatics, oxygen-containing functional groups, etc. During chemical oxidation pretreatment, the oxidant may non-selectively oxidize unsaturated hydrocarbons to generate peroxides, gums or resins, which will increase the risk of catalyst coking and deactivation during low-temperature catalytic high-efficiency cracking.

[0017] According to the present invention, a process for reducing sulfur content in raw materials for producing sustainable aviation fuel is provided, wherein the water content in the oil phase does not exceed 0.5 wt%; and the molybdenum-based hydrotreating catalyst uses γ-Al2O3 modified with MgO and CeO2 as a support.

[0018] By limiting the water content in the oil phase after oil-water separation to a certain range, the operating cost and complexity of oil-water separation can be reduced. More importantly, by modifying the γ-Al2O3 support with MgO+CeO2 composite, the competitive reaction of MgO with water consumes the small amount of water entering the low-temperature catalytic high-efficiency cracking stage, thereby delaying the reaction between water and γ-Al2O3 that leads to skeletal rearrangement and crystallization of γ-Al2O3 into boehmite, which is beneficial to improving the catalyst lifetime. Furthermore, the Mg(OH)2 generated by the competitive reaction of MgO with water has a plate-like structure, which provides physical support for the γ-Al2O3 support in the mesopores of γ-Al2O3, while also maintaining the specific surface area of ​​γ-Al2O3 during the reaction.

[0019] CeO2 possesses unique oxygen storage and release capabilities and a redox cycle; its surface oxygen vacancies can also heterolytically dissociate water molecules, generating surface hydroxyl groups and protons. In addition to Lewis acid sites, γ-Al2O3 also has Brønsted acid sites. Alkenes and aromatics undergo protonation at the Brønsted acid sites on the γ-Al2O3 surface to generate carbocations, which are precursors to coking. Meanwhile, CeO2... 3+ The sites can transfer electrons to carbon, activate C-C bonds, and make carbon more susceptible to attack by -OH to generate CO, thereby significantly delaying the coking process on the surface of γ-Al2O3 support and further extending the maintenance time of the specific surface area state of γ-Al2O3, which is beneficial for low-temperature catalytic high-efficiency cracking.

[0020] Overall, modifying the γ-Al2O3 support with MgO+CeO2 composite can synergistically and significantly reduce the risk of hydrothermal deactivation, while also improving the catalyst's resistance to coking and extending its lifespan.

[0021] According to the present invention, a process for reducing sulfur content in raw materials for producing sustainable aviation fuel is provided, wherein the molybdenum-based hydrotreating catalyst carrier has a MgO loading of 2-5 wt% and a CeO2 loading of 3-8 wt%.

[0022] According to the present invention, a process for reducing sulfur content in raw materials for producing sustainable aviation fuel is provided, wherein the molybdenum-based active metal is composed of MoO3 and WO3.

[0023] According to the present invention, a process for reducing sulfur content in raw materials for producing sustainable aviation fuel is provided, wherein the loading ratio of MoO3 to WO3 is (3-4):1.

[0024] According to the present invention, a desulfurization process for producing sustainable aviation fuel using γ-Al2O3 modified with MgO and CeO2 is as follows:

[0025] γ-Al2O3 was impregnated in Ce(NO3)3 aqueous solution, ultrasonically dispersed, allowed to stand, removed, dried, and calcined to obtain CeO2 modified γ-Al2O3;

[0026] The CeO2-modified γ-Al2O3 was impregnated in an aqueous solution of Mg(NO3)2, ultrasonically dispersed, allowed to stand, dried, and then calcined to obtain γ-Al2O3 modified by MgO and CeO2.

[0027] By employing a stepwise impregnation-calcination method that first uses Ce and then Mg, Ce(NO3)3 preferentially occupies the strong adsorption sites on the Al2O3 surface, forming stable CeO2 anchoring points. Mg(NO3)2 is then loaded, avoiding the direct reaction between Mg and Al to form MgAl2O4 spinel, which would damage the mesopores. Furthermore, the stepwise calcination ensures that both CeO2 and MgO exist as highly dispersed nanophases, without clogging the pores. The support prepared by this method has a high mesopore retention rate and minimal loss of L acid sites.

[0028] According to a desulfurization process for raw materials used in the production of sustainable aviation fuel provided by the present invention, before the oil phase is subjected to hydrogenation desulfurization treatment, the oil phase is subjected to high-speed shearing treatment to destroy the continuous phase characteristics of water.

[0029] By breaking the residual water phase in the oil phase into submicron-sized droplets, the continuous phase characteristics of water are disrupted, reducing the "locally high humidity" microenvironment in which water contacts the catalyst. This avoids a large amount of continuous water attacking γ-Al2O3, which would lead to local deactivation of the catalyst. At the same time, the sheared micro water droplets rapidly vaporize at the reaction temperature, which is beneficial for rapid consumption through the reaction of MgO and CeO2.

[0030] In a second aspect, the present invention provides a desulfurization apparatus for producing sustainable aviation fuel, comprising the following units:

[0031] The oxidation pretreatment unit is used to mix sulfur-containing feedstock oil with an aqueous oxidant solution for oxidation pretreatment to obtain a pretreated mixture.

[0032] An oil-water separation unit is used to separate the oil and water in the pretreated mixture to obtain an oil phase;

[0033] A hydrodesulfurization treatment unit is used to perform hydrodesulfurization treatment on the oil phase to obtain desulfurized feedstock oil; wherein the hydrodesulfurization reaction is carried out using a molybdenum-based hydrotreating catalyst at 150-250℃ and 0.5-1.5MPa.

[0034] A multi-stage adsorption desulfurization unit is used to desulfurize the desulfurized feedstock oil through multi-stage adsorption to obtain the sustainable aviation fuel.

[0035] In a third aspect, the present invention provides a sustainable aviation fuel, which is produced using a desulfurization process for producing sustainable aviation fuel as described in any of the preceding claims.

[0036] In summary, the present invention has at least one of the following beneficial technical effects:

[0037] (1) This invention softens sulfur impurities through chemical oxidation pretreatment, low-temperature catalytic high-efficiency cracking, and multi-stage adsorption, achieving rapid and efficient degradation of sulfur content. Compared with traditional high-pressure hydrodesulfurization, the entire process is more mild, significantly reducing energy consumption and equipment investment while avoiding high-temperature side reactions and inhibiting the generation of harmful byproducts such as dioxins. The final product meets the ASTM D7566 aviation fuel standard.

[0038] (2) This invention changes the desulfurization process, especially by introducing a chemical oxidation pretreatment step. When the water content in the oil phase after oil-water separation meets a certain range, the γ-Al2O3 support is modified by MgO+CeO2 composite, which significantly reduces the risk of hydrothermal deactivation of the catalyst. At the same time, it also improves the catalyst's ability to resist coking and extends the catalyst's lifespan. Attached Figure Description

[0039] Figure 1 The diagram below is a schematic diagram of a desulfurization device for producing sustainable aviation fuel provided by the present invention.

[0040] Figure label:

[0041] 101 - Oxidation pretreatment unit; 102 - Oil-water separation unit; 103 - Hydrogenation desulfurization treatment unit; 104 - Multi-stage adsorption desulfurization unit. Detailed Implementation

[0042] The present invention will be further described in detail below with reference to the embodiments.

[0043] The sulfur-containing feedstock oil is derived from waste plastics, with an initial sulfur content of 850 ppm and a water content of 0.03 wt%.

[0044] γ-Al2O3 support, specific surface area 280 m² / g, pore volume 0.5 cm³ / g, 50 mesh.

[0045] Ammonium molybdate ((NH4)6Mo7O) 24 ·4H2O), purity ≥99%.

[0046] Ammonium metatungstate ((NH4)6H2W) 12 O 40 (xH2O), purity ≥99%.

[0047] Citric acid (C6H8O7·H2O), analytical grade.

[0048] Ammonia water (NH3·H2O), concentration 25wt%.

[0049] Cerium nitrate (Ce(NO3)3·6H2O), purity ≥99%.

[0050] Magnesium nitrate (Mg(NO3)3·6H2O), purity ≥99%.

[0051] Example 1

[0052] Preparation of Mo–W / γ-Al2O3 catalyst

[0053] Weigh out 0.943g of ammonium molybdate, 0.247g of ammonium metatungstate, and 0.2g of citric acid. Dissolve them in deionized water and adjust the pH to 8-9 with dilute ammonia to make the solution clear.

[0054] Place 9.0g of γ-Al2O3 in a rotary evaporator, and slowly add all the impregnation solution dropwise while stirring. Continue stirring for 30 minutes to allow the solution to be uniformly adsorbed.

[0055] Let stand at room temperature for 2 hours, then transfer to an oven and dry at 120℃ for 12 hours.

[0056] The dried sample was placed in a muffle furnace and heated from room temperature to 120°C at a rate of 5°C / min, held for 30 min, and then heated to 500°C at a rate of 2°C / min, held for 4 hours.

[0057] After natural cooling to room temperature, the MoO3–WO3 / γ-Al2O3 oxidized catalyst was obtained, in which the loading ratio of MoO3 to WO3 was 10:3.

[0058] After calcination, the catalyst powder is pressed into tablets at 10-15 MPa, crushed, sieved, and 50-mesh particles are taken for later use.

[0059] The oxidized state of MoO3–WO3 / γ-Al2O3 was catalytically loaded into the packing material of a fluidized bed reactor and converted to MoS2 / WS2 by sulfidation.

[0060] The vulcanization conditions are as follows:

[0061] Vulcanizing agent: 2% DMDS / n-hexane

[0062] Temperature program: Increase the temperature from room temperature to 300℃ at a rate of 2℃ / min.

[0063] Vulcanization temperature: 300℃ for 3 hours.

[0064] Pressure: Atmospheric pressure.

[0065] The sulfur-containing feedstock oil is processed sequentially as follows:

[0066] The sulfur-containing feedstock oil was mixed with 30wt%H2O2 at a volume ratio of 10:1, pH=7, and reacted at 60℃ for 30 minutes under stirring at 500–2000 rpm.

[0067] The oil phase with a water content of 0.5 wt% was obtained by centrifugation using a disc centrifuge.

[0068] A fluidized bed reactor was used for the catalytic reaction at 200℃ and 1.2 MPa using a Mo–W / γ-Al₂O₃ catalyst, with a hydrogen-to-oil ratio of 150 Nm³ / m³ and a liquid hourly space velocity (LHSV) of 1.0 h⁻¹. -1 ;

[0069] The reaction products are passed into a zinc oxide adsorption tower to adsorb H2S gas; then, they are passed through an activated carbon tower to adsorb high-boiling-point sulfides such as alkyl thiols, ultimately yielding aviation fuel feedstock.

[0070] Comparative Example 1

[0071] The Mo–W / γ-Al2O3 catalyst is the same as that in Example 1.

[0072] The sulfur-containing feedstock oil is processed sequentially as follows:

[0073] Sulfur-containing feedstock oil was directly fed into a fluidized bed reactor and catalyzed by a Mo–W / γ-Al₂O₃ catalyst at 320℃ and 5MPa, with a hydrogen-to-oil ratio of 500 Nm³ / m³ and a liquid hourly space velocity (LHSV) of 1.0 h⁻¹. -1 ;

[0074] The reaction products are directly separated into gas and liquid to obtain aviation fuel feedstock.

[0075] Example 2

[0076] The support for the Mo–W / γ-Al2O3 catalyst in Example 1 was replaced with γ-Al2O3 modified by a composite of MgO and CeO2, and a molybdenum-based hydrogenation catalyst was prepared using the method described in Example 1 on the γ-Al2O3 support modified by a composite of MgO and CeO2.

[0077] The method for modifying γ-Al2O3 with MgO and CeO2 is as follows:

[0078] 12.61g of Ce(NO3)3·6H2O was dissolved in deionized water to obtain Ce impregnation solution.

[0079] 19.09 g of Mg(NO3)3·6H2O was dissolved in deionized water to obtain a Mg impregnation solution.

[0080] Place 92g of γ-Al2O3 in a rotary evaporator, add all of the Ce impregnation solution while stirring to ensure uniformity, and let stand at room temperature for 2 hours.

[0081] After drying at 120℃ for 12 hours, the product was transferred to a muffle furnace for calcination. The temperature was increased to 500℃ at 2℃ / min and held for 4 hours. After natural cooling, CeO2 / γ-Al2O3 intermediate was obtained.

[0082] Mix the CeO2 / γ-Al2O3 intermediate with the Mg impregnation solution, stir well, and let stand at room temperature for 2 hours.

[0083] The sample was dried at 120℃ for 12 hours, then transferred to a muffle furnace for calcination. The temperature was increased to 400℃ at 2℃ / min and held for 4 hours. After natural cooling, the MgO–CeO2 / γ-Al2O3 composite modified support was obtained.

[0084] In the prepared MgO–CeO2 / γ-Al2O3 composite modified support, the MgO loading was 3wt% and the CeO2 loading was 5wt%.

[0085] Example 3

[0086] By adjusting the amounts of Ce(NO3)3·6H2O and Mg(NO3)3·6H2O in Example 2, the MgO–CeO2 / γ-Al2O3 composite modified support was prepared with 2wt% MgO and 3wt% CeO2.

[0087] Example 4

[0088] By adjusting the amounts of Ce(NO3)3·6H2O and Mg(NO3)3·6H2O in Example 2, the MgO–CeO2 / γ-Al2O3 composite modified support obtained had a MgO loading of 5wt% and a CeO2 loading of 8wt%.

[0089] Example 5

[0090] By adjusting the amounts of Ce(NO3)3·6H2O and Mg(NO3)3·6H2O in Example 2, the MgO–CeO2 / γ-Al2O3 composite modified support was prepared with a MgO loading of 5wt% and a CeO2 loading of 3wt%.

[0091] Example 6

[0092] By adjusting the amounts of Ce(NO3)3·6H2O and Mg(NO3)3·6H2O in Example 2, the MgO-CeO2 / γ-Al2O3 composite modified support was prepared with a MgO loading of 2wt% and a CeO2 loading of 8wt%.

[0093] Example 7

[0094] Adjusting (NH4)6Mo7O in Example 2 24 ·4H2O and (NH4)6H2W 12 O 40 The amount of xH2O used resulted in a MoO3 to WO3 loading ratio of 3:1 in the prepared molybdenum-based hydrotreating catalyst.

[0095] Example 8

[0096] Adjusting (NH4)6Mo7O in Example 2 24 ·4H2O and (NH4)6H2W 12 O 40 The amount of xH2O used resulted in a MoO3 to WO3 loading ratio of 3.5:1 in the prepared molybdenum-based hydrotreating catalyst.

[0097] Example 9

[0098] Adjusting (NH4)6Mo7O in Example 2 24 ·4H2O and (NH4)6H2W 12 O 40 The amount of xH2O used resulted in a MoO3 to WO3 loading ratio of 4:1 in the prepared molybdenum-based hydrotreating catalyst.

[0099] Example 10

[0100] Based on Example 2, before the oil phase is fed into the fluidized bed reactor, the oil phase is subjected to high-speed shearing treatment by a high-shear emulsification pump at a shear rate of 10,000-20,000 s. -1 .

[0101] Comparative Example 2

[0102] By adjusting the amounts of Ce(NO3)3·6H2O and Mg(NO3)3·6H2O in Example 2, the MgO-CeO2 / γ-Al2O3 composite modified support was prepared with 1wt% MgO and 5wt% CeO2.

[0103] Comparative Example 3

[0104] By adjusting the amounts of Ce(NO3)3·6H2O and Mg(NO3)3·6H2O in Example 2, the MgO–CeO2 / γ-Al2O3 composite modified support was prepared with 6wt% MgO and 5wt% CeO2.

[0105] Comparative Example 4

[0106] By adjusting the amounts of Ce(NO3)3·6H2O and Mg(NO3)3·6H2O in Example 2, the MgO–CeO2 / γ-Al2O3 composite modified support was prepared with MgO loading of 3wt% and CeO2 loading of 2wt%.

[0107] Comparative Example 5

[0108] By adjusting the amounts of Ce(NO3)3·6H2O and Mg(NO3)3·6H2O in Example 2, the MgO–CeO2 / γ-Al2O3 composite modified support was prepared with MgO loading of 3wt% and CeO2 loading of 9wt%.

[0109] Comparative Example 6

[0110] By adjusting the amounts of Ce(NO3)3·6H2O and Mg(NO3)3·6H2O in Example 2, the MgO–CeO2 / γ-Al2O3 composite modified support was prepared with 1 wt% MgO and 9 wt% CeO2.

[0111] Comparative Example 7

[0112] By adjusting the amounts of Ce(NO3)3·6H2O and Mg(NO3)3·6H2O in Example 2, the MgO–CeO2 / γ-Al2O3 composite modified support was prepared with 1wt% MgO and 2wt% CeO2.

[0113] Comparative Example 8

[0114] By adjusting the amounts of Ce(NO3)3·6H2O and Mg(NO3)3·6H2O in Example 2, the MgO–CeO2 / γ-Al2O3 composite modified support obtained had a MgO loading of 6wt% and a CeO2 loading of 2wt%.

[0115] Comparative Example 9

[0116] By adjusting the amounts of Ce(NO3)3·6H2O and Mg(NO3)3·6H2O in Example 2, the MgO–CeO2 / γ-Al2O3 composite modified support was prepared with a MgO loading of 6wt% and a CeO2 loading of 9wt%.

[0117] Comparative Example 10

[0118] The difference from Example 2 is that the water content of the obtained oil phase is 0.53 wt%.

[0119] Comparative Example 11

[0120] The difference from Example 2 is that the water content of the obtained oil phase is 0.6 wt%.

[0121] Comparative Example 12

[0122] Adjusting (NH4)6Mo7O in Example 2 24 ·4H2O and (NH4)6H2W 12 O 40 The amount of xH2O used resulted in a MoO3 to WO3 loading ratio of 4.5:1 in the prepared molybdenum-based hydrotreating catalyst.

[0123] After running continuously for 200 hours, data results for different embodiments and comparative examples were obtained, as detailed in Table 1.

[0124] Table 1:

[0125] Sulfur content (ppm) Carbon deposits (wt%) Specific surface area retention rate (%) Relative energy consumption (%) Example 1 4.9 8.2 72 42 Example 2 3.8 4.5 88 / Example 3 4.1 5.2 84 / Example 4 4 4.9 86 / Example 5 4.3 5.6 82 / Example 6 4.2 5.4 83 / Example 7 4 4.7 87 / Example 8 3.9 4.6 87.5 / Example 9 4.1 4.8 86 / Example 10 3.5 3.9 92 / Comparative Example 1 4.8 9.2 75 100 Comparative Example 2 4.2 5.8 80 / Comparative Example 3 4.4 5.5 83 / Comparative Example 4 4.5 6.7 77 / Comparative Example 5 4.6 6.3 78 / Comparative Example 6 4.7 6.9 75 / Comparative Example 7 5 7.5 71 / Comparative Example 8 4.9 7 74 / Comparative Example 9 5.1 7.2 72 / Comparative Example 10 4.9 8.1 69 / Comparative Example 11 5.2 8.5 64 / Comparative Example 12 4.6 5.3 84 /

[0126] In Table 1, sulfur content refers to the sulfur content of the final aviation fuel feedstock; coke content and specific surface area retention rate refer to the coke content and specific surface area retention rate of the catalyst in the fluidized bed reactor. Coke content is used to characterize the coking state of the catalyst, and specific surface area retention rate is used to characterize the deactivation state of the catalyst, mainly the change in the crystal state of γ-Al2O3; relative energy consumption is calculated based on the absolute energy consumption of Comparative Example 1.

[0127] Analyzing the data in Table 1, compared with Comparative Example 1, the sulfur content of the products in Example 1 does not exceed 5 ppm, which meets the ASTM D7566 aviation fuel standard. At the same time, after continuous operation, the amount of coke deposited and the specific surface area retention rate of the catalyst are similar, but the relative energy consumption of Example 1 is significantly reduced.

[0128] In Examples 2-6, the molybdenum-based hydrogenation catalyst used γ-Al2O3 modified with MgO and CeO2 as a support. Compared with the traditional γ-Al2O3 used as a support in Example 1, the amount of coke deposited (4.5-5.6%) and the specific surface area retention rate (82-88%) were better than those in Example 1 (8.2%, 72%).

[0129] In Comparative Examples 2-9, adjusting the loading of MgO and CeO2 revealed that the specific surface area retention rate would drop below 80%, and the carbon deposition in most comparative examples would increase by more than 6%. The sulfur content of the products generally exceeded that of Examples 2-6, approaching the ASTM D7566 aviation fuel standard of 5 ppm. In Comparative Example 9, although high amounts of MgO and CeO2 were added simultaneously, the sulfur content exceeded 5 ppm. In summary, the optimal range is a loading of 2-5 wt% for MgO and 3-8 wt% for CeO2.

[0130] In Comparative Examples 10 and 11, the water content in the oil phase exceeded 0.5 wt%, and the three phase indicators—sulfur content, coke content, and specific surface area retention rate—were far worse than in Example 2. This indicates that, in order to achieve better hydrogenation and sulfur reduction effects and extend the service life of the catalyst, the water content in the oil phase must be controlled to within 0.5 wt% when using MgO and CeO2 composite modified γ-Al2O3 as a support in this invention.

[0131] In Examples 2, 7-9, and Comparative Example 12, the molybdenum-based active metal was composed of MoO3 and WO3. As the loading ratio of MoO3 to WO3 was in the range of (3-4):1, the three phase indicators of sulfur content, coke content, and specific surface area retention rate showed a trend of first increasing and then decreasing. In summary, the optimal range is the loading ratio of MoO3 to WO3 of (3-4):1.

[0132] In Example 10, after high-speed shearing treatment of the oil phase, the three phase indicators of sulfur content, carbon deposition and specific surface area retention were all effectively improved.

[0133] The combined process of chemical oxidation pretreatment to soften sulfur impurities, low-temperature catalytic high-efficiency cracking, and multi-stage adsorption can not only reduce the sulfur in sulfur-containing feedstock oil to meet the ASTM D7566 aviation fuel standard, but also carry out low-temperature catalytic desulfurization at lower reaction temperatures and pressures, significantly reducing energy consumption while inhibiting the formation of harmful byproducts such as dioxins.

[0134] The purpose of the chemical oxidation pretreatment in this invention to soften sulfur impurities is not, in a thermodynamic sense, "reduction of bond energy," but rather to transform the originally hydrophobic, oil-soluble organic sulfides into water-soluble or more polar intermediates, so that:

[0135] It is easier for it to migrate from the oil phase to the aqueous phase, making it easier to perform preliminary desulfurization through oil-water separation;

[0136] To alter its adsorption behavior in catalytic reactions;

[0137] This provides more easily broken sulfur-carbon or sulfur-oxygen bonds for subsequent low-temperature hydrogenation.

[0138] Therefore, a more accurate chemical description of "softening" is: oxidative modification + polarity enhancement + adsorption site exposure.

[0139] Chemical oxidation pretreatment inevitably introduces an aqueous phase into the oil phase. The aqueous phase is removed by centrifugation, a common industrial method. Under certain water content conditions, γ-Al2O3 modified with MgO and CeO2 is used as a support to load active metals molybdenum and tungsten. The two work synergistically in the hydrogenation desulfurization reaction, significantly reducing the risk of hydrothermal deactivation, improving the catalyst's resistance to coking, extending the catalyst's lifespan, and further improving the desulfurization effect to a certain extent.

[0140] Figure 1 The diagram below is a schematic diagram of a desulfurization device for producing sustainable aviation fuel provided by the present invention. Figure 1 In conjunction with the aforementioned desulfurization process for producing sustainable aviation fuel, this invention will describe a desulfurization device for producing sustainable aviation fuel.

[0141] This invention provides a desulfurization device for producing sustainable aviation fuel, comprising the following units:

[0142] The oxidation pretreatment unit 101 is used to mix sulfur-containing feedstock oil with an aqueous oxidant solution for oxidation pretreatment to obtain a pretreated mixture.

[0143] Oil-water separation unit 102 is used to separate the pretreated mixture into oil and water to obtain an oil phase;

[0144] Hydrodesulfurization treatment unit 103 is used to perform hydrodesulfurization treatment on the oil phase to obtain desulfurized feedstock oil; wherein, the hydrodesulfurization reaction is carried out using a molybdenum-based hydrotreating catalyst at 150-250℃ and 0.5-1.5MPa.

[0145] The multi-stage adsorption desulfurization unit 104 is used to desulfurize the desulfurized feedstock oil through multi-stage adsorption to obtain the sustainable aviation fuel.

[0146] The oxidation pretreatment unit 101, the oil-water separation unit 10, the hydrogenation desulfurization treatment unit 103, and the multi-stage adsorption desulfurization unit 104 are connected in sequence.

[0147] The oxidation pretreatment unit 101 adopts a pretreatment tank; the oil-water separation unit 102 adopts a disc centrifuge; the hydrogenation desulfurization treatment unit 103 adopts a fluidized bed reactor; the multi-stage adsorption desulfurization unit 104 includes a first-stage zinc oxide adsorption tower and a first-stage activated carbon / zeolite adsorption tower.

[0148] The above are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A feedstock desulfurization process for the production of sustainable aviation fuel, characterized in that, Includes the following steps: Sulfur-containing feedstock oil is mixed with an aqueous oxidant solution for oxidation pretreatment to obtain a pretreated mixture. The pretreated mixture is subjected to oil-water separation to obtain an oil phase; The oil phase is subjected to hydrodesulfurization treatment to obtain desulfurized feedstock oil; wherein the hydrodesulfurization reaction is carried out using a molybdenum-based hydrotreating catalyst at 150-250℃ and 0.5-1.5MPa. The desulfurized feedstock oil is subjected to multi-stage adsorption to remove sulfur, thereby obtaining the sustainable aviation fuel.

2. A feedstock desulfurization process for the production of sustainable aviation fuel according to claim 1, characterized in that, The water content in the oil phase does not exceed 0.5 wt%; and the molybdenum-based hydrotreating catalyst uses γ-Al2O3 modified with MgO and CeO2 as a support.

3. A feedstock desulfurization process for the production of sustainable aviation fuel according to claim 2, characterized in that, In the support of the molybdenum-based hydrogenation catalyst, the loading of MgO is 2-5 wt% and the loading of CeO2 is 3-8 wt%.

4. A feedstock desulfurization process for the production of sustainable aviation fuel according to claim 3, characterized in that, The molybdenum-based active metal is composed of MoO3 and WO3.

5. A feedstock desulfurization process for the production of sustainable aviation fuel according to claim 4, characterized in that, The loading ratio of MoO3 to WO3 is (3-4):

1.

6. A feedstock desulfurization process for the production of sustainable aviation fuel according to claim 2, wherein, The method for modifying γ-Al2O3 with a composite of MgO and CeO2 is as follows: γ-Al2O3 was impregnated in Ce(NO3)3 aqueous solution, ultrasonically dispersed, allowed to stand, removed, dried, and calcined to obtain CeO2 modified γ-Al2O3; The CeO2-modified γ-Al2O3 was impregnated in an aqueous solution of Mg(NO3)2, ultrasonically dispersed, allowed to stand, dried, and then calcined to obtain γ-Al2O3 modified by MgO and CeO2.

7. A feedstock desulfurization process for the production of sustainable aviation fuel according to claim 2, wherein, Before hydrogenation and desulfurization treatment of the oil phase, the oil phase is subjected to high-speed shearing treatment to destroy the continuous phase characteristics of water.

8. A feedstock desulfurization apparatus for producing sustainable aviation fuel, characterized by, include: The oxidation pretreatment unit is used to mix sulfur-containing feedstock oil with an aqueous oxidant solution for oxidation pretreatment to obtain a pretreated mixture. An oil-water separation unit is used to separate the oil and water in the pretreated mixture to obtain an oil phase; A hydrodesulfurization treatment unit is used to hydrodesulfurize the oil phase to obtain desulfurized feedstock oil; wherein the hydrodesulfurization reaction is carried out using a molybdenum-based hydrotreating catalyst at 150-250℃ and 0.5-1.5MPa. A multi-stage adsorption desulfurization unit is used to desulfurize the desulfurized feedstock oil through multi-stage adsorption to obtain the sustainable aviation fuel.

9. A sustainable aviation fuel characterized in that, It is prepared using a desulfurization process for producing sustainable aviation fuel as described in any one of claims 1 to 7.

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