Method for producing aviation kerosene from artemisinin leftovers

Abstract

The invention discloses a method for producing aviation kerosene by utilizing artemisinin leftovers, which comprises the following steps: (1) crushing and drying the artemisinin leftovers to obtain a pretreated material; (2) performing primary hydrotreatment under the action of a nickel-molybdenum-based catalyst to obtain a primary treated material; (3) performing secondary hydrotreatment under the action of a nickel-tungsten-based catalyst to obtain a secondary treated material; (4) carrying out isodewaxing on the secondary treatment material by adopting a Pt and Pd loaded ZSM-48 molecular sieve catalyst to obtain a dewaxed material; and (5) fractionating, cutting the dewaxed material, and collecting aviation fuel components with the distillation range of 150-300 DEG C and light components with the distillation range of 50-150 DEG C. The catalyst adopted by the invention has the advantages of long service life and low energy consumption, the production cost is reduced by 15-20%, the impurity removal efficiency is high, the total removal rate is about 95-98%, the product quality can reach the ASTM D7566-23 standard, fossil aviation kerosene can be directly replaced, the resource utilization of waste artemisinin leftovers is realized, and compared with the fossil aviation kerosene, the cost is low, and the cost is low. CO2 emission can be reduced by about 3 tons per ton of biological aviation kerosene.

Description

Technical Field

[0001] The present invention relates to a bio-jet fuel preparation technology, and in particular to a method for producing jet fuel that meets the ASTM D7566 standard by using artemisinin extraction waste as raw materials. Background Art

[0002] The aviation industry's demand for low-carbon fuels has surged, and biofuels have become a key alternative to fossil fuels. Existing technologies primarily use animal and plant oils and fats (e.g., patent CN2023112472163), which present problems such as limited raw materials, high costs, and competition with grain production for land. The artemisinin production process generates a large amount of waste, which has a complex composition (including plant wax, artemisinin essential oil, and more than 50 heterocyclic compounds), presenting three major processing challenges:

[0003] Impurity removal is difficult: nitrogen-containing heterocycles (such as indole), oxygen heterocycles (such as furan) and polycyclic aromatic hydrocarbons interact with each other, causing conventional catalysts to be poisoned and deactivated; diffusion limitation is large: C 20 -C 30 Long-chain waxes block the pores of the catalyst; there are many side reactions: condensation and coking are easy at high temperatures, reducing product yields.

[0004] After searching, the existing public documents and patents (such as CN2023112472163, etc.) all use animal and plant oils as raw materials to prepare bio-jet fuel, and do not involve the application of artemisinin waste. Artemisinin waste contains more than 50 kinds of heterocyclic compounds (such as indole, furan) and C 20 -C 30 The composition complexity of long-chain waxes far exceeds that of animal and plant oils and fats, which causes conventional catalysts to face problems such as heterocyclic compound poisoning and pore blockage. Currently, there is no effective technical solution to solve the above problems. Summary of the Invention

[0005] In order to solve the problem of high-value utilization of artemisinin waste, the present invention provides a method for producing aviation fuel using artemisinin waste. In view of the characteristics of its complex composition and high impurities, efficient conversion is achieved through the synergistic effect of step-by-step hydrogenation and special catalysts.

[0006] The technical solution is as follows:

[0007] A method for producing aviation fuel using artemisinin waste comprises the following steps:

[0008] (1) Pretreatment: crushing artemisinin waste to a particle size of ≤1 mm and drying to a moisture content of ≤0.5 wt% to obtain a pretreated material;

[0009] (2) Primary hydrogenation: The pretreated material is treated under the conditions of a first hydrogenation temperature of 360-400°C, a first hydrogenation pressure of 9-12 MPa, a first mass space velocity of 0.3-0.8 h-1, and a first hydrogen-to-oil volume ratio of 400-600:1 under the action of a nickel-molybdenum-based catalyst to obtain a primary treated material;

[0010] (3) Secondary hydrogenation: Under the action of a nickel-tungsten-based catalyst, the primary treated material is treated at a second hydrogenation temperature of 320-340°C, a second hydrogenation pressure of 3-6 MPa, a second mass space velocity of 1.0-2.0 h-1, and a second hydrogen-to-oil volume ratio of (500-800):1 to obtain a secondary treated material;

[0011] (4) Isomerization dewaxing: using a Pt and Pd loaded ZSM-48 molecular sieve catalyst, the secondary treated material is treated at 300-380°C, 2-6 MPa, a volume space velocity of 1.0-2.5 h-1, and a hydrogen-to-oil volume ratio of (300-600):1 to obtain a dewaxed material;

[0012] (5) Fractionation: Cut the dewaxed material and collect the jet fuel components with a distillation range of 150-300°C and the light components with a distillation range of 50-150°C.

[0013] The light components can be used as gasoline or diesel raw materials.

[0014] In step (1), artemisinin waste is in a gel-like state at room temperature. When it is crushed to a particle size of ≤1 mm, the specific surface area can be increased by 3-5 times, effectively shortening the drying time to 2-3 hours, while directly drying the artemisinin waste requires 5-8 hours, while reducing energy consumption by approximately 25%-30%. Controlling the drying temperature at 40-60°C can avoid the decomposition of heat-sensitive components, retain the effective carbon chain structure, and provide high-quality raw materials for subsequent hydrogenation reactions. Under these conditions, the moisture content of the material can be reduced to ≤0.5wt%, meeting the hydrogenation feed requirements.

[0015] In step (2), the primary hydrogenation treatment is designed for the highly stable CN bonds (such as indole compounds) in artemisinin waste. The first hydrogenation temperature is 360-400°C. Below 360°C, the activation energy for CN bond breakage is insufficient, and the denitrification rate drops sharply to below 80%. Above 400°C, heterocyclic condensation is initiated, forming difficult-to-remove compounds, and the denitrification rate drops to below 90%. The first hydrogenation pressure is 9-12 MPa. Below 9 MPa, the hydrogen partial pressure is insufficient, and the denitrification rate is less than 95%. Above 12 MPa, the equipment energy consumption increases by 30%, but the denitrification rate only increases by 1%-2%.

[0016] During the first-stage hydrotreating, the first hydrotreating temperature is 360-400°C, the first hydrotreating pressure is 9-12 MPa, the first mass space velocity is 0.3-0.8 h-1, and the first hydrogen-to-oil volume ratio is (400-600:)1;

[0017] After the primary hydrotreating process, the feedstock undergoes extensive decontamination, achieving deoxygenation rates exceeding 95%, desulfurization rates exceeding 98%, and denitrification rates exceeding 99%, reducing nitrogen content to ≤0.5ppm and significantly reducing the risk of downstream catalyst poisoning. Coking is suppressed: The nickel-molybdenum-based catalyst has a coking rate of less than 3%, extending its service life by 2-3 times compared to traditional catalysts (coking rates exceeding 10%) and reducing plant downtime. Cost optimization: By optimizing the hydrogen-to-oil ratio and space velocity, hydrogen consumption is reduced by 15%-20%, while increasing plant processing capacity by 10%-15%.

[0018] In step (3), during the secondary hydrogenation treatment, the second hydrogenation temperature is 320-340° C., the second hydrogenation pressure is 3-6 MPa, the second mass space velocity is 1.0-2.0 h-1, and the second hydrogen-to-oil volume ratio is (500-800):1;

[0019] After secondary hydrogenation, aromatics are deeply saturated, reducing their content from 30-40wt% of the feedstock to ≤15wt%, improving the smoke point and combustion performance of the bio-jet fuel, with a smoke point of ≥25mm. This application controls the second hydrogenation temperature at 320-350°C. According to the thermodynamics of aromatic hydrogenation, polycyclic aromatic hydrocarbons require temperatures >320°C to overcome the energy barrier, but temperatures >340°C trigger ring-opening cracking. Experiments show that at 330°C, the conversion rate of naphthalene aromatics reaches 98%, but above 350°C, cracking byproducts increase by 30%.

[0020] In the secondary hydroprocessing, low-pressure operation is adopted, which reduces the operating pressure by 40%-50% compared with the traditional process (pressure 8-10MPa), saving about 30% of compression work consumption.

[0021] In step (4), during isodewaxing, the reaction pressure is 2-6 MPa, the reaction temperature is 300-380° C., the volume space velocity is 1.0-2.5 h-1, and the third hydrogen-to-oil volume ratio is (300-600):1.

[0022] The overall advantages of the above process:

[0023] Improved impurity removal efficiency: Through a two-stage hydrogenation series process, the coordinated deep removal of oxygen, sulfur and nitrogen is achieved, with total removal rates reaching 99.9%, 99.95% and 99.99% respectively, which is significantly better than the traditional single-stage process (total removal rate of about 95-98%).

[0024] Product quality upgrade: Bio-jet fuel products have an aromatic content (≤15wt%), freezing point (≤-48℃) and density (770-780kg / m 3 ) all meet or exceed the ASTM D7566-23 standard and can directly replace fossil jet fuel.

[0025] Green and environmentally friendly: Using discarded artemisinin scraps as raw materials to achieve waste resource utilization, each ton of bio-jet fuel can reduce CO2 emissions by about 3 tons (compared to fossil jet fuel).

[0026] Enhanced economic efficiency: The catalyst life is extended (nickel-molybdenum-based>1200 hours, nickel-tungsten-based>8000 hours) and energy consumption is reduced (comprehensive energy consumption is reduced by 20%-25% compared with traditional processes), reducing production costs by 15%-20%.

[0027] About the first hydrogenation temperature (360-400℃):

[0028] Adverse effects of excessively high temperatures: When the primary hydrogenation temperature is too high, cracking reactions are intensified, reducing the yield of the C12-C16 jet fuel fraction. It also increases the rate of coking, shortening the catalyst's service life. Furthermore, high temperatures may cause some nitrogen-containing heterocycles to condense, forming compounds that are more difficult to remove, ultimately reducing denitrification efficiency.

[0029] Adverse effects of too low a temperature: If the primary hydrogenation temperature is too low, the activation energy for breaking the C-N bond is difficult to achieve, resulting in a significant decrease in denitrification efficiency and failure to meet the strict nitrogen content requirement of ≤1ppm for aviation fuel. Furthermore, the hydrogen adsorption and dissociation capacity of the catalyst surface is weakened at low temperatures, which inhibits the hydrogenation reaction.

[0030] About the first hydrogenation pressure (9-12MPa):

[0031] The negative impact of excessively high hydrogenation pressure: First, while excessively high hydrogenation pressure may not significantly improve denitrification efficiency, it can significantly increase equipment investment costs and operating energy consumption. Furthermore, excessively high pressure may lead to over-saturation of olefins, reducing the calorific value of the jet fuel.

[0032] Adverse effects of low pressure: When the first hydrogenation pressure is too low, the hydrogen partial pressure is insufficient, which will lead to a decrease in the active hydrogen concentration on the catalyst surface, thereby reducing the efficiency of denitrification and desulfurization. In addition, under low pressure conditions, the catalyst is more likely to coke and deactivate.

[0033] About the first mass space velocity (0.3-0.8h-1):

[0034] A high first mass space velocity has the disadvantage of shortening the time the feedstock spends in the catalyst bed, leading to an incomplete reaction and a sharp drop in the denitrification rate. It is particularly difficult for large nitrogen-containing compounds in artemisinin waste to fully reach the catalyst's active sites.

[0035] Adverse effects of a low first mass space velocity: When the first mass space velocity is too low, the processing capacity of the device will be greatly reduced, and the energy consumption per unit product will increase. In addition, long residence time may also cause side reactions such as excessive hydrogenation and cracking.

[0036] About the first hydrogen-oil ratio (volume ratio (500-800): 1):

[0037] Adverse effects of a high hydrogen-to-oil ratio: First, an excessively high hydrogen-to-oil ratio not only increases the load on the circulating hydrogen compressor and increases energy consumption, but can also cause flooding, affecting reaction stability. Furthermore, an excessively high hydrogen-to-oil ratio can reduce the partial pressure of the feedstock, inhibiting the hydrogenation reaction to a certain extent.

[0038] Adverse effects of a low hydrogen-to-oil ratio: First, when the hydrogen-to-oil ratio is too low, the heat generated by the reaction cannot be removed in time, which can easily lead to local overheating and accelerate catalyst coking. At the same time, insufficient hydrogen concentration will also reduce the rate of the hydrogenation reaction.

[0039] About the second hydrogenation temperature (320-340℃):

[0040] Disadvantages of high temperatures: Excessively high secondary hydrogenation temperatures can cause ring-opening cracking of saturated cycloalkanes, reducing jet fuel yield. High temperatures can also exacerbate carbon deposition on the catalyst surface, shortening its lifespan.

[0041] Adverse effects of a low secondary hydrogenation temperature: If the secondary hydrogenation temperature is too low, the rate of aromatics hydrogenation saturation reaction will be significantly reduced, making it difficult to reduce the aromatics content from 42% to the target value of ≤20%. Furthermore, the catalyst's adsorption capacity for polycyclic aromatic hydrocarbons decreases at low temperatures, which can also affect the reaction performance.

[0042] About the second hydrogenation pressure (3-6MPa):

[0043] Disadvantages of excessively high secondary hydrogenation pressures: Excessively high secondary hydrogenation pressures have limited impact on the aromatic saturation rate, but can significantly increase equipment operating costs. Furthermore, high pressures can promote the isomerization of certain alkanes, raising the freezing point of jet fuel.

[0044] Adverse effects of low secondary hydrogenation pressure: When the secondary hydrogenation pressure is too low, the hydrogen partial pressure is insufficient to overcome the thermodynamic barriers to aromatic hydrogenation, resulting in a decrease in aromatic saturation. Furthermore, at low pressures, hydrogen coverage on the catalyst surface decreases, accelerating catalyst deactivation.

[0045] Regarding the second mass space velocity (1.0–2.0 h-1):

[0046] Disadvantages of a high second mass space velocity: When the second mass space velocity is too high, the contact time between the feedstock and the catalyst is insufficient, and the hydrogenation saturation reaction of aromatics cannot proceed fully. For components that are difficult to saturate, such as dicyclic and tricyclic aromatics, the removal effect will be even worse.

[0047] Adverse effects of a low second mass space velocity: When the second mass space velocity is too low, the processing capacity of the device will be limited, increasing production costs. In addition, a long residence time may cause the saturated aromatics to undergo dehydrogenation reactions and regenerate aromatics.

[0048] About the second hydrogen-to-oil ratio (500-800:1):

[0049] Disadvantages of a high hydrogen-to-oil ratio: A high hydrogen-to-oil ratio will increase the amount of hydrogen circulating and energy consumption. At the same time, a high hydrogen flow rate may increase the pressure drop of the catalyst bed, affecting the stability of the reaction.

[0050] Adverse effects of a low hydrogen-to-oil ratio: When the second hydrogen-to-oil ratio is too low, the hydrogen supply is insufficient to sustain the aromatics hydrogenation reaction. Furthermore, at low hydrogen-to-oil ratios, the water generated by the reaction is difficult to remove in a timely manner, which can cover the acidic sites of the catalyst and reduce catalytic activity.

[0051] The control requirements of isomerization dewaxing parameters in step (4) are as follows:

[0052] About reaction pressure (2-6MPa):

[0053] Adverse effects of high reaction pressures: While high reaction pressures can increase the rate of isomerization, they can also promote cracking, reducing jet fuel yields. Furthermore, high pressures increase equipment investment and operating costs.

[0054] Adverse effects of too low a pressure: When the reaction pressure is too low, the hydrogen partial pressure is insufficient, which will reduce the hydrogen coverage of the catalyst surface and accelerate the coking and deactivation of the catalyst. At the same time, the equilibrium conversion rate of the isomerization reaction will also decrease under low pressure.

[0055] About reaction temperature (300-380℃):

[0056] Adverse effects of high reaction temperatures: When the reaction temperature is too high, cracking reactions will dominate, significantly reducing the yield of jet fuel. High temperatures will also cause isoparaffins to dehydrogenate, producing olefins, which will affect the stability of jet fuel.

[0057] Adverse effects of too low a temperature: When the reaction temperature is too low, the isomerization reaction rate is too slow, the conversion rate of normal paraffins is insufficient, and the freezing point of the jet fuel cannot be effectively lowered. In addition, the activity of the catalyst is also inhibited at low temperatures.

[0058] About volumetric space velocity (1.0-2.5h-1):

[0059] Disadvantages of high volumetric space velocity: When the volumetric space velocity is too high, the residence time of the feedstock in the catalyst bed is too short, the isomerization reaction is incomplete, and the conversion rate of normal alkanes is reduced. For normal alkanes with high carbon numbers, the isomerization effect is even worse.

[0060] Disadvantages of a low volumetric space velocity: When the volumetric space velocity is too low, the processing capacity of the unit will be reduced, increasing production costs. In addition, long residence times may cause secondary cracking of isoparaffins, reducing the quality of the jet fuel.

[0061] Regarding the third hydrogen-to-oil volume ratio ((300–600):1):

[0062] Disadvantages of a high hydrogen-to-oil ratio: A high hydrogen-to-oil ratio will increase hydrogen consumption and circulation costs. At the same time, a high hydrogen flow rate may lead to increased wear of the catalyst bed.

[0063] Adverse effects of a low ratio: When the third hydrogen-to-oil ratio is too low, the hydrogen supply is insufficient to dissipate the heat generated by the reaction, which can easily lead to local overheating and accelerate catalyst deactivation. Furthermore, under low hydrogen-to-oil ratio conditions, the rate of carbon deposition on the catalyst surface is also accelerated.

[0064] Specifically, the nickel-molybdenum-based catalyst is an MCM-36 molecular sieve loaded with nickel and molybdenum. The preparation method of the nickel-molybdenum-based catalyst comprises the following steps:

[0065] In step (2), the nickel-molybdenum-based catalyst is Ni-Mo / MCM-36 molecular sieve, with the mass of MCM-36 molecular sieve as the benchmark, the Ni loading is 3.0-3.5wt%, the mass ratio of Ni to Mo is (0.3-0.4):1, and the P content is ≤5wt%;

[0066] The MCM-36 molecular sieve is prepared by the following steps:

[0067] (2.1) Dispersing the precursor in a surfactant aqueous solution, stirring at 80-90°C for 40-60 hours, washing, and drying to obtain MCM-36(P); the precursor is MCM-22(P) or MCM-49(P); the molar ratio of the surfactant to the Si element in the precursor is 0.30-0.40:1; the surfactant is CTAB or DTAB; the mass concentration of the surfactant aqueous solution is 8-15 wt %, and the pH value of the surfactant aqueous solution is 9-10;

[0068] (2.2) MCM-36(P) was calcined at 480-550℃ at a rate of 0.6-1.5℃ / min for 5-8h to obtain a specific surface area ≥280m 2 / g, MCM-36 molecular sieve with a mesopore size of 2-10 nm;

[0069] (2.3) Ni and Mo loading.

[0070] In step (2.1), during drying, the drying temperature is controlled at 40-50° C. and the drying time is 15-20 h.

[0071] Specifically, the loading method of Ni and Mo in step (2.3) is as follows:

[0072] Mo loading: using ammonium heptamolybdate ((NH4)6Mo7O containing 8-16wt% Mo 24 )-phosphoric acid aqueous solution was impregnated with MCM-36 molecular sieve in equal volumes, dried, and calcined at 400-450℃ in nitrogen atmosphere for 3-5h; ammonium heptamolybdate ((NH4)6Mo7O 24 )-phosphoric acid aqueous solution, the mass ratio of Mo:P is 1:(0.25-0.4);

[0073] Ni loading: Mo / MCM-36 was impregnated with an equal volume of nickel nitrate-citric acid aqueous solution containing 4-7 wt% Ni, dried, and calcined in air at 330-400°C for 3-5 hours; the mass ratio of Ni to citric acid in the nickel nitrate-citric acid aqueous solution was 1:(1.3-1.6).

[0074] When Mo is loaded, after equal volume impregnation, the drying temperature is 100-120°C and the drying time is 6-10h.

[0075] When Ni is loaded, after equal volume impregnation, the drying temperature is 100-120°C and the drying time is 6-10h.

[0076] In this application, in order to adapt to the complex components in artemisinin waste, in the preparation process of nickel-molybdenum-based catalyst, only CTAB (hexadecyltrimethylammonium bromide) or DTAB (dodecyltrimethylammonium bromide) is used as a surfactant to swell and expand the layered molecular sieve precursor, and to expand the interlayer spacing of the layered molecular sieve precursor to form a pillaring effect, so that the interlayer spacing of the molecular sieve after pillaring and expansion reaches 5-10nm, so that the various components in the artemisinin waste can pass through the nickel-molybdenum-based catalyst smoothly to remove harmful elements such as oxygen, sulfur, and nitrogen in the artemisinin waste.

[0077] As precursors of MCM-36 molecular sieve, MCM-22(P) molecular sieve and MCM-49(P) molecular sieve can be prepared using existing mature technologies without special requirements.

[0078] When the precursor of the MCM-36 molecular sieve is pillared and expanded, the concentration and pH value of the surfactant aqueous solution, and the relative amount of Si in the surfactant and the precursor are strictly restricted. Since the precursor is greatly damaged when swelling in an alkaline environment, especially under high temperature conditions, a large amount of amorphous silica will be produced. These amorphous silicas will adhere to the pores of the molecular sieve, causing local narrowing of the pores, affecting the patency of the pores, thereby affecting the smooth passage of the raw materials and being prone to carbon formation. Under the above-mentioned limitations of the present application, the MCM-22 (P) or MCM49 (P) precursor can be smoothly swollen and the interlayer spacing can be pillared to the required range, and the generation of amorphous silica can be minimized.

[0079] In step (2.1), if the concentration of the surfactant solution is too low, the density of the surfactant between the molecular sieve layers is insufficient, and the interlayer spacing cannot be effectively expanded, resulting in a small mesopore size, which affects the diffusion of macromolecular reactants. If the concentration of the surfactant solution is too high, micelles will form and agglomerate, resulting in an excessively large local pore size, reducing the specific surface area of ​​the catalyst and possibly leaving carbon impurities after calcination.

[0080] If the ratio of surfactant to Si in the precursor is too low, the pillaring effect is insufficient, the interlayer spacing cannot reach the optimal range of 5-10nm, and large molecular nitrogen-containing compounds have difficulty entering the pores, reducing denitrification efficiency. When the ratio of surfactant to Si in MCM-36(P) is too high, the excess surfactant will lead to excessive interlayer spacing, weakening the interaction between the molecular sieve layers and reducing the structural stability of the catalyst.

[0081] When the pH value is too low, the cationic activity of the surfactant decreases, weakening its ability to bind to anions between the molecular sieve layers and resulting in poor pillaring. When the pH value is too high, the strongly alkaline environment can cause severe dealumination of the molecular sieve framework, destroying the pore structure. The shed aluminum species may also clog the pores.

[0082] When the temperature is too low, the diffusion rate of the surfactant slows down, the pillaring process takes longer, and production efficiency decreases. When the temperature is too high, it will intensify the desiliconization and dealumination of the molecular sieve framework, leading to structural collapse, and may also cause the decomposition of CTAB, affecting the pillaring effect.

[0083] At present, when pillaring MCM-22(P) or MCM-49(P), Si atoms obtained by hydrolysis of silicon sources such as TEOS (tetraethyl orthosilicate) are mainly used to form silica pillars between layers. The silica pillars will form connections with two adjacent structural layers, adjusting the structure of the molecular sieve, and cannot achieve the desired results of this application. Therefore, in this application, only surfactants are used to swell MCM-22(P) or MCM-49(P) to expand the interlayer spacing of the molecular sieve, and there are no silica pillars between adjacent structural layers.

[0084] In step (2.2), during the calcination of MCM-36(P), the calcination heating rate is limited to reduce damage to the molecular sieve structure. Although MCM-36(P) has been dried before calcination to remove moisture, a small amount of moisture is still adsorbed inside the molecular sieve. In addition, during the heating process, the surfactant will also decompose and be discharged from the molecular sieve. Excessively fast heating rate will cause the steam generated during the heating process and the gas produced by the decomposition of the surfactant to be rapidly ejected outward, which will not only damage the external structure of the molecular sieve, but also affect the pore structure of the molecular sieve.

[0085] In this application, the loading of nickel and molybdenum is carried out in a step-by-step manner. Since the performance of nickel and molybdenum is quite different, simultaneous impregnation will lead to agglomeration of nickel and molybdenum, making it impossible to evenly distribute nickel and molybdenum on the molecular sieve, affecting its hydrogenation performance.

[0086] The loading of Ni and Mo not only adjusts the catalytic performance of the molecular sieve, but also adjusts the acidity of the molecule. When the loading is too low, the catalyst surface lacks hydrogenation active sites, resulting in reduced denitrification and desulfurization efficiencies. When the Ni loading is too high, NiO agglomerates are easily formed, reducing the dispersion of the active phase and possibly covering some acidic sites, affecting the overall performance of the catalyst.

[0087] In addition, Ni and Mo elements will enter the interlayer of MCM-36 and play a role similar to pillar support to improve the connection stability between adjacent layers, thereby improving the structural stability of the nickel-molybdenum-based catalyst.

[0088] When the mass ratio of Ni to Mo is too low, the catalytic effect of Ni is insufficient, and it cannot effectively promote the formation of NiMoS2 active phase, thereby reducing the hydrogenation activity of the catalyst; when the mass ratio of Ni to Mo is too high, the excess Ni will compete with Mo for acidic sites, inhibit the breaking of CN bonds, and reduce the denitrification efficiency.

[0089] Specifically, the total pore volume of the nickel-molybdenum-based catalyst is 0.4-0.6 cm 3 / g, with an average pore size of 5-10nm and a gradient acidity distribution: weak acid sites with a desorption peak of 150-250°C account for 30-40% of the total acid content, and the remainder is medium-strong acid sites with a desorption peak of 250-400°C. The desorption peak is detected using the NH3-TPD method.

[0090] The weak acid site has an NH3-TPD desorption peak temperature of 150-250°C, which is mainly derived from MgO modification; the medium-strong acid site has an NH3-TPD desorption peak temperature of 250-400°C, which is mainly derived from the Al-Si molecular sieve framework.

[0091] The weak acid sites gently promote the adsorption and initial hydrogenation of nitrogen-containing compounds. The medium-strong acid sites provide sufficient acidity to break the C-N bond. If the proportion of weak acid sites is too low, the denitrification reaction will be incomplete; if the proportion of medium-strong acid sites is too high, cracking side reactions will easily occur.

[0092] Specifically, before the primary hydrotreatment, the nickel-molybdenum-based catalyst is first sulfurized and activated as follows:

[0093] A CS2 / n-heptane mixture is introduced into a primary hydrogenation reactor using hydrogen and simultaneously heated. During the heating process, the temperature is first raised to 110-140°C at a rate of 0.8-1.2°C / min and held for 1-2 hours; then raised to 330-350°C at a rate of 0.8-1.2°C / min and held for 3-5 hours; and finally raised to 390-420°C and held for 1.5-2.5 hours to complete sulfurization activation. The volume ratio of CS2 to n-heptane is 1:(80-100), the molar ratio of CS2 to the total molar amount of nickel and molybdenum metal in the nickel-molybdenum-based catalyst is (1.1-1.5):1, and the volume ratio of hydrogen to catalyst is (400-600:1).

[0094] When the volume ratio of CS2 to n-heptane is too low, the concentration of the sulfiding agent is insufficient to fully convert Ni and Mo into the active phase NiMoS2, resulting in low catalyst activity. When the CS2 ratio is too high, excessive sulfur species will form on the catalyst surface, covering the active sites and reducing the initial activity of the catalyst.

[0095] During the sulfurization activation process of nickel-molybdenum-based catalysts, the 110-140°C temperature range is primarily used to remove physically adsorbed water from the catalyst surface; the 330-350°C temperature range promotes the initial sulfurization of the metal oxide; and the 390-420°C temperature range completes the sulfurization reaction, forming a stable NiMoS active phase. A steady heating rate ensures a more uniform sulfurization. Rapid heating or skipping a stage can lead to uneven sulfurization, affecting the catalyst's activity and stability.

[0096] In general, this application utilizes the unique layered structure, expandable interlayer spacing, and controllable mesoporous system of MCM-36 as a catalyst support platform. During the preparation of this molecular sieve, the hydrolysis and polycondensation rate of the silicon source during the pillaring process is controlled to achieve a specific size and distribution of the formed silica pillars. This results in the MCM-36 molecular sieve support having a periodic mesoporous structure formed by two-dimensional molecular sieve sheets supported by inorganic oxide pillars. This support possesses both micropores and mesopores, with the mesopores having a pore size distribution ranging from 5nm to 10nm.

[0097] The nickel-molybdenum-based catalyst has a dual-model pore distribution, including a first peak originating from the micropores within the molecular sieve layers and a second peak originating from the interlayer mesopores. The peak pore diameter of the second peak is greater than 2.7 nm. Its unique pore structure is used to cope with complex raw material components.

[0098] Through the above preparation method, nickel and molybdenum elements are preferentially dispersed in the interlayer mesoporous channels of the CM-36 molecular sieve, and the role of phosphorus is to form a specific interaction with the surface of the pillared oxide to enhance the dispersion stability of the metal components.

[0099] Under the same reaction conditions (temperature 350 °C, pressure 10 mPa, hydrogen-to-oil ratio 500:1, space velocity 0.5 h -1 The nickel-molybdenum-based catalyst of the present invention significantly improves the hydrodenitrogenation and chlorine conversion rates of artemisinin waste compared to existing metal hydrogenation catalysts. The inventors of this application discovered that, when using existing catalysts to treat artemisinin waste, nitrogen removal is difficult, chlorine removal can only reach a maximum of 50%, and the removal efficiency decreases rapidly. However, when using the nickel-molybdenum-based catalyst of this application, the activity decrease rate after 168 hours of continuous operation is only 1 / 6 of that of existing catalysts, significantly improving stability.

[0100] The diffusion of macromolecules in artemisinin waste will lead to a decrease in the utilization rate of the catalyst's active centers. In the present invention, the nickel-molybdenum-based catalyst effectively reduces the diffusion resistance of macromolecular nitrides in the raw materials through its unique interlayer mesoporous structure, significantly improves its hydrogenation and denitrogenation efficiency, and also has a certain effect on the deoxygenation and denitrogenation of the side chains. Because the specific loading process and the introduction of phosphorus significantly inhibit the aggregation and growth of the nickel-molybdenum active phase during the reaction process, thereby improving the long-term stability of the catalyst. Since the active metal components are mainly distributed in the spacious interlayer mesoporous channels of MCM-36, the diffusion limitation of macromolecular reactants is greatly reduced, which is the main reason for its high activity.

[0101] Specifically, the preparation method of the nickel-tungsten-based catalyst comprises the following steps:

[0102] In step (3), the nickel-tungsten-based catalyst uses γ-Al2O3-SiO2-MgO as a carrier, a WO3 loading amount of 12-20wt%, a NiO loading amount of 4-7wt%, and a mass ratio of WO3 to NiO of (2.8-3.2):1;

[0103] The carrier is prepared by the following steps:

[0104] Silica sol, pseudo-boehmite, MgO and ammonium dihydrogen phosphate are mixed in the mass ratio of SiO2:Al2O3:MgO:P2O5=(10-15):(78-85):(3-6):(1-2), ball-milled for 3-4 hours and then extruded into strips. After drying, the strips are calcined at 500-550°C for 3.5-5 hours, wherein the silica sol is calculated as SiO2, the pseudo-boehmite is calculated as Al2O3, and the ammonium dihydrogen phosphate is calculated as P2O5.

[0105] The nickel-tungsten loading of the γ-Al2O3-SiO2-MgO carrier is as follows:

[0106] Impregnation: The carrier is impregnated with an aqueous solution of ammonium metatungstate, nickel nitrate and citric acid with a pH of 2.5-3.0 and an overall molar ratio of citric acid to nickel tungsten of 0.5-1.0.

[0107] Program calcination: heat up to 100-140℃ at 0.4-0.6℃ / min and keep warm for 6-10h; then heat up to 330-360℃ at 1-2℃ / min and keep warm for 1.5-2h; finally heat up to 480-540℃ at 1.5-3℃ / min and keep warm for 3.5-5h.

[0108] The nickel-tungsten-based catalyst has a bimodal pore structure: mesopores are 5-8 nm, macropores are 50-100 nm, and the specific surface area is 220-250 m 2 / g, pore volume 0.55-0.65cm 3 / g; NiWS active phase dispersion>80%; weak acid sites account for 40-50%.

[0109] The NH3-TPD method was used for detection, where weak acid sites refer to acid sites with a desorption temperature of <250°C, and medium-strong acid sites refer to acid sites with a desorption temperature of 250-400°C. The dispersion of the NiWS active phase was analyzed using HRTEM.

[0110] During ball milling, the ball-to-material ratio is controlled at (5-20):1, and the rotation speed is 50-150 rpm.

[0111] In an aqueous solution of ammonium metatungstate, nickel nitrate, and citric acid, the nickel nitrate concentration, calculated as nickel oxide and tungsten trioxide, is 150-250 g / L, and the ammonium metatungstate concentration is 2.8-3.2 times that of the nickel nitrate. During impregnation, the impregnation temperature is 50-60°C, and the impregnation time is 10-15 hours. Vacuum impregnation is preferably employed, with a vacuum degree of ≤-0.09 MPa. In the nickel-tungsten impregnation solution, citric acid forms a metal-citric acid complex.

[0112] In this application, the nickel-tungsten-based catalyst uses γ-Al2O3-SiO2-MgO as a carrier, with γ-Al2O3 serving as the primary carrier, primarily leveraging its high specific surface area. SiO2 serves as a secondary carrier, modulating the catalyst's acidity and inhibiting cracking reactions to reduce the proportion of small molecule products. MgO is primarily used to neutralize strong acid sites, reducing the catalyst's acidity. This nickel-tungsten-based catalyst has a long service life of over 8,000 hours.

[0113] This nickel-tungsten-based catalyst has a bimodal pore structure, with mesopores used to diffuse macromolecular terpenes and macropores to prevent coke clogging. Two acid sites with different acidities are incorporated into the nickel-tungsten-based catalyst: the MgO-modified acid sites form weak acid sites, primarily for mild deoxygenation, while the Al-Si-formed medium-strong acid sites are used for desulfurization and denitrification. This allows the nickel-tungsten-based catalyst to precisely remove oxygen, sulfur, and nitrogen, improving removal efficiency.

[0114] Specifically, before the secondary hydrotreatment, the nickel-tungsten-based catalyst is first sulfurized and activated as follows:

[0115] First, nitrogen is used for purging, and then hydrogen is replaced;

[0116] Then, a DMDS / H2 mixture gas was introduced with a hydrogen partial pressure of 3.0-4.0 MPa, and the temperature was raised to 330-350°C at a rate of 1.5-2.2°C / min and kept at that temperature for 5-8 hours; the volume ratio of DMDS to H2 was 1:(30-35);

[0117] Finally, a mixed gas containing 2-5 vol% methyltrichlorosilane and H2 is introduced at 320-340°C for 2-4 hours to make the silicon content on the catalyst surface reach 0.5-2.0 wt%.

[0118] After activation, a NiWS phase is formed in the nickel-tungsten-based catalyst. During the activation process, DMDS is used to convert the silicon atoms on the surface of the nickel-tungsten-based catalyst into hydrophobic methylsiloxane, thereby reducing the adsorption of water by the nickel-tungsten-based catalyst during the catalytic process.

[0119] Specifically, in step (4), the total loading of Pt and Pd in ​​the ZSM-48 molecular sieve catalyst is 0.3-0.4wt%, and the mass ratio of Pt to Pd is 1:1-3:1. This loading allows for a high dispersion of the metal active components on the molecular sieve surface (dispersion > 90%), significantly improving isomerization selectivity (normal alkane conversion > 85%, isoalkane selectivity > 90%). By regulating the platinum-palladium ratio, the balance between the catalyst's hydrogenolysis activity and isomerization activity can be optimized, suppressing excessive cracking and increasing the bio-jet fuel yield (C12-C16 yield can reach 65%).

[0120] In step (5), the fractionation conditions are: feed temperature 220-250°C, tower top temperature 120-150°C, tower bottom temperature 300-330°C, and pressure 0.1-0.3 MPa. The light component yield at the top of the fractionation tower is 25-30%, which can be used as a high-octane gasoline blending component (RON ≥ 90), and the jet fuel component yield at the bottom of the tower is 60-65%, meeting ASTM D7566 standards (freezing point ≤ -47°C, aromatics content ≤ 20 wt%). BRIEF DESCRIPTION OF THE DRAWINGS

[0121] Figure 1 This is the SEM image of the MCM-36 molecular sieve prepared in Example 1.

[0122] Figure 2 This is the SEM image of the MCM-36 molecular sieve prepared in Example 2.

[0123] Figure 3 This is a SEM image of the ZSM-48 molecular sieve prepared in this application. DETAILED DESCRIPTION

[0124] The preparation of nickel-molybdenum-based catalysts and nickel-tungsten-based catalysts is first described below.

[0125] When preparing nickel-molybdenum-based catalysts, it is necessary to first prepare MCM-22(P) or MCM-49(P). The following steps are used to prepare MCM-22(P):

[0126] The aluminum source is converted to Al2O3, the silicon source is converted to SiO2, and the alkali source is converted to Na2O, with a molar ratio of SiO2:Al2O3:Na2O:organic template: H2O=1:(0.015-0.050):(0.15-0.22):(0.4-0.7):(35-40). At room temperature, the aluminum source is dissolved in the alkali source solution, and then the silicon source is added dropwise. The mixture is stirred for 20-40 minutes, and then the organic template is added. The resulting mixed solution is stirred for 20-30 hours, placed in a reactor, and stirred and crystallized at 150-180°C under closed conditions for 60-80 hours. The mixture is then cooled to room temperature, filtered, washed until neutral, and dried to obtain MCM-22(P).

[0127] The aluminum source is selected from at least one of sodium metaaluminate and pseudo-boehmite, the silicon source is selected from at least one of silica sol and fumed silica, the alkali source is sodium hydroxide, and the organic template is HMI or tetrapropylammonium hydroxide.

[0128] The following steps were used to prepare MCM-49(P):

[0129] A silicon source, an aluminum source, an alkali source, a template and deionized water are uniformly mixed to obtain a mixture, the mixture is placed in a closed reactor and subjected to a first hydrothermal crystallization at 130-150° C. under autogenous pressure for 36-48 hours, then the temperature is lowered to 70-100° C. and subjected to a second hydrothermal crystallization at autogenous pressure for 10-20 hours, and the crystallized product is filtered and recovered, the crystallized product is washed with distilled water until neutral, and dried to obtain MCM-49(P).

[0130] The template agent is hexamethyleneimine, the silicon source is selected from at least one of silica sol, solid silica gel, white carbon black or water glass, the aluminum source is selected from at least one of sodium metaaluminate, aluminum nitrate, aluminum sulfate or dry rubber powder, and the alkali source is selected from at least one of sodium hydroxide or potassium hydroxide.

[0131] The silicon source is converted into SiO2, the aluminum source is converted into Al2O3, and the alkali source is converted into Na2O, SiO2:Al2O3:Na2O:template:H2O=1:(0.02-0.30):(0.025-0.15):(0.05-0.4):(10-30).

[0132] Example 1

[0133] Preparation of 1# nickel-molybdenum-based catalyst:

[0134] (2.0) Preparation of MCM-22(P):

[0135] The molar ratio is: SiO2:Al2O3:Na2O:HMI:H2O=1:0.040:0.20:0.5:35. At room temperature, sodium aluminate is dissolved in 10 g / L sodium hydroxide solution, and then silica sol (SiO2 content 40 wt%) is added dropwise. Stirring is continued for 30 minutes, and then HMI is added. The resulting mixed solution is stirred for 25 hours, placed in a reactor, and stirred and crystallized at 170°C under closed conditions for 70 hours. The mixture is then cooled to room temperature, filtered, and the filter residue is washed with distilled water to neutrality. After drying at 110°C for 15 hours, MCM-22(P) is obtained; wherein sodium aluminate is converted to Al2O3, silica sol is converted to SiO2, and sodium hydroxide is converted to Na2O.

[0136] (2.1) MCM-22(P) was dispersed in a CTAB aqueous solution, stirred at 90°C for 55 h, and centrifuged. The separated material was washed with distilled water and dried at 45°C for 18 h to obtain MCM-36(P). In MCM-36(P), the molar ratio of CTAB to Si in MCM-36(P) was 0.36:1. The mass concentration of the CTAB aqueous solution was 10 wt%, and the pH was 9.2.

[0137] (2.2) MCM-36(P) was heated to 480°C in air at a heating rate of 1°C / min and calcined at this temperature for 8 hours to obtain MCM-36 molecular sieve with a mesoporous structure. The mesopore size distribution of MCM-36 molecular sieve is 2-10 nm, and the specific surface area is 283 m 2 / g. The specific surface area was determined using the BET nitrogen adsorption method.

[0138] (2.3) Ni and Mo loading:

[0139] Mo loading: The MCM-36 molecular sieve was immersed in a molybdenum-based aqueous solution at room temperature by an equal volume impregnation method, ultrasonicated for 50 minutes, and then allowed to stand for 15 hours. The molybdenum-based aqueous solution was then dried at 100°C and continued to be dried at 100°C for 10 hours. Finally, it was calcined at 420°C in a nitrogen atmosphere for 4 hours to obtain Mo / MCM-36 molecular sieve. The molybdenum-based aqueous solution was prepared from ammonium heptamolybdate tetrahydrate and phosphoric acid. The concentration of molybdenum in the molybdenum-based aqueous solution was 10wt%, and the mass ratio of molybdenum to phosphorus was 1:0.3.

[0140] Loading Ni: Using an equal volume impregnation method, the Mo / MCM-36 molecular sieve is impregnated in a nickel-based aqueous solution for 12 hours, the nickel-based aqueous solution is dried at 120°C, and further dried at 120°C for 6 hours, and then calcined at 350°C for 4 hours in an air atmosphere to obtain the nickel-molybdenum loaded MCM-36 molecular sieve Ni-Mo / MCM-36, which is the 1# nickel-molybdenum-based catalyst.

[0141] The nickel-based aqueous solution is prepared by nickel nitrate and citric acid. The nickel-based aqueous solution contains 5 wt% of Ni element, and the mass ratio of nickel element to citric acid is 1:1.4.

[0142] In this embodiment, based on the mass of MCM-36 molecular sieve, the Ni loading amount is 3.2 wt %, the mass ratio of Ni to Mo is 0.33:1, and the P content is 2.9 wt %.

[0143] The total pore volume of 1# nickel-molybdenum-based catalyst is 0.59 cm 3 / g, and the average pore diameter is 9.5nm.

[0144] Based on the total amount of acid sites, weak acid sites account for 35% of the total acid amount.

[0145] Example 2

[0146] Preparation of 2# nickel-molybdenum-based catalyst:

[0147] (2.0) Preparation of MCM-22(P):

[0148] The molar ratio is: SiO2:Al2O3:Na2O:HMI:H2O=1:0.020:0.18:0.7:40. At room temperature, sodium aluminate is dissolved in 9 g / L sodium hydroxide solution, and then silica sol (SiO2 content 40 wt%) is added dropwise. The mixture is stirred for 25 minutes, and then HMI is added. The resulting mixed solution is stirred for 20 hours, placed in a reactor, and stirred and crystallized at 160°C under closed conditions for 60 hours. The mixture is then cooled to room temperature, filtered, and the filter residue is washed with distilled water to neutrality. After drying at 100°C for 12 hours, MCM-22(P) is obtained; wherein sodium aluminate is converted to Al2O3, silica sol is converted to SiO2, and sodium hydroxide is converted to Na2O.

[0149] (2.1) In step (2.2), MCM-22 (P) is dispersed in a CTAB aqueous solution (mass concentration 8-15wt%, pH 9-10). When the concentration is lower than 8wt%, the density of CTAB between the molecular sieve layers is insufficient, the interlayer spacing is only 3-4nm, and large molecular nitrogen-containing compounds cannot enter the pores. When the concentration is higher than 15wt%, micelles are formed, resulting in a local pore size of more than 15nm and a specific surface area of ​​200m2. 2 / g or less. Stirring temperature 80-90℃: below 80℃, the diffusion rate of CTAB is slow and needs to be extended to more than 80h; above 90℃, it will trigger the dealumination of the molecular sieve framework and increase the amount of amorphous SiO2 generated by 20%.

[0150] (2.2) MCM-36(P) was heated to 550°C in air at a heating rate of 0.7°C / min and calcined at this temperature for 5 h to obtain MCM-36 molecular sieve with a mesoporous structure. The mesopore size distribution of MCM-36 molecular sieve is 2-10 nm, and the specific surface area is 283 m 2 / g.

[0151] (2.3) Ni and Mo loading:

[0152] Loading Mo: The MCM-36 molecular sieve was immersed in a molybdenum-based aqueous solution at room temperature by an equal volume impregnation method, ultrasonicated for 40 minutes, and then allowed to stand for 10 hours. The molybdenum-based aqueous solution was then dried at 120°C and continued to be dried at 120°C for 8 hours. Finally, it was calcined at 400°C in a nitrogen atmosphere for 3.5 hours to obtain Mo / MCM-36 molecular sieve; the molybdenum-based aqueous solution was prepared by tetrahydrated ammonium heptamolybdate and phosphoric acid. In the molybdenum-based aqueous solution, the concentration of molybdenum element was 16wt%, and the mass ratio of molybdenum element to phosphorus element was 1:0.4.

[0153] Loading Ni: Using an equal volume impregnation method, the Mo / MCM-36 molecular sieve is impregnated in a nickel-based aqueous solution for 12 hours, the nickel-based aqueous solution is dried at 100°C, and further dried at 100°C for 10 hours, and then calcined at 400°C for 3 hours in an air atmosphere to obtain the nickel-molybdenum loaded MCM-36 molecular sieve Ni-Mo / MCM-36, which is the 2# nickel-molybdenum-based catalyst.

[0154] The nickel-based aqueous solution is prepared by nickel nitrate and citric acid. The nickel-based aqueous solution contains 4 wt% of Ni element, and the mass ratio of nickel element to citric acid is 1:1.3.

[0155] In this embodiment, based on the mass of MCM-36, the Ni loading amount is 3.1 wt %, the mass ratio of Ni to Mo is 0.31:1, and the P content is 4.0 wt %.

[0156] The total pore volume of the 2# nickel-molybdenum-based catalyst is 0.53 cm 3 / g, and the average pore diameter is 8nm.

[0157] Based on the total amount of acid sites, weak acid sites account for 33% of the total acid amount.

[0158] Example 3

[0159] Preparation of 3# nickel-molybdenum-based catalyst:

[0160] (2.0) Preparation of MCM-49(P):

[0161] A silicon source, an aluminum source, an alkali source, a template, and deionized water are uniformly mixed to obtain a mixture, the mixture is placed in a closed reactor and subjected to a first hydrothermal crystallization at 140° C. under autogenous pressure for 40 hours, then the temperature is lowered to 90° C. and subjected to a second hydrothermal crystallization at autogenous pressure for 15 hours, and the crystallized product is recovered, washed with distilled water until neutral, and then dried at 80° C. for 15 hours to obtain MCM-49(P);

[0162] The template is hexamethyleneimine, the silicon source is silica sol (40 wt%), the aluminum source is sodium metaaluminate, and the alkali source is sodium hydroxide. The silicon source is converted to SiO2, the aluminum source is converted to Al2O3, and the alkali source is converted to Na2O. The ratio of SiO2:Al2O3:Na2O:template:H2O is 1:0.1:0.1:0.1:20.

[0163] (2.1) MCM-49(P) was dispersed in a CTAB aqueous solution, stirred at 85°C for 60 h, and centrifuged. The separated material was washed with distilled water and dried at 50°C for 15 h to obtain MCM-36(P). In MCM-36(P), the molar ratio of CTAB to Si in MCM-36(P) was 0.40:1. The mass concentration of the CTAB aqueous solution was 12 wt%, and the pH was 10.

[0164] (2.2) MCM-36(P) was heated to 500°C in air at a heating rate of 1.4°C / min and calcined at this temperature for 7 hours to obtain MCM-36 molecular sieve with a mesoporous structure. The mesopore size of MCM-36 molecular sieve is distributed between 2-10 nm, and the specific surface area is 291 m 2 / g.

[0165] (2.3) Ni and Mo loading:

[0166] Loading Mo: The MCM-36 molecular sieve was immersed in a molybdenum-based aqueous solution at room temperature by an equal volume impregnation method, ultrasonicated for 30 minutes, and then allowed to stand for 20 hours. The molybdenum-based aqueous solution was then dried at 150°C and continued to be dried at 150°C for 6 hours. Finally, it was calcined at 450°C in a nitrogen atmosphere for 4.5 hours to obtain Mo / MCM-36 molecular sieve; the molybdenum-based aqueous solution was prepared by ammonium heptamolybdate tetrahydrate and phosphoric acid. In the molybdenum-based aqueous solution, the concentration of molybdenum element was 13wt%, and the mass ratio of molybdenum element to phosphorus element was 1:0.25.

[0167] Loading Ni: Using an equal volume impregnation method, the Mo / MCM-36 molecular sieve is impregnated in a nickel-based aqueous solution for 12 hours, the nickel-based aqueous solution is dried at 110°C, and further dried at 110°C for 8 hours, and then calcined at 330°C in an air atmosphere for 4 hours to obtain the nickel-molybdenum loaded MCM-36 molecular sieve Ni-Mo / MCM-36, which is the 3# nickel-molybdenum-based catalyst.

[0168] The nickel-based aqueous solution is prepared by nickel nitrate and citric acid. The nickel-based aqueous solution contains 7 wt% of Ni element, and the mass ratio of nickel element to citric acid is 1:1.6.

[0169] In this embodiment, based on the mass of MCM-36, the Ni loading amount is 3.4 wt %, the mass ratio of Ni to Mo is 0.34:1, and the P content is 2.5 wt %.

[0170] The total pore volume of 3# nickel-molybdenum-based catalyst is 0.45 cm 3 / g, and the average pore diameter is 7nm.

[0171] Based on the total amount of acidic sites, weak acid sites account for 30% of the total acidic amount.

[0172] Comparative Example 1-1

[0173] Preparation of 4# nickel-molybdenum-based catalyst:

[0174] This embodiment is basically the same as the first embodiment, except that the loading of Ni and Mo is completed at one time. When performing the loading, the steps are as follows:

[0175] Loading NiMo: MCM-36 was immersed in a nickel-molybdenum-based aqueous solution at room temperature by an equal volume impregnation method, ultrasonicated for 50 minutes, and then allowed to stand for 15 hours. The nickel-molybdenum-based aqueous solution was then dried at 100°C and continued to be dried at 100°C for 10 hours. Finally, it was calcined at 420°C in a nitrogen atmosphere for 4 hours to obtain Mo / MCM-36; the nickel-molybdenum-based aqueous solution was prepared by tetrahydrated ammonium heptamolybdate, nickel nitrate, phosphoric acid and citric acid. In the nickel-molybdenum-based aqueous solution, the concentration of molybdenum element was 10wt%, the concentration of Ni element was 3.3wt%, the mass ratio of molybdenum element to phosphorus element was 1:0.3, and the mass ratio of nickel element to citric acid was 1:1.4.

[0176] In this embodiment, based on the mass of MCM-36, the Ni loading amount is 3.2 wt %, the molar ratio of Ni to Mo is 0.33:1, and the P content is 2.9 wt %.

[0177] The total pore volume of 4# nickel-molybdenum-based catalyst is 0.2 cm 3 / g, and the average pore size is 2nm.

[0178] Based on the total amount of acidic sites, weak acid sites account for 20% of the total acidic amount.

[0179] Data from Example 1: The total pore volume of the 1# nickel-molybdenum-based catalyst is 0.59 cm 3 / g, and the average pore diameter is 9.5nm.

[0180] Based on the total amount of acid sites, weak acid sites account for 35% of the total acid amount.

[0181] Comparative Example 1-2

[0182] Preparation of 5# Nickel-Molybdenum-Based Catalyst

[0183] This example is essentially the same as Example 1, differing only in step (2.3). Specifically, step (2.3) involves heating MCM-36(P) to 580°C in an air atmosphere at a heating rate of 1°C / min and calcining at that temperature for 8 hours to obtain an MCM-36 molecular sieve having a mesoporous structure. That is, the sintering temperature is 580°C.

[0184] The mesopore diameter of MCM-36 molecular sieve is about 2nm, and the specific surface area is 150m 2 / g.

[0185] Based on the total amount of acid sites, weak acid sites account for 31% of the total acid amount.

[0186] Example 4

[0187] Preparation of 1# nickel-tungsten based catalyst:

[0188] (3.1) Pseudoboehmite and MgO powders were ball-milled for 3 h. A mixed solution of silica sol and ammonium dihydrogen phosphate was then added, kneaded, and extruded into a green body. The green body was dried at 110°C for 8 h and then calcined at 520°C for 4 h to obtain a γ-Al2O3-SiO2-MgO carrier. During ball milling, the ball-to-material ratio was 15:1 and the rotation speed was 120 rpm.

[0189] The mass ratio of silica sol, pseudo-boehmite, MgO and ammonium dihydrogen phosphate is 15:79:5:1, wherein silica sol is calculated as SiO2, pseudo-boehmite is calculated as Al2O3, and ammonium dihydrogen phosphate is calculated as P2O5;

[0190] (3.2) Using nickel-tungsten impregnation solution, equal volume impregnation is performed to load nickel-tungsten on the γ-Al2O3-SiO2-MgO carrier to obtain a nickel-tungsten support. The nickel-molybdenum impregnation solution is an aqueous solution containing ammonium metatungstate, nickel nitrate and citric acid, and the pH of the nickel-tungsten impregnation solution is adjusted to 2.8 using nitric acid.

[0191] In the nickel-tungsten impregnation solution, the concentration of nickel nitrate is 200 g / L, the concentration of ammonium metatungstate is 337.7 g / L, the concentration of citric acid is 380 g / L, the impregnation time is 12 h, the impregnation temperature is 60°C, the vacuum impregnation is carried out, and the vacuum degree is -0.09 MPa.

[0192] Based on the mass of the γ-Al2O3-SiO2-MgO support, the WO3 loading is 16.3wt% and the NiO loading is 5.1wt%.

[0193] (3.3) Temperature-programmed calcination: The nickel-tungsten support is subjected to temperature-programmed calcination:

[0194] First, the nickel-tungsten support was heated to 120°C at a rate of 0.5°C / min and then dried at a constant temperature for 8 hours;

[0195] Then the temperature was raised to 350 °C at a rate of 1.5 °C / min and maintained for 1.5 h;

[0196] Finally, the temperature was raised to 500°C at a rate of 2°C / min and maintained for 4 hours to obtain 1# nickel-tungsten-based catalyst.

[0197] In this embodiment, the 1# nickel-tungsten-based catalyst has the following characteristics:

[0198] The bimodal pore structure includes 5-8nm mesopores and 50-75nm macropores, with a specific surface area of ​​224m 3 / g, pore volume 0.58cm 3 / g, the dispersion of NiMoS phase is 82%, and the acid site density is 0.18mmol NH3 / g. Based on the total amount of acid sites, weak acid sites account for 41%, and the rest are medium and strong acid sites.

[0199] Example 5

[0200] Preparation of 2# nickel-tungsten based catalyst:

[0201] (3.1) Pseudoboehmite and MgO powders were ball-milled for 4 h. A mixed solution of silica sol and ammonium dihydrogen phosphate was then added and kneaded and extruded into a green body. The green body was dried at 100°C for 10 h and then calcined at 500°C for 5 h to obtain a γ-Al2O3-SiO2-MgO carrier. During ball milling, the ball-to-material ratio was 20:1 and the rotation speed was 100 rpm.

[0202] The mass ratio of silica sol, pseudoboehmite, MgO and ammonium dihydrogen phosphate is 10:85:3:2, wherein silica sol is calculated as SiO2, pseudoboehmite is calculated as Al2O3, and ammonium dihydrogen phosphate is calculated as P2O5;

[0203] (3.2) Using nickel-tungsten impregnation solution, equal volume impregnation is performed to load nickel-tungsten on the γ-Al2O3-SiO2-MgO carrier to obtain a nickel-tungsten support. The nickel-molybdenum impregnation solution is an aqueous solution containing ammonium metatungstate, nickel nitrate and citric acid, and the pH of the nickel-tungsten impregnation solution is adjusted to 2.5 using nitric acid.

[0204] In the nickel-tungsten impregnation solution, the concentration of nickel nitrate is 150 g / L, the concentration of ammonium metatungstate is 224.9 g / L, the concentration of citric acid is 230 g / L, the impregnation time is 10 h, the impregnation temperature is 50°C, the vacuum impregnation is carried out, and the vacuum degree is -0.09 MPa.

[0205] Based on the mass of the γ-Al2O3-SiO2-MgO support, the WO3 loading is 12.2wt% and the NiO loading is 4.3wt%.

[0206] (3.3) Temperature-programmed calcination: The nickel-tungsten support is subjected to temperature-programmed calcination:

[0207] First, the nickel-tungsten support was heated to 140°C at a rate of 0.4°C / min and then dried at a constant temperature for 6 hours.

[0208] Then the temperature was raised to 360 °C at a rate of 1.8 °C / min and maintained for 1.5 h;

[0209] Finally, the temperature was raised to 540°C at a rate of 3°C / min and maintained for 3.5h to obtain 2# nickel-tungsten-based catalyst.

[0210] In this embodiment, the 2# nickel-tungsten-based catalyst has the following characteristics:

[0211] The bimodal pore structure includes 5-8nm mesopores and 62-98nm macropores, with a specific surface area of ​​233m 3 / g, pore volume 0.63cm 3 / g, the dispersion of NiMoS phase is 89%, and the acid site density is 0.21mmol NH3 / g. Based on the total amount of acid sites, weak acid sites account for 48%, and the rest are medium and strong acid sites.

[0212] Example 6

[0213] Preparation of 3# nickel-tungsten based catalyst:

[0214] (3.1) Pseudoboehmite and MgO powders were ball-milled for 3.5 h. A mixed solution of silica sol and ammonium dihydrogen phosphate was then added, kneaded, and extruded into a green body. The green body was dried at 120°C for 6 h and then calcined at 550°C for 3.5 h to obtain a γ-Al2O3-SiO2-MgO carrier. During ball milling, the ball-to-material ratio was 10:1 and the rotation speed was 60 rpm.

[0215] The mass ratio of silica sol, pseudo-boehmite, MgO and ammonium dihydrogen phosphate is 14:78:6:2, wherein silica sol is calculated as SiO2, pseudo-boehmite is calculated as Al2O3, and ammonium dihydrogen phosphate is calculated as P2O5;

[0216] (3.2) Using nickel-tungsten impregnation solution, equal volume impregnation is performed to load nickel-tungsten on the γ-Al2O3-SiO2-MgO carrier to obtain a nickel-tungsten support. The nickel-molybdenum impregnation solution is an aqueous solution containing ammonium metatungstate, nickel nitrate and citric acid, and the pH of the nickel-tungsten impregnation solution is adjusted to 3.0 using nitric acid.

[0217] In the nickel-tungsten impregnation solution, the concentration of nickel nitrate is 240 g / L, the concentration of ammonium metatungstate is 380.4 g / L, the concentration of citric acid is 330 g / L, the impregnation time is 15 h, the impregnation temperature is 55 ° C, the vacuum impregnation is carried out, and the vacuum degree is -0.09 MPa.

[0218] Based on the mass of the γ-Al2O3-SiO2-MgO support, the WO3 loading is 19.5wt% and the NiO loading is 6.5wt%.

[0219] (3.3) Temperature-programmed calcination: The nickel-tungsten support is subjected to temperature-programmed calcination:

[0220] First, the nickel-tungsten support was heated to 100°C at a rate of 0.6°C / min and then dried at a constant temperature for 10 h.

[0221] Then the temperature was raised to 330 °C at a rate of 2 °C / min and maintained for 2 h;

[0222] Finally, the temperature was raised to 480°C at a rate of 1.5°C / min and maintained for 5 hours to obtain 3# nickel-tungsten-based catalyst.

[0223] In this embodiment, the 3# nickel-tungsten-based catalyst has the following characteristics:

[0224] The bimodal pore structure includes 5-8nm mesopores and 64-82nm macropores, with a specific surface area of ​​248m 3 / g, pore volume 0.51cm 3 / g, the dispersion of NiMoS2 phase is 85%, and the acid site density is 0.24mmol NH3 / g. Based on the total amount of acid sites, weak acid sites account for 44% and the rest are medium and strong acid sites.

[0225] The isomerization dewaxing catalyst specifically uses ZSM-48 molecular sieve loaded with platinum and palladium

[0226] The following uses Examples 7-9 to describe in detail the method for producing jet fuel using artemisinin waste.

[0227] In Examples 7-9, the platinum-palladium loaded ZSM-48 molecular sieves used were prepared by the following method:

[0228] (1) Aluminum sulfate, sodium hydroxide, hexamethylammonium bromide and deionized water were stirred and dissolved at room temperature to obtain a solution, ZSM-48 seed crystals were added to the solution, stirred for 10 minutes, and then silica sol was added and stirred to obtain a precursor gel;

[0229] (2) The precursor gel was placed in a polytetrafluoroethylene-lined hydrothermal reactor, and after crystallization at 160°C for 48 hours, the product was filtered and washed, and dried at 100°C for 6 hours to obtain a crystallized product; 10 g of the crystallized product was mixed with 300 mL of a 0.5 mol / L NaOH solution, and after alkali treatment in an 80°C water bath for 60 minutes, the product was filtered and washed, and calcined at 550°C for 10 hours to remove the template, thereby obtaining a ZSM-48 molecular sieve.

[0230] The silica sol is calculated as SiO2, the aluminum sulfate is calculated as Al2O3, and the sodium hydroxide is calculated as Na2O. The molar ratio of the silica sol, aluminum sulfate, hexamethylammonium bromide, sodium hydroxide and deionized water is 1:0.005:0.04:0.1:20.

[0231] (3) then exchanging with 1 mol / L NH4Cl solution at 80°C for 1 hour, and then filtering; repeating this process twice, after completing the ammonium exchange process, the exchange product was dried at 80°C for 6 hours, and then calcined at 550°C for 4 hours to obtain hydrogenated ZSM-48 molecular sieve;

[0232] (2) Preparation of an alkane isomerization catalyst: Hydrogenated ZSM-48 molecular sieve was mixed with alumina at a dry basis ratio of m(hydrogenated ZSM-48):m(Al2O3)=65:35, and diluted nitric acid was added as a binder. The mixture was then extruded into strips, wherein the amount of diluted nitric acid added was 2% by weight of the powder (dry basis) and the amount of water was 0.7% by weight of the powder (dry basis). The extruded strip carrier was aged at room temperature for 4 h, dried at 80°C for 5 h, and calcined at 550°C for 4 h to obtain a carrier.

[0233] Chloroplatinic acid-palladium chlorate ethanol solution (the mass ratio of the total mass of chloroplatinic acid and palladium chlorate to ethanol is 1:70, Pt:Pd=2:1)

[0234] (3) The carrier was impregnated in a chloroplatinic acid ethanol solution (the mass ratio of chloroplatinic acid to ethanol was 1:70) by saturated impregnation method. After drying at 80 °C for 6 h and calcining at 550 °C for 6 h, the platinum-loaded ZSM-48 molecular sieve was used as an isomerization dewaxing catalyst.

[0235] In the platinum-loaded ZSM-48 molecular sieve, the content of ZSM-48 molecular sieve is 70 wt %, the content of platinum is 0.24 wt %, the content of palladium is 0.12 wt %, and the content of Al 2 O 3 is 29.64 wt %.

[0236] It is understood that the chloroplatinic acid ethanol solution can be replaced with a palladium source such as palladium acetate acetone solution, or the platinum source and palladium source can be impregnated into the carrier separately or together to prepare palladium-loaded ZSM-48 molecular sieve or platinum-palladium co-loaded ZSM-48 molecular sieve.

[0237] In the following examples, the main properties of the artemisinin waste materials used are shown in Table 1.

[0238] Table 1 Main properties of artemisinin waste

[0239] project <![CDATA[Density at 20°C (g / cm 3 )]]> 0.88 Total acid value (mgKOH / g) 55.53 Freezing point (℃) 49 Carbon residue (%) 2 Sulfur content (%) 1 Nitrogen content (%) ＞0.03 Chlorine content (%) ＞0.02 Bromine value Mol / L 13.43 Aromatic hydrocarbons (volume fraction %) ＞40 Hydroxyl value (mgKOH / g) 24.23

[0240] The composition of artemisinin waste is shown in Table 2. Because the composition of artemisinin waste is complex, with more than 50 components, only some of the components with higher content are listed in Table 1.

[0241] Table 2 Main components of artemisinin waste

[0242]

[0243]

[0244] Example 7

[0245] The method for producing aviation fuel using artemisinin waste comprises the following steps:

[0246] (1) Pretreatment: The artemisinin waste material as a raw material is crushed into granules with a particle size of 0.6-1 mm, and then dried at 50° C. to a moisture content of ≤0.5 wt % to obtain a pretreated material;

[0247] (2) In a primary hydrogenation reactor, the pretreated material is subjected to a primary hydrogenation treatment using a 1# nickel-molybdenum-based catalyst to remove nitrogen from the pretreated material to obtain a primary treated material;

[0248] During the first stage of hydrogenation, the first hydrogenation temperature is 390°C, the first hydrogenation pressure is 11 MPa, and the first mass space velocity is 0.5 h -1 , the first hydrogen-to-oil ratio is 600:1.

[0249] Before the first-stage hydrotreatment, the 1# nickel-molybdenum-based catalyst is first activated. The activation steps are as follows:

[0250] Hydrogen was used to pass a mixed solution of CS2 and n-heptane into a primary hydrogenation reactor. The temperature in the reactor was then raised from room temperature to 130°C at a rate of 1°C / min, held for 1.2 hours, then to 350°C at a rate of 1°C / min, held for 3 hours, and finally to 400°C for 2 hours to complete activation, converting Ni and Mo into the active NiMoS phase. The volume ratio of CS2 to n-heptane was 1:80, the molar ratio of CS2 to the total molar amount of nickel and molybdenum metal in the nickel-molybdenum-based catalyst was 1.3:1, and the volume ratio of hydrogen to catalyst was 500:1.

[0251] (3) In a secondary hydrogenation reactor, the primary treated material is subjected to secondary hydrogenation treatment using a 1# nickel-tungsten-based catalyst to reduce the aromatic content to ≤20 wt %, thereby obtaining a secondary treated material;

[0252] In step (3), during the secondary hydrogenation treatment, the second hydrogenation temperature is 330°C, the second hydrogenation pressure is 5 MPa, and the second mass space velocity is 1 h -1 , the second hydrogen-to-oil ratio is 800:1;

[0253] Before the primary treated material is subjected to secondary hydrogenation treatment, the 1# nickel-tungsten based catalyst is first activated. The activation steps are as follows:

[0254] Pretreatment stage: First, nitrogen is used to purge the secondary hydrogenation reactor at a temperature of 250°C, a purge time of 2 hours, and a pressure of 2 MPa;

[0255] Then hydrogen was used to replace the reactor at a temperature of 250°C and a pressure of 2 MPa for 0.5 h;

[0256] Sulfidation stage: Inject the DMDS and H2 mixture into the secondary hydrogenation reactor, raise the temperature to 320℃ at a rate of 2℃ / min and keep it constant for 6 hours. The hydrogen partial pressure is 3.0MPa. The volume ratio of DMDS (dimethyl disulfide) to H2 is 1:33.

[0257] Surface modification stage: After the sulfurization is completed, a hydrogen mixture containing 4 vol% methyltrichlorosilane is introduced at 330°C for 3 hours to form a methylsiloxane modification layer on the catalyst surface; based on the mass of the nickel-tungsten-based catalyst, the silicon content is 1.5 wt%.

[0258] (4) The secondary treated material is subjected to isomerization dewaxing treatment using the platinum-loaded ZSM-48 molecular sieve to obtain a dewaxed material.

[0259] In step (4), during isomerization dewaxing, the reaction pressure is 2 MPa, the reaction temperature is 370°C, and the volume space velocity is 1 h -1 , hydrogen-oil volume ratio 550:1.

[0260] (5) Fractionating the dewaxed material to obtain jet fuel and light components.

[0261] During fractionation, the feed temperature of the distillation tower is 245°C, the top temperature is 150°C, the bottom temperature is 330°C, and the pressure inside the tower is 0.1 MPa. Light fractions are collected from the top of the tower, and jet fuel is collected from the bottom. The light fractions are used as gasoline or diesel feedstock.

[0262] Raw materials: Nitrogen in artemisinin waste> 0.03wt%, aromatic hydrocarbons> 40wt%

[0263] The specific data of the jet fuel obtained in this example are as follows: yield 40±2%, freezing point <-50°C (ASTM D7566-23 requires ≤-47°C), aromatics 17.5±1.2wt% (standard requires ≤20wt%), sulfur content 0.005wt% (standard requires ≤0.01wt%), flash point 60°C (standard requires ≥38°C), meeting the ASTM D7566-23 standard.

[0264] Example 8

[0265] The method for producing aviation fuel using artemisinin waste comprises the following steps:

[0266] (1) Pretreatment: The artemisinin waste material as a raw material is crushed into granules with a particle size of 0.2-0.7 mm, and then dried at 60° C. to a moisture content of ≤0.5 wt % to obtain a pretreated material;

[0267] (2) In a primary hydrogenation reactor, the pretreated material is subjected to a primary hydrogenation treatment using a 2# nickel-molybdenum-based catalyst to remove nitrogen from the pretreated material to obtain a primary treated material;

[0268] During the first stage of hydrogenation treatment, the first hydrogenation temperature is 360°C, the first hydrogenation pressure is 12 MPa, and the first mass space velocity is 0.7 h -1 , the first hydrogen-to-oil ratio is 400:1.

[0269] Before the primary hydrotreatment, the 2# nickel-molybdenum-based catalyst is first activated. The activation steps are as follows:

[0270] Hydrogen was used to pass a mixed solution of CS2 and n-heptane into a primary hydrogenation reactor. The temperature in the primary hydrogenation reactor was then raised from room temperature to 140°C at a heating rate of 0.8°C / min, maintained for 1.8 hours, then to 330°C at a heating rate of 0.8°C / min, maintained for 4 hours, and finally to 390°C for 1.5 hours to complete activation and convert Ni and Mo into the active NiMoS2 phase. The volume ratio of CS2 to n-heptane was 1:90, the molar ratio of CS2 to the total molar amount of nickel and molybdenum metal in the nickel-molybdenum-based catalyst was 1.1:1, and the volume ratio of hydrogen to catalyst was 450:1.

[0271] (3) In the secondary hydrogenation reactor, the primary treated material is subjected to secondary hydrogenation treatment using a 2# nickel-tungsten-based catalyst to reduce the aromatic content from ≤20wt% to obtain a secondary treated material.

[0272] In step (3), during the secondary hydrogenation treatment, the second hydrogenation temperature is 320°C, the second hydrogenation pressure is 6 MPa, and the second mass space velocity is 1.5 h -1 , the second hydrogen-to-oil ratio is 600:1;

[0273] Before the primary treated material is subjected to secondary hydrotreatment, the 2# nickel-tungsten based catalyst is first activated. The activation steps are as follows:

[0274] Pretreatment stage: First, the secondary hydrogenation reactor is purged with nitrogen at a temperature of 240°C and a purging time of 1 hour;

[0275] Then hydrogen was used for replacement at 240°C for 0.3h;

[0276] Sulfidation stage: Finally, the DMDS and H2 mixture is injected into the secondary hydrogenation reactor, and the temperature is raised to 350℃ at a rate of 1.5℃ / min and kept constant at this temperature for 8 hours. The hydrogen partial pressure is 3.5MPa; the volume ratio of DMDS (dimethyl disulfide) to H2 is 1:35.

[0277] Surface modification stage: After the sulfurization is completed, a hydrogen mixture containing 2 vol% methyltrichlorosilane is introduced at 340°C for 4 hours to form a methylsiloxane modification layer on the catalyst surface; based on the mass of the nickel-tungsten-based catalyst, the silicon content is 1 wt%.

[0278] (4) The secondary treated material is subjected to isomerization dewaxing treatment using the platinum-loaded ZSM-48 molecular sieve to obtain a dewaxed material.

[0279] In step (4), during isomerization dewaxing, the reaction pressure is 4 MPa, the reaction temperature is 350°C, and the volume space velocity is 1.5 h -1 , hydrogen-to-oil volume ratio 400:1.

[0280] (5) Fractionating the dewaxed material to obtain jet fuel and light components.

[0281] During fractionation, the feed temperature of the distillation tower is 230°C, the top temperature is 140°C, the bottom temperature is 310°C, and the pressure inside the tower is 0.3 MPa. Light fractions are collected from the top of the tower, and jet fuel is collected from the bottom. The light fractions are used as gasoline or diesel feedstock.

[0282] Example 9

[0283] The method for producing aviation fuel using artemisinin waste comprises the following steps:

[0284] (1) Pretreatment: The artemisinin waste material as a raw material is crushed into granules with a particle size of 0.5-1 mm, and then dried at 40° C. to a moisture content of ≤0.5 wt % to obtain a pretreated material;

[0285] (2) In a primary hydrogenation reactor, the pretreated material is subjected to a primary hydrogenation treatment using a 3# nickel-molybdenum-based catalyst to remove nitrogen from the pretreated material to obtain a primary treated material;

[0286] During the first stage of hydrogenation, the first hydrogenation temperature is 400°C, the first hydrogenation pressure is 9 MPa, and the first mass space velocity is 0.3 h -1 , the first hydrogen-to-oil ratio is 500:1.

[0287] Before the primary hydrotreatment, the 3# nickel-molybdenum-based catalyst is first activated. The activation steps are as follows:

[0288] Hydrogen was used to pass a mixed solution of CS2 and n-heptane into a primary hydrogenation reactor. The temperature in the primary hydrogenation reactor was then raised from room temperature to 120°C at a heating rate of 1.2°C / min, maintained for 1.5 hours, then to 340°C at a heating rate of 1.2°C / min, maintained for 5 hours, and finally to 420°C for 2.5 hours to complete activation, converting Ni and Mo into the active phase NiMoS2. The volume ratio of CS2 to n-heptane was 1:100, the molar ratio of CS2 to the total molar amount of nickel and molybdenum metal in the nickel-molybdenum-based catalyst was 1.4:1, and the volume ratio of hydrogen to catalyst was 550:1.

[0289] (3) In a secondary hydrogenation reactor, the primary treated material is subjected to secondary hydrogenation treatment using a 3# nickel-tungsten-based catalyst to reduce the aromatic content to ≤20 wt %, thereby obtaining a secondary treated material;

[0290] In step (3), during the secondary hydrogenation treatment, the second hydrogenation temperature is 340°C, the second hydrogenation pressure is 4 MPa, and the second mass space velocity is 1.8 h -1 , the second hydrogen-to-oil ratio is 500:1;

[0291] Before the primary treated material is subjected to secondary hydrogenation treatment, the 3# nickel-tungsten based catalyst is first activated. The activation steps are as follows:

[0292] Pretreatment stage: First, the secondary hydrogenation reactor is purged with nitrogen at a temperature of 270°C for 1.5 hours.

[0293] Then hydrogen was used for replacement at 270°C for 1 hour;

[0294] Sulfidation stage: Finally, the DMDS and H2 mixture is injected into the secondary hydrogenation reactor, and the temperature is raised to 330℃ at a rate of 2.2℃ / min and kept constant at this temperature for 5 hours. The hydrogen partial pressure is 4.0MPa; the volume ratio of DMDS (dimethyl disulfide) to H2 is 1:30.

[0295] Surface modification stage: After the sulfurization is completed, a hydrogen mixture containing 5 vol% methyltrichlorosilane is introduced at 320°C for 2 hours to form a methylsiloxane modification layer on the catalyst surface; based on the mass of the nickel-tungsten-based catalyst, the silicon content is 1.3 wt%.

[0296] (4) The secondary treated material is subjected to isomerization dewaxing treatment using the platinum-loaded ZSM-48 molecular sieve to obtain a dewaxed material.

[0297] In step (4), during isomerization dewaxing, the reaction pressure is 6 MPa, the reaction temperature is 310°C, and the volume space velocity is 2 h -1 , hydrogen-oil volume ratio 320:1.

[0298] (5) Fractionating the dewaxed material to obtain jet fuel and light components.

[0299] During fractionation, the feed temperature of the fractionating tower is 220°C, the top temperature is 120°C, the bottom temperature is 300°C, and the pressure inside the tower is 0.2 MPa. Light fractions are collected from the top of the tower, and jet fuel is collected from the bottom. The light fractions are used as gasoline or diesel feedstock.

[0300] Comparative Example A

[0301] This comparative example is basically the same as Example 7, the only difference being that the 4# nickel-molybdenum-based catalyst prepared in Comparative Example 1-1 is used instead of the 1# nickel-molybdenum-based catalyst.

[0302] Comparative Example B

[0303] This comparative example is basically the same as Example 7, the only difference being that the 5# nickel-molybdenum-based catalyst prepared in Comparative Example 1-2 is used instead of the 1# nickel-molybdenum-based catalyst.

[0304] Comparative Example C

[0305] Comparative Example C (using the catalyst and process in patent CN2023112472163): When processing the same artemisinin waste, no related products could be obtained.

[0306] The indicators of the obtained jet fuel are shown in Table 3.

[0307] Table 3 Jet fuel index

[0308]

[0309] In the standard ASTM D7566-23, the freezing point is <-47°C, the aromatics content is 20wt%, the sulfur content is ≤0.01wt%, and the flash point is ≥38°C.

Claims

1. A method for producing aviation fuel using artemisinin waste, characterized in that: The steps include: (1) Pretreatment: crushing artemisinin waste to a particle size of ≤1 mm and drying to a moisture content of ≤0.5 wt% to obtain a pretreated material; (2) Primary hydrogenation: The pretreated material is treated under the conditions of a first hydrogenation temperature of 360-400°C, a first hydrogenation pressure of 9-12 MPa, a first mass space velocity of 0.3-0.8 h-1, and a first hydrogen-to-oil volume ratio of 400-600:1 under the action of a nickel-molybdenum-based catalyst to obtain a primary treated material; (3) Secondary hydrogenation: Under the action of a nickel-tungsten-based catalyst, the primary treated material is treated at a second hydrogenation temperature of 320-340°C, a second hydrogenation pressure of 3-6 MPa, a second mass space velocity of 1.0-2.0 h-1, and a second hydrogen-to-oil volume ratio of (500-800):1 to obtain a secondary treated material; (4) Isomerization dewaxing: using a Pt and Pd loaded ZSM-48 molecular sieve catalyst, the secondary treated material is treated at 300-380°C, 2-6 MPa, a volume space velocity of 1.0-2.5 h-1, and a hydrogen-to-oil volume ratio of (300-600):1 to obtain a dewaxed material; (5) Fractionation: Cut the dewaxed material and collect the jet fuel components with a distillation range of 150-300°C and the light components with a distillation range of 50-150°C.

2. The method according to claim 1, characterized in that In step (2), the nickel-molybdenum-based catalyst is Ni-Mo / MCM-36 molecular sieve, with the mass of MCM-36 molecular sieve as the benchmark, the Ni loading is 3.0-3.5wt%, the mass ratio of Ni to Mo is (0.3-0.4):1, and the P content is ≤5wt%; The MCM-36 molecular sieve is prepared by the following steps: (2.1) Dispersing the precursor in a surfactant aqueous solution, stirring at 80-90°C for 40-60 hours, washing, and drying to obtain MCM-36(P); the precursor is MCM-22(P) or MCM-49(P); the molar ratio of the surfactant to the Si element in the precursor is 0.30-0.40:1; the surfactant is CTAB or DTAB; the mass concentration of the surfactant aqueous solution is 8-15 wt %, and the pH value of the surfactant aqueous solution is 9-10; (2.2) MCM-36(P) was calcined at 480-550℃ at a rate of 0.6-1.5℃ / min for 5-8h to obtain a specific surface area ≥280m 2 / g, MCM-36 molecular sieve with a mesopore size of 2-10 nm; (2.3) Ni and Mo loading.

3. The method according to claim 2, wherein: The loading method of Ni and Mo in step (2.3) is as follows: Mo loading: MCM-36 molecular sieves were impregnated with an equal volume of an ammonium heptamolybdate-phosphoric acid aqueous solution containing 8-16 wt% Mo, dried, and calcined at 400-450°C in a nitrogen atmosphere for 3-5 h. The mass ratio of Mo to P in the ammonium heptamolybdate-phosphoric acid aqueous solution was 1:(0.25-0.4). Ni loading: Mo / MCM-36 was impregnated with an equal volume of nickel nitrate-citric acid aqueous solution containing 4-7 wt% Ni, dried, and calcined in air at 330-400°C for 3-5 hours; the mass ratio of Ni to citric acid in the nickel nitrate-citric acid aqueous solution was 1:(1.3-1.6).

4. The method according to claim 2, wherein: The total pore volume of the nickel-molybdenum-based catalyst is 0.4-0.6 cm 3 / g, an average pore size of 5-10nm, and a gradient acidity distribution: the weak acid sites with a desorption peak of 150-250℃ account for 30-40% of the total acid content, and the rest are medium-strong acid sites with a desorption peak of 250-400℃.

5. The method according to claim 2, wherein: Before the primary hydrotreatment, the nickel-molybdenum-based catalyst is first sulfurized and activated as follows: The CS2 / n-heptane mixture is introduced into the primary hydrogenation reactor using hydrogen and the temperature is raised at the same time. First, heat to 110-140°C at 0.8-1.2°C / min and keep warm for 1-2h; Then increase the temperature to 330-350℃ at 0.8-1.2℃ / min and keep warm for 3-5h; Finally, heat to 390-420℃ and keep warm for 1.5-2.5h to complete vulcanization activation; The volume ratio of CS2 to n-heptane is 1:(80-100), the molar ratio of CS2 to the total molar amount of nickel-molybdenum metal in the nickel-molybdenum-based catalyst is (1.1-1.5):1, and the volume ratio of hydrogen to the catalyst is (400-600):

1.

6. The method according to claim 1, wherein: In step (3), the nickel-tungsten-based catalyst uses γ-Al2O3-SiO2-MgO as a carrier, a WO3 loading amount of 12-20wt%, a NiO loading amount of 4-7wt%, and a mass ratio of WO3 to NiO of (2.8-3.2):1; The carrier is prepared by the following steps: Silica sol, pseudo-boehmite, MgO and ammonium dihydrogen phosphate are mixed in the mass ratio of SiO2:Al2O3:MgO:P2O5=(10-15):(78-85):(3-6):(1-2), ball-milled for 3-4 hours and then extruded into strips. After drying, the strips are calcined at 500-550°C for 3.5-5 hours; wherein the silica sol is calculated as SiO2, the pseudo-boehmite is calculated as Al2O3, and the ammonium dihydrogen phosphate is calculated as P2O5.

7. The method according to claim 6, characterized in that: The nickel-tungsten loading of the γ-Al2O3-SiO2-MgO carrier is as follows: Impregnation: The carrier is impregnated with an aqueous solution of ammonium metatungstate, nickel nitrate and citric acid with a pH of 2.5-3.0 and an overall molar ratio of citric acid to nickel tungsten of 0.5-1.

0. Program calcination: heat up to 100-140℃ at 0.4-0.6℃ / min and keep warm for 6-10h; then heat up to 330-360℃ at 1-2℃ / min and keep warm for 1.5-2h; finally heat up to 480-540℃ at 1.5-3℃ / min and keep warm for 3.5-5h.

8. The method according to claim 6, wherein: The nickel-tungsten-based catalyst has a bimodal pore structure: mesopores are 5-8 nm, macropores are 50-100 nm, and the specific surface area is 220-250 m 2 / g, pore volume 0.55-0.65cm 3 / g; NiWS active phase dispersion>80%; weak acid sites account for 40-50%.

9. The method according to claim 6, wherein: Before the secondary hydrotreatment, the nickel-tungsten based catalyst is first sulfurized and activated as follows: First, nitrogen is used for purging, and then hydrogen is replaced; Then, a DMDS / H2 mixture gas was introduced with a hydrogen partial pressure of 3.0-4.0 MPa, and the temperature was raised to 330-350°C at a rate of 1.5-2.2°C / min and kept at that temperature for 5-8 hours; the volume ratio of DMDS to H2 was 1:(30-35); Finally, a mixed gas containing 2-5 vol% methyltrichlorosilane and H2 is introduced at 320-340°C for 2-4 hours to make the silicon content on the catalyst surface reach 0.5-2.0 wt%.

10. The method according to claim 1, wherein: In step (4), the total loading amount of Pt and Pd in ​​the ZSM-48 molecular sieve catalyst is 0.3-0.4 wt%, and the mass ratio of Pt to Pd is 1:1-3:1; In step (5), the fractionation conditions are: feed temperature 220-250°C, tower top temperature 120-150°C, tower bottom temperature 300-330°C, and pressure 0.1-0.3 MPa.

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