A flaky FAU molecular sieve catalyst, a preparation method thereof and its application in the synthesis of high-density endothermic aviation fuel

Abstract

The invention discloses a method for preparing a catalyst, comprising the following steps: (1) mixing a silicon source, an aluminum source, an alkali source and water; (2) adding a soft template; (3) crystallizing the obtained mixed solution at a certain temperature for a period of time; (4) separating and drying the solid; (5) calcining to obtain a flaky FAU molecular sieve; (6) measuring the saturated water absorption; (7) preparing an active metal precursor solution; (8) using an enhanced strong electrostatic adsorption method to load the active metal in the metal precursor solution onto the flaky FAU molecular sieve; (9) ultrasonic treatment and drying; (10) calcining to obtain a highly dispersed flaky FAU molecular sieve catalyst. The invention also discloses the highly dispersed flaky FAU molecular sieve catalyst and its application in the catalytic reaction of synthesizing high-density endothermic aviation fuel by one-step hydrogenation conversion of polycyclic aromatic hydrocarbons.

Description

Technical Field

[0001] The invention belongs to the field of catalysts, and in particular relates to a flaky FAU molecular sieve catalyst, a preparation method thereof and an application thereof in the synthesis of high-density endothermic aviation fuel. Background Art

[0002] Traditional petroleum-based aviation fuel contains a large amount of chain alkanes, which have low energy density and thermal oxidation stability. It is difficult to maintain stability at high temperatures and cannot meet the needs of the development of modern supersonic aircraft. In addition, an important function of aviation fuel is to cool the structural parts of the aircraft that are dynamically heated due to friction with the high-speed ram air flow. High-density endothermic aviation fuel refers to aviation fuel with a density greater than 0.80g / mL and excellent heat absorption capacity. It can greatly increase the flight speed, flight distance and payload of the aircraft within a limited tank volume, and is the power source of supersonic aircraft.

[0003] The carbon number of polycyclic aromatic hydrocarbons such as acenaphthene, fluorene, phenanthrene, and anthracene is similar to that of aviation fuel. By performing one-step hydrogenation conversion on them, high-density endothermic aviation fuel with a density of ≥0.90 g / mL can be prepared. The fuel has high density, high calorific value, and high thermal oxidation stability. In the one-step hydrogenation conversion reaction, polycyclic aromatic hydrocarbons will be preferentially hydrogenated to form polycyclic alkanes, and then further undergo hydrogenation isomerization, skeleton rearrangement, selective ring opening, and other reactions to form alkyl adamantane (PSA) and selective ring opening products (SRO). The carbon number of PSA and SRO is consistent with that of saturated polycyclic alkanes, which reduces resource waste. PSA and SRO are high-energy density endothermic aviation fuel components with better performance. They are usually prepared by two-step catalytic reactions in industry. In the first step, a hydrogenation catalyst is used to hydrogenate polycyclic aromatic hydrocarbons to form polycyclic alkanes; in the second step, a catalyst with isomerization and ring opening properties is used, and saturated polycyclic alkanes undergo isomerization and ring opening reactions under the action of the catalyst. However, the two-step preparation method has complicated reaction steps and requires different catalysts in different reaction stages, which is costly. Therefore, the use of multifunctional catalysts to hydroconvert polycyclic aromatic hydrocarbons into high energy density endothermic aviation fuels is currently a hot topic.

[0004] The bifunctional catalyst composed of acidic molecular sieve loaded active metal is an excellent one-step hydrogenation catalyst for polycyclic aromatic hydrocarbons. The applicant has disclosed in the previously applied patent CN2023104054230 that the Pt / HY catalyst has the best one-step hydrogenation catalytic activity for polycyclic aromatic hydrocarbons. However, the inherent microporous structure of the molecular sieve will limit the diffusion of large molecular polycyclic aromatic hydrocarbons, resulting in a decrease in the yield of the target product high-density endothermic aviation fuel. A large number of studies have shown that the preparation of mesoporous molecular sieves can inhibit cracking, promote the diffusion of large molecular reactants, and improve the yield of aviation fuel. For this reason, the present invention is proposed. Summary of the invention

[0005] The present invention discloses a highly dispersed flaky FAU molecular sieve catalyst, a preparation method thereof, and an application thereof in improving the yield of synthesizing high-density endothermic aviation fuel components PSA and SRO by one-step hydrogenation conversion of polycyclic aromatic hydrocarbons. The method of the present invention uses a silanization agent as a soft template to synthesize a mesoporous flaky FAU molecular sieve, and uses an enhanced strong electrostatic adsorption method to load active metals to synthesize a highly dispersed flaky FAU molecular sieve catalyst. The catalyst has a higher mesoporous pore volume and external specific surface area, and exhibits more excellent catalytic performance in the one-step hydrogenation conversion reaction of synthesizing high-energy-density endothermic aviation fuel using polycyclic aromatic hydrocarbons as raw materials, greatly enhancing the yield of high-density endothermic aviation fuel.

[0006] The technical solution of the present invention is as follows:

[0007] The first aspect of the present invention discloses a method for preparing a catalyst, comprising the following steps:

[0008] (1) uniformly mixing a certain amount of silicon source, aluminum source, alkali source and water;

[0009] (2) weighing a soft template and adding it to the solution obtained in (1), and mixing at a certain temperature for a period of time;

[0010] (3) crystallizing the mixed solution obtained in (2) at a certain temperature for a period of time; crystallizing at 70-120° C. for 72-120 h, with the reactor remaining stationary during the crystallization process; preferably, the crystallization temperature is 85° C. and the crystallization time is 96 h;

[0011] (4) naturally cooling the crystallized mixture of (3) to room temperature to separate the solid, and drying it at a certain temperature for a period of time; drying at 80-130° C. for 5-16 h; preferably, the drying temperature is 120° C. and the drying time is 6 h;

[0012] (5) calcining the solid obtained in (4) at a certain temperature for a period of time to obtain a solid powder, which is a flaky FAU molecular sieve;

[0013] (6) Measure the saturated water absorption of the obtained thin-sheet FAU molecular sieve, repeat the measurement three times, and take the average value;

[0014] (7) preparing an active metal precursor solution, using water as a solvent, wherein the mass of water in the active metal precursor solution is equal to the saturated water absorption capacity of the thin-sheet FAU molecular sieve carrier used; adjusting the pH value of the active metal precursor solution to 9-13, preferably 11.5, using ammonia water; the active metal content in the active metal precursor solution is 0.02-6.00wt%, preferably 0.8-2.0wt%;

[0015] (8) The active metals of (7) are loaded onto the flaky FAU molecular sieve by an enhanced strong electrostatic adsorption method;

[0016] (9) subjecting the sample obtained after electrostatic adsorption in (8) to ultrasonic treatment for a period of time, and then drying it at a certain temperature for a period of time; the ultrasonic treatment time is 0.2-2h, and the drying treatment time is 6-24h;

[0017] (10) The solid obtained in (9) is calcined at a certain temperature for a period of time to obtain a highly dispersed flaky FAU molecular sieve catalyst.

[0018] Preferably, the silicon source in step (1) is one or more of water glass, sodium silicate, methyl orthosilicate, fumed silica, ethyl orthosilicate, and silica sol, the aluminum source is one or more of sodium aluminate, aluminum sulfate, aluminum nitrate, boehmite, and aluminum isopropoxide, and the alkali source is one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate; more preferably, the silicon source is sodium silicate, the aluminum source is sodium aluminate, and the alkali source is sodium hydroxide.

[0019] Preferably, the soft template in step (2) is N,N-dimethyl-N-[3-(trimethoxysilyl)propyl]dodecyl ammonium chloride, N,N-dimethyl-N-[3-(trimethoxysilyl)propyl]hexadecyl ammonium chloride, N,N-dimethyl-N-[3-(trimethoxysilyl)propyl]octadecyl ammonium chloride, [C 22 H 45 N + (CH3)2C6H 12 N + (CH3)2C6H 13 ](Br -1 )2. [C 20 H 41 N+(CH3)2C6H 12 N+(CH3)2C6H 13 ](Br -1 )2. [C 18 H 37 N+(CH3)2C6H 12 N + (CH3)2C6H 13 ](Br -1 )2, or [C 16 H 31 N + (CH3)2C6H 12 N + (CH3)2C6H 13 ](Br -1 )2 or more; more preferably, the template is N,N-dimethyl-N-[3-(trimethoxysilyl)propyl]octadecyl ammonium chloride.

[0020] Preferably, the calcination temperature in step (5) is 450-600°C, and the calcination time is 3-10h; more preferably, the calcination temperature is 550°C, and the calcination time is 6h;

[0021] Preferably, the active metal in step (7) is one or more of Pt, Pd, Ir, Ru, Rh, Au, Ni, Cu, Zn, Co, and Fe; more preferably, the active metal is Pt, and its precursor is tetraammine platinum nitrate;

[0022] Preferably, the calcination temperature in step (10) is 300-500° C. and the calcination time is 3-10 h.

[0023] The second aspect of the present invention discloses a flaky FAU molecular sieve catalyst prepared by the preparation method.

[0024] The third aspect of the present invention discloses the use of the flaky FAU molecular sieve catalyst in the catalytic reaction of one-step hydrogenation conversion of polycyclic aromatic hydrocarbons to synthesize high-density endothermic aviation fuel.

[0025] Preferably, the one-step hydrogenation conversion of polycyclic aromatic hydrocarbons to synthesize high-density endothermic aviation fuel catalytic reaction comprises the following steps:

[0026] (A) FAU molecular sieve catalyst in a flaky form is made into particles of 30-40 mesh; generally, the particles are pressed into particles of 30-40 mesh under a certain pressure, such as 10 MPa;

[0027] (B) loading the catalyst particles obtained in (A) into a stainless steel reaction tube of a fixed bed reactor, fixing the catalyst particles in the middle of the stainless steel reaction tube with quartz wool, filling the remaining part of the reaction tube with silicon carbide, and then installing it on the fixed bed reactor;

[0028] (C) Performing a leak test on the fixed bed reactor; generally, nitrogen is used to adjust the pressure of the fixed bed reactor to 50 bar for leak test. If there is no significant change in the pressure of the fixed bed reactor within 0.5 h, it indicates that the sealing of the device is good;

[0029] (D) using hydrogen to stabilize the reactor pressure at 20-80 bar, adjusting the hydrogen flow rate to 100-300 mL / min, raising the temperature to 300-500° C. for reduction for 2-6 h; preferably, the pressure is 40 bar, the hydrogen flow rate is 100-200 mL / min, and the reduction temperature is 450° C.;

[0030] (E) preparing a polycyclic aromatic hydrocarbon reaction raw material and dissolving the polycyclic aromatic hydrocarbon in an alkane solvent;

[0031] (F) adding the polycyclic aromatic hydrocarbon solution of step (E) to the fixed bed reactor of step (D), adjusting the reaction conditions as follows: reaction pressure of 20-80 bar, reaction temperature of 150-300° C., hydrogen-to-oil ratio of 200-800 NmL / mL, feed mass space velocity (WHSV) of the raw material of 5-50 h -1 ;

[0032] (G) After the catalytic reaction reaches a steady state, the liquid product after the reaction is collected (F), which is a high-density endothermic aviation fuel. Due to the complexity of the hydrogenation products, Shimadzu comprehensive two-dimensional gas chromatography (GC×GC-MS / FID, Shimadzu QP2010Ultra) is used to perform qualitative and quantitative analysis of the products.

[0033] Preferably, the polycyclic aromatic hydrocarbons are one or more of fluorene, phenanthrene, anthracene or their alkyl substitutes, and the alkane solvent is one or more of decahydronaphthalene, cyclohexane, octane, hexane and heptane; preferably, the alkane solvent is octane.

[0034] Beneficial effects of the present invention:

[0035] The preparation method of the present invention adopts a soft template agent and loads active metals by an enhanced strong electrostatic adsorption method to successfully prepare a flaky FAU molecular sieve catalyst. The flaky FAU molecular sieve catalyst of the present invention has a rich two-dimensional flaky layered structure on its surface, which is used for the catalytic reaction of synthesizing high-density endothermic aviation fuel by one-step hydrogenation conversion of polycyclic aromatic hydrocarbons, and can provide more reaction sites for the reaction of polycyclic aromatic hydrocarbons, and promote the diffusion of large molecular polycyclic aromatic hydrocarbons and inhibit cracking. Compared with traditional FAU molecular sieves, the flaky FAU molecular sieve catalyst prepared by the present invention significantly improves the yield of high-density endothermic aviation fuel. The flaky FAU molecular sieve catalyst Pt / MY in the embodiment of the present invention presents a PSA yield of 43.3wt% and an SRO yield of 18.0wt%, which is significantly better than the PSA yield (37.8wt%) and SRO yield (14.8wt%) obtained by the Pt / TY catalyst used in the comparative example. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 X-ray crystal diffraction patterns (XRD) of the flaky FAU molecular sieve (MY) prepared in the example and the conventional FAU molecular sieve (TY) in the comparative example.

[0037] Figure 2 Scanning electron microscopy (SEM) images of TY (a and b) and MY (c and d) molecular sieves.

[0038] Figure 3 This is a diagram of the fixed bed reactor apparatus.

[0039] Figure 4Schematic diagram of the one-step hydrogenation reaction pathway of the polycyclic aromatic hydrocarbon phenanthrene.

[0040] Figure 3 The figures in the figure are marked as: 1: feed tank, 2: electronic balance, 3: filter, 4: high pressure liquid chromatography pump, 5: mass flow meter, 6: safety valve, 7: heating furnace, 8: temperature sensor, 9: condenser, 10: gas-liquid separator, 11: pressure sensor, 12: back pressure valve, 13: wet anti-corrosion gas flow meter, 14: waste liquid tank, 15: computer. DETAILED DESCRIPTION

[0041] In order to make the purpose and technical scheme of the present invention clearer, detailed description is given in conjunction with the following examples, which are intended to illustrate the content of the present invention rather than to further limit the scope of protection of the present invention. The process, conditions, reagents, experimental methods, etc. implemented, except for the content specifically mentioned below, are common knowledge and common common sense in the art, and the present invention has no special restrictions. The experimental methods for which specific conditions are not indicated in each embodiment are usually in accordance with conventional conditions or according to the conditions recommended by the manufacturer. Unless otherwise indicated, the meanings of all professional terms and scientific terms used in this specification are the same as those generally understood by technicians in the technical field to which the present invention belongs. However, in case of conflict, the present specification including the definition shall prevail.

[0042] Example: Preparation of flaky FAU molecular sieve catalyst and method for one-step hydrogenation conversion of polycyclic aromatic hydrocarbon phenanthrene to synthesize high-density endothermic aviation fuel, the steps are as follows:

[0043] (1) Weigh 22.50g of sodium silicate solution, 6.26g of sodium aluminate, 3.01g of sodium hydroxide and 93.12g of water in a three-necked flask equipped with a mechanical stirrer and mix them evenly. Stir in a 30°C water bath for 2h. Use a constant pressure dropping funnel to drop 2.35g of N,N-dimethyl-N-[3-(trimethoxysilyl)propyl] octadecyl ammonium chloride reagent, then continue to stir and age in a 30°C water bath for 24h, then transfer to a hydrothermal crystallization reactor, place in an oven, and statically crystallize at 85°C for 96h. After the crystallization is completed, the crystallization reactor is naturally cooled to room temperature, the solid product is separated, and the sample is washed with ultrapure water until it is neutral. The washed sample is transferred to an oven and dried at 120°C for 12h. Finally, it is placed in a muffle furnace and heated to 550°C at a rate of 1°C / min and calcined for 6h to obtain a synthesized flaky FAU molecular sieve.

[0044] (2) Weigh 0.072g of tetraammine platinum nitrate and dissolve it in water to prepare a metal precursor solution. Then, add ammonia water dropwise to adjust the pH of the solution to 11.5. Stir for 2.0h. After the pH stabilizes, add 2.0g of the synthesized flaky FAU molecular sieve. Stir vigorously for 0.5h and then ultrasonically treat for 0.5h. Then, vacuum dry it in a drying oven at 80℃ for 12h, then place it in a muffle furnace and heat it to 450℃ at a rate of 1℃ / min and calcine it for 4h. The obtained solid is a highly dispersed flaky FAU molecular sieve catalyst, recorded as Pt / MY. Finally, a powder tablet press is used to press the synthesized Pt / MY catalyst into 30-40 mesh particles.

[0045] (3) Weigh 1g of the compressed 30-40 mesh Pt / MY catalyst and load it into the stainless steel reaction tube of the fixed bed reactor. Fill the two ends with quartz wool and silicon carbide in turn, and then install it into the fixed bed reactor. After checking the sealing with nitrogen, pressurize the device to 40 bar with hydrogen, and set the hydrogen flow rate to 200mL / min. Then, turn on the temperature rise, and activate the catalyst by in-situ reduction at 450℃ for 4h.

[0046] (4) After the catalyst reduction is completed, the temperature of the heating furnace is lowered to the catalytic reaction temperature, and the hydrogen flow rate is set to 100 mL / min. The high-pressure liquid phase feed pump is turned on to feed the reaction raw material polycyclic aromatic hydrocarbon phenanthrene into the reaction tube for catalytic reaction. The solvent is octane, and the weight hourly space velocity is 8.4 h -1 After the reaction stabilized, the liquid product was separated into gas and liquid and collected through the sampling port, and then analyzed by Shimadzu comprehensive two-dimensional gas chromatography.

[0047] Comparative Example:

[0048] In order to highlight the excellent properties of the highly dispersed flaky FAU molecular sieve catalyst prepared in the example in the one-step hydrogenation conversion of polycyclic aromatic hydrocarbons to synthesize high-density endothermic aviation fuel; this comparative example synthesized a traditional FAU molecular sieve carrier as a comparison, and the molecular sieve synthesis steps and catalytic reaction evaluation are as follows.

[0049] (1) Weigh 22.50g of sodium silicate solution, 6.26g of sodium aluminate, 3.01g of sodium hydroxide and 93.12g of water in a three-necked flask equipped with a mechanical stirrer and mix them evenly. Stir and age them in a 30°C water bath for 24h, then transfer them to a hydrothermal crystallization reactor, place them in an oven, and statically crystallize them at 85°C for 96h. After the crystallization, the crystallization reactor is naturally cooled to room temperature, the solid product is separated, and the sample is washed with ultrapure water until it is neutral. The washed sample is transferred to an oven and dried at 120°C for 12h, and finally placed in a muffle furnace and heated to 550°C at a rate of 1°C / min for calcination for 6h to obtain the synthesized traditional FAU molecular sieve.

[0050] (2) Weigh 0.072g of tetraammine platinum nitrate and dissolve it in water to prepare a metal precursor solution. Then, add ammonia water dropwise to adjust the pH of the solution to 11.5. Stir for 2.0h. After the pH stabilizes, add 2.0g of the synthesized traditional FAU molecular sieve. Stir vigorously for 0.5h and then ultrasonically treat for 0.5h. Then, vacuum dry it in a drying oven at 80℃ for 12h, put it in a muffle furnace and heat it to 450℃ at a rate of 1℃ / min for 4h, which is the synthesized highly dispersed traditional FAU molecular sieve catalyst, recorded as Pt / TY. Finally, use a powder tablet press to press the synthesized Pt / TY catalyst into 30-40 mesh particles.

[0051] (3) Weigh 1g of the compressed 30-40 mesh Pt / TY catalyst and load it into the stainless steel reaction tube of the fixed bed reactor. Fill the two ends with quartz wool and silicon carbide in turn, and then install it into the fixed bed reactor. After checking the sealing with nitrogen, pressurize the device to 40 bar with hydrogen, and set the hydrogen flow rate to 200mL / min. Then, turn on the temperature rise, and activate the catalyst by in-situ reduction at 450℃ for 4h.

[0052] (4) After the catalyst reduction is completed, the temperature of the heating furnace is lowered to the catalytic reaction temperature, and the hydrogen flow rate is set to 100 mL / min. The high-pressure liquid phase feed pump is turned on to feed the reaction raw material polycyclic aromatic hydrocarbon phenanthrene into the reaction tube for catalytic reaction. The solvent is octane, and the weight hourly space velocity is 8.4 h -1 After the reaction stabilized, the liquid product was separated into gas and liquid and collected through the sampling port, and then analyzed by Shimadzu comprehensive two-dimensional gas chromatography.

[0053] Figure 1 The X-ray crystal diffraction patterns (XRD) of the flaky FAU molecular sieve (MY) prepared in the example and the conventional FAU molecular sieve (TY) in the comparative example are shown in FIG. Figure 1 It can be seen that TY and MY molecular sieves exhibit obvious characteristic diffraction peaks at 6.2°, 10.1°, 11.9°, 15.6°, 18.7°, 20.3°, 23.6°, 27.0° and 31.4°, which correspond to the (111), (220), (311), (331), (511), (440), (533), (642) and (555) crystal planes of FAU topology, respectively, indicating that TY and MY molecular sieves with FAU topology have been successfully synthesized. In addition, it can be seen from the figure that the crystallinity of MY molecular sieve is lower than that of TY molecular sieve, which is due to the rich mesoporous structure in MY molecular sieve, resulting in a decrease in the crystallinity of the molecular sieve.

[0054] Figure 2 Figure 2 is the scanning electron microscope (SEM) image of TY (a and b) and MY (c and d) molecular sieves. Figure 2It can be seen that the traditional TY molecular sieve exhibits a typical faujasite morphology with an average particle size of 5.2 μm; while the flaky MY molecular sieve presents a spherical morphology with an average particle size of 4.9 μm, and an obvious two-dimensional layered stacked flaky morphology can be observed on the surface of the molecular sieve crystal, proving that the embodiment successfully synthesized the flaky MY molecular sieve, and the two-dimensional layered stacked structure on the surface of the flaky MY molecular sieve has a larger surface area and mesoporous structure, which provides more reaction sites for the hydrogenation conversion of polycyclic aromatic hydrocarbons, can significantly promote the diffusion of large molecular polycyclic aromatic hydrocarbons, and thus presents more excellent catalytic performance.

[0055] Table 1 shows the quantitative data of the acid sites of Pt / TY and Pt / MY catalysts. The flake Pt / MY catalyst exhibits a reduced total acid content of 1.269 mmol / g, which is beneficial for suppressing the degree of cracking of the polycyclic aromatic hydrocarbons hydroconversion products, thereby increasing the yield of high-density endothermic aviation fuel components.

[0056] Table 1 Quantitative data of acid sites of Pt / TY and Pt / MY catalysts

[0057]

[0058] The Pt / TY and Pt / MY catalysts obtained in the examples and comparative examples were used for the catalytic reaction of one-step hydrogenation conversion of polycyclic aromatic hydrocarbons to synthesize high energy density endothermic aviation fuel. The reaction was carried out in a fixed bed reactor. Figure 3 The fixed bed reactor device is shown in Figure 1. The fixed bed reactor device consists of four parts: I. Feed system; II. Reaction system; III. Sampling system; IV. Control system. Hydrogen and polycyclic aromatic hydrocarbons are fed into the reaction system through the feed system for catalytic reaction. After the reaction, they flow into the sampling system for sampling and analysis. The reaction temperature and pressure are adjusted by the control system. Figure 3 In the figure, 1: feed tank, 2: electronic balance, 3: filter, 4: high pressure liquid chromatography pump, 5: mass flow meter, 6: safety valve, 7: heating furnace, 8: temperature sensor, 9: condenser, 10: gas-liquid separator, 11: pressure sensor, 12: back pressure valve, 13: wet anti-corrosion gas flow meter, 14: waste liquid tank, 15: computer.

[0059] A fixed bed reactor was used with a reaction pressure of 40 bar, a hydrogen-to-oil ratio of 500 NmL / mL, and a weight hourly space velocity of 8.4 h -1 Under the reaction conditions, high-density endothermic aviation fuel is synthesized by one-step hydrogenation conversion using polycyclic aromatic hydrocarbon phenanthrene as raw material and octane as solvent. Figure 4 The schematic diagram of the one-step hydrogenation reaction pathway of the polycyclic aromatic hydrocarbon phenanthrene is shown in Figure 1. Figure 4It can be seen that the hydrogenation conversion products of polycyclic aromatic hydrocarbons phenanthrene are very complex; in the one-step hydrogenation conversion reaction of phenanthrene (PHE), PHE will first be hydrogenated to form perhydrophenanthrene (PHP), and then PHP will further isomerize to form skeletal isomerization products (PSI), and then PSI will undergo hydrogenation isomerization, skeletal rearrangement and selective ring opening reactions to form alkyl adamantane (PSA) and selective ring opening products (SRO). PSA and SRO are high-density endothermic aviation fuel components with better performance.

[0060] Table 2 shows the yield of high energy density aviation fuel synthesized by one-step hydrogenation of polycyclic aromatic hydrocarbon phenanthrene using conventional Pt / TY catalyst obtained in comparative example using fixed bed reactor. Reaction conditions: pressure 40 bar, temperature 210-230℃, hydrogen-to-oil ratio 500 NmL / mL, weight hourly space velocity 8.4 h -1 , the solvent is n-octane. Under the reaction conditions adopted, the conversion rate of phenanthrene reaches 100%. At a low temperature of 210°C, the yield of alkyl adamantane (PSA) is 19.2wt%, and the yield of selective ring-opening product (SRO) is 10.1wt%. As the reaction temperature increases, the yields of PSA and SRO increase accordingly, and the highest PSA yield of 37.8wt% and SRO yield of 14.8wt% are shown at 220°C. As the reaction temperature further increases, the yields of PSA and SRO decrease significantly, which is because the excessively high reaction temperature promotes the cracking reaction.

[0061] Table 2 One-step hydrogenation conversion of polycyclic aromatic hydrocarbons catalyzed by Pt / TY catalyst

[0062]

[0063] Table 3 shows the situation of one-step hydrogenation conversion of polycyclic aromatic hydrocarbon phenanthrene to high energy density aviation fuel using the thin-flaked Pt / MY catalyst obtained in the example using a fixed bed reactor. Reaction conditions: pressure 40 bar, temperature 200-230°C, hydrogen-to-oil ratio 500 NmL / mL, weight hourly space velocity 8.4 h -1, the solvent is n-octane. It can be seen from Table 3 that under the reaction conditions adopted, the conversion rate of phenanthrene reaches 100%, and the Pt / MY catalyst shows excellent deep hydrogenation catalytic activity. At a low temperature of 210°C, the yield of PSA is as high as 15.9wt%, and the yield of SRO is 12.4wt%; the Pt / MY catalyst shows the highest PSA yield of 43.3wt% and SRO yield of 10.7wt% at 230°C. In addition, under the same temperature conditions, the cracking rate of the Pt / MY catalyst is significantly lower than that of the Pt / TY catalyst in the comparative example, indicating that the flaky Pt / MY catalyst prepared by the present invention can significantly inhibit cracking, improve the yields of PSA and SRO, components of high-density endothermic aviation fuel, and show excellent catalytic performance for the one-step hydrogenation conversion of polycyclic aromatic hydrocarbons to synthesize high-density endothermic aviation fuel.

[0064] Table 3 One-step hydrogenation conversion of polycyclic aromatic hydrocarbons catalyzed by Pt / MY catalyst

[0065]

[0066] The embodiments are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. Application of a flaky FAU molecular sieve catalyst in the catalytic reaction of one-step hydrogenation conversion of polycyclic aromatic hydrocarbons to synthesize high-density endothermic aviation fuel, characterized in that: The preparation method of the catalyst comprises the following steps: (1) Evenly mix a certain amount of silicon source, aluminum source, alkali source and water; (2) Weighing a soft template agent and adding it dropwise to the solution obtained in (1) using a constant pressure dropping funnel, and mixing at a certain temperature for a period of time; The soft template is N,N-dimethyl-N-[3-(trimethoxysilyl)propyl] dodecyl ammonium chloride; (3) crystallizing the mixed solution obtained in (2) at 85°C for 96 hours; (4) separating the crystallized mixture from (3) to obtain a solid, and drying it at a certain temperature for a period of time; (5) calcining the solid obtained in (4) at a certain temperature for a period of time to obtain a solid powder, which is a flaky FAU molecular sieve having a spherical morphology; (6) Measure the saturated water absorption of the obtained thin-sheet FAU molecular sieve, repeat the measurement three times, and take the average value; (7) preparing an active metal precursor solution, using water as a solvent, wherein the mass of water in the active metal precursor solution is equal to the saturated water absorption capacity of the thin-flaky FAU molecular sieve carrier used; The pH of the active metal precursor solution is adjusted to 9-13 by using ammonia water; the active metal content in the active metal precursor solution is 0.02-6.00wt%; (8) using an electrostatic adsorption method to load the active metal in the active metal precursor solution in (7) onto the flaky FAU molecular sieve; (9) subjecting the sample obtained after electrostatic adsorption in (8) to ultrasonic treatment for a period of time, and then drying it at a certain temperature for a period of time; (10) calcining the solid sample obtained in (9) at a certain temperature for a period of time to obtain a highly dispersed flaky FAU molecular sieve catalyst; The one-step hydrogenation conversion of polycyclic aromatic hydrocarbons to synthesize high-density endothermic aviation fuel catalytic reaction comprises the following steps: (A) FAU molecular sieve catalyst in the form of flakes is made into particles of 30-40 mesh; (B) loading the catalyst particles obtained in (A) into a stainless steel reaction tube of a fixed bed reactor, fixing the catalyst particles in the middle of the stainless steel reaction tube with quartz wool, filling the remaining part of the reaction tube with silicon carbide, and then installing it on the fixed bed reactor; (C) Conducting leak detection on fixed bed reactors; (D) Using hydrogen to stabilize the reactor pressure at 40 bar, adjusting the hydrogen flow rate to 200 mL / min, and raising the temperature to 450 °C for reduction for 4 h; (E) preparing phenanthrene, a polycyclic aromatic hydrocarbon reaction raw material, and dissolving the polycyclic aromatic hydrocarbon raw material in octane, an alkane solvent; (F) Adding the polycyclic aromatic hydrocarbon solution of step (E) into the fixed bed reactor of step (D), adjusting the reaction conditions to: reaction pressure of 40 bar, reaction temperature of 230° C., hydrogen-to-oil ratio of 500 NmL / mL, and feed mass space velocity of the raw material of 8.4 h -1 ; (G) After the catalytic reaction reaches a steady state, the liquid product after the reaction is collected (F), which is a high-density endothermic aviation fuel.

2. The use according to claim 1, characterized in that: In step (1), the silicon source is one or more of sodium silicate, methyl orthosilicate, fumed silica, ethyl orthosilicate, or silica sol; the aluminum source is one or more of sodium aluminate, aluminum sulfate, aluminum nitrate, boehmite, and aluminum isopropoxide; and the alkali source is one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate.

3. The use according to claim 1, characterized in that: The calcination temperature of step (5) is 450-600°C and the calcination time is 3-10h.

4. The use according to claim 1, characterized in that: The active metal in step (7) is one or more of Pt, Pd, Ir, Ru, Rh, Au, Ni, Cu, Zn, Co, and Fe.

5. The use according to claim 1, characterized in that: The calcination temperature in step (10) is 300-500°C and the calcination time is 3-10h.

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