Hydrocracking process for producing aviation kerosene using a catalyst containing a beta-type molecular sieve and a shape-selective molecular sieve catalyst

Abstract

This invention relates to the field of aviation fuel production and discloses a hydrocracking method for producing aviation kerosene using a Beta-type molecular sieve catalyst and a shape-selective molecular sieve catalyst. The method includes: (1) reacting hydrogen and kerosene fractions with a first hydrocracking catalyst at a temperature not lower than 260°C to obtain a first product, wherein the first hydrocracking catalyst comprises a first support and a first metal component, the first support containing a Beta-type molecular sieve and the first metal component being a Group VIB metal component; reacting the first product with a second hydrocracking catalyst to undergo a second hydrocracking reaction, wherein the second hydrocracking catalyst comprises a second support and a second metal component; wherein the density of the diesel fraction is 0.81-0.90 g / cm³. 3 The distillation range is 160–360℃; the organic nitrogen content is less than 50 μg / g. High-density aviation kerosene can be prepared using this method.

Description

Technical Field

[0001] This invention relates to the field of aviation fuel production, and more specifically to a hydrocracking method for producing aviation kerosene using a Beta-type molecular sieve catalyst and a shape-selective molecular sieve catalyst. Background Technology

[0002] High-density jet fuel, also known as high-density kerosene, is characterized by its high density and high volumetric calorific value. This contrasts with conventional jet fuel (whose commercial density is typically 0.77-0.81 g / cm³). 3 Compared to other fuels, this method can improve driving range and has heat-absorbing stability, showing broad application prospects. GJB1603-93 specifies fuel standards applicable to high-speed turbine engines, with a density of 0.835 g / cm³. 3 The flash point is even higher.

[0003] Existing technologies mainly prepare it through hydrorefining of cycloalkyl kerosene fractions, hydrocracking of high-density secondary processed diesel fractions, and hydrocracking of cycloalkyl VGO fractions.

[0004] In 1985, the Qilu Petrochemical Research Institute conducted laboratory research on high-density aviation kerosene. Using kerosene fractions from isolated naphthenic feedstock as raw materials, they carried out high-pressure hydrorefining experiments and obtained high-density aviation kerosene. However, due to the limitation of raw materials, the density was only 0.835–0.837 g / cm³. 3 .

[0005] The University of Pennsylvania (PSU) has developed and successfully developed JP900 aviation fuel, which contains a high content of aromatic and cycloalkanes (cyclic hydrocarbons) in coal. The aromatics in this fuel have been converted into cycloalkanes, exhibiting high stability. Furthermore, these cycloalkanes act as stabilizers, significantly inhibiting fuel decomposition. Experiments show that this coal-based fuel meets all the technical specifications of current jet fuels and has a significant advantage: it remains stable for extended periods at 900°F (482°C) without producing carbon deposits that clog valves, nozzles, or other parts. Therefore, it is also called JP900. This jet fuel not only serves as a power source for aircraft but also has a high heat capacity, allowing it to absorb a large amount of heat generated by the engine without significantly increasing its own temperature, thus effectively cooling the engine. This plays a positive role in promoting the development of advanced turbine engines (VAATE) for fifth-generation fighter jets.

[0006] Current research mainly focuses on producing high-density jet fuel from secondary-processed low-quality coal and diesel fractions. However, increasingly stringent requirements on the blending ratio of secondary fractions and the pressure rating of jet fuel hydrogenation units are significantly limiting these technologies.

[0007] Therefore, developing a new process to obtain high-density aviation fuel will have broad application value. Summary of the Invention

[0008] The purpose of this invention is to overcome the problems existing in the prior art and provide a method for producing aviation kerosene using a Beta-type molecular sieve catalyst and a shape-selective molecular sieve catalyst. This method yields high-density aviation fuel.

[0009] To achieve the above objectives, a first aspect of the present invention provides a method for producing aviation kerosene, the method comprising:

[0010] (1) Hydrogen and diesel fractions are subjected to a first hydrocracking reaction with a first hydrocracking catalyst at a temperature of not less than 260°C to obtain a first product. The first hydrocracking catalyst includes a first support and a first metal component supported on the first support. The first support contains a Beta-type molecular sieve and the first metal component is a Group VIB metal component.

[0011] (2) The first product obtained in step (1) is subjected to a second hydrocracking reaction with a second hydrocracking catalyst. The second hydrocracking catalyst includes a second support and a second metal component supported on the second support. The second support contains an MFI type molecular sieve, and the second metal component includes group VIB and group VIII metal components.

[0012] The density of the diesel fraction is 0.81-0.90 g / cm³. 3 The distillation range is 160-360℃.

[0013] The organic nitrogen content of the diesel fraction is less than 50 μg / g.

[0014] The beneficial effects of the present invention through the above technical solution include:

[0015] The method provided by this invention uses a low-NOx diesel fraction with relatively low density and a low distillation range for a secondary continuous hydrocracking reaction. In the hydrocracking process, a first hydrocracking catalyst containing a first support with a Beta-type molecular sieve and a single metal active component is rationally graded, and a second hydrocracking catalyst containing a second support with an MFI-type molecular sieve and a bimetallic active component is used. The temperature of the first hydrocracking reaction is controlled to be no less than 260°C, so as to obtain aviation kerosene with higher density as described in this invention.

[0016] The method of this invention adopts a two-stage series hydrocracking process, which is highly flexible in operation. It can be achieved by setting different hydrocracking reaction zones on the existing hydrocracking reactor, or by adding another hydrocracking reactor. The operation process is simple, and it can save investment costs and is easy to modify. Detailed Implementation

[0017] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0018] In this invention, the density of the diesel fraction is the density at 20°C.

[0019] In this invention, the dry basis of a substance refers to the solid product obtained by calcining the substance at 600°C for 3 hours.

[0020] In this invention, "optional" means not necessary, and can be understood as containing or not containing, adding or not adding, or using or not using.

[0021] The first aspect of this invention provides a method for producing aviation kerosene, the method comprising:

[0022] (1) Hydrogen and diesel fractions are subjected to a first hydrocracking reaction with a first hydrocracking catalyst at a temperature of not less than 260°C to obtain a first product. The first hydrocracking catalyst includes a first support and a first metal component supported on the first support. The first support contains a Beta-type molecular sieve and the first metal component is a Group VIB metal component.

[0023] (2) The first product obtained in step (1) is subjected to a second hydrocracking reaction with a second hydrocracking catalyst. The second hydrocracking catalyst includes a second support and a second metal component supported on the second support. The second support contains an MFI type molecular sieve, and the second metal component includes group VIB and group VIII metal components.

[0024] The density of the diesel fraction is 0.81-0.90 g / cm³. 3 The distillation range is 160-360℃.

[0025] The organic nitrogen content of the diesel fraction is less than 50 μg / g.

[0026] Preferably, the diesel fraction has a distillation range of 170-330°C.

[0027] In this invention, the organic nitrogen content in the diesel fraction is less than 50 μg / g, preferably less than 20 μg / g. This preferred embodiment is beneficial for improving the smoke point of aviation kerosene.

[0028] The present invention does not particularly limit the source of the diesel fraction feedstock. Any diesel fraction that meets the above requirements is within the scope of the present invention. Diesel fractions that meet the above requirements can be used, or diesel fractions that meet the above requirements can be obtained by conventional methods such as hydrorefining.

[0029] When using conventional methods, the present invention does not impose any particular limitations on the conditions of the conventional methods, in order to obtain a diesel fraction that meets the above requirements.

[0030] In this invention, the reaction temperature of the first hydrocracking reaction is not lower than 260°C, preferably 265-330°C. Using this preferred embodiment, the selectivity of aviation kerosene can be improved in the first cracking reaction, while also resulting in aviation kerosene products with both high density and high smoke point.

[0031] According to the present invention, preferably, the second hydrocracking reaction temperature is 40-200°C higher than the first hydrocracking reaction temperature, more preferably 60-180°C higher. This preferred embodiment is advantageous for improving the selectivity of high-density jet fuel component products.

[0032] According to some embodiments of the present invention, the first hydrocracking catalyst includes a first support and a first metal component supported on the first support, wherein the first support contains a Beta-type molecular sieve, and the first metal component is a Group VIB metal component. Preferably, to obtain the target product of the present invention, the first hydrocracking catalyst does not contain a Group VIII metal component. In this preferred embodiment, the first hydrocracking catalyst uses a single-metal hydrocracking component, combined with a support containing a Beta-type molecular sieve, which is beneficial for improving the selectivity of converting heavy fractions in the feed into jet fuel.

[0033] According to the present invention, preferably, based on the dry weight of the first hydrocracking catalyst, the content of the first metal component in the first hydrocracking catalyst, calculated as oxide, is 5-30% by weight, preferably 10-25% by weight.

[0034] According to the present invention, preferably, based on the dry weight of the first hydrocracking catalyst, the content of the first support in the first hydrocracking catalyst, on a dry basis, is 70-95% by weight, preferably 75-90% by weight.

[0035] In the first hydrocracking catalyst, the sum of the contents of each component is 100%.

[0036] In this invention, the Group VIB metal component can be a conventional choice in the art. Preferably, the Group VIB metal component is Mo and / or W, more preferably W. This preferred embodiment is advantageous in improving the selectivity of converting heavy fractions in the feed into jet fuel products.

[0037] According to the present invention, preferably, the SiO2 / Al2O3 molar ratio of the Beta-type molecular sieve is 10-300, more preferably 20-150.

[0038] According to the present invention, preferably, the specific surface area of ​​the Beta-type molecular sieve is 150-450 m². 2 / g, preferably 300-450m 2 / g.

[0039] According to the present invention, preferably, the pore volume of the Beta-type molecular sieve is 0.1-0.6 mL / g, more preferably 0.2-0.5 mL / g.

[0040] Using Beta-type molecular sieves with the above characteristics is beneficial to improving the selectivity of converting heavy fractions in the feed into high smoke point jet fuel products.

[0041] According to the present invention, preferably, the first support in the first hydrocracking catalyst further contains heat-resistant inorganic oxides.

[0042] The heat-resistant inorganic oxide described in this invention refers to a porous material with a maximum operating temperature of not less than 600°C. This heat-resistant inorganic oxide can improve the strength of hydrocracking catalysts and improve and regulate their physicochemical properties, such as improving the pore structure of the catalyst.

[0043] This invention allows for a wide range of choices of heat-resistant inorganic oxides, and can employ various commonly used heat-resistant inorganic oxides in the art. Preferably, the heat-resistant inorganic oxide is selected from at least one of silicon oxide, aluminum oxide, and titanium oxide, with aluminum oxide being the most preferred.

[0044] According to the present invention, preferably, based on the total weight of the first carrier, the content of the Beta-type molecular sieve is 35-90% by weight, more preferably 35-80% by weight; and the content of the heat-resistant inorganic oxide is 10-65% by weight, more preferably 20-65% by weight.

[0045] The present invention does not impose any particular limitation on the preparation method of the first hydrocracking catalyst. It can be prepared by conventional methods or obtained by commercial purchase. The present invention does not impose any particular limitation on this.

[0046] In this invention, the second hydrocracking catalyst comprises a second support and a second metal component supported on the second support, wherein the second support contains an MFI-type molecular sieve, and the second metal component comprises Group VIB and Group VIII metal components. In this preferred embodiment, the second hydrocracking catalyst employs a bimetallic hydrocracking component, combined with a support containing an MFI-type molecular sieve, which is beneficial for further improving the smoke point and density of aviation kerosene.

[0047] According to the present invention, preferably, based on the dry weight of the second hydrocracking catalyst, the content of the second metal component in the second hydrocracking catalyst, calculated as oxide, is 5-30% by weight, preferably 10-30% by weight.

[0048] According to the present invention, preferably, the mass ratio of the Group VIB metal component to the Group VIII metal component, based on oxides, is 1:0.05-0.4, more preferably 1:0.08-0.35.

[0049] In this invention, the Group VIB metal component can be a conventional choice in the art. Preferably, the Group VIB metal component is Mo and / or W.

[0050] In this invention, the Group VIII metal component can be a conventional choice in the art. Preferably, the Group VIII metal component is Ni and / or Co.

[0051] According to the present invention, preferably, the second hydrocracking catalyst further contains an additive selected from at least one of phosphorus, fluorine and boron.

[0052] According to the present invention, preferably, the content of the additive, based on the dry basis mass of the second hydrocracking catalyst and calculated as oxides, is 1-8% by weight.

[0053] According to the present invention, preferably, the second hydrocracking catalyst further contains organic additives.

[0054] According to the present invention, preferably, the content of the organic additive is 0.5-15% by weight, based on the total weight of the second hydrocracking catalyst.

[0055] According to the present invention, preferably, the organic additive is selected from at least one of alcohols, carboxylic acids and organic amines.

[0056] The present invention allows for a wide range of carboxylic acid compounds, including various carboxylic acid compounds commonly found in the art. Preferably, the carboxylic acid compound is selected from at least one of acetic acid, maleic acid, oxalic acid, aminotriacetic acid, aminoacetic acid, citric acid, tartaric acid, and malic acid.

[0057] The present invention allows for a wide range of selections of alcohol compounds, including various alcohol compounds commonly found in the art. Preferably, the alcohol compound is selected from at least one of ethylene glycol, glycerol, polyethylene glycol, diethylene glycol, and butanediol.

[0058] The present invention allows for a wide range of selections of the organic amine compounds, including various organic amine compounds commonly found in the art. Preferably, the organic amine compound is selected from at least one of ethylenediamine, diethylenetriamine, cyclohexanediaminetetraacetic acid, ethylenediaminetetraacetic acid, and ammonium ethylenediaminetetraacetate.

[0059] In the second hydrocracking catalyst, the sum of the contents of each component is 100%.

[0060] According to the present invention, preferably, the SiO2 / Al2O3 molar ratio of the MFI type molecular sieve is 15-300, more preferably 20-80.

[0061] According to the present invention, preferably, the specific surface area of ​​the MFI type molecular sieve is 180-650 m². 2 / g, preferably 300-450m 2 / g.

[0062] According to the present invention, preferably, the pore volume of the MFI type molecular sieve is 0.1-0.6 mL / g, more preferably 0.2-0.5 mL / g.

[0063] Using MFI-type molecular sieves with the above characteristics is beneficial for further improving the density of aviation kerosene.

[0064] The present invention has a wide range of choices for the types of MFI molecular sieves. Preferably, the MFI molecular sieve is ZSM-5 molecular sieve.

[0065] According to the present invention, preferably, the second support in the second hydrocracking catalyst further contains a heat-resistant inorganic oxide. Using the heat-resistant inorganic oxide described in this invention can improve the strength of the hydrocracking catalyst and improve and regulate its physicochemical properties, such as improving the pore structure of the catalyst.

[0066] The selection of the type of heat-resistant inorganic oxide in the second carrier of the present invention can be the same as that in the first carrier, and will not be repeated here.

[0067] According to the present invention, preferably, based on the total weight of the second carrier, the content of the MFI type molecular sieve is 40-90% by weight, preferably 50-80% by weight; and the content of the heat-resistant inorganic oxide is 10-60% by weight, preferably 20-50% by weight.

[0068] The present invention does not impose any particular limitation on the preparation method of the above-mentioned second hydrocracking catalyst, as long as the second hydrocracking catalyst with the above composition can be prepared. In order to further improve the catalytic performance of the second hydrocracking catalyst, the present invention also provides a preparation method of the above-mentioned second hydrocracking catalyst.

[0069] According to the present invention, preferably, the preparation method of the second hydrocracking catalyst includes the following steps:

[0070] (a) A second support is prepared by mixing MFI-type molecular sieves with an optional heat-resistant inorganic oxide precursor;

[0071] (b) Introducing a second metal component, optional auxiliaries, and optional organic additives onto the second carrier by impregnation.

[0072] In this invention, the method for preparing the second support described in step (a) is well known to those skilled in the art, and this invention does not impose any particular limitations on it. For example, the method described in step (a) may include: mixing an MFI-type molecular sieve with an optional heat-resistant inorganic oxide precursor, followed by drying and calcination to obtain the second support. The heat-resistant inorganic oxide precursor can be a conventional choice in the art. The molding described in step (a) can be performed using any conventional method in the art, such as tablet molding, ball rolling, or extrusion molding. The drying and calcination conditions described in step (a) can be performed using conventional methods in the art, and this invention does not impose any particular limitations on them.

[0073] The present invention does not impose any particular restrictions on the shape of the second carrier obtained, which can be spherical, strip-shaped (including solid or hollow strips), block-shaped, etc. The strip shape can be clover-shaped, four-leaf clover-shaped, or other multi-leaf clover-shaped and their variants.

[0074] According to the present invention, preferably, step (b) includes: introducing a second metal component, optional auxiliaries, and optional organic additives onto the second carrier by impregnation.

[0075] Preferably, in step (b), the step of introducing the second metal component onto the second carrier by impregnation includes: contacting the second carrier with an impregnation solution containing a second metal precursor, optional auxiliary precursor and optional organic additive, followed by drying and optional calcination.

[0076] In this invention, when introducing the additive, the second metal component and the additive can be introduced together or separately; this invention does not require either. This invention uses the method of joint introduction as an example.

[0077] The present invention does not particularly limit the contact temperature in step (b), and it can be any temperature achievable by the impregnation liquid. There is also no particular limitation on the contact time, as long as the required amount of metal precursor is loaded onto the carrier. Generally, the higher the contact temperature and the greater the concentration of the impregnation liquid, the shorter the time required to achieve the same impregnation amount (i.e., the weight difference between the carrier before and after impregnation); conversely, the lower the contact temperature and the greater the concentration of the impregnation liquid, the shorter the time required; and vice versa. Once the required impregnation amount and conditions are determined, it is easy to select a suitable contact time. The specific operation of the impregnation method is well known to those skilled in the art, and the impregnation method can be a saturated impregnation method or a supersaturated impregnation method. There is no particular limitation on the environment of the impregnation method; it can be carried out under sealed conditions or in an open environment according to conventional methods in the art. Solvent lost during the contact process can be replenished or not. Various gases, such as air, nitrogen, and water vapor, can be introduced during the contact process, or no new components can be introduced.

[0078] The present invention does not impose any particular limitation on the type or amount of solvent in the impregnation solution, and can refer to conventional methods in the art.

[0079] Preferably, the second metal precursor is a soluble compound of the second metal, and is preferably selected from at least one of oxides, inorganic salts, and organic compounds of the second metal. For example, the inorganic salt of the second metal may be selected from at least one of nitrates, carbonates, basic carbonates, hypophosphites, phosphates, sulfates, and chlorides of the second metal. The organic substituent in the organic compound of the second metal may be selected from at least one of hydroxyl, carboxyl, amino, ketone, ether, and alkyl groups.

[0080] The precursor of the adjuvant described in this invention can be any conventionally chosen material in the art, as long as it contains an adjuvant element. For example, a soluble salt of the adjuvant, an inorganic acid of the adjuvant, etc.

[0081] This invention does not impose any particular limitation on the order in which the above-mentioned substances are added during step (b); they can be added together or separately. This invention uses the method of adding them together as an example.

[0082] The drying and calcination described in step (b) are standard steps in catalyst preparation and are not subject to any particular limitations. For example, the drying conditions in step (b) can be: a temperature of 80-350°C, preferably 100-300°C; and a time of 0.5-24 hours, preferably 1-12 hours. The calcination conditions in step (b) can be: a temperature of 350-600°C, preferably 400-550°C; and a time of 0.2-12 hours, preferably 1-10 hours.

[0083] According to the present invention, preferably, the conditions for the first hydrocracking reaction include: a reaction pressure of 10-17 MPa; a reaction temperature of 265-330°C; a hydrogen-to-oil volume ratio of 700-1300:1; and a liquid hourly space velocity of 0.5-4 h⁻¹. -1 .

[0084] According to the present invention, preferably, the conditions for the second hydrocracking reaction include: a reaction pressure of 10-17 MPa; a reaction temperature of 330-430°C; a hydrogen-to-oil volume ratio of 700-1300:1; and a liquid hourly space velocity of 0.5-4 h⁻¹. -1 .

[0085] In this invention, the first hydrocracking catalyst and the second hydrocracking catalyst can be loaded into different reaction zones of the same reactor or into different reactors, depending on the actual situation. This invention does not have any particular limitation on this.

[0086] The hydrocracking reaction described in this invention can be carried out in any reactor that allows the hydrocarbon feedstock to react with the catalyst under hydrogenation reaction conditions, such as a fixed-bed reactor, a moving-bed reactor, a fluidized-bed reactor, or a slurry-bed reactor. This invention does not have any particular limitation in this regard.

[0087] Preferably, the products of the second hydrocracking reaction are separated to obtain aviation kerosene. Specific separation methods can be found in accordance with conventional methods used by those skilled in the art, such as fractional distillation, which will not be detailed here.

[0088] Preferably, the first and second hydrocracking catalysts are pre-sulfurized before use.

[0089] The present invention does not impose any particular limitation on the specific conditions for pre-vulcanization, and can refer to the methods commonly used in the art.

[0090] The pre-vulcanization described in this invention can be carried out outside the apparatus or in situ inside the apparatus to convert it into a sulfide form.

[0091] According to the present invention, preferably, the density of the aviation kerosene product is higher than 835 kg / m³. 3 The preferred value is 836-845 kg / m³. 3 .

[0092] According to the present invention, preferably, the smoke point of the aviation kerosene product is greater than 20 mm, and more preferably 21-25 mm.

[0093] According to the present invention, preferably, based on the total mass of the aviation kerosene product, the mass content of bicyclic and polycyclic aromatic hydrocarbons in the aviation kerosene product is less than 2%, and more preferably less than 1.5%.

[0094] It should be noted that when the smoke point of aviation kerosene is greater than 20 mm and the mass content of bicyclic and higher aromatic hydrocarbons is within the range described in this invention, it meets the existing application requirements for aviation kerosene.

[0095] Compared with existing aviation kerosene products, the aviation kerosene product obtained by the present invention has the advantage of high density. When used as jet fuel, it can improve the driving range and has broad application prospects.

[0096] The present invention will be described in detail below through embodiments.

[0097] In the following examples, the properties of aviation kerosene were tested according to the standard method of GB 6537-2018;

[0098] The pore volume and specific surface area of ​​the molecular sieve were determined using an ASAP 2400 automatic adsorption analyzer from Micromertics Instruments, USA, via the static low-temperature adsorption capacity method (according to the national standard GB / T5816-1995). The specific method was as follows: the sieve was degassed under vacuum at 250℃ and 1.33 Pa for 4 hours, and nitrogen was used as the adsorbate. The sieve was then contacted with the adsorbate at -196℃ until static adsorption equilibrium was reached. The amount of nitrogen adsorbed by the adsorbent was calculated from the difference between the amount of nitrogen introduced and the amount remaining in the gas phase after adsorption. The pore size distribution was then calculated using the BJH formula, and the specific surface area and pore volume were calculated using the BET formula.

[0099] The crystal structure of the molecular sieve was determined using a Siemens D5005 X-ray diffractometer, according to the industry standard SH / T0339-92. Experimental conditions: Cu target, Ka radiation, solid-state detector, tube voltage 40 kV, tube current 40 mA, step scan, step size 0.02°, pre-set time 2 s, scan range 5°–70°. The diffraction angle position refers to the 2θ angle value of the highest peak value.

[0100] The silicon and aluminum contents of the molecular sieve were determined using a Rigaku Electric Industries, Ltd. 3271E X-ray fluorescence spectrometer. The determination method was as follows: powder sample was pressed into a pellet, rhodium target was used, laser voltage was 50kV, laser current was 50mA, scintillation counter and proportional counter were used to detect the intensity of the spectral lines of each element, and the element content was quantitatively and semi-quantitatively analyzed by external standard method.

[0101] The content of each component of the catalyst is calculated by the amount of feed.

[0102] Example 1

[0103] Boehmite (produced by Sinopec Catalyst Changling Branch, trade name PB90, 68 wt% on dry basis) and Beta molecular sieve (85 wt% on dry basis, specific surface area 415 m²) were compared. 2The mixture (containing a silicon-aluminum molar ratio of 26 and a pore volume of 0.38 mL / g) was extruded into trilobal strips with an outer circle diameter of 1.6 mm, dried at 120 °C for 3 h, and calcined at 600 °C for 3 h to obtain the first support. The first support was impregnated with 152 mL of an aqueous solution containing ammonium metatungstate, dried at 120 °C for 3 h, and calcined at 480 °C for 4 h to obtain the first hydrocracking catalyst C-Beta-1. Its composition is shown in Table 1.

[0104] Boehmite (produced by Sinopec Catalyst Changling Branch, trade name PB90, 71 wt%) was compared with ZSM-5 molecular sieve (dry basis 95 wt%, specific surface area 332 m²). 2 The mixture (containing silicon and aluminum in a molar ratio of 30 and a pore volume of 0.32 mL / g) was extruded into trilobal strips with an outer diameter of 1.6 mm, dried at 120 °C for 3 h, and calcined at 600 °C for 3 h to obtain the second support. At room temperature, the second support prepared by the aforementioned method was impregnated with a 75 mL aqueous solution containing 51% molybdenum oxide and nickel oxide (basic nickel carbonate), 61% phosphoric acid (phosphoric acid), and citric acid, and dried at 120 °C for 3 h to obtain the second hydrocracking catalyst C-MFI-1. Its composition is shown in Table 1.

[0105] Hydrocracking activity tests were conducted on a fixed-bed reactor using diesel fraction-1 feedstock as described in Table 2. Along the feed stream direction, C-Beta-1 and C-MFI-1 were sequentially placed in two reactors for two separate hydrocracking reactions. Before use, the catalysts underwent programmed temperature sulfidation: using straight-run kerosene containing 2% dimethyl disulfide as the sulfiding oil, the temperature was increased from 110°C to 230°C at a rate of 20°C / h and held for 6 hours; then increased to 360°C at a rate of 20°C / h and held for 6 hours.

[0106] The C-Beta-1 and C-MFI-1 catalysts were loaded in a volume ratio of 1.5, the reaction pressure was 10.5 MPa, the hydrogen-to-oil volume ratio was 750, and the liquid hourly space velocity was 1.5 h⁻¹. -1 The first hydrocracking reaction was carried out at a temperature of 280℃, and the second hydrocracking reaction was carried out at a temperature of 380℃. The product of the second hydrocracking reaction was fractionated to obtain jet fuel fraction (180-295℃). The jet fuel fraction in the product oil was analyzed, and the results are shown in Table 3.

[0107] Example 2

[0108] Boehmite (68 wt% on dry basis) and Beta molecular sieve (85 wt% on dry basis, specific surface area 360 m²) were mixed. 2The mixture (containing silicon and aluminum in a molar ratio of 120 and a pore volume of 0.45 mL / g) was extruded into trilobal strips with an outer circle diameter of 1.6 mm, dried at 120 °C for 3 h, and calcined at 600 °C for 3 h to obtain the first support. 200 g of the first support was impregnated with 152 mL of an aqueous solution containing ammonium metatungstate, dried at 120 °C for 3 h, and calcined at 480 °C for 4 h to obtain the first hydrocracking catalyst C-Beta-2. Its composition is shown in Table 1.

[0109] Boehmite (71 wt%) was mixed with ZSM-5 molecular sieve (95 wt% on dry basis, specific surface area 401 m²). 2 The mixture (containing silicon and aluminum in a molar ratio of 70 and a pore volume of 0.38 mL / g) was extruded into trilobal strips with an outer circle diameter of 1.6 mm, dried at 120 °C for 3 h, and calcined at 600 °C for 3 h to obtain the second support. At room temperature, a 75 mL aqueous solution containing 51% molybdenum oxide and nickel oxide (basic nickel carbonate), 61% phosphoric acid (phosphoric acid), and citric acid was completely dissolved and impregnated with the second support prepared by the aforementioned method. The solution was then dried at 120 °C for 3 h to obtain the second hydrocracking catalyst C-MFI-2. Its composition is shown in Table 1.

[0110] Hydrocracking activity tests were conducted on a fixed-bed reactor using diesel fraction-1 feedstock as described in Table 2. In the hydrocracking section, C-Beta-2 and C-MFI-2 were sequentially placed in two separate reactors for two separate hydrocracking reactions. Before use, the catalysts underwent programmed temperature sulfidation: using straight-run kerosene containing 2% dimethyl disulfide as the sulfiding oil, the temperature was increased from 110°C to 230°C at a rate of 20°C / h and held for 6 hours; then increased to 360°C at a rate of 20°C / h and held for 6 hours.

[0111] The C-Beta-2 and C-MFI-2 catalysts were loaded in a volume ratio of 1.5, the reaction pressure was 15 MPa, the hydrogen-to-oil volume ratio was 1200, and the liquid hourly space velocity was 0.8 h⁻¹. -1 The temperature of the first hydrocracking reaction was 330℃, and the temperature of the second hydrocracking reaction was 390℃. The aviation kerosene fraction in the product oil was analyzed, and the results are shown in Table 3.

[0112] Table 1

[0113]

[0114] Comparative Example 1

[0115] 103 g of boehmite (71% by weight, dry basis) and 422 g of ZSM-5 molecular sieve (specific surface area 325 m²) were mixed. 2The mixture (containing 70 g / g of silicon and aluminum in a molar ratio of 70, a pore volume of 0.31 mL / g, and 95% by weight on a dry basis) was extruded into a trilobal strip with an outer circle diameter of 1.6 mm, dried at 120 °C for 3 h, and calcined at 600 °C for 3 h to obtain the support. After cooling to room temperature, 150 g of the support was impregnated with 75 ml of NiW standard solution (38.4 g of nickel nitrate and 44 g of ammonium metatungstate, and an appropriate amount of water were mixed and stirred evenly, heated to 80 °C until completely dissolved, and water was added to adjust the volume to 75 ml to obtain the standard solution), and dried at 120 °C for 3 h to obtain catalyst R-1.

[0116] Hydrocracking activity tests were conducted on a fixed-bed hydrocracking unit using the diesel fraction-1 feedstock described in Table 2. The refining section used industrial catalyst RN-411 (produced by Sinopec Catalyst Changling Branch), and the cracking section used catalyst R-1. The volume ratio of refining catalyst to cracking catalyst was 1.5, the reaction pressure was 10.5 MPa, the hydrogen-to-oil volume ratio was 750, and the liquid hourly space velocity (LHSV) was 1.5 h⁻¹. -1 The refining temperature is 330℃, and the cracking temperature is 280℃.

[0117] The cracking reaction products were fractionated to obtain aviation kerosene fractions (180-295℃). The aviation kerosene fractions in the generated oil were analyzed, and the results are shown in Table 3.

[0118] Comparative Example 2

[0119] The procedure was carried out according to Example 1, except that the positions of C-Beta-1 and C-MFI-1 were interchanged; that is, C-MFI-1 was used for the first hydrocracking reaction and C-Beta-1 was used for the second hydrocracking reaction. The jet fuel fraction in the product oil was analyzed, and the results are shown in Table 3.

[0120] Comparative Example 3

[0121] The method was followed as in Example 1, except that the comparative diesel fraction-2 feedstock in Table 2 was used. The aviation kerosene fraction in the resulting oil was analyzed, and the results are shown in Table 3.

[0122] Comparative Example 4

[0123] The method was carried out according to Example 1, except that the temperature of the first hydrocracking reaction was changed to 230°C. The aviation kerosene fraction in the product oil was analyzed, and the results are shown in Table 3.

[0124] Table 2

[0125] Crude oil name Diesel fraction-1 Diesel fraction-2 <![CDATA[Density (20 °C) g / cm 3 > 0.8516 0.8012 S / (μg / g) <10 <10 Organic nitrogen (μg / g) <10 <30 Distillation range (D-1160), °C 172-318 185-350

[0126] Table 3

[0127]

[0128] As can be seen from the results in Table 3, the smoke point of the aviation kerosene prepared by the method of the present invention meets the application requirements, and it has a significantly higher density. When used as jet fuel, it can improve the driving range and has broad application prospects.

[0129] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for producing aviation kerosene, the method comprising: (1) Hydrogen and diesel fractions are subjected to a first hydrocracking reaction with a first hydrocracking catalyst at 265-330°C to obtain a first product. The first hydrocracking catalyst is a first support and a first metal component supported on the first support. The first support contains a Beta-type molecular sieve, and the first metal component is a Group VIB metal component. The first hydrocracking catalyst does not contain a Group VIII metal component. (2) The first product obtained in step (1) is subjected to a second hydrocracking reaction with a second hydrocracking catalyst, wherein the second hydrocracking catalyst is a second support and a second metal component supported on the second support, wherein the second support contains an MFI type molecular sieve and the second metal component is a group VIB and a group VIII metal component. The density of the diesel fraction is 0.81-0.90 g / cm³. 3 The distillation range is 160-360℃. The organic nitrogen content of the diesel fraction is less than 50 μg / g; The second hydrocracking reaction temperature is 40-200℃ higher than the first hydrocracking reaction temperature. The products of the second hydrocracking reaction are separated to obtain aviation kerosene, which has a density higher than 835 kg / m³. 3 ; In the second hydrocracking catalyst, the mass ratio of Group VIB metal components to Group VIII metal components, calculated as oxides, is 1:0.05-0.

4.

2. The method according to claim 1, wherein, The second hydrocracking reaction temperature is 60-180℃ higher than the first hydrocracking reaction temperature.

3. The method according to claim 1, wherein, Based on the dry weight of the first hydrocracking catalyst, the content of the first metal component, calculated as oxides, in the first hydrocracking catalyst is 5-30% by weight; and / or Based on the dry weight of the first hydrocracking catalyst, the content of the first support in the first hydrocracking catalyst is 70-95% by weight on a dry basis.

4. The method according to claim 3, wherein, Based on the dry weight of the first hydrocracking catalyst, the content of the first metal component, calculated as oxides, in the first hydrocracking catalyst is 10-25% by weight; and / or Based on the dry weight of the first hydrocracking catalyst, the content of the first support in the first hydrocracking catalyst is 75-90% by weight on a dry basis.

5. The method according to claim 1, wherein, In the first hydrocracking catalyst, the Group VIB metal component is Mo and / or W.

6. The method according to claim 5, wherein, In the first hydrocracking catalyst, the Group VIB metal component is W.

7. The method according to any one of claims 1-6, wherein, The SiO2 / Al2O3 molar ratio of the Beta-type molecular sieve is 10-300; the specific surface area of ​​the Beta-type molecular sieve is 150-450 m². 2 / g; the pore volume of the Beta-type molecular sieve is 0.1-0.6 mL / g.

8. The method according to claim 7, wherein, The SiO2 / Al2O3 molar ratio of the Beta-type molecular sieve is 20-150; the specific surface area of ​​the Beta-type molecular sieve is 300-450 m². 2 / g; the pore volume of the Beta-type molecular sieve is 0.2-0.5 mL / g.

9. The method according to any one of claims 1-6, wherein, In the first hydrocracking catalyst, the first support also contains heat-resistant inorganic oxides; Based on the total weight of the first carrier, the content of the Beta-type molecular sieve is 35-90% by weight; the content of the heat-resistant inorganic oxide is 10-65% by weight. The heat-resistant inorganic oxide is selected from at least one of silicon oxide, aluminum oxide, and titanium oxide.

10. The method according to claim 9, wherein, In the first hydrocracking catalyst, based on the total weight of the first support, the content of the Beta-type molecular sieve is 35-80% by weight; and the content of the heat-resistant inorganic oxide is 20-65% by weight.

11. The method according to any one of claims 1-6, wherein, Based on the dry weight of the second hydrocracking catalyst, the content of the second metal component in the second hydrocracking catalyst, calculated as oxide, is 5-30% by weight.

12. The method according to claim 11, wherein, Based on the dry weight of the second hydrocracking catalyst, the content of the second metal component in the second hydrocracking catalyst, calculated as oxide, is 10-30% by weight.

13. The method according to any one of claims 1-6, wherein, In the second hydrocracking catalyst, the mass ratio of the Group VIB metal component to the Group VIII metal component, based on oxides, is 1:0.08-0.

35.

14. The method according to any one of claims 1-6, wherein, In the second hydrocracking catalyst, the Group VIB metal component is Mo and / or W; In the second hydrocracking catalyst, the Group VIII metal component is Ni and / or Co.

15. The method according to any one of claims 1-6, wherein, The second hydrocracking catalyst also contains an additive selected from at least one of phosphorus, fluorine, and boron; Based on the dry basis mass of the second hydrocracking catalyst, the content of the auxiliary agent, calculated as oxide, is 1-8% by weight.

16. The method according to claim 15, wherein, The second hydrocracking catalyst also contains organic additives; Based on the total weight of the second hydrocracking catalyst, the content of the organic additive is 0.5-15% by weight. The organic additive is selected from at least one of alcohols, carboxylic acids, and organic amines.

17. The method according to claim 16, wherein, The carboxylic acid compound is selected from at least one of acetic acid, maleic acid, oxalic acid, aminotriacetic acid, aminoacetic acid, citric acid, tartaric acid, and malic acid. The alcohol compound is selected from at least one of ethylene glycol, glycerol, polyethylene glycol, and butanediol; The organic amine compound is selected from at least one of ethylenediamine, diethylenetriamine, cyclohexanediaminetetraacetic acid, ethylenediaminetetraacetic acid, and ethylenediaminetetraacetic acid ammonium.

18. The method according to claim 16, wherein, The alcohol compound is diethylene glycol.

19. The method according to any one of claims 1-6, wherein, The SiO2 / Al2O3 molar ratio of the MFI-type molecular sieve is 15-300; the specific surface area is 180-650 m². 2 / g; pore volume is 0.1-0.6 mL / g.

20. The method according to claim 19, wherein, The SiO2 / Al2O3 molar ratio of the MFI-type molecular sieve is 20-80; the specific surface area is 300-450 m². 2 / g; pore volume is 0.2-0.5 mL / g.

21. The method according to any one of claims 1-6, wherein, The MFI type molecular sieve is ZSM-5 molecular sieve.

22. The method according to claim 16, wherein, In the second hydrocracking catalyst, the second support also contains heat-resistant inorganic oxides; Based on the total weight of the second carrier, the content of the MFI-type molecular sieve is 40-90% by weight; the content of the heat-resistant inorganic oxide is 10-60% by weight. The heat-resistant inorganic oxide is selected from at least one of silicon oxide, aluminum oxide, and titanium oxide.

23. The method according to claim 22, wherein, In the second hydrocracking catalyst, based on the total weight of the second support, the content of the MFI type molecular sieve is 50-80% by weight; and the content of the heat-resistant inorganic oxide is 20-50% by weight.

24. The method according to claim 22, wherein, The preparation method of the second hydrocracking catalyst includes the following steps: (a) A second support is prepared by mixing MFI-type molecular sieves with heat-resistant inorganic oxide precursors; (b) Introducing a second metal component, auxiliaries and organic additives onto the second carrier by impregnation.

25. The method according to any one of claims 1-6, wherein, The conditions for the first hydrocracking reaction include: a reaction pressure of 10-17 MPa; a reaction temperature of 265-330 °C; a hydrogen-to-oil volume ratio of 700-1300:1; and a liquid hourly space velocity of 0.5-4 h⁻¹. -1 ; The conditions for the second hydrocracking reaction include: a reaction pressure of 10-17 MPa; a reaction temperature of 330-430 °C; a hydrogen-to-oil volume ratio of 700-1300:1; and a liquid hourly space velocity of 0.5-4 h⁻¹. -1 .

26. The method according to any one of claims 1-6, wherein, The density of aviation kerosene products is 836-845 kg / m³. 3 .

27. The method according to any one of claims 1-6, wherein, The smoke point of aviation kerosene products is greater than 20 mm; based on the total mass of aviation kerosene products, the mass content of bicyclic and polycyclic aromatic hydrocarbons is less than 2%.

28. The method according to claim 27, wherein, The smoke point of aviation kerosene products is 21-25 mm; based on the total mass of aviation kerosene products, the mass content of bicyclic and polycyclic aromatic hydrocarbons is less than 1.5%.

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