Hydrocracking method for catalytically producing aviation fuel by adopting Y-type molecular sieve-containing catalyst and shape-selective molecular sieve-containing catalyst

Abstract

The invention relates to the field of aviation fuel production, and discloses a hydrocracking method for catalytically producing aviation fuel by adopting a Y-type molecular sieve-containing catalyst and a shape-selective molecular sieve-containing catalyst. The method comprises the steps that hydrogen and diesel oil fractions and a first hydrocracking catalyst are subjected to a first hydrocracking reaction at the temperature not higher than 250 DEG C, a first product is obtained, the first hydrocracking catalyst comprises a first carrier and a first metal component, the first carrier contains a Y-type molecular sieve, and the first metal component is a VIB group metal component; the first product and a second hydrocracking catalyst are subjected to a second hydrocracking reaction, the second hydrocracking catalyst comprises a second carrier and a second metal component, and the second carrier contains an MFI type molecular sieve; wherein the density of the diesel fraction is 0.81-0.90 g / cm < 3 >, the distillation range is 160-360 DEG C, and the content of organic nitrogen in the diesel fraction is lower than 50 mu g / g. According to the method, the high-density aviation fuel can be obtained.

Description

Technical Field

[0001] The invention relates to the field of aviation fuel production, and in particular to a hydrocracking method for producing aviation fuel by catalyzing a Y-type molecular sieve catalyst and a shape-selective molecular sieve catalyst. Background Art

[0002] High-density jet fuel, also known as high-density jet fuel, has the characteristics of high density and high volume calorific value. Compared with conventional jet fuel (commercial density is generally 0.77-0.81g / cm 3 ) can improve the cruising range and has heat-absorbing stability, which has a wide range of application prospects. GJB1603-93 stipulates the fuel standard for high-speed turbine engines, with a density of 0.835g / cm 3 The flash point is higher. The existing technology is mainly prepared by hydrofining of naphthenic kerosene fraction, hydrocracking of high-density secondary processed diesel fraction, and hydrocracking of naphthenic VGO fraction.

[0003] Pennsylvania State University (PSU) in the United States proposed and successfully developed JP900 aviation fuel, which contains a large amount of aromatic hydrocarbons and cycloalkanes and other cyclic hydrocarbons in coal. The aromatic hydrocarbons in this fuel have all become cycloalkanes with high stability. In addition, these cycloalkanes act as stabilizers in the fuel and can greatly inhibit the decomposition of the fuel. Experiments show that this coal-based fuel meets the various technical indicators of current jet fuels and has an outstanding advantage that it can remain stable for a long time at a temperature of 900°F (482℃) without generating carbon deposits that clog valve nozzles and other parts. Therefore, this jet fuel, also known as JP900, can not only be used as a power source for aircraft, but also has a high heat capacity and can absorb a large amount of heat generated by the engine without a significant increase in its own temperature, achieving the purpose of cooling the engine, which plays a positive role in promoting the development of the advanced turbine engine (VAATE) for the fifth-generation fighter.

[0004] CN105733670A discloses a method for producing high-density aviation kerosene by catalytic recycling oil hydrogenation, including mixing catalytic recycling oil with hydrogen and entering a hydroprocessing reaction zone, contacting with a hydrogenation protective agent, a hydrorefining catalyst and a hydromodification catalyst A in sequence for hydrogenation reaction; the hydroprocessing effluent enters a hydromodification reaction zone, and the hydromodification reaction zone uses a hydromodification catalyst B containing amorphous silica-alumina and modified Y zeolite, and performs a hydromodification reaction in the presence of hydrogen; the obtained hydromodification effluent enters a hydrorefining reaction zone for hydrorefining reaction, and the hydrorefining product is separated to obtain high-density aviation kerosene. This application uses catalytic recycling oil as a raw material to produce high-density aviation kerosene with high density, high volume calorific value, low aromatic content and good low-temperature performance in the largest amount, which can broaden the raw material source of high-density aviation kerosene products.

[0005] Existing technology research mainly focuses on the production of high-density jet fuel using secondary processed low-quality coal diesel fractions. However, China has formulated jet fuel production management measures, which have clear requirements on the proportion of secondary fractions added to the jet fuel hydrogenation unit and the pressure level of the unit. This has significantly limited the above technology.

[0006] Therefore, developing a new process to obtain high-density aviation fuel will have wide application value. Summary of the invention

[0007] The purpose of the present invention is to overcome the problems existing in the prior art and provide a hydrocracking method for producing aviation fuel using a Y-type molecular sieve catalyst and a shape-selective molecular sieve catalyst. The method can obtain high-density aviation fuel.

[0008] In order to achieve the above object, the present invention provides a hydrocracking method for producing aviation kerosene, which comprises:

[0009] (1) subjecting hydrogen and diesel fraction to a first hydrocracking reaction with a first hydrocracking catalyst at a temperature not higher than 250° C. to obtain a first product, wherein the first hydrocracking catalyst comprises a first carrier and a first metal component supported on the first carrier, wherein the first carrier comprises a Y-type molecular sieve, and the first metal component is a Group VIB metal component;

[0010] (2) subjecting the first product obtained in step (1) to a second hydrocracking reaction with a second hydrocracking catalyst, wherein the second hydrocracking catalyst comprises a second carrier and a second metal component supported on the second carrier, wherein the second carrier comprises an MFI molecular sieve, and the second metal component comprises a VIB group and a VIII group metal component;

[0011] Wherein, the density of the diesel fraction is 0.81-0.90 g / cm 3 ; The distillation range is 160-360°C, and the organic nitrogen content in the diesel fraction is less than 50μg / g.

[0012] Through the above technical solution, the beneficial effects of the present invention include:

[0013] The method provided by the present invention uses a low-nitrogen diesel fraction raw material with relatively small density and low distillation range as a raw material, adopts a first hydrocracking catalyst composed of a first carrier containing a Y-type molecular sieve and a monometallic active component and a second hydrocracking catalyst composed of a second carrier containing an MFI-type molecular sieve and a bimetallic active component, and is reasonably graded to carry out secondary continuous hydrocracking reactions and control the temperature of the first hydrocracking reaction to be no higher than 250°C, which is conducive to obtaining high-density aviation kerosene.

[0014] The method of the present invention adopts a two-stage series hydrocracking process flow, which has great operational flexibility and can be achieved by setting different hydrocracking reaction zones on the original hydrocracking reactor, or by adding another hydrocracking reactor. The operation process is simple, and investment costs can be saved and transformation is convenient. DETAILED DESCRIPTION

[0015] The endpoints and any values ​​of the ranges disclosed in this article 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 each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0016] In the present invention, the density of the diesel fraction is the density at 20°C.

[0017] In the present invention, the dry basis of a substance refers to a solid product obtained by calcining the substance at 600° C. for 3 hours.

[0018] In the present invention, "optional" means not essential, and can be understood as containing or not containing, adding or not adding, adopting or not adopting.

[0019] One aspect of the present invention provides a hydrocracking method for producing aviation kerosene, the method comprising:

[0020] (1) subjecting hydrogen and diesel fraction to a first hydrocracking reaction with a first hydrocracking catalyst at a temperature not higher than 250° C. to obtain a first product, wherein the first hydrocracking catalyst comprises a first carrier and a first metal component supported on the first carrier, wherein the first carrier comprises a Y-type molecular sieve, and the first metal component is a Group VIB metal component;

[0021] (2) subjecting the first product obtained in step (1) to a second hydrocracking reaction with a second hydrocracking catalyst, wherein the second hydrocracking catalyst comprises a second carrier and a second metal component supported on the second carrier, wherein the second carrier comprises an MFI molecular sieve, and the second metal component comprises a VIB group and a VIII group metal component;

[0022] Wherein, the density of the diesel fraction is 0.81-0.90 g / cm 3 , the distillation range is 160-360°C, and the organic nitrogen content in the diesel fraction is less than 50 μg / g.

[0023] Preferably, the distillation range of the diesel fraction is 170-330°C.

[0024] In the present 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 to improving the smoke point of aviation kerosene.

[0025] The present invention has no particular limitation on the source of the diesel fraction raw material. As long as the diesel fraction meets the above requirements, it is within the applicable scope of the present invention.

[0026] In the present invention, the reaction temperature of the first hydrocracking reaction is not higher than 260° C., preferably 180-250° C. The preferred embodiment is adopted to improve the selective conversion of heavy aromatics and cycloalkanes in the feed in the first cracking reaction, so that the obtained jet fuel product has both higher density and higher smoke point.

[0027] According to the present invention, preferably, the second hydrocracking reaction temperature is 40-250° C. higher than the first hydrocracking reaction temperature, preferably 70-250° C. higher. By adopting this preferred embodiment, the selectivity of high-density aviation fuel component products is improved.

[0028] According to some embodiments of the present invention, the first hydrocracking catalyst comprises a first carrier and a first metal component supported on the first carrier, wherein the first carrier contains a Y-type molecular sieve and the first metal component is a VIB group metal component. In order to obtain the target product of the present invention, preferably, the first hydrocracking catalyst does not contain a VIII group metal component. With this preferred embodiment, the first hydrocracking catalyst uses a single metal hydrogenation component and cooperates with a carrier containing a Y-type molecular sieve, which is conducive to improving the selectivity of converting heavy fractions in the feed into high smoke point jet fuel products.

[0029] According to the present invention, preferably, based on the total 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 wt%, preferably 10-25 wt%.

[0030] According to the present invention, preferably, based on the total dry weight of the first hydrocracking catalyst, the content of the first carrier in the first hydrocracking catalyst is 70-95 wt %, preferably 75-90 wt %, calculated on a dry basis.

[0031] In the first hydrocracking catalyst, the sum of the contents of the various components is 100%.

[0032] In the present invention, the VIB group metal component can be a conventional choice in the art. Preferably, the VIB group metal component is Mo and / or W, preferably W. This preferred embodiment is advantageous in improving the selectivity of converting the heavy fraction in the feed into a high smoke point jet fuel product.

[0033] According to the present invention, preferably, the SiO2 / Al2O3 molar ratio of the Y-type molecular sieve is 5-80, preferably 8-30.

[0034] According to the present invention, preferably, the specific surface area of ​​the Y-type molecular sieve is 500-800m 2 / g, preferably 500-750m 2 / g.

[0035] According to the present invention, preferably, the pore volume of the Y-type molecular sieve is 0.1-0.6 mL / g, preferably 0.2-0.5 mL / g.

[0036] The use of Y-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.

[0037] In the present invention, the type of the Y-type molecular sieve can be selected from a wide range of types, and can be various Y-type molecular sieves commonly used in the art. Preferably, the Y-type molecular sieve is an ion-modified Y molecular sieve and / or an ultra-stable Y molecular sieve.

[0038] Preferably, the ion modification includes at least one of rare earth ion modification, alkaline earth metal ion modification, transition metal ion modification and phosphorus modification.

[0039] Further preferably, the Y-type molecular sieve is USY molecular sieve.

[0040] According to the present invention, preferably, in the first hydrocracking catalyst, the first carrier further contains a heat-resistant inorganic oxide.

[0041] The heat-resistant inorganic oxide of the present invention refers to a porous material with a maximum use temperature of not less than 600° C. The heat-resistant inorganic oxide can increase the strength of the hydrocracking catalyst and improve and adjust the physicochemical properties of the hydrocracking catalyst, such as improving the pore structure of the catalyst.

[0042] The present invention has a wide range of heat-resistant inorganic oxides, and various heat-resistant inorganic oxides commonly used in the art can be used. Preferably, the heat-resistant inorganic oxide is selected from at least one of silicon oxide, aluminum oxide and titanium oxide, preferably aluminum oxide.

[0043] According to the present invention, preferably, based on the total weight of the first carrier, the content of the Y-type molecular sieve is 35-90 wt%, preferably 35-80 wt%; the content of the heat-resistant inorganic oxide is 10-65 wt%, preferably 20-65 wt%.

[0044] The present invention has no particular limitation on the source of the first hydrocracking catalyst, which can be purchased from commercial sources or prepared by conventional methods in the art.

[0045] In the present invention, the second hydrocracking catalyst comprises a second carrier and a second metal component supported on the second carrier, wherein the second carrier contains an MFI type molecular sieve, and the second metal component comprises a VIB group and a VIII group metal component. In this preferred embodiment, the second hydrocracking catalyst uses a bimetallic hydrogenation component and a carrier containing an MFI type molecular sieve, which is conducive to improving the selectivity of the high-density aviation kerosene component in the product.

[0046] According to the present invention, preferably, based on the total 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 wt%, preferably 10-30 wt%.

[0047] According to the present invention, preferably, the mass ratio of the VIB group metal component to the VIII group metal component, calculated as oxide, is 1:0.05-0.4, preferably 1:0.1-0.35.

[0048] In the present invention, the Group VIB metal component can be selected from conventional materials in the art. Preferably, the Group VIB metal component is Mo and / or W.

[0049] In the present invention, the Group VIII metal component can be selected from conventional materials in the art. Preferably, the Group VIII metal component is Ni and / or Co.

[0050] According to the present invention, preferably, the second hydrocracking catalyst further contains an auxiliary agent, and the auxiliary agent is selected from at least one of phosphorus, fluorine and boron.

[0051] According to the present invention, preferably, based on the dry mass of the second hydrocracking catalyst, the content of the additive is 0.1-15 wt % in terms of oxide.

[0052] According to the present invention, preferably, the second hydrocracking catalyst further contains an organic additive.

[0053] According to the present invention, preferably, based on the total weight of the second hydrocracking catalyst, the content of the organic additive is 0.5-15 wt%.

[0054] According to the present invention, preferably, the organic additive is an oxygen-containing organic compound and / or a nitrogen-containing organic compound, preferably at least one selected from alcohol compounds, carboxylic acid compounds and organic amine compounds.

[0055] The present invention has a wide range of selection for the type of the carboxylic acid compound, which can be various carboxylic acid compounds commonly used 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.

[0056] The present invention has a wide range of alcohol compound types, which can be various alcohol compounds commonly used in the art. Preferably, the alcohol compound is selected from at least one of ethylene glycol, glycerol, polyethylene glycol, diethylene glycol and butanediol.

[0057] The present invention has a wide range of selection for the type of the organic amine compound, which can be various organic amine compounds commonly used in the art. Preferably, the organic amine compound is selected from at least one of ethylenediamine, diethylenetriamine, cyclohexanediaminetetraacetic acid, ethylenediaminetetraacetic acid and ammonium ethylenediaminetetraacetate.

[0058] In the second hydrocracking catalyst, the sum of the contents of the various components is 100%.

[0059] According to the present invention, preferably, the SiO2 / Al2O3 molar ratio of the MFI molecular sieve is 15-300, preferably 20-80.

[0060] According to the present invention, preferably, the specific surface area of ​​the MFI molecular sieve is 180-650m 2 / g, preferably 300-450m 2 / g.

[0061] According to the present invention, preferably, the pore volume of the MFI molecular sieve is 0.1-0.6 mL / g, preferably 0.2-0.5 mL / g.

[0062] The use of MFI molecular sieves with the above characteristics is beneficial to improving the selectivity of high-density aviation kerosene components in the product.

[0063] In the present invention, the type of the MFI molecular sieve can be selected in a wide range, and the MFI molecular sieve is a ZSM-5 molecular sieve.

[0064] According to the present invention, preferably, in the second hydrocracking catalyst, the second carrier further contains a heat-resistant inorganic oxide.

[0065] The heat-resistant inorganic oxide of the present invention refers to a porous material with a maximum use temperature of not less than 600° C. The heat-resistant inorganic oxide can increase the strength of the hydrocracking catalyst and improve and adjust the physicochemical properties of the hydrocracking catalyst, such as improving the pore structure of the catalyst.

[0066] The present invention has a wide range of heat-resistant inorganic oxides, and various heat-resistant inorganic oxides commonly used in the art can be used. Preferably, the heat-resistant inorganic oxide is selected from at least one of silicon oxide, aluminum oxide, zirconium oxide and titanium oxide, preferably aluminum oxide.

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

[0068] The present invention has no particular limitation on the preparation method of the above-mentioned second hydrocracking catalyst, as long as the second hydrocracking catalyst of the above-mentioned 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] Preferably, the preparation method of the second hydrocracking catalyst comprises the following steps:

[0070] (a) mixing an MFI molecular sieve and an optional heat-resistant inorganic oxide precursor to prepare a second carrier;

[0071] (b) introducing the second metal component and optionally the auxiliary agent and optionally the organic additive onto the second support by impregnation.

[0072] In the present invention, the method for preparing the second carrier in step (a) is well known to those skilled in the art, and the present invention has no particular limitation on this. For example, the method in step (a) may include: mixing and molding the MFI molecular sieve with an optional heat-resistant inorganic oxide precursor, and then drying and calcining to obtain the second carrier. The heat-resistant inorganic oxide precursor may be a conventional choice in the art. The molding in step (a) may be carried out by any conventional method in the art, for example, the molding may be carried out by tablet molding, ball rolling molding or extrusion molding. The drying and calcining conditions in step (a) may be carried out by conventional methods in the art, and the present invention has no particular limitation on this.

[0073] The present invention also has no particular limitation on the shape of the second carrier, which may be spherical, bar-shaped (including solid or hollow bars), block-shaped, etc. The bar-shaped may be a clover-shaped, four-leaf clover-shaped, or other multi-leaf clover-shaped or deformed forms thereof.

[0074] According to the present invention, preferably, step (b) comprises: introducing the second metal component and optional auxiliary agent and optional organic additive 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 comprises: contacting the second carrier with an impregnation solution containing a second metal precursor, an optional auxiliary agent precursor and an optional organic additive in the presence of an organic additive, followed by drying and optional calcination.

[0076] In the present invention, when introducing the auxiliary agent, the second metal component and the auxiliary agent can be introduced together or separately, and the present invention has no requirement for this. The present invention adopts the method of introducing together as an example.

[0077] Preferably, the second metal precursor is a soluble compound of the second metal, preferably selected from at least one of an oxide of the second metal, an inorganic salt of the second metal, and an organic substance of the second metal. For example, the inorganic salt of the second metal may be selected from at least one of a nitrate of the second metal, a carbonate of the second metal, a basic carbonate of the second metal, a hypophosphite of the second metal, a phosphate of the second metal, a sulfate of the second metal, and a chloride of the second metal. The organic substituent in the organic substance of the second metal may be selected from at least one of a hydroxyl group, a carboxyl group, an amine group, a ketone group, an ether group, and an alkyl group.

[0078] The auxiliary agent precursor of the present invention can be any conventional choice in the art, as long as it contains an auxiliary agent, for example, a soluble salt of an auxiliary agent, an inorganic acid of an auxiliary agent, etc.

[0079] The present invention has no particular limitation on the order of adding the above substances in step (b), and they can be added together or separately. The present invention adopts the method of adding together as an example.

[0080] The present invention has no particular limitation on the type and amount of the solvent in the impregnation solution containing the second metal precursor, and the method can be carried out according to conventional methods in the art.

[0081] The present invention does not have any particular limitation on the contact temperature of step (b), which can be any temperature that the impregnation liquid can reach. There is no particular limitation on the contact time, as long as the required amount of metal precursor can be loaded on the carrier. In general, the higher the contact temperature and the greater the concentration of the impregnation liquid, the shorter the time required to reach the same impregnation amount (i.e., the weight difference between the carrier after impregnation and before impregnation); 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. According to conventional methods in the art, it can be carried out under sealed conditions or in an open environment. The lost solvent can be replenished during the contact process, or it can not be replenished. Various gases, such as air, nitrogen, water vapor, etc., can be introduced during the contact process, or no new components can be introduced.

[0082] The drying and calcining in step (b) are conventional steps for preparing catalysts and are not particularly limited. For example, the drying conditions in step (b) may be: a temperature of 80-350° C., preferably 100-300° C.; a time of 0.5-24 hours, preferably 1-12 hours. The calcining conditions in step (b) may be: a temperature of 350-600° C., preferably 400-550° C.; a time of 0.2-12 hours, preferably 1-10 hours.

[0083] According to the present invention, preferably, the conditions of the first hydrocracking reaction include: reaction pressure of 10-17 MPa; reaction temperature of 180-250°C; hydrogen-oil volume ratio of 700-1300:1; liquid hourly space velocity of 0.5-3h -1 .

[0084] Preferably, the conditions of the second hydrocracking reaction include: reaction temperature of 330-430°C; reaction pressure of 10-17 MPa; hydrogen-oil volume ratio of 700-1300:1; liquid hourly space velocity of 0.5-4h -1 .

[0085] In the present invention, the first hydrocracking catalyst and the second hydrocracking catalyst may be loaded in different reaction zones of the same reactor, or may be loaded in different reactors. The selection may be made according to actual conditions, and the present invention has no particular limitation on this.

[0086] The hydrocracking reaction of the present invention can be carried out in any reactor that is sufficient to allow the hydrocarbon feedstock to contact and react with the catalyst under hydrogenation reaction conditions, for example, it can be a fixed bed reactor, a moving bed reactor, an ebullating bed reactor or a slurry bed reactor, and the present invention has no particular limitation on this.

[0087] Preferably, the second hydrocracking reaction product is separated to obtain an aviation kerosene product. The specific separation method can refer to conventional methods of those skilled in the art, such as fractional distillation, etc., which will not be described in detail in the present invention.

[0088] Preferably, the first hydrocracking catalyst and the second hydrocracking catalyst are presulfided before use.

[0089] The present invention has no particular limitation on the specific conditions of the pre-sulfurization, and the pre-sulfurization can be carried out according to the commonly used methods in the art.

[0090] The pre-sulfurization of the present invention can be carried out outside the vessel, or in-situ sulfidation can be carried out inside the vessel to convert it into a sulfide type.

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

[0092] According to the present invention, preferably, the smoke point of the aviation kerosene product is greater than 20 mm, preferably 21-25 mm; based on the total mass of the aviation kerosene product, the mass content of bicyclic and higher aromatic hydrocarbons in the aviation kerosene product is less than 2%, preferably less than 1.5%.

[0093] It should be noted that when the smoke point of aviation kerosene is greater than 20 mm and the mass content of dicyclic and higher aromatic hydrocarbons is within the range described in the present invention, the existing application requirements for aviation kerosene are met.

[0094] Compared with existing aviation kerosene products, the aviation kerosene product obtained by the present invention has the advantage of high density, can be used as jet fuel, can improve the cruising range, and has broad application prospects.

[0095] The present invention will be described in detail below through examples.

[0096] In the following examples, the properties of aviation kerosene were tested with reference to the standard method of GB 6537-2018;

[0097] The pore volume and specific surface area of ​​the molecular sieve were determined by the static low-temperature adsorption capacity method (using the national standard GB / T5816-1995 method) using an ASAP 2400 automatic adsorption instrument from Micromertics Instruments, Inc., USA. The specific method is as follows: vacuum degassing for 4 hours at 250°C and 1.33 Pa, using nitrogen as the adsorbent, contacting with the adsorbent at -196°C, and static adsorption equilibrium was achieved; the amount of nitrogen adsorbed by the adsorbent was calculated from the difference between the nitrogen intake and the amount remaining in the gas phase after adsorption, and then the pore size distribution was calculated using the BJH formula, and the specific surface area and pore volume were calculated using the BET formula;

[0098] The crystal structure of the molecular sieve was determined using a D5005 X-ray diffractometer from Siemens, Germany, using the industry standard SH / T0339-92 method. Experimental conditions: Cu target, Ka radiation, solid detector, tube voltage 40kV, tube current 40mA, step scan, step width 0.02°, prefabrication time 2s, scanning range 5°~70°. The diffraction angle position refers to the 2θ angle value of the highest value of the diffraction peak;

[0099] The silicon content and aluminum content of the molecular sieve and the phosphorus content and metal component content of the catalyst were determined by using a 3271E X-ray fluorescence spectrometer produced by Rigaku Corporation of Japan. The determination method is as follows: the powder sample was pressed into tablets, a rhodium target was used, a laser voltage of 50 kV, a laser current of 50 mA, a scintillation counter and a proportional counter were used to detect the intensity of the spectral lines of each element, and the external standard method was used to perform quantitative and semi-quantitative analysis of the element content.

[0100] The organic additive content of the catalyst is calculated by the feed amount.

[0101] Example 1

[0102] Pseudo-boehmite (produced by Sinopec Catalyst Changling Branch, trade name PB90, 71 wt% on dry basis) and USY molecular sieve (85 wt% on dry basis, specific surface area 568 m 2 / g, silicon aluminum molar ratio of 23, pore volume of 0.4mL / g) were mixed, extruded into a trilobal strip with a circumscribed circle diameter of 1.6 mm, dried at 120°C for 3h, and calcined at 550°C for 3h to obtain the first carrier. Then, it was impregnated with 75mL aqueous solution containing ammonium metatungstate, dried at 120°C for 3h, and calcined at 480°C for 4h to obtain the first hydrocracking catalyst C-USY-1. Its composition is shown in Table 1.

[0103] Pseudo-boehmite (produced by Sinopec Catalyst Changling Branch, trade name PB90, 71 wt% on dry basis) and ZSM-5 molecular sieve (95 wt% on dry basis, specific surface area 325 m 2 / g, silicon aluminum molar ratio of 23, pore volume of 0.28mL / g) were mixed, extruded into a trilobal strip with an circumscribed circle diameter of 1.6 mm, dried at 120°C for 3h, and calcined at 600°C for 3h to obtain a second carrier. At room temperature, 75mL of an aqueous solution containing molybdenum oxide, nickel carbonate with a nickel oxide weight content of 51%, phosphoric acid with a phosphorus oxide weight content of 61%, and citric acid was impregnated with the second carrier prepared by the above method, and dried at 120°C for 3h to obtain a second hydrocracking catalyst C-MFI-1. Its composition is shown in Table 1.

[0104] The hydrocracking activity test was conducted on a fixed bed hydrocracking unit using the diesel fraction-1 feedstock described in Table 1. In the direction of the flow, the cracking section used C-USY-1 and C-MFI-1, which were placed in two reactors in sequence for two hydrocracking reactions. The above catalyst was subjected to programmed temperature sulfurization before use: using straight-run kerosene containing 2% dimethyl disulfide by mass as the sulfurized oil, the temperature was increased from 110°C to 230°C at a rate of 20°C / h, and maintained for 6h; then the temperature was increased to 360°C at a rate of 20°C / h, and maintained for 6h.

[0105] The volume ratio of C-USY-1 and C-MFI-1 catalysts was 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 The temperature of the first hydrocracking reaction is 200°C, the temperature of the second hydrocracking reaction is 380°C, and the product of the second hydrocracking reaction is fractionated to obtain a jet fuel fraction (180-295°C). The jet fuel fraction in the generated oil was analyzed, and the results are shown in Table 3.

[0106] Example 2

[0107] Pseudo-boehmite (produced by Sinopec Catalyst Changling Branch, trade name PB90, 71 wt% on dry basis) and USY molecular sieve (75 wt% on dry basis, specific surface area of ​​680 m 2 / g, silicon aluminum molar ratio of 11, pore volume of 0.36mL / g) were mixed, extruded into a trilobal strip with an circumscribed circle diameter of 1.6 mm, dried at 120°C for 3h, and calcined at 650°C for 3h to obtain the first carrier. Then, it was impregnated with 75mL of an aqueous solution containing 41.2g of ammonium metatungstate, dried at 120°C for 3h, and calcined at 480°C for 4h to obtain the first hydrocracking catalyst C-USY-2. Its composition is shown in Table 1.

[0108] Pseudo-boehmite (produced by Sinopec Catalyst Changling Branch, trade name PB90, 71 wt% on dry basis) and ZSM-5 molecular sieve (95 wt% on dry basis, specific surface area 423 m 2 / g, silicon aluminum molar ratio of 60, pore volume of 0.4mL / g) were mixed, extruded into trilobal strips with an circumscribed circle diameter of 1.6 mm, dried at 120°C for 3h, and calcined at 600°C for 3h to obtain a second carrier. At room temperature, 75mL of an aqueous solution containing molybdenum oxide, nickel carbonate with a nickel oxide weight content of 51%, phosphoric acid with a phosphorus oxide weight content of 61%, and 15.1g of citric acid was impregnated with the second carrier prepared by the above method, and dried at 120°C for 3h to obtain a second hydrocracking catalyst C-MFI-2. Its composition is shown in Table 1.

[0109] The hydrocracking activity test was conducted on a fixed bed hydrocracking unit using the diesel fraction-1 feedstock described in Table 2. In the direction of the flow, the cracking section used C-USY-2 and C-MFI-2 and was sequentially placed in two reactors for two hydrocracking reactions. The above catalyst was subjected to programmed temperature sulfurization before use: using straight run kerosene containing 2% dimethyl disulfide by mass as the sulfurized oil, the temperature was increased from 110°C to 230°C at a rate of 20°C / h and maintained for 6h; then the temperature was increased to 360°C at a rate of 20°C / h and maintained for 6h.

[0110] The volume ratio of C-USY-2 and C-MFI-2 catalysts was 1.5, the reaction pressure was 16 MPa, the hydrogen-to-oil volume ratio was 1250, and the liquid hourly space velocity was 3 h -1 The temperature of the first hydrocracking reaction is 250°C, the temperature of the second hydrocracking reaction is 330°C, and the product of the second hydrocracking reaction is fractionated to obtain a jet fuel fraction (180-295°C). The jet fuel fraction in the generated oil was analyzed, and the results are shown in Table 3.

[0111] Table 1

[0112]

[0113] Example 3

[0114] The method of Example 1 was followed, except that the carrier of the first hydrocracking catalyst was a Y-type molecular sieve containing MoNi. Specifically, at room temperature, 75 mL of an aqueous solution containing 51% by weight of basic nickel carbonate containing molybdenum oxide and nickel oxide was impregnated into the USY-type molecular sieve described in Example 1, dried at 120° C. for 3 h, and calcined at 550° C. for 4 h to obtain a Y-type molecular sieve containing MoNi. Based on the total mass of the Y-type molecular sieve containing MoNi, the mass content of nickel oxide was 2.6%, and the mass content of molybdenum oxide was 9.2%, calculated as oxides. The results are shown in Table 3.

[0115] Comparative Example 1

[0116] 103 g of pseudo-boehmite (produced by Sinopec Catalyst Changling Branch, trade name PB90, 71 wt% on dry basis) and 422 g of ZSM-5 molecular sieve (produced by Sinopec Catalyst Jianchang Branch, specific surface area 325 m 2 / g, framework silicon aluminum molar ratio of 70, pore volume of 0.31mL / g, dry basis 95 weight%), extruded into a trilobal strip with an circumscribed circle diameter of 1.6 mm, dried at 120°C for 3h, and calcined at 600°C for 3h to obtain a carrier. After cooling to room temperature, 150g of the carrier was impregnated with 75ml NiW standard solution (38.4g nickel nitrate and 44g ammonium metatungstate, and appropriate amount of water were mixed and stirred evenly, heated to 80°C, completely dissolved, and water was added to adjust to 75ml to obtain the standard solution), dried at 120°C for 3h to obtain catalyst R-1.

[0117] The hydrocracking activity test was 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), the cracking section used catalyst R-1, the refining catalyst and cracking catalyst loading volume ratio was 1.5, the reaction pressure was 10.5 MPa, the hydrogen-to-oil volume ratio was 750, and the refined liquid hourly space velocity was 1.5 h -1 The refining temperature is 330℃, the cracking temperature is 280℃, and the cracking reaction product is fractionated to obtain the aviation kerosene fraction (180-295℃). The aviation kerosene fraction in the generated oil was analyzed, and the results are shown in Table 3.

[0118] Comparative Example 2

[0119] The method of Example 1 was followed, except that C-USY-1 and C-MFI-1 were swapped, i.e., C-MFI-1 was used in the first hydrocracking reaction, and C-USY-1 was used in the second hydrocracking reaction. The results are shown in Table 3.

[0120] Comparative Example 3

[0121] The method of Example 1 was followed, except that the diesel fraction-2 in Table 2 was used as raw material. The results are shown in Table 3.

[0122] Comparative Example 4

[0123] The method of Example 1 was followed, except that the temperature of the first hydrocracking reaction was changed to 270° C. The results are shown in Table 3.

[0124] Table 2

[0125] Raw 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), ℃ 172-318 185-350

[0126] Table 3

[0127]

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

[0129] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A hydrocracking method for producing aviation kerosene, the method comprising: (1) subjecting hydrogen and diesel fraction to a first hydrocracking reaction with a first hydrocracking catalyst at a temperature not higher than 250° C. to obtain a first product, wherein the first hydrocracking catalyst comprises a first carrier and a first metal component supported on the first carrier, wherein the first carrier comprises a Y-type molecular sieve, and the first metal component is a Group VIB metal component; (2) subjecting the first product obtained in step (1) to a second hydrocracking reaction with a second hydrocracking catalyst, wherein the second hydrocracking catalyst comprises a second carrier and a second metal component supported on the second carrier, wherein the second carrier comprises an MFI molecular sieve, and the second metal component comprises a VIB group and a VIII group metal component; Wherein, the density of the diesel fraction is 0.81-0.90 g / cm 3 , the distillation range is 160-360°C, and the organic nitrogen content in the diesel fraction is less than 50 μg / g.

2. The method according to claim 1, wherein: The reaction temperature of the first hydrocracking reaction is 180-250°C; Preferably, the second hydrocracking reaction temperature is 40-250°C higher than the first hydrocracking reaction temperature, preferably 70-250°C higher.

3. The method according to claim 1, wherein: Based on the total dry weight of the first hydrocracking catalyst, the first metal component content in the first hydrocracking catalyst is 5-30 wt%, preferably 10-25 wt%, calculated as oxide; and / or Based on the total dry weight of the first hydrocracking catalyst, the first carrier content in the first hydrocracking catalyst is 70-95% by weight, preferably 75-90% by weight, calculated on a dry basis; Preferably, the VIB Group metal component is Mo and / or W, preferably W.

4. The method according to any one of claims 1 to 3, wherein: The SiO2 / Al2O3 molar ratio of the Y-type molecular sieve is 5-80, preferably 8-30; the specific surface area of ​​the Y-type molecular sieve is 500-800m 2 / g, preferably 500-750m 2 / g; the pore volume of the Y-type molecular sieve is 0.1-0.6mL / g, preferably 0.2-0.5mL / g; Preferably, the Y-type molecular sieve is USY molecular sieve; Preferably, in the first hydrocracking catalyst, the first carrier further comprises a heat-resistant inorganic oxide; Preferably, based on the total weight of the first carrier, the content of the Y-type molecular sieve is 35-90% by weight, preferably 35-80% by weight; the content of the heat-resistant inorganic oxide is 10-65% by weight, preferably 20-65% by weight; Preferably, the heat-resistant inorganic oxide is selected from at least one of silicon oxide, aluminum oxide and titanium oxide.

5. The method according to any one of claims 1 to 4, wherein: Based on the total 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 wt%, preferably 10-30 wt%; Preferably, the mass ratio of the Group VIB metal component to the Group VIII metal component, calculated as oxide, is 1:0.05-0.4, preferably 1:0.1-0.35; Preferably, the VIB Group metal component is Mo and / or W; Preferably, the Group VIII metal component is Ni and / or Co.

6. The method according to any one of claims 1 to 5, wherein: The second hydrocracking catalyst further contains an auxiliary agent, wherein the auxiliary agent is selected from at least one of phosphorus, fluorine and boron; Preferably, based on the dry mass of the second hydrocracking catalyst, the content of the additive is 0.1-15 wt % in terms of oxide; Preferably, the second hydrocracking catalyst further contains an organic additive; Preferably, the content of the organic additive is 0.5-15 wt % based on the total weight of the second hydrocracking catalyst; Preferably, the organic additive is an oxygen-containing organic compound and / or a nitrogen-containing organic compound, preferably at least one selected from alcohol compounds, carboxylic acid compounds and organic amine compounds; 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; Preferably, the alcohol compound is selected from at least one of ethylene glycol, glycerol, polyethylene glycol, diethylene glycol and butanediol; Preferably, the organic amine compound is selected from at least one of ethylenediamine, diethylenetriamine, cyclohexanediaminetetraacetic acid, ethylenediaminetetraacetic acid and ammonium ethylenediaminetetraacetate.

7. The method according to any one of claims 1 to 6, wherein: The SiO2 / Al2O3 molar ratio of the MFI molecular sieve is 15-300, preferably 20-80; the specific surface area is 180-650m 2 / g, preferably 300-450m 2 / g; the pore volume is 0.1-0.6mL / g, preferably 0.2-0.5mL / g; Preferably, the MFI molecular sieve is a ZSM-5 molecular sieve; Preferably, in the second hydrocracking catalyst, the second carrier further comprises a heat-resistant inorganic oxide; Preferably, based on the total weight of the second carrier, the content of the MFI molecular sieve is 40-90% by weight, preferably 50-80% by weight; the content of the heat-resistant inorganic oxide is 10-60% by weight, preferably 20-50% by weight; Preferably, the heat-resistant inorganic oxide is selected from at least one of silicon oxide, aluminum oxide, zirconium oxide and titanium oxide.

8. The method according to claim 7, wherein: The preparation method of the second hydrocracking catalyst comprises the following steps: (a) mixing the MFI molecular sieve and an optional heat-resistant inorganic oxide precursor to prepare a second support; (b) introducing the second metal component and optionally the auxiliary agent and optionally the organic additive onto the second support by impregnation.

9. The method according to any one of claims 1 to 8, wherein: The conditions of the first hydrocracking reaction include: reaction pressure of 10-17 MPa; reaction temperature of 180-250°C; hydrogen-oil volume ratio of 700-1300:1; liquid hourly space velocity of 0.5-3h -1 ; Preferably, the conditions of the second hydrocracking reaction include: reaction temperature of 330-430°C; reaction pressure of 10-17 MPa; hydrogen-oil volume ratio of 700-1300:1; liquid hourly space velocity of 0.5-4h -1 .

10. The method according to any one of claims 1 to 9, wherein: The density of aviation kerosene products is higher than 835kg / m 3 , preferably 836-845kg / m 3 ; Preferably, the smoke point of the aviation kerosene product is greater than 20 mm, preferably 21-25 mm; based on the total mass of the aviation kerosene product, the mass content of dicyclic and higher aromatic hydrocarbons in the aviation kerosene product is less than 2%, preferably less than 1.5%.

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