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

Abstract

The present application relates to the field of aviation fuel production, and discloses a hydrocracking method for producing aviation fuel by using Y-type molecular sieve catalyst and shape-selective molecular sieve catalysts, which comprises the following steps: carrying out first hydrocracking reaction of hydrogen and diesel fraction with a first hydrocracking catalyst at a temperature not higher than 250 DEG C to obtain a first product, wherein the first hydrocracking catalyst comprises a first carrier and a first metal component, the first carrier contains Y-type molecular sieve, and the first metal component is a group VIB metal component; and carrying out second hydrocracking reaction of the first product with a second hydrocracking catalyst, wherein the second hydrocracking catalyst comprises a second carrier and a second metal component, and the second carrier contains 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 organic nitrogen content in the diesel fraction is less than 50 mu g / g. The method can obtain aviation fuel with high density.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aviation fuel production, and particularly relates to a hydrocracking method for producing aviation fuel by using Y-type molecular sieve catalyst and shape-selective molecular sieve catalyst. BACKGROUND

[0002] High-density aviation kerosene, also known as high-density jet fuel, has the characteristics of high density and high volume heat value. Compared with conventional jet fuel (the commercial density is generally 0.77-0.81 g / cm 3 ), it can improve the endurance mileage, has heat absorption stability, and has a wide application prospect. GJB1603-93 specifies the fuel standard suitable for high-speed turbine engines, and the density reaches 0.835 g / cm 3 , and the flash point is higher. The existing technology mainly prepares it by means of hydrofining of naphthenic kerosene fraction, hydrocracking of high-density secondary processed diesel fraction, and hydrocracking of naphthenic VGO fraction.

[0003] The University of Pennsylvania (PSU) proposed and successfully developed JP900 aviation fuel with a high content of cyclic hydrocarbons such as aromatic hydrocarbons and naphthenes in coal. The aromatics in the fuel have all been changed into naphthenes with high stability, and in addition, these naphthenes act as stabilizers in the fuel to greatly inhibit the decomposition of the fuel. Experiments show that this coal-based fuel meets the current technical indicators of jet fuel and has a prominent advantage, that is, it can maintain stability at a temperature of 900°F (482°C) for a long time without producing carbon deposits that block the valve nozzle and other parts. Therefore, this jet fuel is not only used as a power source for aircraft, but also has a high heat capacity itself, can absorb a large amount of heat generated by the engine, and does not have a significant temperature rise itself, thereby achieving the purpose of cooling the engine. It plays a positive role in the research and development of the advanced turbine engine (VAATE) of the fifth-generation fighter.

[0004] CN105733670A discloses a method for producing high-specific-gravity aviation kerosene by catalytically hydroprocessing recycled oil, which comprises the following steps: the recycled oil is mixed with hydrogen and then enters a hydroprocessing reaction zone, and is sequentially contacted with a hydroprocessing protective agent, a hydrofining catalyst and a hydro-upgrading catalyst A to perform a hydroprocessing reaction; the hydroprocessing effluent enters a hydro-upgrading reaction zone, and a hydro-upgrading catalyst B containing amorphous silicon aluminum and modified Y zeolite is used in the hydro-upgrading reaction zone to perform a hydro-upgrading reaction in the presence of hydrogen; the obtained hydro-upgrading effluent enters a hydrofinishing reaction zone to perform a hydrofinishing reaction, and the hydrofinishing product is separated to obtain high-specific-gravity aviation kerosene. This application uses catalytic recycled oil as the raw material to produce high-density, high-volume-heat-value, low-aromatic-content and low-temperature-performance aviation kerosene, which can broaden the raw material sources of high-specific-gravity aviation kerosene.

[0005] The prior art research mainly focuses on producing high specific gravity aviation coal by using secondary processing of inferior coal diesel oil fraction. However, China has formulated aviation coal production management methods, which have clear requirements for the proportion of secondary fraction mixed into the device for producing aviation coal and the pressure grade of the device. This limits the above-mentioned technology.

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

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

[0008] In order to achieve the above-mentioned purpose, one aspect of the present application provides a hydrocracking method for producing aviation kerosene, which comprises:

[0009] (1) carrying out first hydrocracking reaction of hydrogen and diesel oil fraction with first hydrocracking catalyst at not higher than 250 DEG C to obtain first product, wherein the first hydrocracking catalyst comprises first carrier and first metal component supported on the first carrier, wherein the first carrier contains Y-type molecular sieve, and the first metal component is Group VIB metal component;

[0010] (2) carrying out second hydrocracking reaction of the first product obtained in step (1) with second hydrocracking catalyst, wherein the second hydrocracking catalyst comprises second carrier and second metal component supported on the second carrier, wherein the second carrier contains MFI-type molecular sieve, and the second metal component comprises Group VIB and Group VIII metal components;

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

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

[0013] The method provided by the present application uses low-nitrogen diesel oil fraction raw material with relatively small density and low distillation range as raw material, uses first hydrocracking catalyst containing Y-type molecular sieve first carrier and single-metal active component and second hydrocracking catalyst containing MFI-type molecular sieve second carrier and double-metal active component for reasonable grading, carries out secondary continuous hydrocracking reaction, and controls the temperature of the first hydrocracking reaction to be not higher than 250 DEG C, which is beneficial to obtain high-density aviation kerosene.

[0014] The method of the present application adopts two-stage series hydrocracking process, has great operation flexibility, can be realized by setting different hydrocracking reaction zones on the original hydrocracking reactor, or can be realized by additionally increasing hydrocracking reactor, has simple operation process, and can save investment cost and facilitate modification. DETAILED DESCRIPTION

[0015] The endpoints of the ranges and any values claimed herein are not to be understood as being limited to the exact values recited as implicitly included within the range. Ranges can be expressed as from about one particular value to about another; however, when such a compound is recited, it is to be understood as constituting each and every dictated value between the upper and lower bounds of the given range. For example, the range of "from about 1 to about 10" should be read to include, in addition to the recited limits of 1 and 10, each and every stated value between the stated range limits of 1 and 10.

[0016] In the present application, the diesel fraction has a density of 20℃.

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

[0018] In the present application, "optional" means non-essential, and can be understood as containing or not containing, adding or not adding, using or not using.

[0019] In one aspect of the present application, a hydrocracking method for producing aviation kerosene is provided, which comprises:

[0020] (1) subjecting hydrogen and a diesel fraction to a first hydrocracking reaction at a temperature of not higher than 250℃ with a first hydrocracking catalyst to obtain a first product, wherein the first hydrocracking catalyst comprises a first carrier and a first metal component supported on the first carrier, the first carrier contains 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, the second carrier contains an MFI-type molecular sieve, and the second metal component comprises a Group VIB and a Group VIII metal component;

[0022] wherein the diesel fraction has a density of 0.81-0.90 g / cm 3 , a distillation range of 160-360℃, and an organic nitrogen content of less than 50 μg / g in the diesel fraction.

[0023] Preferably, the diesel fraction has a distillation range of 170-330℃.

[0024] In the present application, the organic nitrogen content in the diesel fraction is less than 50 μg / g, preferably less than 20 μg / g. With this preferred embodiment, the smoke point of the aviation kerosene is improved.

[0025] The diesel fraction raw material in the present application is not particularly limited, as long as the diesel fraction meeting the above requirements is within the scope of the present application.

[0026] In the present application, the reaction temperature of the first hydrocracking reaction is not higher than 260°C, preferably 180-250°C. With this preferred embodiment, the selective conversion of heavy aromatic hydrocarbons and naphthenes in the feed in the first cracking reaction is improved, and the obtained aviation kerosene product has both high density and high smoke point.

[0027] According to the present application, preferably, the second hydrocracking reaction temperature is 40-250°C higher than the first hydrocracking reaction temperature, preferably 70-250°C higher. With this preferred embodiment, the selectivity of the high-density aviation kerosene component product is improved.

[0028] According to some embodiments of the present application, 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 Group VIB metal component. In order to obtain the target product of the present application, preferably, the first hydrocracking catalyst does not contain a Group VIII metal component. With this preferred embodiment, the first hydrocracking catalyst uses a single-metal hydrogenation component in combination with a carrier containing a Y-type molecular sieve, which is advantageous for improving the selectivity of the conversion of heavy fractions in the feed into a high-smoke-point aviation kerosene product.

[0029] According to the present application, preferably, the content of the first metal component in the first hydrocracking catalyst is 5-30% by weight, preferably 10-25% by weight, based on the total amount of the first hydrocracking catalyst on a dry basis.

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

[0031] In the first hydrocracking catalyst, the content of each component adds up to 100%.

[0032] In the present application, the Group VIB metal component can be a conventional selection in the art. Preferably, the Group VIB metal component is Mo and / or W, preferably W. With this preferred embodiment, the selectivity of the conversion of heavy fractions in the feed into a high-smoke-point aviation kerosene product is improved.

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

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

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

[0036] The Y-type molecular sieve with the above characteristics is advantageous to improve the selectivity of converting heavy distillate in the feed to high smoke point aviation kerosene product.

[0037] In the present application, the Y-type molecular sieve has a wide selection range, and can be various Y-type molecular sieves commonly used in the art. Preferably, the Y-type molecular sieve is ion-modified Y molecular sieve and / or ultrastable 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 application, preferably, in the first hydrocracking catalyst, the first carrier further contains heat-resistant inorganic oxide.

[0041] The heat-resistant inorganic oxide in the present application refers to a porous material with a maximum use temperature of not less than 600℃. The heat-resistant inorganic oxide can improve 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 heat-resistant inorganic oxide has a wide selection range, 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 application, 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%; and the content of the heat-resistant inorganic oxide is 10-65 wt%, preferably 20-65 wt%.

[0044] The source of the first hydrocracking catalyst is not particularly limited, and can be obtained by commercial purchase or self-preparation by the conventional method in the art.

[0045] In the present application, the second hydrocracking catalyst comprises a second carrier and a second metal component supported on the second carrier, wherein the second carrier contains MFI type molecular sieve, and the second metal component comprises Group VIB and Group VIII metal components. With this preferred embodiment, the second hydrocracking catalyst uses bimetallic hydrogenation component in combination with the carrier containing MFI type molecular sieve, which is beneficial to improve the selectivity of high-density aviation kerosene components in the product.

[0046] According to the present application, preferably, the content of the second metal component in the second hydrocracking catalyst is 5-30 wt%, preferably 10-30 wt% based on the total amount of the second hydrocracking catalyst on a dry basis.

[0047] According to the present application, preferably, the mass ratio of the Group VIB metal component to the Group VIII metal component is 1:0.05-0.4, preferably 1:0.1-0.35 based on the oxides.

[0048] In the present application, the Group VIB metal component can be a conventional selection in the art. Preferably, the Group VIB metal component is Mo and / or W.

[0049] In the present application, the Group VIII metal component can be a conventional selection in the art. Preferably, the Group VIII metal component is Ni and / or Co.

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

[0051] According to the present application, preferably, the content of the additive is 0.1-15 wt% based on the mass of the second hydrocracking catalyst on a dry basis.

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

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

[0054] According to the present application, preferably, the organic additive is at least one of oxygen-containing organic compounds and nitrogen-containing organic compounds, preferably selected from at least one of alcohol compounds, carboxylic acid compounds and organic amine compounds.

[0055] The carboxylic acid compound can be any carboxylic acid compound known in the art. Preferably, the carboxylic acid compound is at least one of acetic acid, maleic acid, oxalic acid, amino triacetic acid, amino acetic acid, citric acid, tartaric acid and malic acid.

[0056] The alcohol compound can be any alcohol compound known in the art. Preferably, the alcohol compound is at least one of ethylene glycol, glycerol, polyethylene glycol, diethylene glycol and butanediol.

[0057] The organic amine compound can be any organic amine compound known in the art. Preferably, the organic amine compound is at least one of ethylenediamine, diethylenetriamine, cyclohexanediaminetetraacetic acid, ethylenediaminetetraacetic acid and ethylenediaminetetraacetic acid ammonium.

[0058] In the second hydrocracking catalyst, the content of each component adds up to 100%.

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

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

[0061] According to the present application, 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 the MFI molecular sieve with the above characteristics is advantageous for improving the selectivity of high-density aviation kerosene components in the product.

[0063] The MFI molecular sieve can be any MFI molecular sieve known in the art. Preferably, the MFI molecular sieve is ZSM-5 molecular sieve.

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

[0065] The heat-resistant inorganic oxide refers to a porous material with a maximum use temperature of not less than 600℃. The heat-resistant inorganic oxide can improve 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 kind of the heat-resistant inorganic oxide is wide in the present application, and various heat-resistant inorganic oxides commonly used in the art can be used. Preferably, the heat-resistant inorganic oxide is at least one selected from the group consisting of silicon oxide, aluminum oxide, zirconium oxide and titanium oxide, and is preferably aluminum oxide.

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

[0068] The preparation method of the second hydrocracking catalyst is not particularly limited in the present application, 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 application further provides a preparation method of the second hydrocracking catalyst.

[0069] Preferably, the preparation method of the second hydrocracking catalyst comprises the following steps:

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

[0071] (b) introducing the second metal component and optional adjuvants and optional organic additives into the second carrier by impregnation method.

[0072] In the present application, the method for preparing the second carrier in step (a) is well known to those skilled in the art, and the present application does not have a particular limitation. For example, the method in step (a) can include: mixing the MFI type molecular sieve with optional heat-resistant inorganic oxide precursor into a shape, and then drying and calcining to obtain the second carrier. The heat-resistant inorganic oxide precursor can be a conventional selection in the art. The shaping in step (a) can be performed by any method commonly used in the art, for example, the shaping can be performed by tabletting, balling or extruding. The conditions of drying and calcining in step (a) can be performed by a method commonly used in the art, and the present application does not have a particular limitation.

[0073] The shape of the prepared second carrier is also not particularly limited in the present application, and can be spherical, strip-shaped (including solid or hollow strip-shaped), blocky, etc. The strip-shaped can be clover-shaped, four-leaf clover-shaped and other multi-leaf clover-shaped and their deformations.

[0074] According to the present application, preferably, step (b) comprises: introducing the second metal component and optional adjuvants and optional organic additives into the second carrier by impregnation method.

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

[0076] In the present application, when the promoter is introduced, the second metal component and the promoter can be introduced together or separately, and the present application does not have any requirement in this regard. The present application takes the way of introducing together as an example.

[0077] Preferably, the second metal precursor is a soluble compound of the second metal, preferably at least one selected from the group consisting of an oxide of the second metal, an inorganic salt of the second metal and an organic compound of the second metal. For example, the inorganic salt of the second metal can be at least one selected from the group consisting 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 compound of the second metal can be at least one selected from the group consisting of a hydroxyl group, a carboxyl group, an amine group, a ketone group, an ether group and an alkyl group.

[0078] The promoter precursor in the present application can be a conventional selection in the art as long as it contains the promoter. For example, a soluble salt of the promoter, an inorganic acid of the promoter, etc.

[0079] The present application does not have any particular limitation on the order of adding the above-mentioned substances in step (b), and they can be added together or separately. The present application takes the way of adding together as an example.

[0080] The present application does not have any particular limitation on the type and amount of the solvent in the impregnation solution containing the second metal precursor, and it can be performed according to a conventional method in the art.

[0081] The temperature for the contacting in step (b) is not particularly limited and can be any temperature that the impregnation solution can reach. The time for the contacting is also not particularly limited, as long as the desired amount of metal precursor is loaded on the support. Generally, the higher the temperature for the contacting, the greater the concentration of the impregnation solution, and the shorter the time needed to reach the same impregnation amount (i.e., the weight difference between the support after impregnation and before impregnation). Conversely, the lower the temperature for the contacting, the lower the concentration of the impregnation solution, and the longer the time needed to reach the same impregnation amount. Once the desired impregnation amount and conditions are determined, the appropriate contacting time can be easily selected. The impregnation method can be a saturation impregnation method or a supersaturation impregnation method, which are well known to those skilled in the art. The environment for the impregnation method is not particularly limited and can be performed under a sealed condition or in an open environment according to conventional methods in the art. The lost solvent can or can not be replenished during the contacting. Any gas, such as air, nitrogen, water vapor, etc., can or can not be introduced during the contacting.

[0082] The drying and calcination in step (b) are conventional steps for preparing a catalyst and are not particularly limited. For example, the drying in step (b) can be performed at a temperature of 80-350°C, preferably 100-300°C, for a time period of 0.5-24 hours, preferably 1-12 hours. The calcination in step (b) can be performed at a temperature of 350-600°C, preferably 400-550°C, for a time period of 0.2-12 hours, preferably 1-10 hours.

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

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

[0085] In the present application, the first hydrocracking catalyst and the second hydrocracking catalyst can be loaded in different reaction zones of the same reactor or in different reactors, which can be selected according to the actual situation and are not particularly limited in the present application.

[0086] The hydrocracking reaction in the present application can be performed in any reactor that is sufficient for the hydrocarbon feedstock to contact with the catalyst under hydrocracking conditions, such as a fixed bed reactor, a moving bed reactor, a boiling bed reactor, or a slurry bed reactor, which are not particularly limited in the present application.

[0087] Preferably, the second hydrocracking reaction product is separated to obtain the aviation kerosene product. The specific separation method can refer to the conventional method of those skilled in the art, for example, fractionation can be used, and the present application will not be described in detail here.

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

[0089] The present application does not have special limitations on the specific conditions of the pre-sulfurization, which can be carried out according to the conventional method in the art.

[0090] The pre-sulfurization of the present application can be carried out ex situ or in situ in the reactor to convert it into a sulfide type.

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

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

[0093] It should be noted that when the smoke point of the aviation kerosene is greater than 20 mm and the mass content of di- and polycyclic aromatic hydrocarbons is within the range described in the present application, it meets the existing application requirements for aviation kerosene.

[0094] Compared with the existing aviation kerosene product, the aviation kerosene product obtained by the present application has the advantage of high density, which can improve the endurance mileage when used as jet fuel, and has a wide application prospect.

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

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

[0097] The pore volume and specific surface area of the molecular sieve are measured by static low-temperature adsorption capacity method using an ASAP 2400 automatic adsorption instrument of the American Micromertics Instrument Company (using the method of national standard GB / T5816-1995), the specific method is: vacuum degassing at 250℃, 1.33Pa for 4h, using nitrogen as the adsorbate, contacting with the adsorbate at-196℃, reaching adsorption equilibrium statically; the amount of nitrogen adsorbed by the adsorbent is calculated from the difference between the nitrogen inlet amount and the residual amount in the gas phase after adsorption, and then the pore size distribution is calculated by BJH formula, and the specific surface area and pore volume are calculated by BET formula;

[0098] The crystal structure of the molecular sieve was determined by using a D5005 X-ray diffractometer from Siemens, Germany, according to the industry standard SH / T0339-92. The experimental conditions were as follows: Cu target, Ka radiation, solid detector, tube voltage 40 kV, tube current 40 mA, step scanning, step size 0.02°, pre-setting time 2 s, scanning range 5°-70°. The diffraction angle position refers to the 2θ angle value of the highest peak 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 from Rigaku Denki Kogyo K.K., Japan. The determination method was as follows: the powder sample was pressed into a tablet, a rhodium target was used, the laser voltage was 50 kV, the laser current was 50 mA, the spectral line intensity of each element was detected by using a scintillation counter and a proportional counter, and the element content was quantitatively and semi-quantitatively analyzed by using an external standard method;

[0100] The organic additive content of the catalyst was calculated by the amount of the added material.

[0101] Example 1

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

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

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

[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, the liquid hourly space velocity was 1.5 h -1 -1, the temperature of the first hydrocracking reaction was 200°C, the temperature of the second hydrocracking reaction was 380°C, and the second hydrocracking reaction product was subjected to fractionation to obtain a jet fuel fraction (180-295°C). The jet fuel fraction in the product 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, dry basis 71% by mass) was mixed with USY molecular sieve (dry basis 75% by mass, specific surface area 680 m 2 / g, molar ratio of silicon to aluminum 11, pore volume 0.36 mL / g), extruded into three-leaf-shaped strips with an inscribed circle diameter of 1.6 mm, dried at 120°C for 3 h, and calcined at 650°C for 3 h to obtain a first carrier. The first hydrocracking catalyst C-USY-2 was obtained by impregnating the first carrier with a 75 mL aqueous solution containing 41.2 g of ammonium metatungstate, drying at 120°C for 3 h, and calcining at 480°C for 4 h. The composition is shown in Table 1.

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

[0109] The diesel fraction-1 feedstock described in Table 2 was used to perform a hydrocracking activity test on a fixed bed hydrocracking unit. In the stream direction, the cracking section was sequentially placed in two reactors using C-USY-2 and C-MFI-2, respectively, to perform two hydrocracking reactions. The above catalysts were subjected to programmed temperature sulfidation before use: straight-run kerosene containing 2% by mass of dimethyl disulfide was used as the sulfidation oil, and the temperature was raised from 110°C to 230°C at a rate of 20°C / h, and maintained for 6h; then the temperature was raised 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 3h -1 The temperature of the first hydrocracking reaction was 250°C, the temperature of the second hydrocracking reaction was 330°C, and the second hydrocracking reaction product was subjected to fractionation to obtain a jet fuel fraction (180-295°C). The jet fuel fraction in the product 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 support used in the first hydrocracking catalyst was a MoNi-containing Y-type molecular sieve. Specifically, 75 mL of an aqueous solution of basic nickel carbonate containing 51% by mass of molybdenum oxide and nickel oxide was impregnated into the USY-type molecular sieve described in Example 1 at room temperature, dried at 120°C for 3h, and calcined at 550°C for 4h to obtain a MoNi-containing Y-type molecular sieve. Based on the total mass of the MoNi-containing Y-type molecular sieve, the mass content of nickel oxide was 2.6% and the mass content of molybdenum oxide was 9.2% on an oxide basis. The results are shown in Table 3.

[0115] Comparative Example 1

[0116] PB90, dry basis 71% by mass) was mixed with 422g of ZSM-5 molecular sieve (produced by Sinopec Catalysts Jianlong Branch, specific surface area 325m 2The 150 g of the carrier was impregnated with 75 ml of a standard solution of NiW (38.4 g of nickel nitrate and 44 g of ammonium metatungstate, and an appropriate amount of water were mixed and stirred to homogeneity, heated to 80°C, completely dissolved, and adjusted to 75 ml with water to obtain the standard solution), dried at 120°C for 3 h to obtain the catalyst R-1.

[0117] The diesel fraction-1 described in Table 2 was used as the raw material for the hydrogenation cracking activity test on a fixed bed hydrogenation cracking device. The industrial catalyst RN-411 (produced by Sinopec Catalyst Changling Co., Ltd.) was used in the refining section, and the catalyst R-1 was used in the cracking section, the volume ratio of the refining catalyst to the cracking catalyst was 1.5, the reaction pressure was 10.5 MPa, the hydrogen / oil volume ratio was 750, the liquid hourly space velocity of the refining was 1.5 h-1, the refining temperature was 330°C, the cracking temperature was 280°C, and the cracking reaction product was obtained by fractionation to obtain the aviation kerosene fraction (180-295°C). The aviation kerosene fraction in the generated oil was analyzed, and the results are shown in Table 3. -1

[0118] Comparative Example 2

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

[0120] Comparative Example 3

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

[0122] Comparative Example 4

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

[0124] Table 2

[0125] Feedstock oil name Diesel fraction-1 Diesel fraction-2 Density (20°C) g / cm 3 ]] 0.8516 0.8012 S / (pg / g) <10 <10 Organic nitrogen / (pg / g) <10 <30 Distillation range (D-1 160), °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 application meets the application requirement, and the aviation kerosene has obviously higher density, and when used as jet fuel, the endurance mileage can be improved, and has wide application prospect.

[0129] The preferred embodiments of the present application are described in detail above, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including that each technical feature is combined in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application, and all fall within the protection scope of the present application.

Claims

1. A hydrocracking method for producing aviation kerosene, the method comprising: (1) subjecting hydrogen and a 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, the first hydrocracking catalyst being a first support and a first metal component supported on the first support, wherein the first support contains 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, the second hydrocracking catalyst being 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 Group VIII metal component; and separating the second hydrocracking reaction product to obtain an aviation kerosene product. wherein the diesel fraction has a density of 0.81 to 0.90 g / cm3 at 20°C 3 , a distillation range of 160 to 360°C, and an organic nitrogen content of less than 50 μg / g in the diesel fraction.

2. The method according to claim 1, wherein the first hydrocracking reaction is carried out at a temperature of 180-250°C.

3. The method according to claim 1, wherein the second hydrocracking reaction is carried out at a temperature 40-250°C higher than the first hydrocracking reaction.

4. The method according to claim 3, wherein the second hydrocracking reaction is carried out at a temperature 70-250°C higher than the first hydrocracking reaction.

5. The method of claim 1, wherein, the content of the first metal component in the first hydrocracking catalyst is 5-30% by weight based on the total amount of the first hydrocracking catalyst on a dry basis; and / or the content of the first support in the first hydrocracking catalyst is 70-95% by weight based on the total amount of the first hydrocracking catalyst on a dry basis.

6. The method of claim 5, wherein, the content of the first metal component in the first hydrocracking catalyst is 10-25% by weight based on the total amount of the first hydrocracking catalyst on a dry basis; and / or the content of the first support in the first hydrocracking catalyst is 75-90% by weight based on the total amount of the first hydrocracking catalyst on a dry basis.

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

8. The method according to claim 7, wherein the Group VIB metal component in the first hydrocracking catalyst is W.

9. The method according to any one of claims 1-8, wherein The Y-type molecular sieve has a molar ratio of SiO2 / Al2O3 of 5-80; a specific surface area of 500-800 m 2 / g; and a pore volume of 0.1-0.6 mL / g.

10. The method according to claim 9, wherein The Y-type molecular sieve has a molar ratio of SiO2 / Al2O3 of 8-30; a specific surface area of 500-750 m 2 / g; and a pore volume of 0.2-0.5 mL / g.

11. The method according to any one of claims 1-8, wherein the Y-type molecular sieve is a USY molecular sieve.

12. The method according to any one of claims 1-8, wherein the first support in the first hydrocracking catalyst further contains a heat-resistant inorganic oxide; the content of the Y-type molecular sieve is 35-90% by weight based on the total weight of the first support; and the content of the heat-resistant inorganic oxide is 10-65% by weight based on the total weight of the first support; the heat-resistant inorganic oxide is selected from at least one of silicon oxide, aluminum oxide and titanium oxide.

13. The method according to claim 12, wherein The content of the Y-type molecular sieve is 35-80% by weight based on the total weight of the first support; the content of the heat-resistant inorganic oxide is 20-65% by weight.

14. The method of any one of claims 1-8, wherein, The content of the second metal component in the second hydrocracking catalyst is 5-30% by weight based on the total dry basis of the second hydrocracking catalyst.

15. The method of claim 14, wherein, The content of the second metal component in the second hydrocracking catalyst is 10-30% by weight based on the total dry basis of the second hydrocracking catalyst.

16. The method according to any one of claims 1-8, wherein, The mass ratio of the Group VIB metal component to the Group VIII metal component in the second hydrocracking catalyst is 1:0.05-0.4 based on oxides.

17. The method according to claim 16, wherein, The mass ratio of the Group VIB metal component to the Group VIII metal component in the second hydrocracking catalyst is 1:0.1-0.35 based on oxides.

18. The method according to any one of claims 1-8, wherein, The Group VIB metal component in the second hydrocracking catalyst is Mo and / or W; The Group VIII metal component in the second hydrocracking catalyst is Ni and / or Co.

19. The method according to any one of claims 1-8, wherein, The second hydrocracking catalyst further contains an auxiliary selected from at least one of phosphorus, fluorine and boron; The content of the auxiliary in the second hydrocracking catalyst is 0.1-15% by weight based on oxides based on the dry mass of the second hydrocracking catalyst.

20. The method according to claim 19, wherein, The second hydrocracking catalyst further contains an organic additive; The content of the organic additive is 0.5-15% by weight based on the total weight of the second hydrocracking catalyst; The organic additive is an oxygen-containing organic compound and / or a nitrogen-containing organic compound.

21. The method according to claim 20, wherein, The organic additive is selected from at least one of an alcohol compound, a carboxylic acid compound and an organic amine compound.

22. The method according to claim 21, wherein, The carboxylic acid compound is selected from at least one of acetic acid, maleic acid, oxalic acid, amino triacetic acid, amino acetic 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.

23. The method according to claim 21, wherein, The alcohol compound is diethylene glycol.

24. The method according to any one of claims 1-8, wherein, The MFI type molecular sieve has a SiO2 / Al2O3 molar ratio of 15-300; a specific surface area of 180-650 m 2 / g; and a pore volume of 0.1-0.6 mL / g.

25. The method according to claim 24, wherein, The MFI type molecular sieve has a SiO2 / Al2O3 molar ratio of 20-80; a specific surface area of 300-450 m 2 / g; and a pore volume of 0.2-0.5 mL / g.

26. The method according to any one of claims 1-8, wherein, The MFI-type molecular sieve is ZSM-5 molecular sieve.

27. The method according to claim 20, wherein, In the second hydrocracking catalyst, the second carrier further contains a heat-resistant inorganic oxide; The content of the MFI type molecular sieve is 40-90% by weight, and the content of the heat-resistant inorganic oxide is 10-60% by weight, based on the total weight of the second carrier. The heat-resistant inorganic oxide is selected from at least one of silicon oxide, aluminum oxide, zirconium oxide and titanium oxide.

28. The method of claim 27, wherein, 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, based on the total weight of the second carrier.

29. The method of claim 27, wherein, The preparation method of the second hydrocracking catalyst comprises the following steps: (a) mixing the MFI type molecular sieve with optional heat-resistant inorganic oxide precursors to form a second carrier; (b) introducing a second metal component and optional adjuvants and optional organic additives to the second carrier by an impregnation method.

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

31. The method of any one of claims 1-8, wherein, The density of the aviation kerosene product is higher than 835 kg / m 3 .

32. The method of claim 31, wherein, The density of the aviation kerosene product is 836-845 kg / m 3 .

33. The method of any one of claims 1-8, wherein, The smoke point of the aviation kerosene product is greater than 20 mm; the mass content of di-cyclic and above aromatic hydrocarbons in the aviation kerosene product is less than 2%, based on the total mass of the aviation kerosene product.

34. The method of claim 33, wherein, The smoke point of the aviation kerosene product is 21-25 mm; the mass content of di-cyclic and above aromatic hydrocarbons in the aviation kerosene product is less than 1.5%, based on the total mass of the aviation kerosene product.

Images