CN116060111A - Hydrocracking catalyst for producing middle distillate oil, and preparation method and application thereof - Google Patents

Hydrocracking catalyst for producing middle distillate oil, and preparation method and application thereof Download PDF

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CN116060111A
CN116060111A CN202111269658.9A CN202111269658A CN116060111A CN 116060111 A CN116060111 A CN 116060111A CN 202111269658 A CN202111269658 A CN 202111269658A CN 116060111 A CN116060111 A CN 116060111A
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molecular sieve
catalyst
beta
phase product
liquid
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孙晓艳
樊宏飞
于政敏
王继锋
陈玉晶
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Sinopec Dalian Petrochemical Research Institute Co ltd
China Petroleum and Chemical Corp
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China Petroleum and Chemical Corp
Sinopec Dalian Research Institute of Petroleum and Petrochemicals
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    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J29/80—Mixtures of different zeolites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
    • B01J35/61—Surface area
    • B01J35/615—100-500 m2/g
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    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
    • B01J35/61—Surface area
    • B01J35/617—500-1000 m2/g
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
    • B01J35/63—Pore volume
    • B01J35/633—Pore volume less than 0.5 ml/g
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
    • B01J35/63—Pore volume
    • B01J35/635—0.5-1.0 ml/g
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G47/00—Cracking of hydrocarbon oils, in the presence of hydrogen or hydrogen- generating compounds, to obtain lower boiling fractions
    • C10G47/02—Cracking of hydrocarbon oils, in the presence of hydrogen or hydrogen- generating compounds, to obtain lower boiling fractions characterised by the catalyst used
    • C10G47/10—Cracking of hydrocarbon oils, in the presence of hydrogen or hydrogen- generating compounds, to obtain lower boiling fractions characterised by the catalyst used with catalysts deposited on a carrier
    • C10G47/12—Inorganic carriers
    • C10G47/16—Crystalline alumino-silicate carriers
    • C10G47/20—Crystalline alumino-silicate carriers the catalyst containing other metals or compounds thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J29/076—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof containing arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J29/08—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the faujasite type, e.g. type X or Y
    • B01J29/16—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the faujasite type, e.g. type X or Y containing arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • B01J29/166—Y-type faujasite
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J29/70—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of types characterised by their specific structure not provided for in groups B01J29/08 - B01J29/65
    • B01J29/78—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of types characterised by their specific structure not provided for in groups B01J29/08 - B01J29/65 containing arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • B01J29/7815—Zeolite Beta
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

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  • Organic Chemistry (AREA)
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  • Crystallography & Structural Chemistry (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
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  • General Chemical & Material Sciences (AREA)
  • Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)

Abstract

The invention discloses a hydrocracking catalyst for producing middle distillate, a preparation method and application thereof. The catalyst comprises the following components by taking the weight of the catalyst as a reference: the content of the active metal is 4 to 40 weight percent of oxide; the content of the carrier is 60-96 wt%; wherein, the carrier, based on the total mass of the carrier, comprises: 10 to 15 weight percent of Al-SBA-15/beta core-shell composite molecular sieve, 5 to 15 weight percent of Y molecular sieve, 20 to 60 weight percent of amorphous silica-alumina and 15 to 50 weight percent of adhesive component. The catalyst is suitable for heavy oil hydrocracking reaction, and has the characteristics of high activity, high medium oil selectivity and good product property.

Description

Hydrocracking catalyst for producing middle distillate oil, and preparation method and application thereof
Technical Field
The invention relates to a hydrocracking catalyst for producing middle distillate, a preparation method and application thereof.
Background
Because of the problems of shortage of petroleum resources, increasingly strict environmental protection requirements, inadaptation of petroleum product structures to market demands and the like, the hydrocracking technology becomes an effective technical measure for improving the quality of petroleum products, reducing environmental pollution and increasing market strain capacity, and becomes the most important process technology of modern refineries. Meanwhile, the increasingly strict motor fuel emission standard makes the problem of directly producing high-quality clean fuel by processing inferior heavy oil increasingly prominent, and the hydrocracking technology for producing middle distillate oil in maximum quantity and the development of a middle oil type catalyst matched with the hydrocracking technology are also more active.
The core of the hydrocracking technology is a hydrocracking catalyst, the technological progress of which depends on the improvement of the catalyst level, and a molecular sieve is used as a main acidic component of the hydrocracking catalyst and plays a decisive role in the activity, the selectivity and the product quality of the catalyst. In the traditional hydrocracking catalyst, though Y and beta molecular sieves are subjected to different modification treatments, the pore distribution is improved, and the silicon-aluminum ratio is improved, when heavy oil products with high sulfur content, nitrogen content, complex molecular structure and high carbon number are treated, the heavy oil products are limited by the properties of the molecular sieves, the diffusion resistance of the polycyclic aromatic hydrocarbon with larger kinetic size is larger, the inside of an access hole is influenced to contact with the richer inner surface of an acid center, and the advantage of preferential competitive adsorption of the polycyclic aromatic hydrocarbon is difficult to play; some medium molecules have small kinetic size and small diffusion resistance, and easily enter the micropores of the catalyst to generate secondary cracking reaction, so that the selectivity of middle distillate of the reaction is reduced, and the selectivity of medium oil and the quality of products are not ideal.
The successful synthesis of mesoporous materials not only expands the size range of the molecular sieve from micropores to mesopores in the traditional sense, but also establishes a bridge between the microporous materials and the mesoporous materials. Compared with other micro-mesoporous composite materials, the core-shell type composite mode can fully exert the respective advantages of the micro-mesoporous materials, thereby achieving the aim of effectively treating macromolecular reactants. The SBA-15/beta core-shell type composite molecular sieve hierarchical pore structure utilizes the characteristics of large pore diameter and weak acidity of a shell material to perform a macromolecular raw material presplitting reaction, and chain scission is performed on a side chain with weak macromolecular bond energy, so that macromolecules can easily enter a core material with a small pore canal, and then the cracking reaction is performed by virtue of the strong acidity advantage of the core material, so that the gradual reaction of hydrocracking is realized. Can solve the problem of petrochemical industry development caused by the increasing strictness of petrochemical product upgrading and updating and environmental protection regulations.
CN201010228038.6 describes a method for preparing a mesoporous-microporous core-shell composite molecular sieve catalyst, wherein microporous zeolite is used as a core, and mesoporous silica or mesoporous silica containing aluminum is used as a shell. The obtained composite molecular sieve has a reserved zeolite micropore framework and an ordered two-dimensional hexagonal mesoporous structure, mesoporous pore channels are vertical to the surfaces of zeolite particles, the pore channel openness is high, the thickness of mesoporous shell layers is adjustable, and after the mesoporous shell layers are wrapped, the high smoothness between the mesoporous and micropores can be maintained. The mesoporous shell pore size of the shell-core composite zeolite molecular sieve is generally smaller than 3nm, and is smaller for complex heavy oil and residual oil molecules.
US5536687 describes a catalyst comprising a beta molecular sieve and a Y molecular sieve. When the catalyst is used for producing middle distillate, the composition is as follows: y molecular sieve (1 wt% -15 wt%) and beta molecular sieve (1-15 wt%) and dispersed silicon-aluminum, aluminium oxide, metal W and Ni. The catalyst has low reactivity and low medium oil selectivity, and is difficult to meet the requirement of further increasing the yield of the middle distillate.
The catalyst is used in the reaction of producing middle distillate oil by heavy oil catalytic cracking, and has the problems of low middle distillate oil selectivity, poor activity and poor product quality in different degrees. In particular to a composite molecular sieve with a core-shell structure, which is inevitably easy to cause the separation of a shell and a core or the damage of a framework caused by the influence of external environment, thereby affecting the application of the composite molecular sieve in hydrocracking. Therefore, the further research of the catalyst suitable for the heavy oil hydrocracking reaction to produce high-quality middle oil fraction has great significance.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a hydrocracking catalyst for producing middle distillate, a preparation method and application thereof. The catalyst is suitable for heavy oil hydrocracking reaction, especially in one-stage serial hydrocracking process, and has the features of high activity, high medium oil selectivity and good product quality.
The first aspect of the invention provides a hydrocracking catalyst for producing middle distillate, which comprises the following components by weight of the catalyst: the content of the active metal is 4 to 40 weight percent of oxide; the content of the carrier is 60-96 wt%; wherein, the carrier, based on the total mass of the carrier, comprises: 10 to 15 weight percent of Al-SBA-15/beta core-shell composite molecular sieve, 5 to 15 weight percent of Y molecular sieve, 20 to 60 weight percent of amorphous silica-alumina and 15 to 50 weight percent of adhesive component.
According to the invention, the active metal comprises at least one of a group VIB metal and a group VIII metal.
According to the invention, the content of group VIB metals is preferably between 10 wt.% and 30 wt.% calculated as oxides, based on the weight of the catalyst.
According to the present invention, preferably, the group VIII metal is contained in an amount of 4 to 12wt% in terms of oxide based on the weight of the catalyst.
According to the invention, the group VIB metal comprises W and/or Mo; the group VIII metal comprises Co and/or Ni.
According to the invention, the specific surface area of the catalyst is 280-600 m 2 /g; the pore volume is 0.3-0.7 mL/g.
According to the present invention, the composite molecular sieve comprises: al-SBA-15 is taken as a shell, and beta-type molecular sieve is taken as a core; the mass ratio of the shell to the core is 20:80-30:70; siO of the composite molecular sieve 2 /Al 2 O 3 The molar ratio is 40-60.
According to the invention, the mass ratio of framework aluminum to non-framework aluminum in the composite molecular sieve is 95:5-99:1.
According to the invention, siO in the amorphous silica-alumina 2 The content is 20 to 60wt percent, preferably 25 to 35wt percent; the pore volume is 0.6-1.1 mL/g, preferably 0.8-1.0 mL/g; specific surface area of 300-500 m 2 Preferably 350 to 500m 2 And/g. The amorphous silica-alumina can be prepared by conventional methods, preferably coprecipitation or graftingA copolymerization process.
According to the invention, the Y molecular sieve has the following properties: specific surface area of 700-1000 m 2 Per gram, the total pore volume is 0.40-1.0 mL/g, the relative crystallinity is 95-130%, siO 2 /Al 2 O 3 The molar ratio is 35-60, the unit cell parameter is 2.428-2.432 nm, and the total infrared acid amount is 0.2-0.4 mmol/g. The Y-type molecular sieve can be prepared by a conventional method in the prior art.
The second aspect of the present invention provides a method for preparing the hydrocracking catalyst, comprising the steps of: mixing Al-SBA-15/beta core-shell composite molecular sieve, Y molecular sieve, amorphous silica-alumina and adhesive, molding, drying and roasting to obtain a catalyst carrier; and loading active metal on the carrier to obtain the catalyst.
According to the invention, the Al-SBA-15/beta core-shell composite molecular sieve is prepared according to the following preparation method, which comprises the following steps:
(1) Adding a silicon source into the acid solution, uniformly mixing, standing and aging to obtain a silicon source hydrolysate;
(2) Uniformly mixing part of the silicon source hydrolysate in the step (1), the first beta molecular sieve and the first template agent, performing a first reaction, and performing first solid-liquid separation to obtain a first solid-phase product and a first liquid-phase product;
controlling the solid content of the first liquid phase product to be 0.1-8wt%, preferably 0.5-2wt%, and more preferably 0.8-1.5wt%;
(3) Uniformly mixing part of the silicon source hydrolysate in the step (1), the second beta molecular sieve, part of the first liquid phase product obtained in the step (2) and the second template agent, and performing a second reaction and second solid-liquid separation to obtain a second solid phase product and a second liquid phase product;
Controlling the solid content of the second liquid phase product to be 0.1-8wt%, preferably 0.5-2wt%, and more preferably 0.8-1.5wt%;
(4) And taking the mixture of the first solid-phase product and the second solid-phase product and the first liquid-phase product and/or the second liquid-phase product as raw materials, carrying out hydrothermal crystallization, washing, drying and roasting to obtain the Al-SBA-15/beta core-shell composite molecular sieve.
According to the preparation method of the core-shell composite molecular sieve, the silicon source in the step (1) is one or more of methyl orthosilicate, ethyl orthosilicate TEOS, propyl orthosilicate, isopropyl orthosilicate and butyl orthosilicate. The acid is one or more of hydrochloric acid, sulfuric acid and phosphoric acid. The pH of the acid solution is 2 to 5, preferably 2.5 to 4.0.
According to the preparation method of the core-shell composite molecular sieve, in the step (1), the mechanical stirring mode is adopted for mixing, and the stirring time is 1-12 hours, preferably 4-8 hours; the standing aging time is 4 to 120 hours, preferably 24 to 96 hours.
According to the preparation method of the core-shell composite molecular sieve, in the step (2), the first template agent is a polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, which is abbreviated as P123; preferably, the template P123 is first dissolved in an acid solution and then mixed with the other raw materials. The acid is one or more of hydrochloric acid, sulfuric acid and phosphoric acid. The molar concentration of hydrogen ions in the acid solution is 0.2 to 0.7mol/L, preferably 0.3 to 0.5mol/L.
According to the preparation method of the core-shell composite molecular sieve, the molar concentration of hydrogen ions in the mixed material obtained in the step (2) is 0.2-0.7 mol/L, preferably 0.3-0.5 mol/L; the mass content of the first template agent in the system is 0.3-3%, preferably 0.5-2%; the mass content of the silicon source in the system is 1% -7%, preferably 2% -6%; the mass content of the first beta molecular sieve in the system is 0.5-12%, preferably 1.0-8%.
According to the preparation method of the core-shell composite molecular sieve, the conditions of the first reaction in the step (2) are as follows: the reaction temperature is 30-60 ℃, preferably 35-50 ℃, and the reaction time is 2-12 h, preferably 4-8 h.
According to the preparation method of the core-shell composite molecular sieve, in the step (2), one or more of centrifugal separation and filtering separation are adopted for the first solid-liquid separation; the first solid-liquid separation is not as aimed at as conventional separation, and this separation requires the retention of a suitable solid content in the liquid phase.
According to the preparation method of the core-shell composite molecular sieve, the first beta molecular sieve in the step (2) is a hydrogen beta molecular sieve.
According to the invention, in the preparation method of the core-shell composite molecular sieve, the first beta molecular sieve Na in the step (2) 2 The weight content of O is less than 0.3 percent; silicon to aluminum molar ratio SiO 2 /Al 2 O 3 30 to 45; specific surface area of 400-700 m 2 /g; the pore volume is 0.3-0.6 mL/g; the grain diameter is 500-1000 nm.
According to the preparation method of the core-shell composite molecular sieve, the second beta molecular sieve in the step (3) is a hydrogen beta molecular sieve.
According to the invention, in the preparation method of the core-shell composite molecular sieve, the second beta molecular sieve Na in the step (3) 2 The weight content of O is less than 0.3 percent; silicon to aluminum molar ratio SiO 2 /Al 2 O 3 30 to 45; specific surface area of 400-700 m 2 /g; the pore volume is 0.3-0.6 mL/g, and the grain diameter is 500-1000 nm.
According to the preparation method of the core-shell composite molecular sieve, in the step (3), the second template agent is a polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, which is abbreviated as P123; preferably, the template P123 is first dissolved in an acid solution and then mixed with the other raw materials. The acid is one or more of hydrochloric acid, sulfuric acid and phosphoric acid. The molar concentration of hydrogen ions of the acid solution is 0.1 to 0.6mol/L, preferably 0.3 to 0.5mol/L.
According to the preparation method of the core-shell composite molecular sieve, the molar concentration of hydrogen ions in the mixed material obtained in the step (3) is 0.2-0.7 mol/L, preferably 0.3-0.5 mol/L. The mass content of the added second template agent in the system is 0.3-3%, preferably 0.2-2%; the mass content of the added silicon source in the system is 1-7%, preferably 2-6%; the mass content of the added second beta molecular sieve in the system is 0.5-12%, preferably 1.0-8%. The addition amount of the first liquid phase product accounts for 60-80% of the mass fraction of the mixed material system in the step (3), and preferably 60-75%.
According to the preparation method of the core-shell composite molecular sieve, the conditions of the second reaction in the step (3) are as follows: the reaction temperature is 30-60 ℃, preferably 35-50 ℃, and the reaction time is 2-12 h, preferably 4-8 h.
According to the preparation method of the core-shell composite molecular sieve, in the step (3), one or more of centrifugal separation and filtering separation are adopted for the second solid-liquid separation.
According to the preparation method of the core-shell composite molecular sieve, in the step (4), the liquid-solid mass ratio of the mixed raw materials is controlled to be 1:1-10:1, preferably 1:1-8:1, and more preferably 1:1-5:1 by adjusting the addition amount of the first liquid-phase product and/or the second liquid-phase product. The first liquid phase product and/or the second liquid phase product are/is used for hydrothermal crystallization to synthesize the raw materials of the molecular sieve, and the rest part can be recycled.
According to the preparation method of the core-shell composite molecular sieve, ammonia water is added into the mixed material until the pH value is 3-7, preferably 4-5, before the hydrothermal crystallization in the step (4).
According to the preparation method of the core-shell composite molecular sieve, the hydrothermal crystallization condition in the step (4) is as follows: the crystallization temperature is 80-140 ℃, preferably 100-120 ℃; the crystallization time is 4 to 48 hours, preferably 24 to 30 hours. The drying temperature is 100-120 ℃, and the drying time is 6-10 h. The roasting temperature is 500-550 ℃ and the roasting time is 4-6 h.
According to the preparation method of the core-shell composite molecular sieve, siO in the raw material in the step (4) 2 /Al 2 O 3 Molar ratio to the composite molecular sieve SiO in step (4) 2 /Al 2 O 3 The ratio of the molar ratio is 97% -100%.
According to the present invention, in the preparation method of the hydrocracking catalyst, the binder may be a binder commonly used in the art, preferably small pore alumina; the pore volume of the small pore alumina is 0.3-0.5 mL/g, and the specific surface area is 200-400 m 2 /g。
In the method for producing a hydrocracking catalyst according to the present invention, the molding may be selected as usual as required. The shape can be cylindrical strips, clover, etc. In the process of forming the catalyst, forming aids such as peptizing acid, extrusion aids and the like can be added, and the peptizing agent can generally adopt inorganic acid and/or organic acid, and the extrusion aids such as sesbania powder. The drying is carried out for 3-10 hours at the temperature of 80-150 ℃. The roasting is carried out for 3-12 hours at 400-800 ℃.
In the preparation method of the hydrocracking catalyst according to the present invention, the method of loading the active metal may employ a conventional loading method, preferably an impregnation method, and may be saturated impregnation, excessive impregnation or complex impregnation. Further, the impregnation method is to impregnate the carrier with a solution containing active metal, dry and bake the carrier to obtain the catalyst. The drying is carried out for 1-12 hours at 100-150 ℃. The roasting is carried out for 3-12 hours at 400-750 ℃.
The third aspect of the invention provides the use of the hydrocracking catalyst described above in heavy oil hydrocracking reactions.
According to the invention, the method used is a series hydrocracking process for producing middle distillates.
According to the present invention, the heavy oil includes one or more of various hydrocarbon oils such as vacuum gas oil, coker gas oil, deasphalted oil, thermally cracked gas oil, catalytically cracked circulating oil, and the like. The heavy oil is typically a hydrocarbon containing a distillation range of 300 to 600 c, and the nitrogen content is typically 50 to 2500 μg/g.
According to the invention, the hydrocracking conditions in the one-stage tandem hydrocracking process are as follows: the reaction temperature is 350-420 ℃, preferably 360-390 ℃; the reaction pressure is 6-20 MPa, preferably 9-16 MPa; the volume ratio of hydrogen to oil is 500-2000:1, preferably 800-1500: 1, a step of; the liquid hourly space velocity is 0.5 to 1.8h -1 Preferably 0.8 to 1.5h -1 。
Compared with the prior art, the invention has the following beneficial technical effects:
(1) In the present invention, the catalyst comprises, based on the weight of the catalyst: the content of the active metal is 4 to 40 weight percent of oxide; the content of the carrier is 60-96 wt%; wherein, the carrier, based on the total mass of the carrier, comprises: 10 to 15 weight percent of Al-SBA-15/beta core-shell composite molecular sieve, 5 to 15 weight percent of Y molecular sieve, 20 to 60 weight percent of amorphous silica-alumina and 15 to 50 weight percent of adhesive component. The special Al-SBA-15/beta core-shell type composite molecular sieve is selected in the catalyst composition, the morphology of the composite molecular sieve is more uniform, and the 'core-shell' structure is more complete. The Al-SBA-15/beta molecular sieve and the Y molecular sieve are used as cracking centers together, the pore volume, the specific surface area, the gradient acid distribution and pore distribution pore channels consisting of mesopores and micropores are larger, and the size of the macromolecular material can be reduced and the capability of treating the macromolecular material of the microporous molecular sieve can be enhanced through the pre-cracking of the shell Al-SBA-15 weak acid site; and secondly, the free and smooth gradient pore canal is beneficial to the rapid escape of the reaction molecules from the catalytic surface, so that the reaction molecules are prevented from being excessively reacted. The beta molecular sieve has good isomerization effect on long side chains on alkane or arene, can effectively reduce the condensation point of the product, and meanwhile, the Y-type molecular sieve has high ring opening selectivity on arene, so that the product property of the product is improved. Therefore, the catalyst of the invention is used for producing middle distillate in the hydrocracking process, has the characteristics of higher middle oil selectivity, and has good product quality, in particular to aviation kerosene smoke point and diesel oil with higher cetane number.
(2) In the method, in particular to the preparation step of the Al-SBA-15/beta core-shell type composite molecular sieve, the solid content of a liquid phase product is controlled, and the shell type molecular sieve is introduced in a plurality of steps, so that the phase separation of the phase separation SBA-15 material and the beta molecular sieve is restrained, the morphology of the formed composite molecular sieve is more uniform, and the 'core-shell' structure is more complete. In the method, the silicon source is hydrolyzed in advance, and the method maintains the complete structure and higher crystallinity of the beta molecular sieve. In the method, SBA-15 is synthesized in an acid system, the characteristic that beta molecular sieve is dealuminated in specific acid concentration is utilized, non-framework aluminum formed by dealumination is released from pore channels of a microporous molecular sieve in the system to serve as an aluminum source for synthesizing a mesoporous molecular sieve, the synthesis of the composite molecular sieve fully utilizes the non-framework aluminum removed by the microporous molecular sieve, an aluminum source externally added during conventional preparation of the SBA-15 molecular sieve is omitted, and the removed Al is adjusted by the pH value of the system 3+ Hydrolysis to form Al-OH, which polymerizes with Si-OH hydroxyl groups of silicon into SBA-15 boneIn the rack. Meanwhile, the in-situ aluminum supplementing of SBA-15 and the acidic dealumination modification of the beta molecular sieve are completed. Meanwhile, the silicon-aluminum ratio of the beta molecular sieve is improved, and the structure and crystallinity of the beta molecular sieve are well maintained. The Al-SBA-15/beta molecular sieve prepared by the method has larger pore volume, specific surface area, and gradient acid distribution and pore distribution pore canal composed of mesopores and micropores, and is suitable for the field of macromolecular catalysis. In particular to the heavy oil hydrocracking reaction, the catalyst prepared by the method has higher activity and middle distillate selectivity, and the product quality is good, in particular to aviation kerosene smoke point and diesel oil cetane number are higher.
(3) In the invention, the catalyst is suitable for heavy oil hydrocracking reaction, and is preferably applied to heavy oil hydrocracking in a one-stage serial hydrocracking process to produce middle distillate. The catalyst has the advantages of high medium oil selectivity, high activity, good product quality, and high cetane number of aviation kerosene smoke point and diesel oil. Under the condition of 63 percent conversion, the selectivity of oil in the catalyst can reach 88.4 percent, the smoke point of jet fuel can reach 29mm, and the cetane number of diesel oil can reach 73.
Drawings
FIG. 1 is a small angle XRD spectrum of an example molecular sieve;
wherein: line 1 is the composite molecular sieve Al-SBA-15/beta-1 of example 1, line 2 is the composite molecular sieve Al-SBA-15/beta-2 of example 2, and line 3 is the composite molecular sieve Al-SBA-15/beta-3 of example 3;
FIG. 2 is a small angle XRD spectrum of the molecular sieves of the examples and comparative examples;
wherein: line 1 is the composite molecular sieve Al-SBA-15/beta-3-1 of comparative example 1, line 2 is the composite molecular sieve Al-SBA-15/beta-3 of example 3, line 3 is the composite molecular sieve Al-SBA-15/beta-3-2 of comparative example 2, and line 4 is the composite molecular sieve Al-SBA-15/beta-3-3 of comparative example 3;
FIG. 3 is a high angle XRD spectrum of the molecular sieves of the examples and comparative examples;
Wherein: line 1 is molecular sieve beta-1, line 2 is composite molecular sieve Al-SBA-15/beta-1 of example 1, line 3 is composite molecular sieve Al-SBA-15/beta-2 of example 2, and line 4 is composite molecular sieve Al-SBA-15/beta-3 of example 3;
FIG. 4 is XRD spectra of molecular sieves of examples and comparative examples;
wherein: line 1 is molecular sieve beta-1, line 2 is comparative example 4 molecular sieve beta-2, line 3 is comparative example 5 molecular sieve beta-3, and line 4 is comparative example 1 composite molecular sieve Al-SBA-15/beta-3-1; line 5 is the composite molecular sieve Al-SBA-15/beta-3-2 of comparative example 2, and line 6 is the composite molecular sieve Al-SBA-15/beta-3-3 of comparative example 3;
FIG. 5 is a TEM image of the composite molecular sieve Al-SBA-15/beta-3 prepared in example 3;
FIG. 6 is a TEM image of the composite molecular sieve Al-SBA-15/beta-3-1 prepared in comparative example 1.
Detailed Description
In the invention, the specific surface area and pore volume of the product are measured by adopting ASAP2405 and a low-temperature liquid nitrogen adsorption method.
In the invention, the acid amount is measured by an infrared spectrometer, and the adsorbent used is pyridine.
In the present invention, TEM analysis was performed on a JEM-2100 high resolution transmission electron microscopy device.
In the present invention, the relative crystallinity is measured by XRD. The relative crystallinity of the beta molecular sieve is based on the hydrogen form of the beta molecular sieve in step (2) of example 1. The relative crystallinity of the Y molecular sieve is based on the starting Y molecular sieve in example 1. The molar ratio of silicon to aluminum is determined by a chemical method.
In the present invention, both skeletal aluminum and non-skeletal aluminum 27 Al MAS NMR characterization used a Bruker AV-500 Nuclear magnetic resonance instrument, switzerland.
In the invention,% is mass fraction unless otherwise specified.
The solid content of the liquid phase in the process according to the invention is defined as the ratio of the weight of the solid after evaporation of the water removed to the total mass of the liquid phase.
Example 1:
(1) Under stirring, 10.0g of TEOS was added to 25.0g of HCl solution with ph=2.7, and after stirring at room temperature for 4 hours, the solution was changed from a turbid solution to a clear solution, and was left to stand for 24 hours, to obtain a silicon source hydrolysate.
(2) 1.2g of P123 are dissolved in 120g of 0.50mol/L hydrochloric acid solution; separating 5.8g of hydrogen form betaSub-sieves, designated beta-1 (specific surface 685 m) 2 Per g, pore volume 0.52mL/g, particle size 800nm, siO 2 /Al 2 O 3 Molar ratio of 37, na 2 Mixing the silicon source hydrolysate with the O weight content of 0.1% and the relative crystallinity of 100% with 40g of water, adding the mixture into the mixed solution of hydrochloric acid and P123, stirring for 5min, and then adding the silicon source hydrolysate obtained in the step (1) in 1/2 to mix uniformly. The molar concentration of hydrogen ions in the mixed material is 0.45mol/L; stirring at constant temperature of 45 ℃ for 4h. And then centrifugal separation is carried out to obtain a solid-phase product and a liquid-phase product. The solid content of the liquid phase product was controlled to be 0.8wt%.
(3) And (2) dissolving P123 in 0.50mol/L hydrochloric acid solution, adding 2/3 of the liquid phase product obtained in the step (2), adding hydrogen beta molecular sieve with the same property as the beta-1 molecular sieve in the step (2), and mixing the rest silicon source hydrolysate uniformly. The molar concentration of hydrogen ions in the mixed material is 0.45mol/L, and the mass content of the added P123 in the system is 0.73%; the mass content of the added silicon source TEOS in the system is 5%; the mass content of the added hydrogen type beta molecular sieve in the system is 1.8 percent. The added amount of the liquid phase product in the step (2) accounts for 65% of the mass fraction of the mixed material system in the step (3). Stirring at constant temperature of 45 ℃ for 4h. And then filtering and separating to obtain a solid-phase product and a liquid-phase product. The solid content of the liquid phase product was controlled to be 0.8wt%.
(4) And (3) hydrothermal crystallization: mixing the solid-phase products obtained in the step (2) and the step (3) to obtain a solid-phase raw material of the step (4); mixing the liquid-phase product remained in the step (2) with the liquid-phase product obtained in the step (3) to obtain a liquid-phase raw material of the step (4); and feeding according to the metering ratio, and controlling the liquid-solid mass ratio of the mixed materials to be 2:1. Stirring uniformly, adding ammonia water to regulate pH to 4.0, crystallizing at 100deg.C for 24 hr, filtering, washing, drying at 100deg.C for 6 hr, and calcining at 550deg.C for 4 hr to obtain core-shell composite molecular sieve, which is designated as Al-SBA-15/beta-1. Step (4) SiO in the raw material 2 /Al 2 O 3 Molar ratio and composite molecular sieve SiO 2 /Al 2 O 3 The molar ratio was 99%. The physical parameters of the composite molecular sieve are shown in Table 1.XRD patterns are shown in fig. 1 and 3.
20.1 g of the Al-SBA-15/. Beta. -1 molecular sieve of example 1, 11.5 g of the Y molecular sieve (specific surface area 807m 2 Per gram, total pore volume 0.58mL/g, relative crystallinity 100%, siO 2 /Al 2 O 3 Molar ratio 48, unit cell parameter 2.430nm, total infrared acid content 0.273 mmol/g), 93 g amorphous silica alumina (pore volume 1.0mL/g, specific surface area 380m 2 Per gram, silica weight content 31%), and 35 g of small-pore alumina (pore volume 0.35mL/g, specific surface area 330 m) 2 And/g) and 40 g of 10wt% dilute nitric acid, mixing and grinding in a rolling machine, adding water, grinding into paste, extruding the paste, drying the extruded paste at 110 ℃ for 4 hours, and roasting at 550 ℃ for 4 hours to obtain the carrier TCAT-1.
The carrier is immersed in immersion liquid containing tungsten and nickel for 2 hours at room temperature, dried for 4 hours at 120 ℃, and baked for 4 hours at a temperature of 500 ℃ by programming, thus obtaining the catalyst CAT-1, and the properties of the catalyst are shown in Table 2.
The catalyst CAT-1 was subjected to an activity evaluation test. The tests were carried out on a 200mL small hydrogenation unit using a one-stage serial hydrocracking process with the properties of the feedstock oil as shown in table 3. The hydrocracking operating conditions were as follows: the reaction pressure is 15.7MPa, and the hydrogen-oil volume ratio is 1200:1, liquid hourly space velocity 1.0h -1 The results of the catalyst evaluation after 300 hours of operation are shown in Table 4.
Example 2:
(1) Under stirring, 10.0g of teos was added to 25.0g of 25.0gpH =2.8 HCl solution, and after stirring at room temperature for 4 hours, the solution was changed from a turbid solution to a clear solution, and was left to stand for 24 hours, to obtain a silicon source hydrolysate.
(2) 1.4g of P123 are dissolved in 120g of 0.48mol/L hydrochloric acid solution; 6.5g of hydrogen beta molecular sieve (specific surface area 608 m) 2 Per g, pore volume 0.47mL/g, particle size 800nm, siO 2 /Al 2 O 3 Molar ratio 31, na 2 Mixing O with weight content of 0.1% and relative crystallinity of 101%) with 40g of water, adding into the mixed solution of hydrochloric acid and P123, stirring for 5min, and adding 1/2 of silicon source hydrolysate obtained in step (1) and mixing uniformly. The molar concentration of hydrogen ions in the mixed material is 0.43mol/L; stirring at 48 ℃ for 4 hours at constant temperature. And then centrifugal separation is carried out to obtain a solid-phase product and a liquid-phase product. The solid content of the liquid phase product was controlled to be 1.0wt%.
(3) And (2) dissolving P123 in 0.48mol/L hydrochloric acid solution, adding 2/3 of the liquid phase product obtained in the step (2), adding hydrogen beta molecular sieve with the same molecular sieve property as that in the step (2), and mixing the rest silicon source hydrolysate uniformly. The molar concentration of hydrogen ions in the mixed material is 0.43mol/L, and the mass content of the added P123 in the system is 0.80 percent; the mass content of the added silicon source TEOS in the system is 4.6%; the mass content of the added hydrogen type beta molecular sieve in the system is 2.6 percent. The added amount of the liquid phase product in the step (2) accounts for 62% of the mass fraction of the mixed material system in the step (3). Stirring at constant temperature of 45 ℃ for 4h. And then filtering and separating to obtain a solid-phase product and a liquid-phase product. The solid content of the liquid phase was controlled to be 1.0wt%.
(4) And (3) hydrothermal crystallization: mixing the solid-phase products obtained in the step (2) and the step (3) to obtain a solid-phase raw material of the step (4); mixing the liquid-phase product remained in the step (2) with the liquid-phase product obtained in the step (3) to obtain a liquid-phase raw material of the step (4); and feeding according to the metering ratio, and controlling the liquid-solid mass ratio of the mixed materials to be 2:1. Stirring uniformly, adding ammonia water to regulate pH to 4.5, crystallizing at 100deg.C for 24 hr, filtering, washing, drying at 100deg.C for 6 hr, and calcining at 550deg.C for 4 hr to obtain core-shell composite molecular sieve, which is designated as Al-SBA-15/beta-2. Step (4) SiO in the raw material 2 /Al 2 O 3 Molar ratio and composite molecular sieve SiO 2 /Al 2 O 3 The molar ratio was 98%. The physical parameters of the composite molecular sieve are shown in Table 1.XRD patterns are shown in fig. 1 and 3.
18.3 g of the Al-SBA-15/. Beta. -2 molecular sieve of the present example, 12.5 g of the Y molecular sieve (specific surface area 798m 2 Per gram, total pore volume 0.56mL/g, relative crystallinity 107%, siO 2 /Al 2 O 3 Molar ratio 45, unit cell parameter 2.430nm, total infrared acid content 0.279 mmol/g), 93 g amorphous silica alumina (pore volume 1.0mL/g, specific surface area 380m 2 Per gram, silica weight content 31%), and 32 grams of small pore alumina (pore volume 0.32mL/g, specific surface area 310 m) 2 Per g) with 37 g of 10% by weight dilute nitric acid, mixing in a roller millGrinding, adding water, grinding into paste, extruding, drying at 110deg.C for 4 hr, and calcining at 550deg.C for 4 hr to obtain carrier TCAT-2.
The carrier is immersed in immersion liquid containing tungsten and nickel for 2 hours at room temperature, dried for 4 hours at 120 ℃, and baked for 4 hours at a temperature of 500 ℃ by programming, thus obtaining the catalyst CAT-2, and the properties of the catalyst are shown in Table 2.
The catalyst CAT-2 was subjected to an activity evaluation test. The tests were carried out on a 200mL small hydrogenation unit using a one-stage serial hydrocracking process with the properties of the feedstock oil as shown in table 3. The hydrocracking operating conditions were as follows: the reaction pressure is 15.7MPa, and the hydrogen-oil volume ratio is 1200:1, liquid hourly space velocity 1.0h -1 The results of the catalyst evaluation after 300 hours of operation are shown in Table 4.
Example 3:
(1) 10.0g of TEOS was added to 25.0g of HCl solution with pH=2.9 under stirring, and after stirring at room temperature for 4 hours, the solution was changed from turbid solution to clear solution, and left to stand for 24 hours to obtain silicon source hydrolysate.
(2) 1.6g of P123 are dissolved in 120g of 0.45mol/L hydrochloric acid solution; 7.5g of hydrogen type beta molecular sieve (specific surface 541 m) 2 Per g, pore volume 0.40mL/g, particle size 800nm, siO 2 /Al 2 O 3 Molar ratio 41, na 2 Mixing O with weight content of 0.1% and relative crystallinity of 101%) with 40g of water, adding into the mixed solution of hydrochloric acid and P123, stirring for 5min, and adding 1/2 of silicon source hydrolysate obtained in step (1) and mixing uniformly. The molar concentration of hydrogen ions in the mixed material is 0.40mol/L; stirring at 48 ℃ for 4 hours at constant temperature. And then centrifugal separation is carried out to obtain a solid-phase product and a liquid-phase product. The solid content of the liquid phase product was controlled to be 1.2wt%.
(3) And (2) dissolving P123 in 0.45mol/L hydrochloric acid solution, adding 2/3 of the liquid phase product obtained in the step (2), adding hydrogen beta molecular sieve with the same property as the beta molecular sieve in the step (2), and mixing the rest silicon source hydrolysate uniformly. The molar concentration of hydrogen ions in the mixed material is 0.42mol/L, and the mass content of the added P123 in the system is 0.78%; the mass content of the added silicon source TEOS in the system is 4%; the mass content of the added beta molecular sieve in the system is 3.5 percent. The added amount of the liquid phase product in the step (2) accounts for 64% of the mass fraction of the mixed material system in the step (3). Stirring at 48 ℃ for 4 hours at constant temperature. And then filtering and separating to obtain a solid-phase product and a liquid-phase product. The solid content of the liquid phase was controlled to be 1.2wt%.
(4) And (3) hydrothermal crystallization: mixing the solid-phase products obtained in the step (2) and the step (3) to obtain a solid-phase raw material of the step (4); mixing the liquid-phase product remained in the step (2) with the liquid-phase product obtained in the step (3) to obtain a liquid-phase raw material of the step (4); and feeding according to the metering ratio, and controlling the liquid-solid mass ratio of the mixed materials to be 3:1. Stirring uniformly, adding ammonia water to regulate pH to 4.8, crystallizing at 100deg.C for 24 hr, filtering, washing, drying at 100deg.C for 6 hr, and calcining at 550deg.C for 4 hr to obtain core-shell composite molecular sieve, which is designated as Al-SBA-15/beta-3. Step (4) SiO in the raw material 2 /Al 2 O 3 Molar ratio and composite molecular sieve SiO 2 /Al 2 O 3 The molar ratio was 99%. The physical parameters of the composite molecular sieve are shown in Table 1.XRD patterns are shown in fig. 1 and 3. The TEM image is shown in FIG. 5.
23.9 g of the Al-SBA-15/. Beta. -3 molecular sieve of the present example, 10.6 g of the Y molecular sieve (specific surface area 760m 2 Per gram, total pore volume 0.55mL/g, relative crystallinity 118%, siO 2 /Al 2 O 3 Molar ratio 42, unit cell parameter 2.430nm, total infrared acid content 0.295 mmol/g), 100 g amorphous silica alumina (pore volume 0.9mL/g, specific surface area 350m 2 Per gram, 30% by weight of silica), 35 g of small-pore alumina (pore volume 0.38mL/g, specific surface area 360 m) 2 And/g) and 40 g of 10wt% dilute nitric acid, mixing and grinding in a rolling machine, adding water, grinding into paste, extruding the paste, drying the extruded paste at 110 ℃ for 4 hours, and roasting at 550 ℃ for 4 hours to obtain the carrier TCAT-3.
The carrier is immersed in immersion liquid containing tungsten and nickel for 2 hours at room temperature, dried for 4 hours at 120 ℃, and baked for 4 hours at a temperature of 500 ℃ by programming, thus obtaining the catalyst CAT-3, and the properties of the catalyst are shown in Table 2.
The catalyst CAT-3 was subjected to an activity evaluation test. The test was performed on a 200mL small hydrogenation unit using a one-stage serial hydrocracking processThe properties of the raw oil used are shown in Table 3. The operating conditions were as follows: the reaction pressure is 15.7MPa, and the hydrogen-oil volume ratio is 1200:1, liquid hourly space velocity 1.0h -1 The results of the catalyst evaluation after 300 hours of operation are shown in Table 4.
Comparative example 1:
(1) 5.0g of TEOS was added to 12.5g of HCl solution with pH=2.9 under stirring, and after stirring at room temperature for 4 hours, the solution was changed from turbid solution to clear solution, and left to stand for 24 hours to obtain silicon source hydrolysate.
(2) 1.6g of P123 are dissolved in 120g of a 0.45mol/L hydrochloric acid solution; 7.5g of hydrogen beta molecular sieve (raw material hydrogen beta molecular sieve in the step (2) in the example 3) and 40g of water are mixed, added into the mixed solution of hydrochloric acid and P123, stirred for 5min, and then added into the silicon source hydrolysate obtained in the step (1) to be uniformly mixed. The molar concentration of hydrogen ions in the mixed material is 0.40mol/L; stirring at constant temperature of 50 ℃ for 4 hours.
(3) And (3) hydrothermal crystallization: adding ammonia water into the product of the step (2) to adjust the pH of the system to 4.8, crystallizing at 100 ℃ for 24 hours, filtering, washing, drying at 100 ℃ for 6 hours, and roasting at 550 ℃ for 4 hours to obtain the core-shell composite molecular sieve, which is denoted as Al-SBA-15/beta-3-1. SiO in the raw material 2 /Al 2 O 3 Molar ratio and composite molecular sieve SiO 2 /Al 2 O 3 The ratio of the molar ratios was 92%. The physical parameters of the composite molecular sieve are shown in Table 1.XRD patterns are shown in FIG. 2 and FIG. 4, and TEM patterns are shown in FIG. 6.
23.9 g of the Al-SBA-15/. Beta. -3-1 molecular sieve of this example and 10.6 g of the Y molecular sieve (specific surface area 760m 2 Per gram, total pore volume 0.55mL/g, relative crystallinity 118%, siO 2 /Al 2 O 3 Molar ratio 42, unit cell parameter 2.430nm, total infrared acid content 0.295 mmol/g), 100 g amorphous silica alumina (pore volume 0.9mL/g, specific surface area 350m 2 Per gram, 30% by weight of silica), 35 g of small-pore alumina (pore volume 0.38mL/g, specific surface area 360 m) 2 And/g) and 40 g of 10wt% dilute nitric acid, mixing and grinding the mixture in a rolling machine, adding water, grinding the mixture into paste, extruding the paste, drying the extruded paste at 110 ℃ for 4 hours, and roasting the dried paste at 550 ℃ for 4 hours to obtain the carrier TCAT-3-1.
The carrier is immersed in the immersion liquid containing tungsten and nickel for 2 hours at room temperature, dried for 4 hours at 120 ℃, and baked for 4 hours at the temperature of 500 ℃ by programming, thus obtaining the catalyst CCAT-3-1, and the catalyst properties are shown in Table 2.
The catalyst CCAT-3-1 was subjected to an activity evaluation test. The tests were carried out on a 200mL small hydrogenation unit using a one-stage serial hydrocracking process with the properties of the feedstock oil as shown in table 3. The operating conditions were as follows: the reaction pressure is 15.7MPa, and the hydrogen-oil volume ratio is 1200:1, liquid hourly space velocity 1.0h -1 The results of the catalyst evaluation after 300 hours of operation are shown in Table 4.
Comparative example 2:
(1) 1.6g of P123 are dissolved in 120g of 0.45mol/L hydrochloric acid solution; 7.5g of hydrogen form beta molecular sieve (raw material hydrogen form beta molecular sieve in the same way as in the step (2) of the example 3) and 40g of water are mixed and added into the mixed solution of the hydrochloric acid and the P123, and the mixture is stirred for 5min, and then 5g of TEOS is slowly added dropwise by a pipette. The molar concentration of hydrogen ions in the mixture is 0.40mol/L, and the mixture is stirred for 30 hours at a constant temperature of 50 ℃.
(2) And (3) hydrothermal crystallization: adding ammonia water to regulate pH to 4.8, crystallizing at 100deg.C for 24 hr, filtering, washing, drying at 100deg.C for 6 hr, and calcining at 550deg.C for 4 hr to obtain core-shell composite molecular sieve, which is designated as Al-SBA-15/beta-3-2. SiO in the raw material 2 /Al 2 O 3 Molar ratio and composite molecular sieve SiO 2 /Al 2 O 3 The ratio of the molar ratio was 70%. The physical parameters of the composite molecular sieve are shown in Table 1.XRD patterns are shown in fig. 2 and 4.
23.9 g of the Al-SBA-15/. Beta. -3-2 molecular sieve of this example and 10.6 g of the Y molecular sieve (specific surface area 760m 2 Per gram, total pore volume 0.55mL/g, relative crystallinity 118%, siO 2 /Al 2 O 3 Molar ratio 42, unit cell parameter 2.430nm, total infrared acid content 0.295 mmol/g), 100 g amorphous silica alumina (pore volume 0.9mL/g, specific surface area 350m 2 Per gram, 30% by weight of silica), 35 g of small-pore alumina (pore volume 0.38mL/g, specific surface area 360 m) 2 And/g) and 40 g of 10wt% dilute nitric acid, mixing and grinding in a rolling machine, adding water, grinding into paste, extruding the paste, drying the extruded paste at 110 ℃ for 4 hours, and roasting at 550 ℃ for 4 hours to obtain the carrier TCAT-3-2.
The carrier is immersed in the immersion liquid containing tungsten and nickel for 2 hours at room temperature, dried for 4 hours at 120 ℃, and baked for 4 hours at the temperature of 500 ℃ by programming, thus obtaining the catalyst CCAT-3-2, and the catalyst properties are shown in Table 2.
The catalyst CCAT-3-2 was subjected to an activity evaluation test. The tests were carried out on a 200mL small hydrogenation unit using a one-stage serial hydrocracking process with the properties of the feedstock oil as shown in table 3. The operating conditions were as follows: the reaction pressure is 15.7MPa, and the hydrogen-oil volume ratio is 1200:1, liquid hourly space velocity 1.0h -1 The results of the catalyst evaluation after 300 hours of operation are shown in Table 4.
Comparative example 3:
(1) Under stirring, 10.0g of teos was added to 25.0g of 25.0gpH =2.9 of HCl solution, and after stirring at room temperature for 4 hours, the solution was changed from a turbid solution to a clear solution, and was left to stand for 24 hours, to obtain a silicon source hydrolysate.
(2) 1.6g of P123 are dissolved in 120g of 0.45mol/L hydrochloric acid solution; 7.5g of hydrogen beta molecular sieve (raw material hydrogen beta molecular sieve in the step (2) in the example 3) and 20g of water are mixed, added into the mixed solution of hydrochloric acid and P123, stirred for 5min, and then added into the silicon source hydrolysate obtained in the step (1) in the 1/2 step, and the mixture is uniformly mixed. The molar concentration of hydrogen ions in the mixed material is 0.40mol/L; stirring at constant temperature of 50 ℃ for 4 hours.
(3) And (3) hydrothermal crystallization: crystallizing the product in the step (2) for 24 hours at 100 ℃, filtering, washing, drying for 6 hours at 100 ℃, and roasting for 4 hours at 550 ℃ to obtain the core-shell structure Al-SBA-15/beta-3-3 material. SiO in the raw material 2 /Al 2 O 3 Molar ratio and composite molecular sieve SiO 2 /Al 2 O 3 The molar ratio was 57%. The physical parameters of the composite molecular sieve are shown in Table 1.XRD patterns are shown in fig. 2 and 4.
23.9 g of the Al-SBA-15/. Beta. -3-3 molecular sieve of this example and 10.6 g of the Y molecular sieve (specific surface area 760m 2 Per gram, total pore volume 0.55mL/g, relative crystallinity 118%, siO 2 /Al 2 O 3 Molar ratio 42, unit cell parameter 2.430nm, total infrared acid content 0.295 mmol/g), 100 g amorphous silica alumina (pore volume 0.9mL/g, specific surface area 350m 2 Per gram, 30% by weight of silica), 35 g of small-pore alumina (pore volume 0.38mL/g, specific surface area)360m of 2 And/g) and 40 g of 10wt% dilute nitric acid, mixing and grinding in a rolling machine, adding water, grinding into paste, extruding the paste, drying the extruded paste at 110 ℃ for 4 hours, and roasting at 550 ℃ for 4 hours to obtain the carrier TCAT-3-3.
The carrier is immersed in the immersion liquid containing tungsten and nickel for 2 hours at room temperature, dried for 4 hours at 120 ℃, and baked for 4 hours at a temperature of 500 ℃ by programming, thus obtaining the catalyst CCAT-3-3, and the catalyst properties are shown in Table 2.
The catalyst CCAT-3-3 was subjected to an activity evaluation test. The tests were carried out on a 200mL small hydrogenation unit using a one-stage serial hydrocracking process with the properties of the feedstock oil as shown in table 3. The operating conditions were as follows: the reaction pressure is 15.7MPa, and the hydrogen-oil volume ratio is 1200:1, liquid hourly space velocity 1.0h -1 The results of the catalyst evaluation after 300 hours of operation are shown in Table 4.
Comparative example 4:
10g of hydrogen type beta molecular sieve (the same as the raw material hydrogen type beta molecular sieve in the step (2) of the example 1) is added into hydrochloric acid solution with the molar concentration of hydrogen ions of 0.4mol/L, the liquid-solid mass ratio is controlled to be 10:1, and the mixture is stirred for 4 hours at the constant temperature of 50 ℃. Filtering, washing, drying at 120 ℃ for 6 hours, and roasting at 550 ℃ for 4 hours to obtain the beta-2 material. The physical parameters of the molecular sieve are shown in Table 1. The XRD spectrum is shown in FIG. 4.
Comparative example 5:
10g of hydrogen type beta molecular sieve (the same as the raw material hydrogen type beta molecular sieve in the step (2) of the example 1) is added into a hydrochloric acid solution with the molar concentration of hydrogen ions of 5mol/L, the liquid-solid mass ratio is controlled to be 10:1, and the mixture is stirred for 4 hours at the constant temperature of 50 ℃. Filtering, washing, drying at 120 ℃ for 6 hours, and roasting at 550 ℃ for 4 hours to obtain the beta-3 material. The physical parameters of the molecular sieve are shown in Table 1. The XRD spectrum is shown in FIG. 4.
Table 1 physicochemical properties of molecular sieves
Figure BDA0003328242490000171
Figure BDA0003328242490000181
The composite molecular sieve is shown in FIG. 5 as a core-shell Al-SBA-15/beta composite molecular sieve. As can be seen from FIGS. 5 and 6, the Al-SBA-15/beta-3 has less split-phase SBA-15, more uniform morphology and more complete "core-shell" structure than the Al-SBA-15/beta-3-1. As can be seen from Table 1, the molecular sieve prepared by the invention simultaneously completes in-situ aluminum supplementation of SBA-15. Meanwhile, the silicon-aluminum ratio of the beta molecular sieve is improved, and the structure and crystallinity of the beta molecular sieve are well maintained.
TABLE 2 physicochemical Properties of the catalysts
Figure BDA0003328242490000182
As can be seen from Table 2, compared with the catalyst of comparative example, the catalyst of the present invention has more uniform morphology and more complete core-shell structure, so that the catalyst has more uniform metal dispersion and larger pore volume and specific surface area. The total amount of infrared acids is also increased.
TABLE 3 Properties of raw oil
Raw oil Iran VGO
Density (20 ℃), g/cm 3 0.9081
Distillation range, DEG C 321～551
Condensation point, DEG C 32
Carbon residue, wt% 0.2
S，wt％ 2.34
N，μg/g 1502
Aromatic hydrocarbon, wt% 43.2
BMCI value 46.9
TABLE 4 evaluation results of catalyst Activity
Figure BDA0003328242490000191
As can be seen from the evaluation results of the catalysts in Table 4, the catalyst prepared by the invention has the characteristics of higher activity and medium oil selectivity, good product properties, especially high aviation kerosene smoke point, diesel oil cetane number, low condensation point and the like under the same operation conditions and with basically the same conversion rate.

Claims (16)

1. A hydrocracking catalyst for producing middle distillates, which is characterized in that the catalyst comprises, based on the weight of the catalyst: the content of the active metal is 4 to 40 weight percent of oxide; the content of the carrier is 60-96 wt%;
wherein, the carrier, based on the total mass of the carrier, comprises: 10 to 15 weight percent of Al-SBA-15/beta core-shell composite molecular sieve, 5 to 15 weight percent of Y molecular sieve, 20 to 60 weight percent of amorphous silica-alumina and 15 to 50 weight percent of adhesive component.
2. The hydrocracking catalyst of claim 1 wherein the active metal comprises at least one of a group VIB metal, a group VIII metal;
further preferably, the group VIB metal comprises W and/or Mo; the group VIII metal comprises Co and/or Ni.
3. The hydrocracking catalyst as claimed in claim 1, wherein the specific surface area of the Y molecular sieve is 700 to 1000m 2 /g; the total pore volume is 0.40-1.0 mL/g; the relative crystallinity is 95-130%; siO (SiO) 2 /Al 2 O 3 The molar ratio is 35-60; the unit cell parameters are 2.428 to 2.432nm; the total infrared acid amount is 0.2-0.4 mmol/g;
and/or SiO in the amorphous silica-alumina 2 The content is 20 to 60wt percent, preferably 25 to 35wt percent; the pore volume is 0.6-1.1 mL/g, preferably 0.8-1.0 mL/g; specific surface area of 300-500 m 2 Preferably 350 to 500m 2 /g。
4. The hydrocracking catalyst as claimed in claim 1, wherein the specific surface area of the catalyst is 280 to 600m 2 /g; the pore volume is 0.3-0.7 mL/g.
5. The hydrocracking catalyst of claim 1, wherein the composite molecular sieve is a shell of Al-SBA-15 and a core of beta molecular sieve; the mass ratio of the shell to the core is 20:80-30:70; siO of the composite molecular sieve 2 /Al 2 O 3 The molar ratio is 40-60;
further preferably, the mass ratio of framework aluminum to non-framework aluminum in the composite molecular sieve is 95:5-99:1.
6. A process for the preparation of a hydrocracking catalyst as claimed in any one of claims 1 to 5, characterized in that it comprises the steps of:
mixing Al-SBA-15/beta core-shell composite molecular sieve, Y molecular sieve, amorphous silica-alumina and adhesive, molding, drying and roasting to obtain a catalyst carrier; and loading active metal on the carrier to obtain the catalyst.
7. The preparation method according to claim 6, wherein the Al-SBA-15/β core-shell composite molecular sieve is prepared according to a method comprising the steps of:
(1) Adding a silicon source into the acid solution, uniformly mixing, standing and aging to obtain a silicon source hydrolysate;
(2) Uniformly mixing part of the silicon source hydrolysate in the step (1), the first beta molecular sieve and the first template agent, performing a first reaction, and performing first solid-liquid separation to obtain a first solid-phase product and a first liquid-phase product;
controlling the solid content of the first liquid phase product to be 0.1-8wt%, preferably 0.5-2wt%, and more preferably 0.8-1.5wt%;
(3) Uniformly mixing part of the silicon source hydrolysate in the step (1), the second beta molecular sieve, part of the first liquid phase product obtained in the step (2) and the second template agent, and performing a second reaction and second solid-liquid separation to obtain a second solid phase product and a second liquid phase product;
controlling the solid content of the second liquid phase product to be 0.1-8wt%, preferably 0.5-2wt%, and more preferably 0.8-1.5wt%;
(4) And taking the mixture of the first solid-phase product and the second solid-phase product and the first liquid-phase product and/or the second liquid-phase product as raw materials, carrying out hydrothermal crystallization, washing, drying and roasting to obtain the Al-SBA-15/beta core-shell composite molecular sieve.
8. The process according to claim 7, wherein the molar concentration of hydrogen ions in the mixed material obtained by the mixing in the step (2) is 0.2 to 0.7mol/L, preferably 0.3 to 0.5mol/L; the mass content of the first template agent in the system is 0.3-3%, preferably 0.5-2%; the mass content of the silicon source in the system is 1% -7%, preferably 2% -6%; the mass content of the first beta molecular sieve in the system is 0.5-12%, preferably 1.0-8%;
And/or, in the mixed material obtained by the step (3), the molar concentration of hydrogen ions is 0.2-0.7 mol/L, preferably 0.3-0.5 mol/L; the mass content of the added second template agent in the system is 0.3-3%, preferably 0.2-2%; the mass content of the added silicon source in the system is 1-7%, preferably 2-6%; the mass content of the added second beta molecular sieve in the system is 0.5-12%, preferably 1.0-8%; the addition amount of the first liquid phase product accounts for 60-80% of the mass fraction of the mixed material system in the step (3), and is preferably 60-75%.
9. The method according to claim 7, wherein the silicon source in the step (1) is one or more of methyl orthosilicate, ethyl orthosilicate TEOS, propyl orthosilicate, isopropyl orthosilicate, butyl orthosilicate; the acid is one or more of hydrochloric acid, sulfuric acid and phosphoric acid; the pH of the acid solution is 2-5, preferably 2.5-4.0;
and/or, in the step (2), the first template agent is P123;
and/or, in the step (2), the first beta molecular sieve is a hydrogen beta molecular sieve;
further preferably, the first beta molecular sieve Na in step (2) 2 The weight content of O is less than 0.3 percent; silicon to aluminum molar ratio SiO 2 /Al 2 O 3 30 to 45; specific surface area of 400-700 m 2 /g; the pore volume is 0.3-0.6 mL/g; the grain diameter is 500-1000 nm;
and/or, in the step (3), the second beta molecular sieve is a hydrogen beta molecular sieve;
further preferably, the second beta molecular sieve Na in step (3) 2 The weight content of O is less than 0.3 percent; silicon to aluminum molar ratio SiO 2 /Al 2 O 3 30 to 45; specific surface area of 400-700 m 2 /g; the pore volume is 0.3-0.6 mL/g, and the grain diameter is 500-1000 nm.
10. The method according to claim 7, wherein the conditions of the first reaction in step (2) are: the reaction temperature is 30-60 ℃, preferably 35-50 ℃, and the reaction time is 2-12 h, preferably 4-8 h;
and/or, the conditions of the second reaction in step (3) are: the reaction temperature is 30-60 ℃, preferably 35-50 ℃, and the reaction time is 2-12 h, preferably 4-8 h.
11. The process according to claim 7, wherein SiO in the raw material of step (4) 2 /Al 2 O 3 Molar ratio to the composite molecular sieve SiO in step (4) 2 /Al 2 O 3 The ratio of the molar ratio is 97% -100%.
12. The method according to claim 7, wherein in the step (4), the liquid-solid mass ratio after mixing the raw materials is controlled to be 1:1 to 10:1, preferably 1:1 to 8:1, and more preferably 1:1 to 5:1 by adjusting the addition amount of the first liquid-phase product and/or the second liquid-phase product.
13. The method according to claim 7, wherein the hydrothermal crystallization conditions in the step (4) are: the crystallization temperature is 80-140 ℃, preferably 100-120 ℃; the crystallization time is 4-48 h, preferably 24-30 h;
and/or the drying temperature is 100-120 ℃, and the drying time is 6-10 h;
and/or the roasting temperature is 500-550 ℃ and the roasting time is 4-6 h.
14. The method according to claim 6, wherein the drying is for 3 to 10 hours at a temperature of 80 to 150 ℃; the roasting is carried out for 3 to 12 hours at the temperature of 400 to 800 ℃;
and/or, the method for loading the active metal is an impregnation method;
further preferably, the impregnation method is to impregnate the carrier with a solution containing active metal, dry and bake the carrier to obtain the catalyst; preferably, the drying is 100-150 ℃ drying for l-12 hours; the roasting is carried out for 3-12 hours at 400-750 ℃.
15. Use of the catalyst of any one of claims 1 to 5 or the catalyst prepared by the method of any one of claims 6 to 14 in a heavy oil hydrocracking reaction; the method is a series hydrocracking process and is used for producing middle distillate.
16. The use according to claim 15, wherein the hydrocracking conditions in the one-stage tandem hydrocracking process are: the reaction temperature is 350-420 ℃, preferably 360-390 ℃; the reaction pressure is 6-20 MPa, preferably 9-16 MPa; the volume ratio of hydrogen to oil is 500-2000:1, preferably 800-1500: 1, a step of; the liquid hourly space velocity is 0.5 to 1.8h -1 Preferably 0.8 to 1.5h -1 。
CN202111269658.9A 2021-10-29 2021-10-29 Hydrocracking catalyst for producing middle distillate oil, and preparation method and application thereof Pending CN116060111A (en)

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