CN117402652A - Method for producing low-freezing diesel oil - Google Patents

Method for producing low-freezing diesel oil Download PDF

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Publication number
CN117402652A
CN117402652A CN202210777955.2A CN202210777955A CN117402652A CN 117402652 A CN117402652 A CN 117402652A CN 202210777955 A CN202210777955 A CN 202210777955A CN 117402652 A CN117402652 A CN 117402652A
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content
catalyst
hydrocracking
reaction zone
oil
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孙晓艳
于政敏
樊宏飞
陈玉晶
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Sinopec Dalian Petrochemical Research Institute Co ltd
China Petroleum and Chemical Corp
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Sinopec Dalian Petrochemical Research Institute Co ltd
China Petroleum and Chemical Corp
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    • 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
    • C10G65/00—Treatment of hydrocarbon oils by two or more hydrotreatment processes only
    • C10G65/02—Treatment of hydrocarbon oils by two or more hydrotreatment processes only plural serial stages only
    • C10G65/12—Treatment of hydrocarbon oils by two or more hydrotreatment processes only plural serial stages only including cracking steps and other hydrotreatment steps
    • 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
    • B01J29/7892—MTT-type, e.g. ZSM-23, KZ-1, ISI-4 or EU-13
    • 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
    • B01J2229/00—Aspects of molecular sieve catalysts not covered by B01J29/00
    • B01J2229/10—After treatment, characterised by the effect to be obtained
    • B01J2229/18—After treatment, characterised by the effect to be obtained to introduce other elements into or onto the molecular sieve itself

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Organic Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Catalysts (AREA)

Abstract

The invention discloses a method for producing low-freezing diesel oil, which comprises the following steps: the raw oil sequentially passes through a hydrofining reaction zone and a hydrocracking reaction zone, wherein the hydrocracking reaction zone is sequentially filled with a hydrocracking catalyst and an isomerization catalyst along the material flow direction, and the filling volume ratio of the hydrocracking catalyst to the isomerization catalyst is 20:1-2:1, preferably 18:1-3:1, and further preferably 15:1-5:1. The method can produce diesel oil in maximum when processing heavy raw oil with high nitrogen content, and has better pour point depressing effect.

Description

Method for producing low-freezing diesel oil
Technical Field
The present invention relates to a method for producing low-freezing point diesel oil, and more particularly, to a method for producing low-freezing point diesel oil in maximum amount by hydrocracking.
Background
With the increasing activity of social and economic activities in winter, people living in alpine regions or winter pay more attention to the low-temperature flow performance of the diesel oil products, and only the low-condensation-point diesel oil products can meet the actual use demands. In winter, a large amount of low-freezing diesel oil is needed in northern cold areas, the low-temperature fluidity (condensation point, cold filtration point, pour point and the like) index of the diesel oil is more important, and the hydrocracking technology is a main technology for producing high-quality diesel oil from heavy raw oil.
When the hydrocracking catalysts containing the Y-type molecular sieve are selected for producing diesel oil by CN104826646A and CN103100403A, the diesel oil congeals point is low, and especially when the diesel oil is deeply pulled or wide-fraction diesel oil is produced, the problem is more remarkable. The catalysts disclosed in CN101578353a and CN106140280a can be used to produce high yields of low freezing point diesel fractions, the molecular sieve component of the catalysts used being selected from beta molecular sieves. When the methods are used for producing diesel oil, a hydrofining and hydrocracking series process is adopted, the selectivity of the diesel oil is low, and the condensation point of the diesel oil is high. CN109988644a discloses a method for producing gasoline and low-freezing diesel oil by catalyst collection technology,
the cracking section catalyst adopts a polar ligand system, and the molecular sieve of the catalyst adopts a Y-type molecular sieve and a beta-type molecular sieve respectively
The sieve is used for processing inferior raw oil such as decompressed wax oil and the like, producing gasoline and diesel oil, and has low selectivity and diesel oil
The oily congealing point is to be further increased.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a method for producing low-freezing diesel oil. The diesel oil is produced in maximum when the heavy raw oil with high nitrogen content is processed, and meanwhile, the diesel oil has better pour point depressing effect.
A method of producing a low freezing point diesel fuel, the method comprising: the raw oil sequentially passes through a hydrofining reaction zone and a hydrocracking reaction zone, wherein the hydrocracking reaction zone is sequentially filled with a hydrocracking catalyst and an isomerization catalyst along the material flow direction, and the filling volume ratio of the hydrocracking catalyst to the isomerization catalyst is 20:1-2:1, preferably 18:1-3:1, and further preferably 15:1-5:1.
In the above method, the raw oil properties are as follows: the weight VGO with the distillation range of 300-600 ℃ has the nitrogen mass content of 800-2500 ppm.
In the above method, the hydrofining catalyst filled in the hydrofining reaction zone is a conventional hydrofining catalyst, generally an alumina carrier is adopted, the VIB group and the VIII group metals are taken as hydrogenation active metal components, the VIB group metals are preferably molybdenum and/or tungsten, and the VIII group metals are preferably cobalt and/or nickel. The content of the VIB group metal (calculated as oxide) is 13.0% -25.0% and the content of the VIII group metal (calculated as oxide) is 4.0% -7.0% based on the weight of the catalyst. In the above method, the operation conditions of the hydrofining reaction zone are as follows: the reaction temperature is 350-400 ℃, preferably 360-390 ℃; the reaction pressure is 10-20 MPa, preferably 12-16 MPa; the volume ratio of hydrogen to oil is 500-2000:1, preferably 800-1200: 1, a step of; liquid hourly space velocity of 0.5-2.0 h -1 Preferably 0.8 to 1.5. 1.5h -1 。
In the method, the hydrocracking catalyst comprises 10-30wt% of beta molecular sieve, 20-60wt% of amorphous silicon aluminum, 10-40wt% of binder, 10-25wt% of VIB group metal (calculated as oxide) and 4-15wt% of VIII group metal (calculated as oxide), wherein the VIB group metal is molybdenum and/or tungsten, and the VIII group metal is cobalt and/or nickel. SiO in the amorphous silicon aluminum 2 The weight content of the amorphous silica-alumina is 20% -50%, preferably 25% -40%, and the properties of the amorphous silica-alumina are as follows: pore volume of 0.7-1.2 mL/g, preferably 0.8-1.0 mL/g, specific surface area of 300-500 m 2 Preferably 350 to 500 and m per gram 2 And/g. The beta molecular sieve has the following properties: na (Na) 2 The weight content of O is less than 0.3 percent; silicon to aluminum molar ratio SiO 2 /Al 2 O 3 60-90; specific surface area of 400-700 m 2 /g; the pore volume is 0.3-0.6 mL/g; the particle size is 500-1000 nm, and the beta-type molecular sieve can be prepared by adopting the prior art.
In the method, the isomerization catalyst comprises 20-60 wt% of HZSM-23 molecular sieve, 15-40 wt% of macroporous alumina, 10-25 wt% of binder, 10-25 wt% of group VIB metal (calculated as oxide) and 4-15 wt% of group VIII metal (calculated as oxide), wherein the group VIB metal is preferably molybdenum and/or tungsten, and the group VIII metal is preferably cobalt and/or nickel. The isomerisation catalyst may be prepared using prior art techniques or using the specific process of the invention, preferably using the latter.
The specific surface area of the isomerization catalyst prepared by the specific method is 250-500 m 2 Per gram, the pore volume is 0.30-0.70 cm 3 /g; the specific surface area is preferably 300-450 m 2 Preferably, the pore volume per gram is 0.37-0.60 cm 3 /g; the weak acid content in the catalyst accounts for 75-90% of the total acid content; preferably, the weak acid content accounts for 80-90% of the total acid content. The isomerization catalyst prepared by the method has high weak acid content, is favorable for isomerization reaction of materials after hydrocracking, and reduces cracking reaction.
In the above method, the operation conditions of the hydrocracking catalyst bed in the hydrocracking reaction zone are as follows: the reaction temperature is 360-420 ℃, preferably 370-390 ℃; the reaction pressure is 10-20 MPa, preferably 12-16 MPa; the volume ratio of hydrogen to oil is 500-2000:1, preferably 800-1200: 1, a step of; liquid hourly space velocity of 0.5-2.0 h -1 Preferably 0.8 to 1.5. 1.5h -1 。
In the above process, the operating conditions of the hydrocracking reaction zone isomerization catalyst bed are as follows: the reaction temperature is 360-400 ℃, preferably 370-390 ℃; the reaction pressure is 10-20 MPa, preferably 12-16 MPa; the volume ratio of hydrogen to oil is 500-2000:1, preferably 800-1200: 1, a step of; liquid hourly space velocity of 0.5-2.0 h -1 Preferably 1.0 to 1.5. 1.5h -1 。 。
In the method for producing low-freezing diesel oil provided by the invention, the hydrocracking reaction zone is sequentially filled with the hydrocracking catalyst and the isomerization catalyst respectively, the refined material is subjected to ring opening and one-time cracking in the beta molecular sieve with a large number of strong acid sites, long-chain alkane is subjected to isomerization in the beta molecular sieve with a small number of weak acid sites, the selectivity of diesel oil fraction of the catalyst is improved, the condensation point of diesel oil is reduced, the cracked material enters the HZSM-23 molecular sieve to be subjected to hydroisomerization, the selectivity of wide fraction diesel oil is improved, the cetane number of the product is improved, and the condensation point of the diesel oil is reduced. The method can produce low-freezing point diesel oil in maximum.
Detailed Description
In the method of the invention, the preparation method of the isomerization catalyst comprises the following steps: mixing ZSM-23 molecular sieve, macroporous alumina and adhesive, shaping, drying and roasting to obtain carrier; then loading hydrogenation active metal. The loading of the hydrogenation active metal can be carried out by adopting a loading method which is conventional in the prior art, preferably an impregnation method, and can be saturated impregnation, excessive impregnation or complexation impregnation, namely, impregnating the catalyst carrier with a solution containing the required active component, drying the impregnated carrier for 4-12 hours at 100-150 ℃, and then roasting for 3-8 hours at 400-750 ℃ to prepare the final isomerization catalyst.
In the preparation method of the isomerization catalyst, the pore volume of the macroporous alumina is 0.7-1.5 mL/g, and the specific surface area is 400-600 m 2 /g。
In the preparation method of the isomerization catalyst of the present invention, the binder may be a binder commonly used in the art, preferably, a small pore alumina. The pore volume of the used small-pore alumina is 0.3-0.5 mL/g, and the specific surface area is 200-400 m 2 /g。
In the preparation method of the isomerization catalyst, the preparation of the ZSM-23 molecular sieve refers to the preparation method of CN202210011752.2, and the preparation steps of the HZSM-23 molecular sieve are as follows:
(1) Preparing a mixed solution containing a structure directing agent and amorphous silicon aluminum or an amorphous silicon aluminum precursor;
(2) Adding a supplemental silicon source to the material of step (1);
(3) And (3) crystallizing, filtering, washing, drying and roasting the material in the step (2) to obtain the ZSM-23 molecular sieve.
(4) And (3) carrying out ammonium exchange on the molecular sieve obtained in the step (3) to obtain the HZSM-23 molecular sieve.
In the step (1) of the method, the structure directing agent is one or more of isopropylamine, pyrrolidine, N-dimethylformamide and dimethylamine.
In the above method step (1), silicon (in terms of silicon oxide) in the mixed solution: the molar ratio of aluminum (calculated as aluminum oxide) is 1 (0.10-0.85), preferably 1 (0.20-0.79), and more preferably 1 (0.24-0.78); the molar ratio of the aluminum (calculated as aluminum oxide) to the structure directing agent is 1 (10-100), preferably 1 (15-85), and more preferably 1 (20-65).
In the step (1) of the method, preparing an amorphous silicon-aluminum precursor mixed solution by adopting a carbonization method, and then adding a structure guiding agent into the amorphous silicon-aluminum precursor mixed solution.
The preparation process of the non-limiting amorphous silicon aluminum precursor mixed solution in the embodiment of the invention comprises the following steps: preparing an aluminum source (preferably sodium aluminate) solution and a silicon-containing compound solution respectively; mixing sodium aluminate solution with partial silicon compound solution, introducing CO 2 The gas is glued, when the CO is introduced 2 When the gas volume amount is 50-100% of the total introduced volume amount, preferably 70-90%, adding the rest silicon compound solution, and introducing the rest CO 2 And (3) preparing an amorphous silicon aluminum precursor mixed solution after gas, optionally aging.
In the preparation process of the amorphous silicon aluminum precursor mixed solution, the residual silicon compound-containing solution accounts for 30-90 wt% of the total added silicon compound-containing solution calculated by silicon dioxide, and is preferably 40-80 wt%.
In the preparation process of the amorphous silicon aluminum precursor mixed solution, the reaction temperature of the gel forming is 10-40 ℃, preferably 15-35 ℃, and the pH value after the gel forming is controlled to be 9-12.
In the preparation process of the amorphous silicon aluminum precursor mixed solution, the silicon-containing compound solution is water glass and/or sodium silicate solution.
In the preparation process of the amorphous silicon aluminum precursor mixed solution, A1 is adopted 2 O 3 The concentration of the aluminum source solution is 15-60 g of Al by mass 2 O 3 L, siO 2 The concentration of the silicon-containing compound solution is 40-260 g SiO by mass 2 L, said CO 2 The concentration of the gas is 30-60 v%.
In the preparation process of the amorphous silicon aluminum precursor mixed solution, the aging time is 5-60 minutes, preferably 10-30 minutes; the aging temperature is 10-40 ℃, preferably 15-35 ℃.
In the step (1) of the method, the mixed solution is stirred at 10-35 ℃ for 0.2-1.5 hours, preferably at 10-25 ℃ for 0.5-1 hour.
In the step (2) of the method, based on aluminum (calculated as aluminum oxide) in the mixed solution in the step (1), the mixed solution is prepared according to SiO 2 : Al 2 O 3 : H 2 O=1 (0.005 to 0.0125): (30 to 60), SDA (structure directing agent)/SiO 2 And (3) adding a supplementary silicon source into the material in the step (1) in a total feeding molar ratio of 0.10-1.8.
In the step (2) of the method, the silicon source is one or more of fumed silica, silica sol and water glass.
In the above method step (3), the crystallization conditions are: crystallizing for 10-48 hours at 160-180 ℃; the drying temperature is 80-120 ℃ and the drying time is 4-8 hours; the roasting temperature is 500-600 ℃ and the roasting time is 2-8 hours.
In the above method step (4), the ammonium exchange is carried out by a conventional method, such as one or more ammonium exchanges, na in HZSM-23 molecular sieve after ammonium exchange 2 The O content is lower than 0.1%; washing, drying and roasting, wherein the drying temperature is 60-130 ℃, the time is 2-12 hours, and the drying is preferably carried out at 80-120 ℃ for 4-8 hours; the roasting temperature is 500-600 ℃, the time is 2-8 hours, and the roasting is preferably carried out for 3-6 hours at 530-570 ℃.
The HZSM-23 molecular sieve had the following properties: the grain size is 300-600 nm, siO 2 /Al 2 O 3 The molar ratio is 80-130, and the specific surface area is 300-400 m 2 Per gram, pore volume of 0.30-0.45 cm 3 And/g. The total acid amount is 0.1-0.25 mmol/g, and the strong acid content is 10-25%; the relative crystallinity is 95-120%, and the relative crystallinity after the steam hydrothermal treatment is 93-115%; preferably, the total acid amount is 0.15-0.25 mmol/g, and the strong acid content is 10-20%; the relative crystallinity is 98-116%, and the relative crystallinity after the steam hydrothermal treatment is 95-114%.
The catalyst of the invention can be molded according to actual needs, and the shape of the catalyst can be cylindrical strips, clover and the like. In the catalyst forming process, forming aids such as peptizing acid, extrusion aids and the like can be added. The catalyst carrier of the invention is dried and roasted by a conventional method, and is concretely as follows: drying at 80-150 deg.c for 3-10 hr and roasting at 400-800 deg.c for 3-12 hr.
In the preparation method of the HZSM-23 molecular sieve, all aluminum sources required by synthesis are added when the amorphous silicon-aluminum precursor is prepared, so that the generation of a primary structural unit of the molecular sieve is promoted; when the structure directing agent is added into the amorphous silicon aluminum precursor, the structure directing agent is preferentially chelated with Al species and then is adsorbed on the surface of a formed primary structural unit, so that the preassembly of a molecular sieve structure is realized, and a large number of crystal nuclei are generated; meanwhile, the binding site of Al atoms can be better controlled, and the ZSM-23 with more weak acid sites can be prepared by later crystallization. After the supplementary silicon source is added to form final gel, a large amount of crystal nucleus can be quickly grown into ZSM-23 molecular sieve with high crystallinity and small grain size through static crystallization.
In order to better illustrate the present invention, the present invention will be further described with reference to examples and comparative examples. The scope of the invention is not limited to the scope of the embodiments.
In the invention, the specific surface area and pore volume are measured by a low-temperature liquid nitrogen physical adsorption method by an ASAP 2405 type physical adsorption instrument of Micromerics corporation.
The molar ratio of silicon to aluminum is determined by chemical analysis.
XRD spectra of the samples were collected using an X-ray diffractometer model Dmax2500 manufactured by Japanese Physics company. The relative crystallinity of the molecular sieve was determined by X-ray powder diffraction (XRD), specifically using the sum of the heights of diffraction peaks at about 11.3 and 19.5-23 DEG in the conventional ZSM-23 molecular sieve XRD spectrum as 100% of the crystallinity, and the crystallinity of H-DZSM-23-1 prepared in example 6 of the present invention was 100, and the relative crystallinity was obtained by comparing other samples.
The grain size was obtained by JSM-7500F field emission scanning electron microscope (JEOL Co., japan).
Acid distribution (bag)Including total acid content and strong acid content) is determined from NH 3 Programmed temperature desorption (NH) 3 TPD), wherein the amount of acid corresponding to a desorption temperature above 350 ℃ is taken as the amount of strong acid. A weak acid at less than 350C,the total acid amount isAcid quantity corresponding to adsorption temperature of 150 DEG C。
In the invention, wt% is mass fraction and v% is volume fraction.
Example 1
(1) Preparation of amorphous silica-alumina precursor
Preparing Al with concentration of 40 g 2 O 3 Collecting SiO-containing working solution of sodium aluminate 2 28 Sodium silicate solution of weight percent, which is diluted again to a concentration of 100 g SiO 2 L sodium silicate working solution. Placing 150 mL sodium aluminate working solution into a gel forming tank, adding 60 mL sodium silicate working solution, controlling the reaction temperature to 20 ℃, and introducing CO with the concentration of 50 v% 2 Stopping introducing CO when pH value reaches 10.0 2 Adding 80 mL sodium silicate working solution, and introducing residual CO 2 And (3) stabilizing gas, and aging for 30 minutes at the temperature of 25 ℃ to obtain the amorphous silicon aluminum precursor. The amorphous silica-alumina precursor is 70 wt% by weight based on the total weight of silica and alumina.
(2) Preparation of gels
According to SiO 2 : Al 2 O 3 : IPA : H 2 Adding isopropylamine into the amorphous silicon aluminum precursor obtained in the step (1) according to the total feeding molar ratio of O=1:0.01:0.04:0.7:45 (IPA is a structure directing agent isopropylamine), and stirring for 0.8 hours at 15 ℃; and then adding a mixture consisting of silica sol and water into the mixture, and uniformly stirring to obtain the silica-alumina gel.
(3) Crystallization
Pouring the gel obtained in the step (2) into a stainless steel reaction kettle, and carrying out static crystallization for 20 hours at 160 ℃. After crystallization, filtering, washing to neutrality, drying at 120 ℃, roasting in air at 550 ℃ for 3 hours, and obtaining molecular sieve raw powder NaZSM-23-1.
(4) Ammonium exchange
A certain amount of NaZSM-23-1 molecular sieve is weighed and placed in an ammonium nitrate solution with the concentration of 2 mol/L, the liquid-solid ratio is 10, and the mixture is filtered and washed after being continuously stirred for 1 hour in a water bath with the temperature of 80-90 ℃. Repeating the operation process twice, placing the sample in an oven at 80-100 ℃ for drying for 8 hours, and roasting for 3 hours in an air atmosphere at 550 ℃ to obtain HZSM-23-1, wherein the relative crystallinity is measured by XRD; after HZSM-23-1 was subjected to steam water heat treatment at 600℃for 2 hours, the relative crystallinity after the steam heat treatment was measured, and specific properties thereof are shown in Table 1.
(5) Catalyst preparation
The catalyst weight percentage of HZSM-23-1 molecular sieve and 40 percent of macroporous alumina (pore volume 0.9mL/g, specific surface area 450m 2 Per g), and 17% of small pore alumina (pore volume 0.35 mL/g, specific surface area 330 m) 2 Adhesive (HNO) consisting of 10% by weight of dilute nitric acid 3 Pinhole Al 2 O 3 Is put into a rolling machine to be mixed and milled, water is added to be milled into paste, the paste is extruded, the extruded bar is dried for 4 hours at 110 ℃, and then the extruded bar is baked for 4 hours at 550 ℃ to obtain the carrier TC-1.
The carrier is immersed in an immersion liquid containing tungsten and nickel for 2 hours at room temperature, dried for 4 hours at 120 ℃, and baked for 4 hours at 500 ℃ with a programmed temperature, so as to obtain a catalyst C-1, and the properties of the corresponding catalyst are shown in Table 2.
Example 2
(1) Preparation of amorphous silica-alumina precursor
Preparing Al with concentration of 40 g 2 O 3 Collecting SiO-containing working solution of sodium aluminate 2 28 Sodium silicate solution of weight percent, which is diluted again to a concentration of 120 g SiO 2 L sodium silicate working solution. Placing 200mL sodium aluminate working solution into a gel forming tank, adding 40 mL sodium silicate working solution, controlling the reaction temperature to 25 ℃, and introducing CO with the concentration of 50 v% 2 Stopping introducing CO when pH value reaches 10.5 2 Adding 60 mL sodium silicate working solution, and introducing residual CO 2 And (3) stabilizing gas, and aging for 20 minutes at 20 ℃ to obtain an amorphous silicon aluminum precursor, wherein the content of the amorphous silicon aluminum precursor is 40wt percent based on the total weight of silicon dioxide and aluminum oxide.
(2) Preparation of gels
According to SiO 2 : Al 2 O 3 : IPA : H 2 Adding isopropylamine into the amorphous silicon aluminum precursor obtained in the step (1) according to the total feeding molar ratio of O=1:0.01:0.04:0.15:60, and stirring for 1 hour at 20 ℃; and then adding a mixture consisting of silica sol and water into the mixture, and uniformly stirring to obtain the silica-alumina gel.
(3) Crystallization
Pouring the gel obtained in the step (2) into a stainless steel reaction kettle, and carrying out static crystallization for 22 hours at 180 ℃. After crystallization, filtering, washing to neutrality, drying at 120 ℃, roasting in air at 550 ℃ for 3 hours, and obtaining molecular sieve raw powder NaZSM-23-2.
(4) Ammonium exchange
HZSM-23-2 was prepared in the same manner as in example 1 (4), except that NaZSM-23-1 molecular sieve was replaced with HZSM-23-2, and specific properties are shown in Table 1.
(5) Catalyst preparation
30% of HZSM-23-2 molecular sieve and 32% of macroporous alumina (pore volume 1.0mL/g, specific surface area 470m 2 Per g), and 15% of small-pore alumina (pore volume 0.35 mL/g, specific surface area 330 m) 2 Adhesive (HNO) composed of dilute nitric acid with concentration of 12% by weight 3 Pinhole Al 2 O 3 Is put into a rolling machine to be mixed and milled, water is added to be milled into paste, the paste is extruded, the extruded bar is dried for 4 hours at 110 ℃, and then the extruded bar is baked for 4 hours at 550 ℃ to obtain the carrier TC-2.
The carrier is immersed in an immersion liquid containing tungsten and nickel for 2 hours at room temperature, dried for 4 hours at 120 ℃, and baked for 4 hours at 500 ℃ with a programmed temperature, so as to obtain a catalyst C-2, and the properties of the corresponding catalyst are shown in Table 2.
Example 3
(1) Preparation of amorphous silica-alumina precursor
Preparing Al with concentration of 35 g 2 O 3 Collecting SiO-containing working solution of sodium aluminate 2 28 Sodium silicate solution of weight percent, which is diluted again to a concentration of 65 g SiO 2 L sodium silicate working solution. Placing 100 mL sodium aluminate working solution into a sizing tank, and then adding 40 mL sodium silicate to workControlling the reaction temperature of the solution to 30 ℃, and introducing CO with the concentration of 50 v percent 2 Stopping introducing CO when pH value reaches 11.0 2 Adding 60 mL sodium silicate working solution, and introducing residual CO 2 And (3) stabilizing gas, and aging for 30 minutes at 20 ℃ to obtain an amorphous silicon aluminum precursor, wherein the content of the amorphous silicon aluminum precursor is 35 wt percent based on the total weight of silicon dioxide and aluminum oxide and calculated on the basis of the silicon dioxide.
(2) Preparation of gels
According to SiO 2 : Al 2 O 3 : IPA : H 2 Adding isopropylamine into the amorphous silicon aluminum precursor obtained in the step (1) according to the total feeding molar ratio of O=1:0.008:0.3:45, and stirring for 1 hour at 15 ℃; and then adding a mixture consisting of silica sol and water into the mixture, and uniformly stirring to obtain the silica-alumina gel.
(3) Crystallization
Pouring the gel obtained in the step (2) into a stainless steel reaction kettle, and carrying out static crystallization for 25 hours at 160 ℃. After crystallization, filtering, washing to neutrality, drying at 120 ℃, roasting in air at 550 ℃ for 3 hours, and obtaining molecular sieve raw powder NaZSM-23-3.
(4) Ammonium exchange
HZSM-23-3 was prepared in the same manner as in example 1 (4), except that NaZSM-23-1 molecular sieve was replaced with HZSM-23-3, and specific properties are shown in Table 1.
(5) Catalyst preparation
40% of HZSM-23-3 molecular sieve and 23% of macroporous alumina (pore volume 1.1mL/g, specific surface area 500m 2 Per g), and 12% of small-pore alumina (pore volume 0.35 mL/g, specific surface area 330 m) 2 Adhesive (HNO) consisting of 10% by weight of dilute nitric acid 3 Pinhole Al 2 O 3 Is put into a rolling machine to be mixed and milled, water is added to be milled into paste, the paste is extruded, the extruded bar is dried for 4 hours at 110 ℃, and then the extruded bar is baked for 4 hours at 550 ℃ to obtain the carrier TC-3.
The carrier is immersed in an immersion liquid containing tungsten and nickel for 2 hours at room temperature, dried for 4 hours at 120 ℃, and baked for 4 hours at 500 ℃ with a programmed temperature, so as to obtain a catalyst C-3, and the properties of the corresponding catalyst are shown in Table 2.
Example 4
(1) Preparation of amorphous silica-alumina precursor
Preparing Al with concentration of 40 g 2 O 3 Collecting SiO-containing working solution of sodium aluminate 2 28 A sodium silicate solution of weight percent was then diluted to a concentration of 60 g SiO 2 L sodium silicate working solution. Placing 150 mL sodium aluminate working solution into a gel forming tank, adding 500 mL sodium silicate working solution, controlling the reaction temperature to 20 ℃, and introducing CO with the concentration of 50 v% 2 Stopping introducing CO when pH value reaches 10.0 2 Adding 50 mL sodium silicate working solution, and introducing residual CO 2 And (3) stabilizing gas, and aging for 20 minutes at the temperature of 25 ℃ to obtain the amorphous silicon aluminum precursor. The amorphous silica-alumina precursor was 50% wt% by weight based on the total weight of silica and alumina, calculated as silica.
(2) Preparation of gels
According to Al 2 O 3 : SiO 2 : IPA : H 2 Adding isopropylamine into the amorphous silicon aluminum precursor obtained in the step (1) according to the total feeding molar ratio of O=1:0.01:0.4:45, and stirring for 1 hour at 15 ℃; and then adding a mixture consisting of fumed silica and water into the mixture, and stirring the mixture uniformly to obtain the silica-alumina gel.
(3) Crystallization
Pouring the gel obtained in the step (2) into a stainless steel reaction kettle, and carrying out static crystallization for 24 hours at 180 ℃. After crystallization, filtering, washing to neutrality, drying at 120 ℃, roasting in air at 550 ℃ for 3 hours, and obtaining molecular sieve raw powder NaZSM-23-4.
(4) Ammonium exchange
HZSM-23-4 was prepared in the same manner as in example 1 (4), except that NaZSM-23-1 molecular sieve was replaced with HZSM-23-4, and specific properties are shown in Table 1.
(5) Catalyst preparation
45% of HZSM-23-4 molecular sieve and 21% of macroporous alumina (pore volume 1.2mL/g, specific surface area 560m 2 Per g), and 11% of small-pore alumina (pore volume 0.35 mL/g, specific surface area 330 m) 2 Adhesive (HNO) consisting of 17% by weight of dilute nitric acid 3 Pinhole Al 2 O 3 Is put into a rolling machine to be mixed and milled, water is added to be milled into paste, the paste is extruded, the extruded bar is dried for 4 hours at 110 ℃, and then the extruded bar is baked for 4 hours at 550 ℃ to obtain the carrier TC-4.
The carrier is immersed in an immersion liquid containing tungsten and nickel for 2 hours at room temperature, dried for 4 hours at 120 ℃, and baked for 4 hours at 500 ℃ with a programmed temperature, so as to obtain a catalyst C-4, and the properties of the corresponding catalyst are shown in Table 2.
Example 5
Beta molecular sieve (800 nm, na 2 O content 0.25wt%, specific surface area 620m 2 Per gram, pore volume 0.57mL/g, siO 2 /Al 2 O 3 Molar ratio 80,), 35% amorphous silica alumina (pore volume 0.9mL/g, specific surface area 390m 2 Per gram, 30% by weight of silica), and 18% of small-pore alumina (pore volume 0.35 mL/g, specific surface area 330 m) 2 /g) with a binder (HNO) consisting of dilute nitric acid at 10% by weight 3 Pinhole Al 2 O 3 Is put into a rolling machine to be mixed and milled, water is added to be milled into paste, the paste is extruded, the extruded bar is dried for 4 hours at 110 ℃, and then the extruded bar is baked for 4 hours at 550 ℃ to obtain the carrier TA.
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 500 ℃ with programmed temperature, thus obtaining the catalyst A.
Example 6 (see CN 101214971A)
Al in the aluminum source in mole ratio 2 O 3 SiO in silicon source 2 NaOH in alkali source, isopropylamine and H 2 O is 0.01:1:0.06:0.8:12, the aluminum source is sodium metaaluminate, the silicon source is silica sol, and the alkali source is sodium hydroxide, so as to prepare a reaction mixture. Firstly, adding an aluminum source into a sodium hydroxide aqueous solution, and uniformly stirring; adding a silicon source and uniformly stirring; and adding isopropylamine, and stirring uniformly to obtain a reaction mixture. The reaction mixture was transferred to an autoclave and subjected to hydrothermal crystallization at 170℃for 3 days. Then filtering, washing to neutrality, and drying at 120 ℃ to obtain the NaDZSM-23-1 molecular sieve.
(2) Ammonium exchange
The H-DZSM-23-1 was prepared in the same manner as in example 1 (4), except that NaZSM-23-1 molecular sieve was replaced with NaDZSM-23-1, and specific properties are shown in Table 1.
(3) Catalyst preparation
The CC-1 catalyst was prepared in the same manner as in example 1 (5) except that the H-ZSM-23-1 molecular sieve was replaced with H-DZSM-23-1, and the specific properties are shown in Table 2.
Example 7 (see CN 102992346A)
8.12 g of H 2 O and 0.092. 0.092 g aluminum sulfate are uniformly mixed, 0.38 g of NaOH is added into the mixture, then 3.32. 3.32 g silica sol with 30.5. 30.5 wt percent of silica content is added under stirring, stirring is continued until the solution becomes uniform, 10 weight percent of ZSM-23 molecular sieve is added as seed crystal (the seed crystal amount is equal to the input SiO) 2 Calculated as mass percent). And (3) adding the reaction raw materials into a polytetrafluoroethylene stainless steel reaction kettle, dynamically crystallizing at 160 ℃ for 10 hours, filtering the product, and drying to obtain a NaDZSM-23-2 molecular sieve product. The proportion of the reaction raw materials is SiO 2 : 0.0083Al 2 O 3 : 0.27Na 2 O : 35H 2 O。
(2) Ammonium exchange
The H-DZSM-23-2 was prepared in the same manner as in example 1 (4), except that NaZSM-23-1 molecular sieve was replaced with NaDZSM-23-2, and specific properties are shown in Table 1.
(3) Catalyst preparation
The CC-2 catalyst was prepared in the same manner as in example 1 (5) except that the H-ZSM-23-1 molecular sieve was replaced with H-DZSM-23-2, and the specific properties are shown in Table 2.
Example 8
(1) Preparation of amorphous silica-alumina precursor
Preparing Al with concentration of 50 g 2 O 3 Collecting SiO-containing working solution of sodium aluminate 2 28 Sodium silicate solution of weight percent, which is diluted again to a concentration of 100 g SiO 2 L sodium silicate working solution. Placing 200mL sodium aluminate working solution into a gel forming tank, adding 60 mL sodium silicate working solution, controlling the reaction temperature to 30 ℃, and introducing CO with the concentration of 50 v% 2 Stopping introducing C when pH value reaches 10.0O 2 Adding 40 mL sodium silicate working solution, and ventilating the residual CO 2 And (3) stabilizing gas, and aging for 30 minutes at 25 ℃ to obtain an amorphous silicon aluminum precursor, wherein the content of the amorphous silicon aluminum precursor is 50 wt percent based on the total weight of silicon dioxide and aluminum oxide and calculated on the basis of the silicon dioxide.
(2) Preparation of gels
According to SiO 2 : Al 2 O 3 : IPA : H 2 And (3) adding a mixture consisting of silica sol, isopropylamine and water into the amorphous silica-alumina precursor obtained in the step (1) according to the total feeding molar ratio of O=1:0.01:0.4:30, and uniformly stirring to obtain silica-alumina gel.
(3) Crystallization
Pouring the gel obtained in the step (2) into a stainless steel reaction kettle, and carrying out static crystallization for 24 hours at 160 ℃. After crystallization, filtering, washing to neutrality, drying at 120 deg.c and molecular sieving. And drying to obtain the NaDZSM-23-2 molecular sieve product. The proportion of the reaction raw materials is SiO 2 : 0.0083Al 2 O 3 : 0.27Na 2 O : 35H 2 O。
(4) Ammonium exchange
The H-DZSM-23-2 was prepared in the same manner as in example 1 (4), except that NaZSM-23-1 molecular sieve was replaced with NaDZSM-23-2, and specific properties are shown in Table 1.
(5) Catalyst preparation
The CC-3 catalyst was prepared in the same manner as in example 1 (5) except that the H-ZSM-23-1 molecular sieve was replaced with H-DZSM-23-3, and the specific properties are shown in Table 2.
Table 1 properties of molecular sieves
TABLE 2 physicochemical Properties of the catalysts
The inventive catalyst and the comparative catalyst are described aboveAnd (5) performing a catalytic performance 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 refined catalyst comprises the following components by mass: the operating conditions of the refined catalyst with a molybdenum oxide content of 18% and a nickel oxide content of 6% are as follows: the reaction pressure is 13.8MPa, and the hydrogen oil volume ratio is 1000:1, liquid hourly space velocity 1.0h -1 The reaction temperature was 375 ℃. The cracking and isomerisation stages operate under the following conditions: the reaction pressure is 13.8MPa, and the hydrogen oil volume ratio is 1000:1, liquid hourly space velocity 1.5h -1 The results of the catalyst evaluation after 300 hours of operation are shown in Table 4.
TABLE 3 Properties of raw oil
TABLE 4 evaluation results of catalyst reactions
As can be seen from the evaluation results of the catalysts in Table 4, the method of the present invention processes depressurized VGO feedstock. Has higher diesel selectivity, good product property, and especially low diesel condensation point.

Claims (12)

1. A method for producing low freezing point diesel oil, characterized in that: the method comprises the following steps: the raw oil sequentially passes through a hydrofining reaction zone and a hydrocracking reaction zone, wherein the hydrocracking reaction zone is sequentially filled with a hydrocracking catalyst and an isomerization catalyst along the material flow direction, and the filling volume ratio of the hydrocracking catalyst to the isomerization catalyst is 20:1-2:1, preferably 18:1-3:1, and further preferably 15:1-5:1.
2. The method according to claim 1, characterized in that: the oil quality of the raw materials is as follows: the weight VGO with the distillation range of 300-600 ℃ has the nitrogen mass content of 800-2500 ppm.
3. The method according to claim 1, characterized in that: the hydrofining catalyst filled in the hydrofining reaction zone is an alumina carrier, and the metals of the VIB group and the VIII group are hydrogenation active metal components.
4. The method according to claim 1, characterized in that: the operating conditions of the hydrofining reaction zone are as follows: the reaction temperature is 350-400 ℃; the reaction pressure is 10-20 MPa; the hydrogen-oil volume ratio is 500-2000:1; liquid hourly space velocity of 0.5-2.0 h -1 。
5. The method according to claim 4, wherein: the operating conditions of the hydrofining reaction zone are as follows: the reaction temperature is 360-390 ℃; the reaction pressure is 12-16 MPa; the volume ratio of hydrogen to oil is 800-1200: 1, a step of; the liquid hourly space velocity is 0.8-1.5 h -1 。
6. The method according to claim 1, characterized in that: the hydrocracking catalyst is characterized in that the weight of the hydrocracking catalyst is taken as a reference, the content of beta molecular sieve is 10-30wt%, the content of amorphous silica-alumina is 20-60wt%, the content of adhesive is 10-40wt%, the content of VIB group metal in terms of oxide is 10-25wt% and the content of VIII group metal in terms of oxide is 4-15wt%.
7. The method according to claim 6, wherein: siO in the amorphous silicon aluminum 2 The weight content of the amorphous silica-alumina is 20% -50%, preferably 25% -40%, and the properties of the amorphous silica-alumina are as follows: pore volume of 0.7-1.2 mL/g, preferably 0.8-1.0 mL/g, specific surface area of 300-500 m 2 Preferably 350 to 500 and m per gram 2 /g。
8. The method according to claim 6, wherein: the beta molecular sieve has the following properties: na (Na) 2 The weight content of O is less than 0.3 percent; silicon to aluminum molar ratio SiO 2 /Al 2 O 3 60-90; specific surface area of 400-700 m 2 /g; the pore volume is0.3-0.6 mL/g; the particle size is 500-1000 nm.
9. The method according to claim 1, characterized in that: the isomerization catalyst is characterized in that the weight of the isomerization catalyst is taken as a reference, the content of HZSM-23 molecular sieve is 20-60 wt%, the content of macroporous alumina is 15-40 wt%, the content of adhesive is 10-25 wt%, the content of VIB group metal in terms of oxide is 10-25 wt% and the content of VIII group metal in terms of oxide is 4-15 wt%.
10. The method according to claim 9, wherein: the specific surface area of the isomerization catalyst is 250-500 m 2 Per gram, the pore volume is 0.30-0.70 cm 3 /g; the specific surface area is preferably 300-450 m 2 Preferably, the pore volume per gram is 0.37-0.60 cm 3 /g; the weak acid content in the catalyst accounts for 75-90% of the total acid content; preferably, the weak acid content accounts for 80-90% of the total acid content.
11. The method according to claim 1, characterized in that: the hydrocracking catalyst bed in the hydrocracking reaction zone is operated under the following conditions: the reaction temperature is 360-420 ℃, preferably 370-390 ℃; the reaction pressure is 10-20 MPa, preferably 12-16 MPa; the volume ratio of hydrogen to oil is 500-2000:1, preferably 800-1200: 1, a step of; liquid hourly space velocity of 0.5-2.0 h -1 Preferably 0.8 to 1.5. 1.5h -1 。
12. The method according to claim 1, characterized in that: the operating conditions of the hydrocracking reaction zone isomerization catalyst bed are as follows: the reaction temperature is 360-400 ℃, preferably 370-390 ℃; the reaction pressure is 10-20 MPa, preferably 12-16 MPa; the volume ratio of hydrogen to oil is 500-2000:1, preferably 800-1200: 1, a step of; liquid hourly space velocity of 0.5-2.0 h -1 Preferably 1.0 to 1.5. 1.5h -1 。
CN202210777955.2A 2022-07-04 2022-07-04 Method for producing low-freezing diesel oil Pending CN117402652A (en)

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