CN110841691B - Catalytic cracking catalyst for processing hydrogenated LCO and preparation method thereof - Google Patents
Catalytic cracking catalyst for processing hydrogenated LCO and preparation method thereof Download PDFInfo
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- B01J29/085—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the faujasite type, e.g. type X or Y containing rare earth elements, titanium, zirconium, hafnium, zinc, cadmium, mercury, gallium, indium, thallium, tin or lead
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- 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
- C10G11/00—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils
- C10G11/02—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils characterised by the catalyst used
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Abstract
One embodiment of the invention provides a catalytic cracking catalyst for processing hydrogenated LCO and a preparation method thereof, wherein the catalyst comprises a modified Y-type molecular sieve; in the modified Y-type molecular sieve, the rare earth content is 4-11 wt% in terms of rare earth oxide, the sodium content is not more than 0.7 wt% in terms of sodium oxide, the zinc content is 0.5-5 wt% in terms of zinc oxide, the phosphorus content is 0.05-10 wt% in terms of phosphorus pentoxide, and the framework silicon-aluminum ratio is SiO2/Al2O3The molar ratio is 7-14, the mass of non-framework aluminum accounts for not more than 20% of the total mass of aluminum, and the pore volume of secondary pores with the pore diameter of 2-100 nm accounts for 15-30% of the total pore volume. The catalyst of the embodiment of the invention takes the modified Y molecular sieve as a new active component, which not only can improve the conversion efficiency of hydrogenated LCO, but also has lower coke selectivity, higher gasoline yield and total yield of ethylene and propylene.
Description
Technical Field
The invention relates to a catalytic cracking catalyst for processing hydrogenated LCO, in particular to a catalytic cracking catalyst for processing hydrogenated LCO, which takes a modified Y-shaped molecular sieve as an active component.
Background
Light aromatic hydrocarbons such as benzene, toluene, xylene (BTX), and the like are important basic organic chemical raw materials, are widely used for producing polyesters, chemical fibers, and the like, and have been in strong demand in recent years. Light aromatics such as benzene, toluene and xylene are mainly obtained from catalytic reforming and steam cracking processes using naphtha as a raw material. Due to the shortage of naphtha raw material, the light aromatics have larger market gap.
The catalytic cracking Light Cycle Oil (LCO) is an important byproduct of catalytic cracking, is large in quantity, is rich in aromatic hydrocarbon, particularly polycyclic aromatic hydrocarbon, and belongs to poor diesel oil fraction. With the development and change of market demand and environmental protection requirement, LCO is greatly limited as a diesel blending component. The hydrocarbon composition of LCO comprises paraffin, naphthene (containing a small amount of olefin) and aromatic hydrocarbon, the hydrocarbon composition of LCO has larger difference according to different catalytic cracking raw oil and different operation severity, but the aromatic hydrocarbon is the main component of the LCO, the mass fraction is usually more than 70%, some aromatic hydrocarbon even reaches about 90%, and the rest is paraffin and naphthene.
The LCO has the highest content of bicyclic aromatics, belongs to typical components of the LCO and is also a key component influencing the catalytic cracking to produce light aromatics. Under the catalytic cracking reaction condition, polycyclic aromatic hydrocarbons are difficult to open-loop crack into light aromatic hydrocarbons, and under the hydrotreating condition, the polycyclic aromatic hydrocarbons are easy to saturate into heavy monocyclic aromatic hydrocarbons such as alkylbenzene and cyclohydrocarbyl benzene (indanes, tetrahydronaphthalenes and indenes). The heavy monocyclic aromatic hydrocarbon is a potential component for producing light aromatic hydrocarbon by catalytic cracking, and can be cracked into the light aromatic hydrocarbon under the catalytic cracking condition. Therefore, LCO is a potential and cheap resource for producing light aromatics, and the production of light aromatics by a hydroprocessing-catalytic cracking technological route has important research value.
CN 103923698A discloses a catalytic conversion method for producing aromatic compounds, in the method, poor quality heavy cycle oil and residual oil are subjected to hydrotreating reaction in the presence of hydrogen and hydrogenation catalysts, and reaction products are separated to obtain gas, naphtha, hydrogenated diesel oil and hydrogenated residual oil; the hydrogenated diesel oil enters a catalytic cracking device, a cracking reaction is carried out in the presence of a catalytic cracking catalyst, and a reaction product is separated to obtain dry gas, liquefied gas, catalytic gasoline rich in benzene, toluene and xylene, catalytic light diesel oil, fractions with the distillation range of 250-450 ℃ and slurry oil; wherein the distillation range of 250-450 ℃ is sent to a residual oil hydrotreater for recycling. The method makes full use of the residual oil hydrogenation condition to maximally saturate aromatic rings in the poor-quality heavy cycle oil, so that the hydrogenated diesel oil can maximally produce benzene, toluene and xylene in the catalytic cracking process.
CN 104560185a discloses a catalytic conversion method for producing gasoline rich in aromatic compounds, in which catalytic cracking light cycle oil is cut to obtain light fraction and heavy fraction, wherein the heavy fraction is hydrotreated to obtain hydrogenated heavy fraction, the light fraction and the hydrogenated heavy fraction separately enter a catalytic cracking device through different nozzles in a layered manner, a cracking reaction is performed in the presence of a catalytic cracking catalyst, and a product including gasoline rich in aromatic compounds and light cycle oil is obtained by separating reaction products. The method adopts a single catalytic cracking device to process the light fraction of the light cycle oil and the hydrogenated heavy fraction and allows the light fraction and the hydrogenated heavy fraction to enter in a layering manner, so that the harsh conditions required by catalytic cracking reaction of different fractions of the light cycle oil can be optimized and met to the maximum extent, and the catalytic gasoline rich in benzene, toluene and xylene can be produced to the maximum extent.
CN 104560187A discloses a catalytic conversion method for producing gasoline rich in aromatic hydrocarbon, which comprises the steps of cutting catalytic cracking light cycle oil to obtain light fraction and heavy fraction, wherein the heavy fraction is subjected to hydrotreating to obtain hydrogenated heavy fraction, the light fraction and the hydrogenated heavy fraction independently and respectively enter different riser reactors of a catalytic cracking device, cracking reaction is carried out in the presence of a catalytic cracking catalyst, and products of the reaction are separated to obtain gasoline rich in aromatic hydrocarbon and products of the light cycle oil. The method adopts a single catalytic cracking device to process the light fraction and the hydrogenated heavy fraction of the light cycle oil, and can optimize and meet the harsh conditions required by the catalytic cracking reaction of different fractions of the light cycle oil to the maximum extent, thereby producing the catalytic gasoline rich in benzene, toluene and xylene to the maximum extent.
In the prior art, LCO is adopted for proper hydrogenation, most polycyclic aromatic hydrocarbons in the LCO are saturated into hydrogenated aromatic hydrocarbons containing naphthenic rings and an aromatic ring, and then cracking reaction is carried out in the presence of a catalytic cracking catalyst to produce BTX light aromatic hydrocarbons. However, the cracking performance of hydrogenated aromatics obtained by hydrogenation of LCO is inferior to that of conventional catalytic cracking raw materials, and the hydrogen transfer performance is much higher than that of general catalytic cracking raw materials, so that the conventional catalytic cracking catalyst used in the prior art cannot meet the requirements of catalytic cracking of hydrogenated LCO.
Disclosure of Invention
It is a primary object of the present invention to provide a catalytic cracking catalyst for processing hydrogenated LCO comprising a modified Y-type molecular sieve; in the modified Y-type molecular sieve, the rare earth content is 4-11 wt% in terms of rare earth oxide, the sodium content is not more than 0.7 wt% in terms of sodium oxide, the zinc content is 0.5-5 wt% in terms of zinc oxide, the phosphorus content is 0.05-10 wt% in terms of phosphorus pentoxide, and the framework silicon-aluminum ratio is SiO2/Al2O3The molar ratio is 7-14, the mass of non-framework aluminum accounts for not more than 20% of the total mass of aluminum, and the pore volume of secondary pores with the pore diameter of 2-100 nm accounts for 15-30% of the total pore volume.
According to an embodiment of the present invention, in the modified Y-type molecular sieve, the total pore volume is 0.33 to 0.39 mL/g.
According to an embodiment of the present invention, the unit cell constant of the modified Y-type molecular sieve is 2.440-2.455 nm.
According to an embodiment of the invention, in the modified Y-type molecular sieve, the rare earth content is 4.5 to 10 wt%, the sodium content is 0.4 to 0.6 wt%, the phosphorus content is 0.1 to 6 wt%, the unit cell constant is 2.440 to 2.453nm, and the framework silicon-aluminum ratio is 8.5 to 12.6.
According to an embodiment of the present invention, in the modified Y-type molecular sieve, the non-framework aluminum accounts for 13 to 19% by mass of the total aluminum.
According to an embodiment of the invention, in the modified Y-type molecular sieve, the pore volume of the secondary pores with a pore diameter of 2 to 100nm accounts for 20 to 30% of the total pore volume.
According to one embodiment of the invention, in the modified Y-type molecular sieve, the ratio of the amount of B acid to the amount of L acid is not less than 3.50 as measured by pyridine adsorption infrared method at 350 ℃.
According to an embodiment of the invention, the catalyst comprises 10-50 wt% of the modified Y-type molecular sieve, a binder and clay. For example, the binder content is 10 to 40 wt% on a dry basis and the clay content is 10 to 80 wt% on a dry basis, based on the weight of the catalyst on a dry basis.
An embodiment of the present invention further provides a method for preparing a catalytic cracking catalyst for processing hydrogenated LCO, including the step of preparing an active ingredient-modified Y-type molecular sieve, the step of preparing the active ingredient-modified Y-type molecular sieve including:
(1) carrying out ion exchange on the NaY molecular sieve and a rare earth salt solution;
(2) roasting the ion exchanged molecular sieve;
(3) carrying out phosphorus modification treatment on the roasted molecular sieve;
(4) reacting the molecular sieve subjected to phosphorus modification treatment with silicon tetrachloride; and
(5) and (4) impregnating the molecular sieve reacted in the step (4) with a zinc salt solution.
According to an embodiment of the invention, in the step (1), the exchange temperature of ion exchange is 15-95 ℃, the exchange time is 30-120 minutes, the mass ratio of the NaY molecular sieve, the rare earth salt and the solvent water is 1 (0.01-0.18) to (5-15), the mass of the NaY molecular sieve is calculated by dry basis, and the mass of the rare earth salt is calculated by rare earth oxide.
According to an embodiment of the present invention, the calcination in the step (2) is performed at 350 to 480 ℃ in an atmosphere having a water vapor content of 30 to 90 vol%, and the calcination time is 4.5 to 7 hours.
According to an embodiment of the present invention, in the step (3), the temperature for performing the phosphorus modification treatment is 15 to 100 ℃ for 10 to 100 minutes.
According to an embodiment of the present invention, in the step (3), the phosphorus compound used for the phosphorus modification treatment is one or more selected from phosphoric acid, ammonium phosphate, ammonium dihydrogen phosphate, and diammonium hydrogen phosphate.
According to one embodiment of the invention, in the step (4), the reaction temperature is 200-650 ℃, the reaction time is 10 minutes to 5 hours, the mass ratio of the silicon tetrachloride to the phosphorus-modified molecular sieve is (0.1-0.7): 1, and the mass of the calcined molecular sieve is calculated on a dry basis.
According to an embodiment of the invention, the step (5) comprises roasting the impregnated molecular sieve, wherein the impregnation temperature is 10-60 ℃, the roasting temperature is 350-600 ℃, and the roasting time is 1-4 hours.
According to an embodiment of the invention, the preparation method comprises the steps of forming a slurry by 10-50 wt% of the modified Y-type molecular sieve, a binder, clay and water, and carrying out spray drying to obtain the catalyst.
An embodiment of the present invention further provides a catalytic cracking process for processing hydrogenated LCO, comprising the step of contacting hydrogenated LCO with the catalyst under catalytic cracking conditions; wherein the catalytic cracking conditions comprise: the reaction temperature is 500-610 ℃, and the weight hourly space velocity is 2-16 h-1The agent-oil ratio is 3-10, and the agent-oil ratio is a weight ratio.
The catalytic cracking catalyst for processing hydrogenated LCO in the embodiment of the invention takes the modified Y molecular sieve as a new active component, thereby not only improving the conversion efficiency of the hydrogenated LCO, but also having lower coke selectivity, higher gasoline yield rich in BTX light aromatic hydrocarbon and higher total yield of ethylene and propylene.
Detailed Description
Exemplary embodiments that embody features and advantages of the invention are described in detail below. It is to be understood that the invention is capable of other and different embodiments and its several details are capable of modification without departing from the scope of the invention, and that the description is intended to be illustrative in nature and not to be construed as limiting the invention. Wherein, the mass of each molecular sieve is calculated on a dry basis; the mass (content) of the rare earth salt and the rare earth is calculated according to the mass (content) of the rare earth oxide; the mass (content) of sodium is calculated by the mass (content) of sodium oxide; the mass (content) of zinc and zinc salt is calculated by the mass (content) of zinc oxide; the mass (content) of phosphorus is calculated by the mass (content) of phosphorus pentoxide.
In order to better meet the requirement of catalytic cracking of hydrogenated LCO to produce more BTX light aromatic hydrocarbons, one embodiment of the invention provides a catalyst, and a high-stability modified molecular sieve with strong cracking capability and weaker hydrogen transfer performance is used as an active component.
The catalytic cracking catalyst for processing the hydrogenated LCO takes the modified Y molecular sieve with high thermal and hydrothermal stability as a new active component, can strengthen the cracking reaction, control the hydrogen transfer reaction, further improve the conversion efficiency of the hydrogenated LCO, and can produce catalytic gasoline rich in benzene, toluene and xylene (BTX) to the maximum extent.
The catalyst of one embodiment of the invention comprises a modified Y-type molecular sieve; in the modified Y-type molecular sieve, the rare earth content is 4-11 wt% in terms of rare earth oxide, the sodium content is not more than 0.7 wt% in terms of sodium oxide, the zinc content is 0.5-5 wt% in terms of zinc oxide, the phosphorus content is 0.05-10 wt% in terms of phosphorus pentoxide, and the framework silicon-aluminum ratio is SiO2/Al2O3The molar ratio is 7-14, the mass of non-framework aluminum accounts for not more than 20% of the total mass of aluminum, and the pore volume of secondary pores with the pore diameter of 2-100 nm accounts for 15-30% of the total pore volume.
In one embodiment, the framework silica to alumina ratio (SiO) of the modified Y-type molecular sieve2/Al2O3The molar ratio) may be 7.3 to 14, and further may be 8.5 to 12.6, for example, 8.79, 10.87, 11.95, and the like.
In one embodiment, the rare earth content (rare earth oxide content) of the modified Y-type molecular sieve may be 4.5 to 10 wt%, for example, 5.6%, 6.3%, 8.4%, etc.
In one embodiment, the sodium content (sodium oxide content) of the modified Y-type molecular sieve may be 0.1 to 0.7 wt%, further 0.3 to 0.7 wt%, further 0.35 to 0.6 wt%, further 0.4 to 0.55 wt%, for example, 0.44%, 0.49%, 0.57%, and the like.
In one embodiment, the zinc content (zinc oxide content) of the modified Y-type molecular sieve may be 1 to 4 wt%, for example, 1%, 2%, 4%, etc.
In one embodiment, the phosphorus content (in P) of the modified Y-type molecular sieve2O5The phosphorus content) may be 0.1 to 6% by weight, and further may be 0.1 to 5% by weight, for example, 0.95%, 2.21%, 3.68%, and the like.
In one embodiment, the percentage of the non-framework aluminum in the modified Y-type molecular sieve to the total aluminum may be 13 to 19% by mass, for example, 13.2%, 16.5%, 18.5%, etc.
In one embodiment, the unit cell constant of the modified Y-type molecular sieve may be 2.440-2.455 nm, further may be 2.440-2.453 nm, and further may be 2.442-2.453 nm, such as 2.443nm, 2.445nm, 2.45nm, and the like.
In one embodiment, the total pore volume of the modified Y-type molecular sieve may be 0.33-0.39 mL/g, further 0.35-0.39 mL/g, further 0.36-0.375 mL/g, such as 0.355mL/g, 0.364mL/g, 0.373mL/g, and the like.
In one embodiment, in the modified Y-type molecular sieve, the pore volume of the secondary pores having a pore diameter (diameter) of 2.0nm to 100nm may be 20% to 30% by volume of the total pores, and may be further 17% to 21%, for example, 17.96%, 19.78%, 20.85%, and the like.
In one embodiment, the specific surface area of the modified Y-type molecular sieve can be 600-670 m2A concentration of 610 to 660m2G, e.g. 633m2/g、640m2/g、652m2And/g, etc.
In one embodiment, the lattice collapse temperature of the modified Y-type molecular sieve is not lower than 1050 ℃, and may be 1055 ℃ to 1080 ℃, and further may be 1057 ℃ to 1075 ℃, such as 1055 ℃, 1061 ℃, 1068 ℃, and the like.
In one embodiment, the ratio of the amount of the B acid to the amount of the L acid in the strong acid amount of the modified Y-type molecular sieve measured at 350 ℃ by using a pyridine adsorption infrared method is not less than 3.50, for example, may be 3.6 to 5.0, further may be 3.7 to 4.3, and specifically may be 3.76, 4.21, 4.95, and the like.
In one embodiment, the modified Y-type molecular sieve has a crystal retention of 35% or more, for example, 38 to 48% or 35 to 45%, for example, 38.95%, 40.55%, 43.45% or the like, after aging for 17 hours at 800 ℃, under normal pressure (1atm) and in an atmosphere of 100 vol% steam.
In one embodiment, the relative crystallinity of the modified Y-type molecular sieve is not less than 60%, for example, 60 to 70%, further 60 to 66%, specifically 60.4%, 62.7%, 65.3%, and the like.
In the catalyst according to an embodiment of the present invention, the content of the modified Y-type molecular sieve may be 10 to 50 wt%, further 15 to 45 wt%, further 25 to 40 wt%, for example, 25%, 30%, 40%, or the like, on a dry basis.
The catalyst of one embodiment of the invention comprises a modified Y-type molecular sieve, an alumina binder and clay.
In one embodiment, the clay may be one or more of the clays used as cracking catalyst components, such as kaolin, halloysite, montmorillonite, diatomaceous earth, halloysite, saponite, rectorite, sepiolite, attapulgite, hydrotalcite, bentonite, and the like. Preferably, the clay content of the catalyst is 10 to 80 wt%, further 20 to 55 wt% or 30 to 50 wt% on a dry basis.
In one embodiment, the content of the alumina binder in the catalyst may be 10 to 40 wt%, and further 20 to 35 wt%.
In one embodiment, the alumina binder may be one or more of alumina, hydrated alumina, and alumina sol in various forms commonly used in cracking catalysts. For example, gamma-alumina, eta-alumina, theta-alumina, chi-alumina, pseudoboehmite (Pseudobioemite), diaspore (Boehmite), Gibbsite (Gibbsite), Bayer stone (Bayerite), alumina sol, and the like. Pseudoboehmite and alumina sol are preferred.
The catalyst according to one embodiment of the present invention contains 2 to 15 wt%, preferably 3 to 10 wt%, based on alumina, of alumina sol, and 10 to 30 wt%, preferably 15 to 25 wt%, based on alumina, of pseudo-boehmite.
The catalyst according to an embodiment of the present invention may further contain another molecular sieve other than the modified Y-type molecular sieve, and the content of the other molecular sieve may be 0 to 40 wt%, further 0 to 30 wt%, and further 1 to 20 wt% on a dry basis based on the mass of the catalyst.
In one embodiment, the other molecular sieve may be one or more of a molecular sieve used in a catalytic cracking catalyst, such as a zeolite having an MFI structure, a zeolite Beta, other Y-type zeolites, and a non-zeolitic molecular sieve. Preferably, the mass of the other Y-type zeolite is not more than 40% of the mass of the other molecular sieve on a dry basis, and may be 1 to 40 wt%, and further may be 0 to 20 wt%.
In one embodiment, the other Y-type zeolite may be, for example, one or more of REY, REHY, DASY, SOY, PSRY; the MFI structure zeolite may be, for example, one or more of HZSM-5, ZRP, ZSP; zeolite Beta, such as H Beta, and the non-zeolitic molecular sieve may be, for example, one or more of an aluminum phosphate molecular sieve (AlPO molecular sieve), a silicoaluminophosphate molecular sieve (SAPO molecular sieve).
The modified Y-type molecular sieve containing phosphorus, rare earth and zinc prepared by the invention has high crystallinity, secondary pore structure and high thermal and hydrothermal stability.
The catalytic cracking catalyst for processing hydrogenated LCO in one embodiment of the invention contains the modified Y-type molecular sieve with high thermal and hydrothermal stability, has higher hydrothermal stability, is used for processing hydrogenated LCO catalytic cracking, has higher LCO conversion efficiency, lower coke selectivity, higher gasoline yield rich in BTX compared with the conventional catalytic cracking catalyst containing the Y-type molecular sieve, and contains more ethylene and propylene in gas products.
An embodiment of the present invention provides a preparation method of the above catalytic cracking catalyst for processing hydrogenated LCO, including a step of preparing an active component modified Y-type molecular sieve, the step including:
(1) carrying out ion exchange reaction on the NaY molecular sieve and a rare earth salt solution to obtain a Y-type molecular sieve with reduced sodium oxide content and unchanged unit cell size and containing rare earth;
(2) roasting the Y-type molecular sieve which contains rare earth and has unchanged unit cell size after ion exchange to obtain the Y-type molecular sieve with reduced unit cell constant;
(3) carrying out phosphorus modification treatment on the roasted Y-shaped molecular sieve with the reduced unit cell constant so as to introduce phosphorus into the molecular sieve;
(4) reacting the molecular sieve subjected to phosphorus modification treatment with silicon tetrachloride to perform dealumination and silicon supplementation to obtain a gas-phase ultrastable modified Y-shaped molecular sieve; and
(5) and (4) dipping the gas-phase ultra-stable modified Y-type molecular sieve reacted in the step (4) by using a zinc salt solution.
In one embodiment, step (1) comprises contacting NaY molecular sieve with a rare earth salt solution to perform an ion exchange reaction, filtering, washing, and optionally drying to obtain a rare earth-containing Y-type molecular sieve with reduced sodium oxide content.
In one embodiment, the NaY molecular sieve in step (1) has a unit cell constant of 2.465-2.472 nm and a framework silicon-aluminum ratio (SiO)2/Al2O3Molar ratio) of 4.5 to 5.2, a relative crystallinity of 85% or more, for example, 85 to 95%, and a sodium oxide content of 13.0 to 13.8 wt%.
In one embodiment, after the ion exchange treatment in step (1), the unit cell constant of the molecular sieve is 2.465-2.472 nm, the sodium content is not more than 9.5 wt% calculated by sodium oxide, and the rare earth content is RE2O3The content of (rare earth oxide) is 4.5-13 wt%.
In one embodiment, after the ion exchange treatment in step (1), the sodium oxide content of the molecular sieve may be 5.5 to 9.5 wt%, and further may be 5.5 to 8.5 wt%, for example, 7.5%; the content of the rare earth oxide may be 5.5 to 13 wt%, and further may be 5.5 to 12 wt% or 4.5 to 11.5 wt%.
In one embodiment, the mass ratio of the NaY molecular sieve (calculated on a dry basis), the rare earth salt (calculated on a rare earth oxide) and the water in the step (1) is 1 (0.01-0.18) to (5-15), and the water can be deionized water, deionized water or a mixture thereof.
In one embodiment, the rare earth salt is rare earth chloride or rare earth nitrate, and the rare earth may be, but is not limited to, one or more of La, Ce, Pr, and Nd.
In one embodiment, the exchange temperature of the ion exchange reaction is 15-95 ℃, and further 65-95 ℃, for example 90-95 ℃; the exchange time may be 30 to 120 minutes, and further 45 to 90 minutes.
In one embodiment, step (1) comprises: mixing NaY molecular sieve with water, adding rare earth salt and/or rare earth salt solution while stirring to exchange rare earth ions and sodium ions, filtering and washing; wherein, the purpose of washing is to wash out the exchanged sodium ions, and deionized water or decationized water can be used for washing.
In one embodiment, the NaY molecular sieve, the rare earth salt, and the water are mixed to form a mixture, and the NaY molecular sieve and the water are slurried prior to adding the aqueous solution of the rare earth salt and/or the rare earth salt to the slurry.
In one embodiment, according to the NaY molecular sieve rare earth salt H2And (5) 15-15) mixing NaY molecular sieve, rare earth salt and water to form a mixture, and stirring at 15-95 ℃ for 30-120 minutes to exchange rare earth ions and sodium ions.
In one embodiment, the calcination treatment in step (2) is to calcine the ion exchanged molecular sieve at 350-480 ℃ for 4.5-7 hours in an atmosphere of 30-90 vol% steam (also referred to as 30-90 vol% steam or 30-90 vol% steam). Preferably, the molecular sieve after ion exchange is roasted for 5-6 hours at the temperature of 380-460 ℃ in the atmosphere of 40-80 vol% of water vapor. For example, the calcination treatment may be performed at a temperature of 390 ℃, 450 ℃ or 470 ℃, under an atmosphere of 50 vol%, 70 vol% or 80 vol% water vapor.
In one embodiment, the water vapor atmosphere in step (2) further contains other gases, such as one or more of air, helium or nitrogen.
In one embodiment, the unit cell constant of the molecular sieve treated in step (2) is reduced to 2.450nm to 2.462nm, and the water content is less than 1 wt%.
In one embodiment, step (3) comprises drying the calcined molecular sieve of step (2) so that the water content in the Y-type molecular sieve with reduced unit cell constant is not more than 1 wt%, and the drying can be performed by air drying, oven drying, flash drying, etc.
In one embodiment, step (3) comprises contacting the Y-type molecular sieve having a reduced unit cell constant obtained in step (2) with an exchange liquid comprising a phosphorus compound.
In one embodiment, the phosphorus compound may be one or more of phosphoric acid, ammonium phosphate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, and the like.
In step (3) of one embodiment, the mass ratio of the mass of water in the exchange liquid to the mass of the molecular sieve (molecular sieve obtained in step (2)) is (2-5): 1, and may further be (3-4): 1,
in step (3) of one embodiment, phosphorus (as P)2O5Calculated) and the mass ratio of the molecular sieve is as follows: (0.0005-0.10): 1, preferably (0.001-0.05): 1.
In one embodiment, the temperature for performing the phosphorus modification treatment in step (3) may be 15 to 100 ℃, further 30 to 95 ℃, and the treatment time may be 10 to 100 minutes.
In one embodiment, the step (3) comprises performing exchange reaction between the molecular sieve and the exchange solution at 15-100 ℃ for 10-100 minutes, filtering, and washing; the washing can be carried out by using water with the mass of 5-15 times of that of the molecular sieve, such as decationized or deionized water.
In one embodiment, the mass ratio of the silicon tetrachloride used in step (4) to the molecular sieve after phosphorus modification treatment (on a dry basis) may be (0.1 to 0.7):1, and may further be (0.3 to 0.6):1, for example, 0.4:1, 0.5:1, 0.6:1, and the like.
In one embodiment, the reaction temperature of the molecular sieve and the silicon tetrachloride in the step (4) may be 200 to 650 ℃, and further may be 350 to 500 ℃, for example, 400 ℃, 480 ℃, 500 ℃, and the like.
In one embodiment, the reaction time of the molecular sieve in the step (4) and the silicon tetrachloride is 10 minutes to 5 hours, and then washing and filtering are carried out to remove Na remained in the molecular sieve+、Cl-And Al3+And the like soluble by-products.
In one embodiment, the washing operation of step (4) may be performed using water, such as decationized water or deionized water. The washing conditions were: the mass ratio of the water to the molecular sieve can be (5-20): 1, and further can be (6-15): 1; the washing temperature is 30-60 ℃; the pH value of the washing liquid can be 2.5-5.0. Usually, no free Na is detected in the washing solution after washing+，Cl-And Al3+And (3) plasma.
In one embodiment, the zinc salt of step (5) may be zinc nitrate or zinc chloride.
In one embodiment, the step (5) includes preparing the zinc salt into a solution, wherein the weight ratio of the zinc salt (calculated as ZnO) to the molecular sieve is ZnO-molecular sieve (0.5-5.0): 100, and the concentration of the zinc salt solution may be 0.020-0.080 g/ml.
In one embodiment, the dipping temperature in step (5) is 10 to 60 ℃, the dipped sample can be dried for 5 hours at a temperature of 130 ℃, and then roasted, the roasting temperature can be 350 to 600 ℃, and the roasting time can be 1 to 4 hours.
The preparation method of the modified Y-type molecular sieve comprises the following steps:
(1) carrying out ion exchange reaction on a NaY molecular sieve (also called NaY zeolite) and a rare earth salt solution, filtering and washing to obtain a Y-type molecular sieve containing rare earth and having a conventional unit cell size and a reduced sodium oxide content; ion exchange is carried out for 30-120 minutes under the conditions of stirring and temperature of 15-95 ℃;
(2) roasting the rare earth-containing Y-type molecular sieve with the normal unit cell size and the reduced sodium oxide content for 4.5-7 hours at the temperature of 350-480 ℃ in the atmosphere containing 30-90 vol% of water vapor, and drying to obtain the Y-type molecular sieve with the reduced unit cell constant and the water content of less than 1 wt%, wherein the unit cell constant is 2.450-2.462 nm;
(3) adding the Y-type molecular sieve with the reduced unit cell constant into an exchange solution containing a phosphorus compound, carrying out exchange reaction for 10-100 minutes at 15-100 ℃, filtering and washing; wherein the mass ratio of water to molecular sieve in the exchange liquid is 2-5, preferably 3E to E4, phosphorus (as P)2O5Calculated) is 0.0005 to 0.10, and drying is carried out to obtain the Y-type molecular sieve with the water content lower than 1 wt% and the unit cell constant of phosphorus being reduced;
(4) a process for preparing a phosphorus-containing molecular sieve having a water content of less than 1 wt% and a reduced unit cell constant4Gas contact of SiCl4A Y-type molecular sieve with a water content of less than 1 wt% and a reduced unit cell constant, wherein the mass ratio of the Y-type molecular sieve (calculated on a dry basis) is (0.1-0.7): 1, the Y-type molecular sieve is subjected to a contact reaction at a temperature of 200-650 ℃ for 10 minutes to 5 hours, and then the Y-type molecular sieve is washed and filtered;
(5) and (3) dipping the modified Y molecular sieve obtained in the step (4) by using a zinc salt solution, wherein the dipping temperature is 10-60 ℃, the dipped sample is dried for 5 hours at 130 ℃, and then roasted for 1-4 hours under the roasting condition of 350-600 ℃ to obtain the modified Y molecular sieve.
In the present invention, the method for preparing the catalyst using the modified Y-type molecular sieve, the binder, the clay and water as raw materials is not limited, and for example, the method disclosed in patent application CN 1098130A, CN 1362472a can be referred to.
In one embodiment, the resulting slurry of modified Y-type molecular sieve, binder, clay and water is subjected to spray drying, optionally washing and drying steps to produce a catalytic cracking catalyst for processing hydrogenated LCO. In the present invention, spray drying, washing, drying and the like are not limited, and conventional methods can be used.
One embodiment of the present invention provides a catalytic cracking process for processing hydrogenated LCO, comprising the step of contacting hydrogenated LCO with the catalyst under catalytic cracking conditions; wherein, the catalytic cracking conditions comprise: the reaction temperature is 500-610 ℃, and the weight hourly space velocity is 2-16 h-1The weight ratio of the components is 3-10.
In one embodiment, the hydrogenated LCO has the following properties: the hydrogenated LCO may have the following properties: density (20 ℃): 0.850-0.920 g/cm3And H content: 10.5 to 12 wt%, S content<50 μ g/g, N content<10 μ g/g, total aromatic content: 70-85 wt% and polycyclic aromatic hydrocarbon content less than or equal to 15 wt%. .
The preparation method provided by the embodiment of the invention can be used for preparing the high-silicon Y-type molecular sieve containing phosphorus, rare earth and zinc and having a certain secondary pore structure, high crystallinity, high thermal stability and high hydrothermal stability, wherein the molecular sieve is uniform in aluminum distribution and low in non-framework aluminum content.
The catalyst prepared by the preparation method of one embodiment of the invention takes the modified molecular sieve as an active component, is used for processing the catalytic cracking of hydrogenated LCO, has high LCO conversion efficiency (high LCO effective conversion rate), lower coke selectivity, higher gasoline yield rich in BTX, and contains more ethylene and propylene in gas products.
The preparation and use of a catalytic cracking catalyst for processing hydrogenated LCO in accordance with one embodiment of the present invention is described in detail below with reference to specific examples, wherein the details of the feedstock used and the associated tests are as follows.
Raw materials
The NaY molecular sieve (also called NaY zeolite) used in the examples and comparative examples was supplied by the zeuginese corporation, petrochemical catalyst ltd, china, and had a sodium oxide content of 13.5 wt% and a framework silica-to-alumina ratio (SiO zeolite)2/Al2O3Molar ratio) of 4.6, unit cell constant 2.470nm, relative crystallinity 90%.
The chlorinated rare earth and the nitric acid rare earth are chemical pure reagents produced by Beijing chemical plants; the zinc nitrate or the zinc chloride is a chemical pure reagent produced by a Beijing chemical plant; the pseudoboehmite is an industrial product produced by Shandong aluminum factories, and has the solid content of 61 wt%; the kaolin is kaolin specially used for a cracking catalyst produced by Suzhou China kaolin company, and the solid content is 76 wt%; the alumina sol was provided by the Qilu division of China petrochemical catalyst, Inc., in which the alumina content was 21 wt%. The chemical reagents used in the comparative examples and examples are not specifically noted, and are specified to be chemically pure.
Analytical method
In each comparative example and example, the elemental content of the zeolite was determined by X-ray fluorescence spectroscopy.
The cell constants and relative crystallinity of zeolite were measured by X-ray powder diffraction (XRD) using RIPP 145-90 and RIPP146-90 standard methods (compiled by petrochemical analysis (RIPP test methods) Yancui et al, published by scientific Press, 1990).
The framework silica to alumina ratio of the zeolite is calculated from the formula: SiO 22/Al2O3＝(2.5858-a0)×2/(a0-2.4191)]Wherein a is0Is the unit cell constant in nm.
The total silicon-aluminum ratio of the zeolite is calculated according to the content of Si and Al elements measured by an X-ray fluorescence spectrometry, and the ratio of the framework Al to the total Al can be calculated by the framework silicon-aluminum ratio measured by an XRD method and the total silicon-aluminum ratio measured by an XRF method, so that the ratio of non-framework Al to the total Al can be calculated.
The crystal structure collapse temperature was determined by Differential Thermal Analysis (DTA).
The acid center type and the acid amount of the molecular sieve are analyzed and determined by adopting an infrared method of pyridine adsorption, and an experimental instrument comprises the following steps: model Bruker IFS113V FT-IR (fourier transform infrared) spectrometer, usa; the experimental method for measuring the acid content at 350 ℃ by using a pyridine adsorption infrared method comprises the following steps: placing the sample self-supporting pressed sheet in an in-situ pool of an infrared spectrometer and sealing; heating to 400 deg.C, and vacuumizing to 10 deg.C-3Keeping the temperature for 2 hours at Pa, and removing gas molecules adsorbed by the sample; the temperature is reduced to room temperature, pyridine vapor with the pressure of 2.67Pa is introduced to keep the adsorption equilibrium for 30 min. Then heating to 350 ℃, and vacuumizing to 10 DEG C-3Desorbing for 30min under Pa, reducing to room temperature for spectrography, scanning wave number range: 1400cm-1～1700cm-1And obtaining the pyridine absorption infrared spectrogram of the sample desorbed at 350 ℃. According to pyridine absorption infrared spectrogram of 1540cm-1And 1450cm-1The strength of the adsorption peak is characterized to obtain the medium-strength molecular sieve
Relative amount of acid center (B acid center) to Lewis acid center (L acid center).
The secondary pore volume was determined as follows: the total pore volume of the molecular sieve was determined from the adsorption isotherm according to RIPP 151-90 Standard method, "petrochemical analysis method (RIPP test method)," compiled by Yankee corporation, published in 1990 ", then the micropore volume of the molecular sieve was determined from the adsorption isotherm according to the T-plot method, and the secondary pore volume was obtained by subtracting the micropore volume from the total pore volume.
Example 1
2000 g of NaY molecular sieve (dry basis) is added into 20L of decationized aqueous solution and stirred to be mixed evenly, 600ml of RE (NO) is added3)3Solutions (rare earth salt solution concentration in RE)2O3Calculated as 319g/L, RE is the mixed rare earth of La and Ce, and La is calculated by the mass of the rare earth oxide2O3:Ce2O32), stirring, heating to 90-95 ℃, keeping for 1 hour, then filtering, washing, drying filter cake at 120 ℃, and obtaining the crystal cell constant of 2.471nm, the content of sodium oxide of 7.0 wt%, RE2O3Y-type molecular sieve with rare earth content of 8.8 wt%.
Thereafter, the molecular sieve was calcined at a temperature of 390 ℃ in an atmosphere containing 50 vol% of water vapor and 50 vol% of air for 6 hours to obtain a Y-type molecular sieve having a unit cell constant of 2.455 nm.
After cooling, the Y-type molecular sieve with a unit cell constant of 2.455nm was added to 6 liters of aqueous solution containing 35 grams of phosphoric acid, the temperature was raised to 90 ℃ for 30 minutes of phosphorus modification treatment, after which the molecular sieve was filtered and washed and the filter cake was dried to a water content of less than 1 wt%.
Then, according to SiCl4The Y-type molecular sieve (dry basis) is set as 0.5:1, and SiCl vaporized by heating is introduced into the molecular sieve after phosphorus modification treatment4The gas was reacted at a temperature of 400 ℃ for 2 hours, and then washed with 20 liters of decationized water, followed by filtration.
2300 ml of Zn (NO) with a concentration of 0.020 g/ml were slowly added to the obtained filter cake3)2The solution is soaked for 4 hours, the soaked sample is firstly dried for 5 hours at 130 ℃, then roasted for 3 hours at 400 ℃, and the modified Y-type molecular sieve is obtained and recorded as SZ1, and the physicochemical properties of the modified Y-type molecular sieve are shown in Table 1.
After aging SZ1 in a naked state for 17 hours at 800 ℃, 1atm and 100% steam, the relative crystallinity of the molecular sieve before and after aging SZ1 is analyzed by an XRD method and the relative crystallinity retention after aging is calculated, and the results are shown in Table 2, wherein:
714.5 g of an alumina sol having an alumina content of 21 wt.% were added to 1565.5 g of decationized water, stirring was started, and 2763 g of kaolin having a solids content of 76 wt.% were added and dispersed for 60 minutes. 2049 g of pseudo-boehmite with the alumina content of 61 wt% is taken and added into 8146 g of decationized water, 210ml of hydrochloric acid with the mass concentration of 36% is added under the stirring state, dispersed kaolin slurry is added after acidification is carried out for 60 minutes, 1500 g (dry basis) of ground SZ1 molecular sieve is added, after uniform stirring, spray drying and washing treatment are carried out, and the catalyst is obtained after drying and is marked as SC 1.
Wherein the obtained SC1 catalyst contains 30 wt% of SZ1 molecular sieve, 42 wt% of kaolin, 25 wt% of pseudo-boehmite and 3 wt% of alumina sol.
Example 2
2000 g of NaY molecular sieve (dry basis) is added into 25L of decationized aqueous solution and stirred to be mixed evenly, 800ml of RECl is added3Solutions (with RE)2O3The solution concentration is measured as: 319g/L, RE is mixed rare earth of La and Ce, and La is calculated by the mass of rare earth oxide2O3:Ce2O32), stirring, heating to 90-95 ℃, keeping for 1 hour, then filtering, washing, drying filter cake at 120 ℃, and obtaining the crystal cell constant of 2.471nm, the content of sodium oxide of 5.5 wt%, RE2O3Y-type molecular sieve with rare earth content of 11.3 wt%.
Then, the molecular sieve is roasted for 5.5 hours at the temperature of 450 ℃ and under 80% of water vapor, and the Y-type molecular sieve with the unit cell constant of 2.461nm is obtained.
After cooling, the Y-type molecular sieve with a unit cell constant of 2.461nm was added to 6 l of aqueous solution containing 268 g of ammonium phosphate, the temperature was raised to 60 ℃ and phosphorus modification treatment was carried out for 50 min, after which the molecular sieve was filtered and washed and the filter cake was dried to a water content of less than 1 wt%.
Then, according to SiCl4Wherein the mass ratio of Y-type zeolite is 0.6:1, and SiCl vaporized by heating is introduced into the molecular sieve after phosphorus modification treatment4The gas was reacted at 480 ℃ for 1.5 hours, and then washed with 20 liters of decationized water, followed by filtration.
2300 ml of ZnCl with a concentration of 0.030 g/ml are slowly added to the obtained filter cake2The solution is soaked for 4 hours, the soaked sample is firstly dried for 5 hours at 130 ℃, then roasted for 3.5 hours at 380 ℃, and the modified Y-type molecular sieve is obtained and recorded as SZ2, and the physicochemical properties of the modified Y-type molecular sieve are shown in Table 1.
After aging of SZ2 in the bare state with 100% steam at 800 ℃ for 17 hours, the crystallinity of the zeolite before and after aging of SZ2 was analyzed by XRD method and the relative crystal retention after aging was calculated, and the results are shown in Table 2.
714.5 g of an alumina sol having an alumina content of 21 wt.% were added to 1565.5 g of decationized water, stirring was started, and 2763 g of kaolin having a solids content of 76 wt.% were added and dispersed for 60 minutes. Adding 2049 g of pseudo-boehmite with the alumina content of 61 wt% into 8146 g of decationized water, adding 210ml of chemically pure hydrochloric acid under a stirring state, acidifying for 60 minutes, adding dispersed kaolin slurry, adding 1500 g (dry basis) of a milled SZ2 molecular sieve, uniformly stirring, performing spray drying and washing treatment, and drying to obtain the catalyst, which is recorded as SC 2.
Wherein the obtained SC2 catalyst contains 30 wt% of SZ2 molecular sieve, 42 wt% of kaolin, 25 wt% of pseudo-boehmite and 3 wt% of alumina sol.
Example 3
2000 g of NaY molecular sieve (dry basis) is added into 22L of decationized aqueous solution and stirred to be mixed evenly, and 570ml of RECl is added3Solutions (with RE)2O3The concentration of the rare earth salt solution is 319g/L, RE is the mixed rare earth of La and Ce, and La is calculated by the mass of rare earth oxide2O3:Ce2O32) stirring, heating to 90-95 ℃, keeping stirring for 1 hour, then filtering, washing, drying filter cakes at 120 ℃ to obtain crystalsCell constant 2.471nm, sodium oxide content 7.5 wt%, based on RE2O3Y-type molecular sieve with rare earth content of 8.5 wt%.
Thereafter, the molecular sieve was calcined at 470 ℃ under 70 vol% steam for 5 hours to obtain a Y-type molecular sieve having a unit cell constant of 2.458 nm.
After cooling, the Y-type molecular sieve with a unit cell constant of 2.458nm was added to 6 liters of aqueous solution with 95 grams of diammonium phosphate dissolved, the temperature was raised to 40 ℃ for 80 minutes of phosphorus modification treatment, after that, the molecular sieve was filtered and washed, and the filter cake was dried to a water content of less than 1 wt%.
Then, according to SiCl4Wherein the mass ratio of Y-type zeolite is 0.4:1, and SiCl vaporized by heating is introduced into the molecular sieve after phosphorus modification treatment4The gas was reacted at a temperature of 500 ℃ for 1 hour, and then washed with 20 liters of decationized water, followed by filtration.
To the resulting filter cake was slowly added 2500 ml of Zn (NO) at a concentration of 0.070 g/ml3)2The sample after 4 hours of solution impregnation is firstly dried at 130 ℃ for 5 hours, then roasted at 500 ℃ for 2 hours to obtain the modified Y-type molecular sieve which is recorded as SZ3 and the physicochemical properties of which are shown in Table 1.
After aging of SZ3 in the bare state with 100% steam at 800 ℃ for 17 hours, the crystallinity of the zeolite before and after aging of SZ3 was analyzed by XRD and the relative crystal retention after aging was calculated, and the results are shown in Table 2.
714.5 g of an alumina sol having an alumina content of 21 wt.% were added to 1565.5 g of decationized water, stirring was started, and 2763 g of kaolin having a solids content of 76 wt.% were added and dispersed for 60 minutes. Adding 2049 g of pseudo-boehmite with the alumina content of 61 wt% into 8146 g of decationized water, adding 210ml of chemically pure hydrochloric acid under a stirring state, acidifying for 60 minutes, adding dispersed kaolin slurry, adding 1500 g (dry basis) of a milled SZ3 molecular sieve, uniformly stirring, performing spray drying and washing treatment, and drying to obtain the catalyst, which is recorded as SC 3.
Wherein the obtained SC3 catalyst contains 30 wt% of SZ3 molecular sieve, 42 wt% of kaolin, 25 wt% of pseudo-boehmite and 3 wt% of alumina sol.
Comparative example 1
2000 g of NaY molecular sieve (dry basis) is added into 20L of decationized aqueous solution, stirred to be uniformly mixed, and 1000 g of (NH) is added4)2SO4Stirring, heating to 90-95 ℃ for 1 hour, filtering and washing.
Drying the filter cake at 120 deg.C, calcining at 650 deg.C under 100% steam for 5 hr for hydrothermal modification, adding into 20L decationized water solution, stirring, adding 1000 g (NH)4)2SO4Stirring, heating to 90-95 ℃ for 1 hour, filtering and washing.
And drying the filter cake at 120 ℃, roasting the filter cake at 650 ℃ for 5 hours under 100 percent of water vapor, and carrying out second hydrothermal modification treatment to obtain the rare earth-free hydrothermal ultrastable Y-type molecular sieve which is subjected to twice ion exchange and twice hydrothermal ultrastable, is recorded as DZ1, and has the physicochemical properties shown in Table 1.
After aging DZ1 in the bare state with 100% steam at 800 ℃ for 17 hours, the crystallinity of the zeolite before and after aging DZ1 was analyzed by XRD and the relative crystal retention after aging was calculated, and the results are shown in Table 2.
DZ1 molecular sieve, kaolin, water, pseudo-boehmite binder and alumina sol are formed into slurry according to a conventional preparation method of a catalytic cracking catalyst, the slurry is spray-dried to prepare a microspherical catalyst, and the prepared catalytic cracking catalyst is marked as DC1 (refer to the preparation method of example 1).
Wherein the obtained DC1 catalyst contains 30 wt% of DZ1 molecular sieve, 42 wt% of kaolin, 25 wt% of pseudo-boehmite and 3 wt% of alumina sol.
Comparative example 2
2000 g of NaY molecular sieve (dry basis) is added into 20L of decationized aqueous solution, stirred to be uniformly mixed, and 1000 g of (NH) is added4)2SO4Stirring, heating to 90-95 ℃ for 1 hour, filtering and washing.
Drying the filter cake at 120 ℃ and then carrying out hydrothermal treatmentModification treatment, wherein the temperature of the hydrothermal modification treatment is 650 ℃, the hydrothermal modification treatment is carried out for 5 hours under 100 percent of water vapor, then the hydrothermal modification treatment is added into 20 liters of decationized aqueous solution, the mixture is stirred and evenly mixed, and 200ml of RE (NO) is added3)3Solutions (with RE)2O3The concentration of the rare earth salt solution is measured as follows: 319g/L, RE is mixed rare earth of La and Ce, and La is calculated by the mass of rare earth oxide2O3:Ce2O33:2) and 900 g (NH)4)2SO4Stirring, heating to 90-95 ℃ for 1 hour, filtering and washing.
The filter cake is dried at 120 ℃ and then is subjected to a second hydrothermal modification treatment (the temperature is 650 ℃, and the filter cake is roasted for 5 hours under 100 percent of water vapor), so that the rare earth-containing hydrothermal ultrastable Y-type molecular sieve which is subjected to twice ion exchange and twice hydrothermal ultrastable is obtained and is marked as DZ2, and the physicochemical properties of the molecular sieve are shown in Table 1.
After aging DZ2 in the bare state with 100% steam at 800 ℃ for 17 hours, the crystallinity of the zeolite before and after aging DZ2 was analyzed by XRD and the relative crystal retention after aging was calculated, and the results are shown in Table 2.
DZ2 molecular sieve, kaolin, water, pseudo-boehmite binder and alumina sol are formed into slurry according to a conventional preparation method of a catalytic cracking catalyst, the slurry is spray-dried to prepare a microspherical catalyst, and the prepared catalytic cracking catalyst is marked as DC2 (refer to the preparation method of example 1).
Wherein the obtained DC2 catalyst contains 30 wt% of DZ2 molecular sieve, 42 wt% of kaolin, 25 wt% of pseudo-boehmite and 3 wt% of alumina sol.
Comparative example 3
2000 g of NaY molecular sieve (dry basis) is added into 22L of decationized aqueous solution and stirred to be mixed evenly, and 570ml of RECl is added3Solutions (with RE)2O3The concentration of the rare earth salt solution is 319g/L, RE is the mixed rare earth of La and Ce, and La is calculated by the mass of rare earth oxide2O3:Ce2O33:2), stirring, heating to 90-95 ℃, keeping stirring for 1 hour, filtering and washing.
Drying the filter cake at 120 ℃ to obtain a product with a unit cell constant of 2.471nm,Sodium oxide content 7.5 wt%, based on RE2O3The Y-type molecular sieve with the rare earth content of 8.5 wt% is calculated, then the molecular sieve is added into 6 liters of water solution dissolved with 95 g of diammonium hydrogen phosphate, the temperature is raised to 40 ℃, the phosphorus modification treatment is carried out for 80 minutes, then the molecular sieve is filtered and washed, and the filter cake is dried, so that the water content is lower than 1 wt%.
Then, according to SiCl4Y-type zeolite is added with SiCl vaporized by heating in a mass ratio of 0.4:14The gas was reacted at 580 ℃ for 1.5 hours, then washed with 20 liters of decationized water and filtered to obtain a modified Y-type molecular sieve designated DZ3, the physicochemical properties of which are shown in Table 1.
After aging DZ3 in the bare state with 100% steam at 800 ℃ for 17 hours, the crystallinity of the zeolite before and after aging with SZ3 was analyzed by XRD and the relative crystal retention after aging was calculated, and the results are shown in Table 2.
DZ3 molecular sieve, kaolin, water, pseudo-boehmite binder and alumina sol are formed into slurry according to a conventional preparation method of a catalytic cracking catalyst, the slurry is spray-dried to prepare a microspherical catalyst, and the prepared catalytic cracking catalyst is marked as DC3 (refer to the preparation method of example 1).
Wherein the obtained DC3 catalyst contains 30 wt% of DZ3 molecular sieve, 42 wt% of kaolin, 25 wt% of pseudo-boehmite and 3 wt% of alumina sol.
Catalytic cracking activity and stability of molecular sieves of application example 1
After the catalytic cracking catalysts SC1, SC2, and SC3 prepared in examples 1 to 3 were subjected to 100% steam aging at 800 ℃ for 4 hours or 17 hours, respectively, the light oil micro-reverse activity of the catalysts was evaluated, and the evaluation results are shown in table 3, and the example numbers corresponding to the catalysts SC1, SC2, and SC3 are application examples 1 to 1, application examples 1 to 2, and application examples 1 to 3, respectively.
Evaluation method of light oil micro-inverse activity:
the light oil micro-reverse activity of the sample is evaluated by adopting a standard method of RIPP92-90 (see the edition of petrochemical analysis method (RIPP test method), Yangcui et al, scientific publishing company, published in 1990), the catalyst loading is 5.0g, the reaction temperature is 460 ℃, the raw oil is Hongkong light diesel oil with the distillation range of 235-337 ℃, the product composition is analyzed by gas chromatography, and the light oil micro-reverse activity is calculated according to the product composition.
Light oil Microreactivity (MA) (gasoline production at less than 216 ℃ in product + gas production + coke production)/total feed × 100%.
Comparative application example 1
After aging the catalysts DC1, DC2 and DC3 at 800 ℃ for 4 hours or 17 hours with 100% steam (17 hours with 100% steam aging means aging for 17 hours in a 100% steam atmosphere), the light oil microreflection activity was evaluated. The evaluation method is shown in application example 1, the evaluation results are shown in Table 3, and the example numbers corresponding to the catalysts DC1, DC2 and DC3 are comparative application examples 1-1, comparative application examples 1-2 and comparative application examples 1-3, respectively.
Application example 2
After the SC1, SC2, and SC3 catalysts were aged at 800 ℃ for 12 hours in a 100% steam atmosphere, their catalytic cracking reaction performance for processing hydrogenated LCO was evaluated in a small fixed fluidized bed reactor (ACE), and cracked gas and product oil were collected separately and analyzed by gas chromatography. The catalyst loading is 9g, the reaction temperature is 500 ℃, and the weight hourly space velocity is 16h－1The mass ratio of the base oil to the oil is shown in Table 5, the properties of the raw materials for the ACE test are shown in Table 4, the evaluation results are shown in Table 5, and the corresponding example numbers of the SC1, SC2 and SC3 catalysts are application example 2-1, application example 2-2 and application example 2-3 respectively.
Wherein LCO effective conversion/% -100-diesel yield-dry gas yield-coke yield-heavy oil yield.
Comparative application example 2
The catalytic cracking performance of the HAC catalyst (comparative application examples 2-4) used in the examples of DC1, DC2, DC3 and CN 104560187a was evaluated on a small fixed fluidized bed reactor (ACE) after aging at 800 ℃ for 12 hours and 100% water vapor (12 hours and 100% water vapor aging means aging for 12 hours in 100% water vapor atmosphere), the evaluation method is shown in application example 2, the properties of the raw materials of the ACE experiment are shown in table 4, the evaluation results are shown in table 5, and the example numbers of the DC1, DC2, DC3 catalyst and the HAC catalyst are respectively comparative application examples 2-1, comparative application examples 2-2, comparative application examples 2-3 and comparative application examples 2-4.
Wherein LCO effective conversion/% -100-diesel yield-dry gas yield-coke yield-heavy oil yield.
TABLE 1
As can be seen from table 1, the modified Y-type molecular sieve containing phosphorus, rare earth, and zinc provided in the embodiments of the present invention has the following advantages: the modified Y-type molecular sieve has low content of sodium oxide, less non-framework aluminum content when the silicon-aluminum content of the modified Y-type molecular sieve is higher, the pore volume of 2.0-100 nm secondary pores in the molecular sieve accounts for higher percentage of the total pore volume, the B acid/L acid (the ratio of the strong B acid content to the L acid content) is higher, the crystallinity value measured when the unit cell constant of the molecular sieve is smaller and the rare earth content is higher, and the thermal stability is high.
TABLE 2
As can be seen from table 2, the modified Y-type molecular sieve containing phosphorus, rare earth, and zinc provided in the embodiment of the present invention has a higher relative crystal retention after being aged under the harsh conditions of 800 ℃ and 17 hours in an exposed state of the molecular sieve sample, which indicates that the modified Y-type molecular sieve provided in the embodiment of the present invention has a high hydrothermal stability.
TABLE 3
TABLE 4 Properties of hydrogenated LCO
| Item | Numerical value |
| Carbon content% | 88.91 |
| Hydrogen content% | 11.01 |
| Density at 20 ℃ in kg/m3 | 910.7 |
| Mass spectrum of hydrocarbon mass composition% | |
| Alkane hydrocarbons | 10.1 |
| Total cycloalkanes | 16.9 |
| Total monocyclic aromatic hydrocarbons | 60.3 |
| Total bicyclic aromatic hydrocarbons | 11.5 |
| Tricyclic aromatic hydrocarbons | 1.2 |
| Total aromatic hydrocarbons | 73 |
| Glue | 0 |
| Total weight of | 100 |
| Nitrogen content, mg/L | 0.9 |
| Sulfur content, mg/L | 49 |
TABLE 5
As can be seen from tables 3 and 5, the catalyst provided in the embodiment of the present invention has higher hydrothermal stability, significantly lower coke selectivity, and significantly higher gasoline yield than the catalyst of the comparative example, the yield of BTX (benzene + toluene + xylene) in gasoline is significantly increased, and the total yield of ethylene and propylene in the gas product is significantly increased.
Unless otherwise defined, all terms used herein have the meanings commonly understood by those skilled in the art.
The described embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of the present invention, and those skilled in the art may make various other substitutions, alterations, and modifications within the scope of the present invention, and thus, the present invention is not limited to the above-described embodiments but only by the claims.
Claims (16)
1. A catalytic cracking catalyst for processing hydrogenated LCO comprising a modified Y-type molecular sieve; in the modified Y-type molecular sieve, the rare earth content is 4-11 wt% in terms of rare earth oxide, the sodium content is not more than 0.7 wt% in terms of sodium oxide, the zinc content is 0.5-5 wt% in terms of zinc oxide, the phosphorus content is 0.05-10 wt% in terms of phosphorus pentoxide, and the framework silicon-aluminum ratio is SiO2/Al2O3Mole ofThe ratio is 7-14, the mass of non-framework aluminum accounts for not more than 20% of the total mass of aluminum, and the pore volume of secondary pores with the pore diameter of 2-100 nm of the modified Y-type molecular sieve accounts for 15-30% of the total pore volume of the modified Y-type molecular sieve.
2. The catalyst of claim 1, wherein the modified Y-type molecular sieve has a total pore volume of 0.33 to 0.39 mL/g.
3. The catalyst according to claim 1, wherein in the modified Y-type molecular sieve, the rare earth content is 4.5 to 10 wt%, the sodium content is 0.4 to 0.6 wt%, the phosphorus content is 0.1 to 6 wt%, the unit cell constant is 2.440 to 2.453nm, and the framework silicon-aluminum ratio is 8.5 to 12.6.
4. The catalyst of claim 1, wherein the non-framework aluminum accounts for 13-19% of the total aluminum in the modified Y-type molecular sieve by mass.
5. The catalyst according to claim 1, wherein in the modified Y-type molecular sieve, the pore volume of the secondary pores with the pore diameter of 2-100 nm accounts for 20-30% of the total pore volume.
6. The catalyst of claim 1 or 2, wherein the ratio of the amount of B acid to the amount of L acid in the modified Y-type molecular sieve is not less than 3.50 as measured by pyridine adsorption infrared at 350 ℃.
7. The catalyst according to claim 1, comprising 10 to 50 wt% of the modified Y-type molecular sieve, a binder and clay.
8. A preparation method of a catalytic cracking catalyst for processing hydrogenated LCO comprises the step of preparing an active component modified Y-type molecular sieve, wherein the step of preparing the active component modified Y-type molecular sieve comprises the following steps:
(1) carrying out ion exchange on the NaY molecular sieve and a rare earth salt solution;
(2) roasting the ion exchanged molecular sieve;
(3) carrying out phosphorus modification treatment on the roasted molecular sieve;
(4) reacting the molecular sieve subjected to phosphorus modification treatment with silicon tetrachloride; and
(5) and (4) impregnating the molecular sieve reacted in the step (4) with a zinc salt solution.
9. The method as claimed in claim 8, wherein in the step (1), the exchange temperature of ion exchange is 15-95 ℃, the exchange time is 30-120 minutes, the mass ratio of the NaY molecular sieve, the rare earth salt and the solvent water is 1 (0.01-0.18) to (5-15), the mass of the NaY molecular sieve is calculated by dry basis, and the mass of the rare earth salt is calculated by rare earth oxide.
10. The method as claimed in claim 8, wherein the firing of the step (2) is performed at 350 to 480 ℃ under an atmosphere having a water vapor content of 30 to 90 vol% for 4.5 to 7 hours.
11. The method according to claim 8, wherein the phosphorus modification treatment is carried out at 15 to 100 ℃ for 10 to 100 minutes in the step (3).
12. The method according to claim 8, wherein in the step (3), the phosphorus compound used for the phosphorus modification treatment is one or more selected from phosphoric acid, ammonium phosphate, ammonium dihydrogen phosphate and diammonium hydrogen phosphate.
13. The method as claimed in claim 8, wherein in the step (4), the reaction temperature is 200-650 ℃, the reaction time is 10 minutes to 5 hours, the mass ratio of the silicon tetrachloride to the phosphorus-modified molecular sieve is (0.1-0.7): 1, and the mass of the calcined molecular sieve is calculated on a dry basis.
14. The method as claimed in claim 8, wherein the step (5) comprises roasting the impregnated molecular sieve, wherein the impregnation temperature is 10-60 ℃, the roasting temperature is 350-600 ℃, and the roasting time is 1-4 hours.
15. The method according to any one of claims 8 to 14, comprising forming 10 to 50 wt% of the modified Y-type molecular sieve, a binder, clay and water into a slurry, and spray-drying to obtain the catalyst.
16. A catalytic cracking process for processing hydrogenated LCO, comprising the step of contacting hydrogenated LCO with the catalyst of any one of claims 1 to 7 under catalytic cracking conditions; wherein the catalytic cracking conditions comprise: the reaction temperature is 500-610 ℃, and the weight hourly space velocity is 2-16 h-1The agent-oil ratio is 3-10, and the agent-oil ratio is a weight ratio.
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| CN201810948782.XA CN110841691B (en) | 2018-08-20 | 2018-08-20 | Catalytic cracking catalyst for processing hydrogenated LCO and preparation method thereof |
| FR1909288A FR3085005B1 (en) | 2018-08-20 | 2019-08-20 | Modified Y-type molecular sieve, catalytic cracking catalyst comprising the same, their preparation and their application |
| SG11202012300PA SG11202012300PA (en) | 2018-08-20 | 2019-08-20 | Modified y-type molecular sieve, catalytic cracking catalyst comprising the same, their preparation and application thereof |
| JP2021509150A JP7394116B2 (en) | 2018-08-20 | 2019-08-20 | Modified Y-type molecular sieve, catalytic cracking catalyst containing it, and their preparation and application |
| US17/268,371 US11130917B2 (en) | 2018-08-20 | 2019-08-20 | Modified Y-type molecular sieve, catalytic cracking catalyst comprising the same, their preparation and application thereof |
| AU2019326622A AU2019326622A1 (en) | 2018-08-20 | 2019-08-20 | Modified Y type molecular sieve, catalytic cracking catalyst having same, preparation methods therefor and applications thereof |
| PCT/CN2019/101513 WO2020038347A1 (en) | 2018-08-20 | 2019-08-20 | Modified y type molecular sieve, catalytic cracking catalyst having same, preparation methods therefor and applications thereof |
| TW108129558A TWI812772B (en) | 2018-08-20 | 2019-08-20 | Modified Y-type molecular sieve, catalytic cracking catalyst containing it, and its preparation and use |
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