CN116037195A - Low-coke catalytic cracking catalyst and preparation method thereof - Google Patents

Low-coke catalytic cracking catalyst and preparation method thereof Download PDF

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CN116037195A
CN116037195A CN202111262834.6A CN202111262834A CN116037195A CN 116037195 A CN116037195 A CN 116037195A CN 202111262834 A CN202111262834 A CN 202111262834A CN 116037195 A CN116037195 A CN 116037195A
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molecular sieve
type molecular
modified
nay
rare earth
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周灵萍
严加松
袁帅
宋海涛
沙昊
张蔚琳
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Sinopec Research Institute of Petroleum Processing
China Petroleum and Chemical Corp
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Sinopec Research Institute of Petroleum Processing
China Petroleum and Chemical Corp
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J29/08—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the faujasite type, e.g. type X or Y
    • B01J29/085—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
    • B01J29/088—Y-type faujasite
    • 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
    • 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
    • C10G11/04—Oxides
    • C10G11/05—Crystalline alumino-silicates, e.g. molecular sieves
    • 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
    • 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
    • B01J2229/30—After treatment, characterised by the means used
    • B01J2229/32—Reaction with silicon compounds, e.g. TEOS, siliconfluoride
    • 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
    • B01J2229/30—After treatment, characterised by the means used
    • B01J2229/37—Acid treatment
    • 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
    • B01J2229/30—After treatment, characterised by the means used
    • B01J2229/42—Addition of matrix or binder particles
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

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  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Materials Engineering (AREA)
  • General Chemical & Material Sciences (AREA)
  • Catalysts (AREA)
  • Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)

Abstract

The invention provides a catalytic cracking catalyst, which comprises a modified Y-shaped molecular sieve, an alumina binder and clay, wherein the modified Y-shaped molecular sieve comprises 4-10 wt% of rare earth, 0.05-6 wt% of phosphorus and 0.1-0.5 wt% of sodium oxide, the ratio of skeleton silicon to aluminum is 8.8-19, the total pore volume is 0.35-0.40 mL/g, the unit cell constant is 2.435-2.450 nm, the lattice collapse temperature is not lower than 1070 ℃, and the relative crystallinity is 60-80%. The invention also provides a method for preparing the catalytic cracking catalyst, which comprises the steps of preparing the modified Y-type molecular sieve, and mixing the modified Y-type molecular sieve with an alumina binder and clay to form slurry; spray drying; and optionally washing and drying. The method can fully recycle Si in the discharged NaY mother liquor generated in the NaY synthesis process, reduce the production cost and reduce the discharge of waste water and waste residues of catalyst production enterprises; and the obtained catalytic cracking catalyst has high heavy oil cracking activity, good coke selectivity, high gasoline yield, high liquefied gas yield and high total liquid yield.

Description

Low-coke catalytic cracking catalyst and preparation method thereof
Technical Field
The invention relates to a catalytic cracking catalyst with low coke formation and a preparation method thereof.
Background
Catalytic Cracking (FCC) is an important crude oil secondary processing process, contributing to about 70% of gasoline in our country, and occupying a vital role in the oil refining industry. In the catalytic cracking process, heavy fractions (such as vacuum distillates or heavier residues) react in the presence of a catalyst and are converted into high value-added products such as liquefied gas, gasoline, diesel oil and the like. The catalytic cracking catalyst is the core of catalytic cracking, and the Y molecular sieve is the main active component of the catalytic cracking catalyst, and the performance of the Y molecular sieve directly affects the performance of the catalytic cracking catalyst. With the increasing weight of catalytic cracking feedstock, catalytic cracking catalysts should have both higher activity and higher thermal and hydrothermal stability to enhance heavy oil conversion and resistance to heavy metal contamination, and thus, the main active group Y molecular sieves of catalytic cracking catalysts are required to have high thermal and hydrothermal stability and maintain a proper distribution of acidic active centers. In order to effectively improve the stability of the Y molecular sieve, the Y molecular sieve must be subjected to ultrastable modification, the silicon-aluminum ratio of a framework is improved, the structure is ultrastable, and the modified high-silicon Y-type molecular sieve with high crystallinity, high activity and high stability is prepared, so that the performance of the catalytic cracking catalyst is further improved, more products with high added value such as liquefied gas, gasoline, diesel oil and the like can be further obtained, and meanwhile, the coke selectivity of the catalyst is improved.
Therefore, how to improve the crystallinity and stability of the modified Y-type molecular sieve, and further improve the activity and stability of the catalytic cracking catalyst is a goal pursued by catalyst manufacturers.
Because the modified high-silicon Y-type molecular sieve is a main active component of the catalytic cracking catalyst, the synthesis of the NaY-type molecular sieve serving as a key process for preparing the modified high-silicon Y-type molecular sieve and a post-modification process thereof occupy very important positions in the catalytic cracking catalyst production process, and the performance of the modified molecular sieve directly influences the performance of the catalytic cracking catalyst.
In addition, as environmental requirements are increasingly strict, the waste water and waste residue emission of catalyst manufacturers currently becomes an important factor for limiting the development of the catalyst manufacturers and even affecting the normal production of the catalyst manufacturers, so how to greatly reduce the waste water and waste residue emission as soon as possible and meet the increasingly strict environmental requirements is a key technical problem to be solved by the catalyst manufacturers.
At present, when the NaY molecular sieve is industrially synthesized, the ratio of the fed silicon to the aluminum is generally 7.5-10, and the ratio of the product silicon to the aluminum is generally 4.5-5.5, so that a large amount of silicon is not utilized in the synthesis mother liquor, and the primary utilization rate of the silicon is low, generally only about 60% -70%. That is, 30 to 40 percent of SiO is still remained 2 Is present in the mother liquor. That is, in the prior art, a part of NaY mother liquor is recycled to the NaY molecular sieve synthesis process, and the recycling rate of Si in the part of NaY mother liquor is generally 62% -75%; the rest part is discharged from a NaY molecular sieve synthesis circulation system due to the limited processing capacity of the existing synthesis process, and Si in the NaY mother liquor cannot be recycled. If such NaY mother liquor is discharged directly into the sewage treatment tank without treatment, a large amount of free SiO therein 2 Is easy to react with other sewage to form colloid, and the subsequent sedimentation is very difficult. The recovery treatment of NaY mother liquor has seriously affected the standard discharge of the discharged sewage. Therefore, how to improve the recovery and utilization rate of NaY mother liquor, reduce the discharge pollution of waste water and waste residue and reduce the production cost is a double requirement of production and environmental protection.
At present, a method for forming silicon-aluminum hydrogel is mainly adopted in industrial NaY production to recycle silicon in mother liquor. However, the main disadvantages of this approach are: (1) The NaY mother liquor produced in actual industry inevitably contains part of microcrystals of P-type hetero-crystals, so that the proportion of the recovered silicon source is limited to a certain extent in order to avoid the adverse effect of the P-type crystal seeds in the recovered silicon-aluminum gel on a synthesis system, and the silicon utilization rate is only about 75%, so that the silicon in the mother liquor cannot be completely recovered; (2) When the recovered solid-phase silica-alumina gel and the liquid-phase silica-alumina source are mixed in a raw material tank to prepare synthetic gel, the uniformity of the gel system composition is difficult to achieve, the generation of P-type hetero-crystals is easy to induce in the crystallization process, and the production process of NaY synthesis is unstable; (3) The reduction of the average particle size of NaY molecular sieves synthesized on the basis of partially recovered silica-alumina gel results in a decrease in the quality of the product, possibly adversely affecting the hydrothermal stability during subsequent use.
Therefore, in the prior art, the recovery of the NaY mother liquor and the direct use thereof in NaY synthesis are limited, the recovery rate of Si can only reach 75%, and the silicon in the NaY mother liquor still cannot be completely recovered.
How to recycle Si in the NaY mother liquor further improves the recovery rate of Si in the NaY mother liquor, further reduces the cost and emission, protects the environment, and is an important technology which is urgently needed to be developed by catalyst production enterprises.
On the other hand, the hydrothermal ultrastable method is one of the most widely used modification methods of Y-type molecular sieves in industry, and is to exchange NaY zeolite with an aqueous solution of ammonium ions to reduce the sodium ion content in zeolite, and then bake the ammonium ion exchanged zeolite at 500-800 ℃ in a water vapor atmosphere to ultrastable it. The method has low cost and is easy for industrialized mass production, but has the defect of serious loss of crystallinity of the ultra-stable Y-type molecular sieve. The reason is that the super-stabilization process of the hydrothermal super-stabilization method is to utilize water molecules to attack aluminum atoms on the molecular sieve framework at high temperature, so that the aluminum atoms are removed from the molecular sieve framework to generate Al (OH) 3 Al atoms on the framework are removed, al vacancies are left, then free Si in the molecular sieve migrates to the Al vacancies and fills the vacancies, so that the dealumination and silicon supplementing process is completed, the framework structure is completed, the framework silicon-aluminum ratio is improved, and the molecular sieve structure is ultra-stable. However, the problem of industrial hydrothermal ultrastable is that the vacancy generated after the aluminum on the framework is removed by steam is that the silicon source near the aluminum of the molecular sieve framework is less, and the molecular sieve dealumination is fast The degree is far greater than the migration speed of silicon, and the silicon cannot migrate to vacancies generated by dealumination in time, so that the crystal lattice collapse of the molecular sieve at the vacancies generated by dealumination is caused, and the crystallinity of the molecular sieve is lost. In general, for a hydrothermal ultrastable molecular sieve with high silicon-aluminum ratio, the dealumination amount is large and the speed is high, so that the migration amount and migration speed of silicon are insufficient, silicon cannot be timely fed into vacancies formed by dealumination, the crystallinity of the molecular sieve is lost, and the production of the hydrothermal ultrastable molecular sieve with high crystallinity and high silicon-aluminum ratio is difficult.
In summary, the prior art can generate excessive NaY mother liquor which cannot be processed in the process of preparing the catalytic cracking catalyst, and the existing hydrothermal ultrastable technology is difficult to prepare the catalyst containing the Y-type molecular sieve with high framework silicon-aluminum ratio and high crystallinity.
Disclosure of Invention
The invention aims to provide a catalytic cracking catalyst suitable for catalytic cracking of heavy oil, which has high thermal and hydrothermal stability, high gasoline yield, strong heavy oil conversion capability and good coke selectivity.
The second technical problem to be solved by the present invention is how to further utilize the portion of NaY mother liquor discharged. Aiming at the problem, the invention provides a preparation method of a catalytic cracking catalyst, which not only can improve the hydrothermal stability, crystallinity and skeleton silicon-aluminum ratio of a Y-type molecular sieve, but also can basically and completely recover Si in the NaY mother liquor, lighten the pressure of the subsequent processing step and is beneficial to environmental protection by utilizing the NaY mother liquor which cannot be recycled in the NaY molecular sieve synthesis process in the prior art to carry out the post-modification of the Y-type molecular sieve.
In one aspect, the present invention provides a catalytic cracking catalyst comprising 10 to 50 wt% of a modified Y-type molecular sieve based on dry weight of the catalyst, 10 to 40 wt% of an alumina binder based on alumina, and 10 to 80 wt% of clay based on dry weight, wherein the modified Y-type molecular sieve comprises 4 to 10 wt%, preferably 4.5 to 9 wt% of RE based on dry weight of the modified Y-type molecular sieve 2 O 3 0.05 to 6 wt%, preferably 0.5 to 4 wt% of rare earth oxide, based on P 2 O 5 0.1 to 0.5 weight percent of sodium oxide based on phosphorus, and the Si/Al ratio of the framework in the modified Y-type molecular sieve is SiO 2 /Al 2 O 3 The molar ratio is 8.8-19, preferably 9.5-18; the total pore volume of the modified Y-type molecular sieve is 0.35-0.40 mL/g, preferably 0.36-0.39 mL/g; the unit cell constant of the modified Y-type molecular sieve is 2.435 nm-2.450 nm, preferably 2.436 nm-2.448 nm; the lattice collapse temperature of the modified Y-type molecular sieve is not lower than 1070 ℃, and 1070-1080 ℃ is preferable; the relative crystallinity of the modified Y-type molecular sieve is 60-80%, preferably 65-75%; the specific surface area of the modified Y-type molecular sieve is 645-670 m 2 Preferably 650-665 m per gram 2 /g。
In one embodiment, the modified Y-type molecular sieve has a relative crystal retention of 45% or more, preferably 46 to 52% after aging at 800℃under normal pressure in a 100% water vapor atmosphere for 17 hours.
In one embodiment, the rare earth oxide content of the modified Y-type molecular sieve is 4.5 to 9 weight percent, the sodium oxide content is 0.1 to 0.5 weight percent, and the phosphorus content is P 2 O 5 The unit cell constant is 2.436-2.448 nm, and the skeleton silicon-aluminum ratio is 9.5-18.
In another aspect, the present invention provides a method of preparing a catalytic cracking catalyst comprising:
preparing a modified Y-type molecular sieve, which comprises the following steps:
(1) Contacting NaY molecular sieve with NaY mother liquor, adding dilute acid solution, mixing to uniformity, and filtering;
(2) Contacting the NaY molecular sieve obtained in the step (1) with a rare earth salt solution for ion exchange reaction, filtering, washing, and optionally drying to obtain a Y-type molecular sieve with reduced sodium oxide content;
(3) Performing mild hydrothermal ultrastable modification treatment on the Y-type molecular sieve with reduced sodium oxide content obtained in the step (2) to obtain the Y-type molecular sieve with reduced unit cell constant;
(4) Carrying out phosphorus modification treatment on the Y-type molecular sieve with the reduced unit cell constant obtained in the step (3) by using a phosphorus compound, and drying to obtain the Y-type molecular sieve with the reduced unit cell constant containing phosphorus;
(5) The Y-type molecular sieve with the reduced unit cell constant containing phosphorus obtained in the step (4) is contacted and reacted with silicon tetrachloride gas, and is optionally washed and optionally filtered to obtain an ultra-stable modified Y-type molecular sieve;
mixing the modified Y-type molecular sieve with an alumina binder, clay and water to form slurry;
spray drying; and
optionally, washing and drying the product,
the catalytic cracking catalyst is obtained.
In one embodiment, in step (1) of preparing the modified Y-type molecular sieve, the dilute acid is dilute hydrochloric acid, dilute sulfuric acid, or dilute nitric acid.
In one embodiment, in step (1) of preparing the modified Y-type molecular sieve, the dilute acid solution is at a concentration of H in solution + The molar concentration of (C) is 0.001 to 0.1mol/L, preferably 0.005 to 0.05mol/L.
In one embodiment, in step (1) of preparing the modified Y-type molecular sieve, the NaY molecular sieve is contacted with the NaY mother liquor while stirring, the mixed slurry is heated to 40 to 90 ℃, preferably 50 to 75 ℃, and the aqueous solution of the dilute acid is added, and after continuing stirring for 20 to 90 minutes, preferably 30 to 60 minutes, filtration is performed.
In one embodiment, in step (1) of preparing the modified Y-type molecular sieve, the ratio of NaY mother liquor to NaY molecular sieve (on a dry basis) is from 1 to 1.9ml NaY mother liquor: 1g of NaY molecular sieve.
In one embodiment, in step (1) of preparing the modified Y-type molecular sieve, the NaY molecular sieve is a commercially available NaY molecular sieve or is a NaY molecular sieve filter cake that has been filtered and washed with industrial water after synthesis of the NaY molecular sieve; and/or the NaY mother liquor is the NaY mother liquor which is discharged after the NaY molecular sieve is synthesized, the solid NaY molecular sieve is filtered and separated from the NaY synthetic slurry, and the mother liquor which is remained after the NaY molecular sieve is not recycled in the NaY molecular sieve synthesis process.
In a real worldIn an embodiment, in step (2) of preparing the modified Y-type molecular sieve, the NaY molecular sieve is prepared as follows: rare earth salt: h 2 O=1: 0.01 to 0.18: 5-15 weight ratio of NaY molecular sieve, rare earth salt and water to form a mixture, and stirring to perform ion exchange reaction, wherein the weight of NaY molecular sieve is calculated on a dry basis, and the weight of rare earth salt is calculated on rare earth oxide. In a further preferred embodiment, forming the NaY molecular sieve, the rare earth salt and water into a mixture is accomplished by mixing the NaY molecular sieve with water, adding the rare earth salt and/or rare earth salt solution with stirring.
In one embodiment, in step (2) of preparing the modified Y-type molecular sieve, the conditions of the ion exchange reaction are: the temperature is 15-95 ℃, preferably 65-95 ℃, and the exchange time is 30-120 minutes, preferably 45-90 minutes.
In one embodiment, the rare earth salt solution is an aqueous solution of a rare earth salt.
In one embodiment, the rare earth salt is rare earth chloride and/or rare earth nitrate.
In one embodiment, in step (3) of preparing the modified Y-type molecular sieve, the Y-type molecular sieve having a reduced sodium oxide content obtained in step (2) is calcined at a temperature of 350 to 520 ℃, preferably 380 to 480 ℃, in a 30 to 85% by volume, preferably 40 to 80% by volume, water vapor atmosphere for 4.5 to 7 hours, preferably 5 to 6 hours.
In one embodiment, in the step (4) of preparing the modified Y-type molecular sieve, the Y-type molecular sieve with reduced unit cell constant obtained in the step (3) is contacted with an exchange liquid containing a phosphorus compound and water, and the exchange reaction is carried out for 10 to 100 minutes under the condition of 15 to 100 ℃ to carry out phosphorus modification treatment; wherein the weight ratio of water in the exchange liquid to the Y-type molecular sieve with reduced unit cell constant on a dry basis is 2-5: 1, preferably 3 to 4:1, a step of; with P 2 O 5 The weight ratio of phosphorus to the Y-type molecular sieve with reduced unit cell constant on a dry basis is 0.0005 to 0.07:1, preferably 0.001 to 0.05:1.
in one embodiment, in step (4) of preparing the modified Y-type molecular sieve, the phosphorus compound is selected from one or more of phosphoric acid, ammonium phosphate, monoammonium phosphate, diammonium phosphate.
In one embodiment, in step (4) of preparing the modified Y-type molecular sieve, the water content in the Y-type molecular sieve having a reduced unit cell constant of phosphorus is no more than 1 wt%.
In one embodiment, in step (5) of preparing the modified Y-type molecular sieve, siCl 4 : weight ratio of the Y-type molecular sieve with reduced unit cell constant of phosphorus on a dry basis=0.1 to 0.7:1, preferably 0.15 to 0.7:1, a step of; the reaction temperature is 200-600 ℃, preferably 250-550 ℃; the reaction time is 10 minutes to 5 hours, preferably 30 minutes to 4 hours.
In one embodiment, the catalytic cracking catalyst prepared according to the method of the present invention contains 10 to 50 wt% of a modified Y-type molecular sieve based on the dry weight thereof, 10 to 40 wt% of an alumina binder based on alumina, and 10 to 80 wt% of clay based on dry weight thereof, wherein the modified Y-type molecular sieve contains 4 to 10 wt%, preferably 4.5 to 9 wt% of RE based on the dry weight thereof 2 O 3 0.05 to 6 wt%, preferably 0.5 to 4 wt% of rare earth oxide, based on P 2 O 5 0.1 to 0.5 weight percent of sodium oxide based on phosphorus, and the Si/Al ratio of the framework in the modified Y-type molecular sieve is SiO 2 /Al 2 O 3 The molar ratio is 8.8-19, preferably 9.5-18; the total pore volume of the modified Y-type molecular sieve is 0.35-0.40 mL/g, preferably 0.36-0.39 mL/g; the unit cell constant of the modified Y-type molecular sieve is 2.435 nm-2.450 nm, preferably 2.436 nm-2.448 nm; the lattice collapse temperature of the modified Y-type molecular sieve is not lower than 1070 ℃, and 1070-1080 ℃ is preferable; the relative crystallinity of the modified Y-type molecular sieve is 60-80%, preferably 65-75%; the specific surface area of the modified Y-type molecular sieve is 645m 2 /g～670m 2 /g, preferably 650m 2 /g～665m 2 /g。
In one aspect, the invention also provides a catalytic cracking process comprising the step of contacting heavy oil with the catalytic cracking catalyst of the invention. The method is applicable to some reactions which are easy to accumulate carbon, such as elevated reaction temperature, high carbon residue raw material oil and the like.
The catalytic cracking catalyst of the invention contains the modified Y-type molecular sieve with high framework silicon-aluminum ratio, high crystallinity and high thermal and hydrothermal stability, and can be used for converting heavy oil or inferior oil.
When the catalytic cracking catalyst is used for heavy oil catalytic cracking, the heavy oil cracking capacity is strong, the coke selectivity is good, the hydrothermal stability is high, and the liquefied gas yield, the gasoline yield, the light oil yield and the total liquid yield are relatively high.
Detailed Description
In the present invention, the weight of the various molecular sieves involved, whether or not explicitly mentioned, is on a dry basis; the weight or the content of the rare earth salt and the rare earth are calculated by the weight or the content of the oxidized rare earth; the weight or content of sodium is calculated by the weight or content of sodium oxide; the weight or content of the phosphorus is that of phosphorus pentoxide (P 2 O 5 ) Weight or content meter of (a); silicon-aluminum ratio of skeleton is SiO 2 /Al 2 O 3 Molar ratio meter; the water vapor is calculated by volume ratio.
In the invention, "heavy oil" refers to the residual heavy oil after the crude oil is used for extracting gasoline and diesel oil, and is characterized by large molecular weight and high viscosity. Examples of heavy oils include, but are not limited to, one or more of atmospheric wax oil, vacuum wax oil, coker wax oil, atmospheric residuum, vacuum residuum, heavy Cycle Oil (HCO).
In the present invention, the term "mild hydrothermal ultrastable treatment" means a vapor dealumination and silicon repair process performed under mild conditions of a vapor atmosphere of 30 to 85 volume% at a temperature of 350 to 520 ℃.
The invention provides a catalytic cracking catalyst, which comprises 10-50 wt% of modified Y-type molecular sieve, 10-40 wt% of alumina binder and 10-80 wt% of clay. In a preferred embodiment, the catalytic cracking catalyst comprises 25 to 40 wt% modified Y-type molecular sieve on a dry basis, 20 to 35 wt% alumina binder on an alumina basis, and 30 to 50 wt% clay on a dry basis.
In one embodiment, in the heavy oil catalytic cracking catalyst provided by the invention, the content of the modified Y-type molecular sieve is 10 to 50 wt%, preferably 15 to 45 wt%, more preferably 25 to 40 wt%, based on the dry weight of the catalyst.
In one embodiment, the modified Y-type molecular sieve contained in the catalytic cracking catalyst of the present invention has a rare earth oxide content of 4 to 10 wt%, preferably 4.5 to 9 wt%, for example, 4.8 wt%, 5.4 wt% or 7.3 wt%, based on the dry weight of the modified Y-type molecular sieve.
In one embodiment, the rare earth in the modified Y-type molecular sieve may be selected from one or more of La, ce, pr, nd and mischmetal, for example. In one embodiment, the misch metal may contain one or more of La, ce, pr, and Nd, or may further contain at least one of rare earths other than La, ce, pr, and Nd.
In one embodiment, in the modified Y-type molecular sieve contained in the catalytic cracking catalyst of the present invention, P is the same based on the dry weight of the modified Y-type molecular sieve 2 O 5 Content (i.e. in P 2 O 5 The phosphorus content by weight) is 0.05 to 6% by weight, preferably 0.5 to 4% by weight, more preferably 0.7 to 3% by weight, for example 0.87%, 1.95% or 2.56% by weight.
In one embodiment, the modified Y-type molecular sieve contained in the catalytic cracking catalyst of the present invention has a sodium oxide content of 0.1 to 0.5 wt%, preferably 0.2 to 0.5 wt%, for example, 0.39 wt%, 0.43 wt% or 0.47 wt%, based on the dry weight of the modified Y-type molecular sieve.
In one embodiment, the modified Y-type molecular sieve has a framework silica to alumina ratio (SiO 2 /Al 2 O 3 Molar ratio) of 8.8 to 19, preferably 9.5 to 18, still preferably 10 to 17.7, more preferably 1117, for example 11.39, 13.95 or 16.63.
In one embodiment, the unit cell constant of the modified Y-type molecular sieve is from 2.435nm to 2.450nm, preferably from 2.436 nm to 2.448nm, for example 2.437nm, 2.440nm or 2.444nm.
In one embodiment, the modified Y-type molecular sieve has a relative crystallinity of not less than 60%, preferably 60% to 80%, more preferably 65% to 75%, for example 66.2%, 68.1% or 70.2%, indicating a higher crystallinity.
In one embodiment, the modified Y-type molecular sieve has a lattice collapse temperature of no less than 1070 ℃, preferably 1070 ℃ to 1080 ℃, such as 1074 ℃, 1076 ℃ or 1079 ℃, indicating a higher thermal stability.
In one embodiment, the modified Y-type molecular sieve has a total pore volume of from 0.35mL/g to 0.40mL/g, preferably from 0.36mL/g to 0.39mL/g, such as 0.365mL/g, 0.369mL/g, or 0.377mL/g.
In one embodiment, the modified Y-type molecular sieve has a specific surface area of 645m 2 /g～670m 2 /g, preferably 650m 2 /g～665m 2 /g, e.g. 653m 2 /g、655m 2 /g or 662m 2 /g。
In one embodiment, the modified Y-type molecular sieve contained in the catalytic cracking catalyst of the present invention contains 4 to 10% by weight of RE based on the dry weight of the modified Y-type molecular sieve 2 O 3 0.05 to 6 weight percent of rare earth oxide calculated as P 2 O 5 0.1 to 0.5 weight percent of sodium oxide based on phosphorus, and the Si/Al ratio of the framework in the modified Y-type molecular sieve is SiO 2 /Al 2 O 3 The molar ratio is 8.8-19; the total pore volume of the modified Y-type molecular sieve is 0.35-0.40 mL/g; the unit cell constant of the modified Y-type molecular sieve is 2.435 nm-2.450 nm; the lattice collapse temperature of the modified Y-type molecular sieve is not lower than 1070 ℃; the relative crystallinity of the modified Y-type molecular sieve is 60-80 percent; the specific surface area of the modified Y-type molecular sieve is 645m 2 /g～670m 2 /g。
In one embodiment, the modified Y-type molecular sieve contained in the catalytic cracking catalyst of the present invention contains 4.5 to 9% by weight of RE based on the dry weight of the modified Y-type molecular sieve 2 O 3 0.5 to 4 weight percent of rare earth oxide calculated as P 2 O 5 Phosphorus, 0.1 to 0.5 weight percent of sodium oxide, and the framework silicon-aluminum ratio is calculated as SiO 2 /Al 2 O 3 The molar ratio is 9.5-18; the total pore volume is 0.36 mL/g-0.39 mL/g; the unit cell constant is 2.436 nm-2.448 nm; the lattice collapse temperature is 1070-1080 ℃; the relative crystallinity is 65-75 percent; specific surface area of 650m 2 /g～665m 2 /g。
In one embodiment, the modified Y-type molecular sieve has a relative crystalline retention of 45% or more, preferably 46 to 52%, such as 48.72%, 48.90% or 49.40%, after aging at 800℃for 17 hours under an atmospheric pressure, 100% steam atmosphere, indicating a relatively high hydrothermal stability. In the present invention, the "normal pressure" means 1atm.
In one embodiment, the catalytic cracking catalyst provided by the present invention may further contain other molecular sieves than the modified Y-type molecular sieve, and the content of the other molecular sieve may be, for example, 0, 1 wt%, 2 wt%, 5 wt% to 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt% or 40 wt%, for example, 0 to 40 wt%, 0 to 30 wt%, 0 to 20 wt%, or 1 to 20 wt%, on a dry basis, based on the dry weight of the catalyst. The other molecular sieve may be selected from molecular sieves used in catalytic cracking catalysts, for example, may be selected from one or more of MFI structure zeolite, beta zeolite, other Y-type zeolite, non-zeolite molecular sieves, and the like. The MFI structure zeolite may be selected from, for example, one or more of HZSM-5, ZRP, ZSP; the other Y-zeolite may be selected from, for example, one or more of REY, REHY, DASY, SOY, PSRY; the Beta zeolite may be, for example, H Beta; the non-zeolitic molecular sieves may be selected from, for example, one or more of aluminum phosphate molecular sieves (AlPO molecular sieves), silicoaluminophosphate molecular sieves (SAPO molecular sieves).
In one embodiment, in the catalytic cracking catalyst provided by the present invention, the content of the alumina binder is 10 to 40 wt% in terms of alumina, preferably 20 to 35 wt% based on the dry weight of the catalyst.
In one embodiment, in the catalytic cracking catalyst provided by the invention, the alumina binder is selected from one or more of alumina, hydrated alumina and alumina sol in various forms commonly used in cracking catalysts. For example, in one embodiment, the alumina binder may be selected from one or more of gamma-alumina, eta-alumina, theta-alumina, chi-alumina, pseudo-Boehmite (pseudoboehmite), boehmite (Boehmite), gibbsite (Gibbsite), bayerite (Bayerite), or an alumina sol, preferably pseudo-Boehmite and an alumina sol. In a preferred embodiment, the catalytic cracking catalyst contains 2 to 15 wt.%, preferably 3 to 10 wt.% of an alumina sol and 10 to 30 wt.%, preferably 15 to 25 wt.% of pseudo-boehmite, calculated as alumina.
In one embodiment, in the catalytic cracking catalyst provided by the present invention, the clay is contained in an amount of 20 to 55 wt%, preferably 30 to 50 wt%, on a dry basis, based on the dry weight of the catalyst.
In one embodiment, in the catalytic cracking catalyst provided by the invention, the clay is selected from one or more of clays used as components of the cracking catalyst, and can be selected from one or more of kaolin, halloysite, montmorillonite, kieselguhr, halloysite, saponite, rectorite, sepiolite, attapulgite, hydrotalcite and bentonite.
In another aspect, the present invention provides a method of preparing a catalytic cracking catalyst comprising:
preparing a modified Y-type molecular sieve, which comprises the following steps:
(1) Contacting NaY molecular sieve with NaY mother liquor, adding dilute acid solution, mixing to uniformity, and filtering;
(2) Contacting the NaY molecular sieve obtained in the step (1) with a rare earth salt solution for ion exchange reaction, filtering, washing, and optionally drying to obtain a Y-type molecular sieve with reduced sodium oxide content;
(3) Performing mild hydrothermal ultrastable modification treatment on the Y-type molecular sieve with reduced sodium oxide content obtained in the step (2) to obtain the Y-type molecular sieve with reduced unit cell constant;
(4) Carrying out phosphorus modification treatment on the Y-type molecular sieve with the reduced unit cell constant obtained in the step (3) by using a phosphorus compound, and drying to obtain the Y-type molecular sieve with the reduced unit cell constant containing phosphorus;
(5) Contacting the Y-type molecular sieve with the reduced unit cell constant of phosphorus obtained in the step (4) with silicon tetrachloride gas for reaction, and optionally washing and optionally filtering to obtain the modified Y-type molecular sieve;
mixing the modified Y-type molecular sieve with an alumina binder, clay and water to form slurry;
spray drying; and
optionally, washing and drying the product,
the catalytic cracking catalyst is obtained.
In one embodiment, in step (1) of preparing the modified Y-type molecular sieve, the NaY molecular sieve is stirred and warmed to facilitate solid-liquid separation while contacting with the NaY mother liquor.
In one embodiment, in the step (1) of preparing the modified Y-type molecular sieve, the NaY molecular sieve is contacted with NaY mother liquor in stirring, the temperature is raised to 40-90 ℃, and a dilute acid solution is slowly added, and after stirring is continued for 20-90 minutes, filtering is performed.
In one embodiment, in step (1) of preparing the modified Y-type molecular sieve, the NaY molecular sieve may be a commercially available NaY molecular sieve. In one embodiment, in step (1) of preparing the modified Y-type molecular sieve, the NaY molecular sieve may be a NaY molecular sieve filter cake that is filtered and washed with industrial water after synthesis of the NaY molecular sieve. In one embodiment, in step (1) of preparing the modified Y-type molecular sieve, the NaY molecular sieve may have a unit cell constant of 2.465 to 2.472nm, a framework silica to alumina ratio (SiO 2 /Al 2 O 3 Molar ratio) of 4.5 to 5.2, and the relative crystallinity of 85% or more, for example, 85 to 95%The sodium oxide content is 13.0 to 13.8 wt%.
In one embodiment, in step (1) of preparing the modified Y-type molecular sieve, the NaY mother liquor is derived from a NaY molecular sieve synthesis process and is a byproduct of the NaY molecular sieve synthesis process. In one embodiment, in step (1) of preparing the modified Y-type molecular sieve, the NaY mother liquor is a NaY mother liquor discharged from a NaY synthesis slurry after synthesis of the NaY molecular sieve, which is not recycled to the NaY molecular sieve synthesis process, and is sometimes referred to herein as an externally discharged NaY mother liquor. In one embodiment, in step (1) of preparing the modified Y-type molecular sieve, the NaY mother liquor comprises about 25 to 40g/L SiO 2 。
In one embodiment, in the step (1) of preparing the modified Y-type molecular sieve, the ratio of the NaY mother liquor to the NaY molecular sieve is 1 to 1.9mL of NaY mother liquor: 1g of NaY molecular sieve. If the proportion of the NaY mother liquor is too low, the recycled Si source is lower, the effect of protecting the crystallinity of the molecular sieve can not be achieved in the subsequent hydrothermal ultrastable, and if the proportion of the NaY mother liquor is too high, amorphous Si in the molecular sieve is excessive, the specific surface area of the molecular sieve can be reduced, and the catalytic performance of the final product catalyst is affected.
In one embodiment, in the step (1) of preparing the modified Y-type molecular sieve, the purpose of adding the dilute acid is to perform a neutralization reaction with alkaline soluble substances in the NaY mother liquor, so that the pH value of the NaY mother liquor is changed, and further, free soluble Si in the NaY mother liquor uniformly forms solid Si in the NaY molecular sieve, so that a sufficient active Si source capable of timely migrating to a dealumination vacancy is provided for the subsequent hydrothermal ultrastable process of the molecular sieve, and the crystallinity of the molecular sieve can be furthest protected from being damaged in the hydrothermal ultrastable process.
In one embodiment, in step (1) of preparing the modified Y-type molecular sieve, the dilute acid may be dilute hydrochloric acid or dilute sulfuric acid or dilute nitric acid. In one embodiment, in step (1) of preparing the modified Y-type molecular sieve, the dilute acid solution is at a concentration of H in solution + The molar concentration of (C) is 0.001 to 0.1mol/L, preferably 0.005 to 0.05mol/L. In one embodimentIn the step (1) of preparing the modified Y-type molecular sieve, the volume of the dilute acid solution can be adjusted so that the free soluble Si in the NaY mother liquor can be completely or almost completely precipitated into the NaY molecular sieve to uniformly form solid Si. In one embodiment, the volume ratio of dilute acid solution to NaY mother liquor may be 0.5 to 1.5:1. in one embodiment, the dilute acid solution is an aqueous solution of dilute acid.
In one embodiment, in the step (1) of preparing the modified Y-type molecular sieve, the NaY molecular sieve is contacted with NaY mother liquor in stirring, the temperature is raised to 50-75 ℃, and dilute acid aqueous solution is slowly added, and after stirring is continued for 30-60 minutes, filtering is carried out.
In one embodiment, in the step (2) of preparing the modified Y-type molecular sieve, the NaY molecular sieve obtained in the step (1) is subjected to an ion exchange reaction with a rare earth salt solution to obtain the Y-type molecular sieve with reduced sodium oxide content.
In one embodiment, in step (2) of preparing the modified Y-type molecular sieve, the NaY molecular sieve (on a dry basis): rare earth salts (in RE) 2 O 3 Meter): h 2 The weight ratio of O is 1:0.01 to 0.18:5 to 15, preferably 1:0.03 to 0.15: 7-12.
In one embodiment, in step (2) of preparing the modified Y-type molecular sieve, the molecular sieve is modified according to NaY (on a dry basis): rare earth salts (in RE) 2 O 3 Meter): h 2 O=1: 0.01 to 0.18: 5-15 weight ratio of NaY molecular sieve, rare earth salt and water to form a mixture, and carrying out the exchange of rare earth ions and sodium ions under stirring. In one embodiment, the water may be selected from, for example, decationized water, deionized water, or mixtures thereof. In one embodiment, the step of forming the NaY molecular sieve, rare earth salt, and water into a mixture may be performed by forming the NaY molecular sieve and water into a slurry, and then adding a rare earth salt and/or rare earth salt solution to the slurry.
In one embodiment, in step (2) of preparing the modified Y-type molecular sieve, the rare earth salt may be rare earth chloride and/or rare earth nitrate. The rare earth may be selected from one or more of La, ce, pr, nd and misch metals, for example. In one embodiment, the misch metal contains one or more of La, ce, pr, and Nd, or at least one of the rare earths other than La, ce, pr, and Nd.
In one embodiment, in step (2) of preparing the modified Y-type molecular sieve, the rare earth salt solution is an aqueous solution of a rare earth salt.
In one embodiment, in the step (2) of preparing the modified Y-type molecular sieve, the conditions for performing the ion exchange reaction by contacting the NaY molecular sieve with the rare earth salt solution are: the exchange temperature is 15-95 ℃, preferably 65-95 ℃, and the exchange time is 30-120 minutes, preferably 45-90 minutes.
In one embodiment, in step (2) of preparing the modified Y-type molecular sieve, the purpose of the wash is to wash away exchanged sodium ions, e.g., deionized or decationized water wash may be used.
In one embodiment, step (2) of preparing the modified Y-type molecular sieve results in a Y-type molecular sieve having a reduced sodium oxide content, based on its dry weight, and a rare earth content, based on RE 2 O 3 The content of sodium oxide is not more than 8 wt%, preferably 4.5-7.5 wt% or 4.5-6.5 wt%, and the unit cell constant is 2.465-2.472 nm.
In one embodiment, in the step (3) of preparing the modified Y-type molecular sieve, the mild hydrothermal ultrastable modification treatment is performed by calcining the Y-type molecular sieve obtained in the step (2) at a temperature of 350 to 520 ℃ under a 30 to 85% by volume water vapor atmosphere for 4.5 to 7 hours. Preferably, the roasting temperature in the step (3) is 380-480 ℃, the roasting atmosphere is 40-80% of water vapor atmosphere by volume, and/or the roasting time is 5-6 hours. In a preferred embodiment, in the step (3) of preparing the modified Y-type molecular sieve, the mild hydrothermal ultrastable modification treatment is performed by calcining the Y-type molecular sieve obtained in the step (2) at a temperature of 380 to 480 ℃ under a 40 to 80% by volume water vapor atmosphere for 5 to 6 hours.
In one embodiment, the water vapor atmosphere contains 30 to 85% by volume, preferably 40 to 80% by volume, of water vapor and further contains other gases, such as one or more of air, helium, or nitrogen. In one embodiment, the water vapor atmosphere contains 70% water vapor by volume and 30% air by volume. In one embodiment, the water vapor atmosphere contains 75% water vapor by volume and 25% air by volume. In one embodiment, the water vapor atmosphere contains 80% water vapor by volume and 20% air by volume.
In one embodiment, the unit cell constant of the reduced unit cell constant Y-type molecular sieve described in step (3) is from 2.450nm to 2.459nm.
In one embodiment, in the step (4) of preparing the modified Y-type molecular sieve, the Y-type molecular sieve having a reduced unit cell constant obtained in the step (3) is subjected to a phosphorus modification treatment with a phosphorus compound to introduce phosphorus into the molecular sieve, thereby improving the coke selectivity of the catalyst and improving the heavy oil cracking ability.
In one embodiment, the phosphorus modification treatment described in step (4) generally comprises contacting the Y-type molecular sieve having a reduced unit cell constant obtained in step (3) with an exchange liquid comprising a phosphorus compound and water, typically at 15 to 100 c, preferably 30 to 95 c, for 10 to 100 minutes, followed by filtration and washing. Wherein the weight ratio of water in the exchange liquid to the Y-type molecular sieve (based on dry basis) is 2-5: 1, preferably 3 to 4:1, phosphorus (in P 2 O 5 Calculated on a dry basis) and the weight ratio of the Y-type molecular sieve (calculated on a dry basis) is 0.0005 to 0.07:1, preferably 0.001 to 0.05:1. in one embodiment, the washing is performed with water, for example with 5 to 15 times the weight of the molecular sieve water, such as decationized or deionized water.
In one embodiment, in step (4) of preparing the modified Y-type molecular sieve, the phosphorus compound may be selected from one or more of phosphoric acid, ammonium phosphate, monoammonium phosphate, diammonium phosphate.
In one embodiment, in step (4) of preparing the modified Y-type molecular sieve, the phosphorus-modified Y-type molecular sieve is also dried so that the water content in the Y-type molecular sieve is preferably not more than 1 wt%. The drying may be carried out by existing methods, for example by air-flow drying, oven-drying, flash drying.
In one embodiment, in step (5) of preparing the modified Y-type molecular sieve, siCl 4 : the weight ratio of the Y-type molecular sieve with the reduced unit cell constant containing phosphorus (based on dry basis) is 0.1-0.7: 1, preferably 0.15 to 0.7:1, wherein the temperature of the reaction is 200-600 ℃, preferably 250-550 ℃, and the reaction time is 10 minutes to 5 hours, preferably 30 minutes to 4 hours.
In one embodiment, step (5) of preparing the modified Y-type molecular sieve may comprise washing. In one embodiment, step (5) may not include washing. In one embodiment, the step (5) may or may not be dried after washing. In one embodiment, in step (5), when washing is performed, a conventional washing method may be employed, for example, washing with water, for example, washing with decationized water or deionized water, in order to remove Na remaining in the molecular sieve + 、Cl - Al and Al 3+ And the like. In one embodiment, the washing conditions may be: the weight ratio of the washing water to the Y-type molecular sieve (on a dry basis) can be 5-20: 1, preferably 6 to 15:1, the pH value of the washing mixed solution is preferably 2.5-5.0, and the washing temperature is 30-60 ℃. In one embodiment, na is present in the washing liquid after washing + 、Cl - Al and Al 3+ The respective content of ions is not more than 0.05% by weight. In a preferred embodiment, no free Na is detected in the washing solution after washing + 、Cl - Al and Al 3+ And (3) plasma.
In one embodiment, in the method for preparing a catalytic cracking catalyst provided by the present invention, preparing a modified Y-type molecular sieve comprises the steps of:
(1) The NaY molecular sieve is contacted with NaY mother liquor in stirring, the temperature is raised to 50 ℃ to 75 ℃, and dilute acid aqueous solution is slowly added, and then the stirring is continued for 30 to 60 minutes, and the filtration is carried out;
(2) Contacting the NaY molecular sieve obtained in the step (1) with a rare earth salt solution, carrying out ion exchange reaction for 30-120 minutes at the temperature of 15-95 ℃, filtering and washing to obtain a Y-type molecular sieve with reduced sodium oxide content;
(3) Roasting the Y-type molecular sieve with reduced sodium oxide content obtained in the step (2) for 4.5-7 hours at the temperature of 350-520 ℃ in the atmosphere containing 30-85% by volume of water vapor, and performing mild hydrothermal ultra-stable modification treatment to obtain the Y-type molecular sieve with reduced unit cell constant;
(4) Contacting the obtained Y-type molecular sieve with reduced unit cell constant with exchange liquid of phosphorus-containing compound and water, carrying out exchange reaction for 10-100 minutes at 15-100 ℃ to carry out phosphorus modification treatment, and then filtering, washing and drying to obtain the Y-type molecular sieve with reduced unit cell constant containing phosphorus;
(5) Combining the Y-type molecular sieve with SiCl, wherein the unit cell constant of the phosphorus-containing molecular sieve is reduced, and the unit cell constant of the phosphorus-containing molecular sieve is reduced, which is obtained in the step (4) 4 The gas is contacted and reacted under the condition of 200-600 ℃, wherein SiCl 4 : weight ratio of Y-type molecular sieve with reduced unit cell constant of phosphorus on dry basis = 0.1-0.7: 1, the reaction time is 10 minutes to 5 hours, and then the modified Y-type molecular sieve is obtained through washing and filtering.
In the method for preparing the catalytic cracking catalyst, firstly, a silicon source is introduced in the step (1) by recovering the NaY mother liquor, so that free soluble Si in the NaY mother liquor uniformly forms solid Si in the NaY molecular sieve, a sufficient active Si source capable of timely migrating to a dealumination vacancy is provided for the subsequent hydrothermal ultrastable process of the molecular sieve, and the crystallinity of the molecular sieve can be furthest protected from being damaged in the hydrothermal ultrastable process. Secondly, in the step (3), the hydrothermal ultrastable process is alleviated by controlling the hydrothermal ultrastable condition, including controlling the temperature to be 350-520 ℃ and controlling the steam atmosphere to contain 30-85% by volume of steam, and controlling the roasting time to be 4.5-7 hours, and the molecular sieve maintains higher crystallinity in the hydrothermal ultrastable process. And (3) in the step (5), silicon tetrachloride gas is contacted with the molecular sieve at a higher temperature to perform isomorphous substitution dealumination silicon supplementing reaction with Al in a molecular sieve framework structure on the basis that the molecular sieve still keeps higher crystallinity after hydrothermal superstable, so that the framework silicon-aluminum ratio of the molecular sieve can be further improved under the condition that the molecular sieve keeps higher crystallinity. The step (1) and the steps (3) and (5) are organically combined to realize relay dealumination and silicon supplementation of the molecular sieve under the condition of keeping higher crystallinity, so that the relative crystallinity of the Y-type molecular sieve obtained by the invention is not lower than 60%, the relative crystallinity retention is not lower than 45%, and the framework silicon-aluminum ratio is up to 8.8-19, preferably 9.5-18; the collapse temperature of the structure is up to 1070 ℃. Therefore, the preparation method provided by the invention improves the skeleton silicon-aluminum ratio, crystallinity and thermal and hydrothermal stability of the obtained catalyst, and further improves the catalytic cracking performance of the catalyst.
In addition, in the method for preparing the catalytic cracking catalyst, through the phosphorus modification in the step (4), the surface of the molecular sieve can be modified, so that the active coke selectivity of the catalyst taking the modified molecular sieve as an active component is improved to a great extent.
In the present invention, the method for preparing the catalyst using the modified Y-type molecular sieve, the alumina binder, the clay and water as raw materials is not limited, and can be prepared by, for example, the method disclosed in patent application CN 1098130A, CN 1362472 a.
In one embodiment, the method for preparing a catalytic cracking catalyst provided by the present invention, the spray drying and optional washing and drying steps may employ methods known in the art, and the present invention is not particularly limited thereto.
The method for preparing the catalytic cracking catalyst provided by the invention can basically recycle Si remained in the discharged NaY mother liquor generated in the NaY molecular sieve synthesis process. In the invention, si in the NaY mother liquor is used for post-modification of the NaY molecular sieve, so that the problem of P-type impurity crystals generated in the process of synthesizing the NaY molecular sieve by using the NaY mother liquor for excessive recycling in the prior art can be avoided. The catalytic cracking catalyst prepared by the method is suitable for catalytic cracking processing of heavy oil, and has high thermal and hydrothermal stability, high yield of liquefied gas and gasoline, strong heavy oil conversion capability and good coke selectivity.
In a further aspect, the present invention provides a catalytic cracking catalyst obtained by the process of the present invention, which comprises 10 to 50% by weight of a modified Y-type molecular sieve, based on the dry weight of the catalyst, and 10 to 40% by weight of oxygen, based on the dry weight of the aluminaAn aluminum-melting binder and 10 to 80 wt% clay on a dry basis; wherein the modified Y-type molecular sieve contains 4 to 10 wt%, preferably 4.5 to 9 wt% of RE based on the dry weight of the modified Y-type molecular sieve 2 O 3 0.05 to 6 wt%, preferably 0.5 to 4 wt% of rare earth oxide, based on P 2 O 5 0.1 to 0.5 weight percent of sodium oxide based on phosphorus, and the Si/Al ratio of the framework in the modified Y-type molecular sieve is SiO 2 /Al 2 O 3 The molar ratio is 8.8-19, preferably 9.5-18; the total pore volume of the modified Y-type molecular sieve is 0.35-0.40 mL/g, preferably 0.36-0.39 mL/g; the unit cell constant of the modified Y-type molecular sieve is 2.435 nm-2.450 nm, preferably 2.436 nm-2.448 nm; the lattice collapse temperature of the modified Y-type molecular sieve is not lower than 1070 ℃, and is preferably 1070-1080 ℃; the relative crystallinity of the modified Y-type molecular sieve is 60-80%, preferably 65-75%; the specific surface area of the modified Y-type molecular sieve is 645m 2 /g～670m 2 /g, preferably 650m 2 /g～665m 2 /g。
In one embodiment, the modified Y-type molecular sieve in the heavy oil catalytic cracking catalyst prepared by the method disclosed by the invention has a relative crystallization retention degree of more than 45%, for example, 46-52%, after severe aging for 17 hours at 800 ℃ under normal pressure in a 100% water vapor atmosphere.
In yet another aspect, the present invention also provides a process for catalytic cracking comprising the step of contacting heavy oil with a catalytic cracking catalyst as described herein. The method is applicable to some reactions which are easy to accumulate carbon, such as elevated reaction temperature, high carbon residue raw material oil and the like.
The catalytic cracking catalyst has higher liquefied gas yield, gasoline yield, light oil yield and total liquid yield when being used for heavy oil catalytic cracking, and has good coke selectivity.
The following examples further illustrate the invention, but are not intended to limit it.
Raw materials
In the examplesAnd in the comparative example, naY molecular sieve (also referred to as NaY zeolite) was used as a catalyst for Chinese petrochemical Co., ltd., qilu division, the sodium oxide content was 13.5% by weight, the framework silica alumina ratio (SiO 2 /Al 2 O 3 Molar ratio) =4.6, unit cell constant of 2.470nm, relative crystallinity of 90%; the NaY mother liquor is provided by the middle petrochemical catalyst Qilu division company and is discharged from the mother liquor which is remained after the solid NaY molecular sieve is filtered and separated in the NaY molecular sieve synthesis slurry and cannot be recycled in the NaY molecular sieve synthesis process, wherein SiO 2 The mass concentration is 30g/L, wherein the Si recycling rate in the NaY mother liquor part recycled to the NaY molecular sieve synthesis process is known to be 75%; the rare earth chloride and the rare earth nitrate are chemical pure reagents produced by Beijing chemical plant; pseudo-boehmite is an industrial product produced by Shandong aluminum factory, and has the solid content of 61 weight percent; the kaolin is special for cracking catalyst produced by Suzhou China kaolin company, and has 76 weight percent of solid content; the alumina sol was supplied by ziluta corporation, a chinese petrochemical catalyst, with an alumina content of 21 wt.%. Raw oil Wu Mi San-2007 is purchased from Zhongpetrochemical Wuhan division. The chemical reagents used in the examples and comparative examples are not particularly noted and are of chemically pure specifications.
Analysis method
In each of the examples and comparative examples, the elemental content of the molecular sieve was determined by X-ray fluorescence spectrometry; the unit cell constant and the relative crystallinity of the Y-type molecular sieve are measured by an X-ray powder diffraction (XRD) method by adopting RIPP145-90 and RIPP146-90 standard methods (see the editions of petrochemical analysis method (RIPP test method) Yang Cuiding, etc., scientific Press, 1990); the framework silicon-aluminum ratio of the Y-type molecular sieve is calculated by the following formula: siO (SiO) 2 /Al 2 O 3 ＝(2.5858-a 0 )×2/(a 0 -2.4191)]Wherein a is 0 Is the unit cell constant, in nm; the collapse temperature of the crystal structure was determined by Differential Thermal Analysis (DTA).
In each of the examples and comparative examples, the total pore volume and specific surface area of the molecular sieve were measured according to adsorption isotherms in accordance with the RIPP 151-90 standard method (RIPP test method) under the heading Yang Cuiding et al, scientific Press, 1990.
In each example, the method for calculating the reuse rate of Si in NaY mother liquor:
the total amount of NaY mother liquor produced per 1 gram of NaY synthesized in the NaY synthesis was about 7.64mL.
Total Si recycle rate in NaY mother liquor = Si recycle rate in NaY mother liquor recycled to NaY synthesis process + Si recycle rate in externally discharged NaY mother liquor used in the present invention
The reuse rate of Si in the NaY mother liquor recycled to the NaY synthesis process in the prior art is known to be about 62% to 75%, whereas the reuse rate of Si in the NaY mother liquor recycled to the NaY synthesis process used in the examples of the present invention is about 75%.
Recovery of Si in the externally discharged NaY mother liquor used in the present invention = recovery amount of externally discharged NaY mother liquor used in the present invention (mL)/NaY dry basis weight (g)/7.64 (mL/g)
Total Si recovery in NaY mother liquor = 75% + the recovery of the externally discharged NaY mother liquor used in the present invention (mL)/NaY dry basis weight (g)/7.64 (mL/g)
The light oil micro-reverse activity evaluation method comprises the following steps:
The micro-reactivity of the light oil of the sample is evaluated by adopting a standard method of RIPP92-90 (see the method of petrochemical analysis (RIPP test method), yang Cuiding, et al, edited by scientific press, 1990), the catalyst loading is 5.0g, the reaction temperature is 460 ℃, the raw oil is light diesel oil in big harbor with the distillation range of 235-337 ℃, the product composition is analyzed by gas chromatography, and the micro-reactivity of the light oil is calculated according to the product composition.
Light oil micro-reaction activity (MA) = (gasoline yield + gas yield + coke yield below 216 ℃ in the product)/total feed x 100%.
In each of the examples and comparative examples, the conversion, light oil yield, total liquid yield and coke selectivity in the evaluation of the heavy oil cracking performance of the catalyst were calculated by the following methods:
conversion = gasoline yield + liquefied gas yield + dry gas yield + coke yield
Light oil yield = petrol yield + diesel yield
Total liquid yield = liquefied gas yield + gasoline yield + diesel yield
Coke selectivity = coke yield/conversion.
Example 1
2000g (dry basis) of NaY molecular sieve filter cake (solid content 46%, sodium oxide content 13.5% by weight, product of Mitsui catalyst Qilu Co., ltd.) was added with stirring to a mixture containing 2050mL of NaY mother liquor (Mitsui catalyst Qilu Co., wherein SiO 2 30 g/L) and heating to 50 ℃ under stirring, then slowly adding H + 1864mL of dilute hydrochloric acid having a molar concentration of 0.011mol/L was added, followed by stirring for 30 minutes and filtration. Then, the mixture was put into a primary exchange tank containing 20L of water and stirred uniformly at 25℃and 720mL of RE (NO) was added 3 ) 3 Solution (rare earth solution concentration with RE) 2 O 3 Measured as 319g/L, RE 2 O 3 Contains 64.5% of Ce 2 O 3 And 35.5% La 2 O 3 ) Stirring, heating to 90-95 deg.C for 1 hr, filtering, washing, and drying the filter cake at 120 deg.C to obtain sodium oxide with unit cell constant of 2.471nm and sodium oxide content of 5.6 wt% and RE 2 O 3 The Y-type molecular sieve with 10.6 weight percent of rare earth content is calculated, then baked for 5.5 hours under the atmosphere of 405 ℃ containing 70 volume percent of water vapor and 30 volume percent of air to obtain the Y-type molecular sieve with the unit cell constant of 2.456nm, after cooling, the molecular sieve is added into 6L of aqueous solution dissolved with 32 g of phosphoric acid, the temperature is raised to 90 ℃ for 30 minutes of phosphorus modification treatment, after that, the molecular sieve is filtered and washed, and the filter cake is dried to have the water content of less than 1 weight percent, and then SiCl is added 4 : y-type molecular sieve (dry basis) =0.55: 1 weight ratio, siCl vaporized by heating is introduced 4 The modified Y-type molecular sieve provided by the invention is obtained by reacting the gas for 2.5 hours at 480 ℃, washing the gas with 20 liters of decationized water, and filtering the gas, wherein the physicochemical properties of the modified Y-type molecular sieve are shown in table 1, the molecular sieve before and after aging of the SZ1 is analyzed by XRD after the SZ1 is aged for 17 hours at 800 ℃ by 1atm and 100% water vapor, and the relative crystallization retention degree after aging is calculated, and the result is shown in table 2, wherein:
Figure BDA0003326435640000181
714.5 g of an alumina sol having an alumina content of 21% by weight was added to 1565.5 g of decationized water, stirring was started, and 2763 g of kaolin having a solid content of 76% by weight was added to disperse for 60 minutes. 2049 g of pseudo-boehmite with the alumina content of 61 weight percent is added into 8146 g of decationized water, 210mL of hydrochloric acid with the mass concentration of 36 percent is added under stirring, the mixture is acidified for 60 minutes, dispersed kaolin slurry is added, 1500 g (dry basis) of ground SZ1 molecular sieve is added, and after uniform stirring, spray drying and washing treatment are carried out, and the catalyst is obtained after drying, and is marked as SC1. The obtained SC1 catalyst contained 30 wt% of SZ1 molecular sieve, 42 wt% of kaolin, 25 wt% of pseudo-boehmite and 3 wt% of alumina sol.
Example 2
2000g (dry basis) of NaY molecular sieve filter cake (solid content 46%, sodium oxide content 13.5% by weight, product of Mitsui catalyst Qilu Co., ltd.) was added with stirring to a solution containing 2415ml of LNaY mother liquor (provided by Mitsui catalyst Qilu Co., ltd., wherein SiO 2 30 g/L) and heating to 70 ℃ under stirring, then slowly adding H + 2012mL of dilute nitric acid having a molar concentration of 0.012mol/L, and then, stirring was continued for 60 minutes, followed by filtration. Then, the mixture was put into a primary exchange tank containing 20L of water, stirred uniformly at 25℃and 890mL of RECl was added 3 Solution (in RE) 2 O 3 The solution concentration was: 319g/L, RE 2 O 3 Contains 64.5% of Ce 2 O 3 And 35.5% La 2 O 3 ) Stirring, heating to 90-95 deg.C for 1 hr, filtering, washing, and drying the filter cake at 120 deg.C to obtain powder with unit cell constant of 2.471nm, sodium oxide content of 5.0 wt% and RE 2 O 3 The Y-type molecular sieve with the rare earth content of 12.5 weight percent is calculated, then baked for 6 hours under the atmosphere of 470 ℃ temperature, 80 percent of water vapor and 20 percent of air to obtain the Y-type molecular sieve with the unit cell constant of 2.457nm, and after cooling, the molecular sieve is added withInto 6L aqueous solution containing 122 g of ammonium phosphate, heating to 60deg.C, performing phosphorus modification treatment for 50 min, filtering and washing molecular sieve, drying the filter cake to water content of less than 1 wt%, and treating with SiCl 4 : y-type molecular sieve = 0.65:1 weight ratio, siCl vaporized by heating is introduced 4 The gas was reacted at 475℃for 2 hours, after which it was washed with 20 liters of decationized water and filtered to give a modified Y-type molecular sieve, designated SZ2. The physical and chemical properties are shown in Table 1, and after SZ2 was aged at 800℃for 17 hours with 100% steam in the bare state, the relative crystallinity of the molecular sieve before and after the aging of SZ2 was analyzed by XRD and the relative crystallinity retention after the aging was calculated, and the results are shown in Table 2.
714.5 g of an alumina sol having an alumina content of 21% by weight was added to 1565.5 g of decationized water, stirring was started, and 2763 g of kaolin having a solid content of 76% by weight was added to disperse for 60 minutes. 2049 g of pseudo-boehmite with the alumina content of 61 weight percent is taken and added into 8146 g of decationized water, 210mL of chemically pure hydrochloric acid is added under stirring, after acidification for 60 minutes, dispersed kaolin slurry is added, 1500 g (dry basis) of ground SZ2 molecular sieve is then added, after uniform stirring, spray drying and washing treatment are carried out, and the catalyst is obtained after drying, and is marked as SC2. The obtained SC2 catalyst contained 30 wt% of SZ2 molecular sieve, 42 wt% of kaolin, 25 wt% of pseudo-boehmite and 3 wt% of alumina sol.
Example 3
2000g (dry basis) of NaY molecular sieve filter cake (solid content 46%, sodium oxide content 13.5% by weight, product of Mitsui catalyst Qilu Co., ltd.) was added with stirring to a mixture containing 2735mL of NaY mother liquor (provided by Mitsui catalyst Qilu Co., wherein SiO 2 30 g/L) and heating to 50 ℃ under stirring, then slowly adding H + 1954mL of dilute sulfuric acid having a molar concentration of 0.014mol/L was stirred for 30 minutes and then filtered. Then, the mixture was put into a primary exchange tank containing 20L of water and stirred uniformly at 25℃and 795mL of RECl was added thereto 3 Solution (in RE) 2 O 3 The concentration of the calculated rare earth solution is 319g/L, RE 2 O 3 Contains 64.5% of Ce 2 O 3 And 35.5% La 2 O 3 ) Stirring, heating to 90-95deg.C, stirring for 1 hr, filtering, washing, and drying the filter cake at 120deg.C to obtain powder with unit cell constant of 2.471nm, sodium oxide content of 5.7 wt% and RE 2 O 3 The Y-type molecular sieve with the rare earth content of 11.7 weight percent is calculated, then baked for 5.5 hours under the atmosphere of 475 ℃ containing 75 volume percent of water vapor and 25 percent of air to obtain the Y-type molecular sieve with the unit cell constant of 2.455nm, after cooling, the molecular sieve is added into 6 liters of aqueous solution dissolved with 83 grams of diammonium hydrogen phosphate, the temperature is raised to 40 ℃ for 80 minutes of phosphorus modification treatment, after filtering and washing the molecular sieve, and drying the filter cake to make the water content of the filter cake lower than 1 weight percent, then the filter cake is processed according to SiCl 4 : y-type molecular sieve (dry basis) =0.45: 1 weight ratio, siCl vaporized by heating is introduced 4 The gas was reacted at 505℃for 2 hours, after which it was washed with 20 liters of decationized water and then filtered to give a modified Y-type molecular sieve, designated SZ3. The physical and chemical properties are shown in Table 1, and after SZ3 was aged at 800℃for 17 hours with 100% steam in the bare state, the relative crystallinity of the molecular sieve before and after the aging of SZ3 was analyzed by XRD and the relative crystallinity retention after the aging was calculated, and the results are shown in Table 2.
714.5 g of an alumina sol having an alumina content of 21% by weight was added to 1565.5 g of decationized water, stirring was started, and 2763 g of kaolin having a solid content of 76% by weight was added to disperse for 60 minutes. 2049 g of pseudo-boehmite with the alumina content of 61 weight percent is taken and added into 8146 g of decationized water, 210mL of chemically pure hydrochloric acid is added under stirring, after acidification for 60 minutes, dispersed kaolin slurry is added, 1500 g (dry basis) of ground SZ3 molecular sieve is then added, after uniform stirring, spray drying and washing treatment are carried out, and the catalyst is obtained after drying, and is marked as SC3. The obtained SC3 catalyst contains 30 weight percent of SZ3 molecular sieve, 42 weight percent of kaolin, 25 weight percent of pseudo-boehmite and 3 weight percent of alumina sol.
Comparative example 1
Get 2000 g of NaY molecular sieve (on a dry basis) are added to 20 liters of the decationized aqueous solution and stirred to mix them well, 1000 g (NH) are added 4 ) 2 SO 4 Stirring, heating to 90-95 deg.C, holding for 1 hr, filtering, washing, drying filter cake at 120 deg.C, calcining at 650 deg.C with 100% water vapor for 5 hr, hydrothermal modifying, adding into 20L of decationizing water solution, stirring, mixing, adding 1000 g (NH 4 ) 2 SO 4 Stirring, heating to 90-95 ℃ and keeping for 1 hour, filtering, washing, drying the filter cake at 120 ℃, roasting at 650 ℃ and 100% steam for 5 hours, and performing a second hydrothermal modification treatment to obtain the twice ion exchange twice hydrothermal ultrastable rare earth-free hydrothermal ultrastable Y-type molecular sieve, which is marked as DZ1. The physical and chemical properties are shown in Table 1, and after DZ1 was aged at 800℃for 17 hours with 100% steam in the bare state, the relative crystallinity of the molecular sieve before and after DZ1 aging was analyzed by XRD and the relative crystallinity retention after aging was calculated, and the results are shown in Table 2.
The preparation method of example 1 was followed, and a microsphere catalyst was obtained by slurrying a DZ1 molecular sieve, kaolin, water, pseudo-boehmite binder, and alumina sol, spray-drying, washing treatment, and drying, and the prepared catalytic cracking catalyst was designated as DC1. Wherein the obtained DC1 catalyst contains 30 weight percent of DZ1 molecular sieve, 42 weight percent of kaolin, 25 weight percent of pseudo-boehmite and 3 weight percent of alumina sol.
Comparative example 2
2000 g of NaY molecular sieve (dry basis) is added into 20L of decationizing water solution and stirred to be evenly mixed, 1000 g (NH) is added 4 ) 2 SO 4 Stirring, heating to 90-95 deg.C, holding for 1 hr, filtering, washing, drying filter cake at 120 deg.C, hydrothermal modifying at 650 deg.C with 100% water vapor for 5 hr, adding into 20L of decationizing aqueous solution, stirring, mixing, adding 200ml RE (NO) 3 ) 3 Solution (in RE) 2 O 3 The concentration of the rare earth solution is as follows: 319g/L, RE 2 O 3 The content of the Chinese medicine is 64.5%Ce 2 O 3 And 35.5% La 2 O 3 ) 900 g (NH) 4 ) 2 SO 4 Stirring, heating to 90-95 ℃ for 1 hour, filtering, washing, drying the filter cake at 120 ℃, and then performing a second hydrothermal modification treatment (roasting for 5 hours at the temperature of 650 ℃ and 100% steam) to obtain the twice ion-exchanged twice hydrothermal ultrastable rare earth-containing hydrothermal ultrastable Y-type molecular sieve, which is marked as DZ2. The physical and chemical properties are shown in Table 1, and after DZ2 was aged at 800℃for 17 hours with 100% steam in the bare state, the relative crystallinity of the molecular sieve before and after DZ2 aging was analyzed by XRD and the relative crystallinity retention after aging was calculated, and the results are shown in Table 2.
The preparation method of example 1 was followed by slurry formation of DZ2 molecular sieve, kaolin, water, pseudo-boehmite binder and alumina sol, spray drying, washing treatment and drying to obtain a microsphere catalyst, and the prepared catalytic cracking catalyst was designated as DC2. Wherein the obtained DC2 catalyst contains 30 weight percent of DZ2 molecular sieve, 42 weight percent of kaolin, 25 weight percent of pseudo-boehmite and 3 weight percent of alumina sol.
Comparative example 3
2000 g NaY molecular sieve (dry basis) was added to 22L of decationized aqueous solution and stirred to mix well, 570mL RECl was added 3 Solution (in RE) 2 O 3 The concentration of the calculated rare earth solution is 319g/L, RE 2 O 3 Contains 64.5% of Ce 2 O 3 And 35.5% La 2 O 3 ) Stirring, heating to 90-95deg.C, stirring for 1 hr, filtering, washing, and drying the filter cake at 120deg.C to obtain powder with unit cell constant of 2.471nm, sodium oxide content of 7.5 wt% and RE 2 O 3 The Y-type molecular sieve with the rare earth content of 8.5 weight percent is calculated, then the molecular sieve is added into 6L of aqueous solution with 95 g of diammonium hydrogen phosphate, the temperature is raised to 40 ℃ for 80 minutes of phosphorus modification treatment, then the molecular sieve is filtered and washed, the filter cake is dried to make the water content of the filter cake lower than 1 weight percent, and then the filter cake is processed according to SiCl 4 : y-type molecular sieve (on a dry basis) =0.4: 1 weight ratio, is introduced into the reactor to be vaporized by heatingSiCl of (a) 4 The gas was reacted at 580℃for 1.5 hours, after which it was washed with 20 liters of decationized water and then filtered to give a modified Y-type molecular sieve, designated DZ3. The physical and chemical properties are shown in Table 1, and after DZ3 was aged at 800℃for 17 hours with 100% steam in the bare state, the relative crystallinity of the molecular sieve before and after DZ3 aging was analyzed by XRD and the relative crystallinity retention after aging was calculated, and the results are shown in Table 2.
The preparation method of example 1 was followed by slurry formation of DZ3 molecular sieve, kaolin, water, pseudo-boehmite binder and alumina sol, spray drying, washing treatment and drying to obtain a microsphere catalyst, and the prepared catalytic cracking catalyst was designated as DC3. Wherein the obtained DC3 catalyst contains 30 weight percent of DZ3 molecular sieve, 42 weight percent of kaolin, 25 weight percent of pseudo-boehmite and 3 weight percent of alumina sol.
Comparative example 4
2000 g of NaY molecular sieve (on a dry basis) was added to 20L of the decationized aqueous solution and stirred to mix well, 600mL of RE (NO) was added 3 ) 3 Solution (rare earth solution concentration with RE) 2 O 3 319 g/L), stirring, heating to 90-95 ℃ for 1 hour, filtering, washing, drying filter cake at 120 ℃ to obtain the product with unit cell constant of 2.471nm, sodium oxide content of 7.0 wt% and RE 2 O 3 The Y-type molecular sieve with rare earth content of 8.8 weight percent is calculated, then baked for 6 hours under the atmosphere of 390 ℃ containing 50 volume percent of water vapor and 50 volume percent of air to obtain the Y-type molecular sieve with unit cell constant of 2.455nm, after cooling, the molecular sieve is added into 6L of aqueous solution dissolved with 35 g of phosphoric acid, the temperature is raised to 90 ℃ for 30 minutes of phosphorus modification treatment, then the molecular sieve is filtered and washed, and the filter cake is dried to make the water content of the filter cake lower than 1 weight percent, and then the filter cake is processed according to SiCl 4 : y-type molecular sieve (dry basis) =0.5: 1 weight ratio, siCl vaporized by heating is introduced 4 The gas was reacted at 400℃for 2 hours, then washed with 20 liters of deionized water, and then filtered to give the modified Y-type molecular sieve of the present invention, designated DZ4, having the physicochemical properties shown in Table 1, in which DZ4 was contained inAfter the bare state was aged for 17 hours at 800℃with 1atm and 100% water vapor, the relative crystallinity of the molecular sieve before and after DZ4 aging was analyzed by XRD and the relative crystallinity retention after aging was calculated, and the results are shown in Table 2.
The preparation method of example 1 was followed by slurry formation of DZ4 molecular sieve, kaolin, water, pseudo-boehmite binder and alumina sol, spray drying, washing treatment and drying to obtain a microsphere catalyst, and the prepared catalytic cracking catalyst was designated as DC4. Wherein the obtained DC4 catalyst contains 30 weight percent of DZ4 molecular sieve, 42 weight percent of kaolin, 25 weight percent of pseudo-boehmite and 3 weight percent of alumina sol.
Examples 4 to 6
The catalytic cracking catalysts SC1, SC2 and SC3 prepared in examples 1 to 3 were aged with 100% steam at 800 ℃ for 4 hours or 17 hours, respectively, and the light oil micro-reactivity of the catalysts was evaluated, and the evaluation results are shown in table 3.
Comparative examples 5 to 8
The light oil micro-reactivity of the catalysts of comparative examples 1 to 4 was evaluated after aging them with 100% steam at 800℃for 4 hours or 17 hours, respectively. The evaluation results are shown in Table 3.
Examples 7 to 9
After the SC1, SC2, SC3 catalysts were aged at 800 ℃ for 17 hours in a 100% steam atmosphere, the catalytic cracking reaction performance was evaluated on a small fixed fluidized bed reactor (ACE), and the cracked gas and product oil were collected and analyzed by gas chromatography. The catalyst loading was 9g, the reaction temperature was 500℃and the weight hourly space velocity was 16h －1 The weight ratio of the agent to the oil is 5, the raw oil for ACE experiments is Wu mixed three-2007, the properties are shown in Table 4, and the evaluation results are shown in Table 5.
Comparative examples 9 to 12
Comparative examples 9 to 12 illustrate the catalytic cracking reaction performance of the catalytic cracking catalysts prepared in comparative examples 1 to 4.
After the DC1, DC2, DC3 and DC4 catalysts were aged for 17 hours at 800 ℃ with 100% steam, the catalytic cracking reaction performance was evaluated on a small fixed fluidized bed reactor (ACE), the evaluation method is shown in examples 7 to 9, the raw oil for ACE experiments is Wu-Mi three-2007, the properties are shown in Table 4, and the evaluation results are shown in Table 5.
TABLE 1
Figure BDA0003326435640000241
As can be seen from Table 1, the modified Y-type molecular sieve provided by the invention has high stability and high crystallinity, and simultaneously has low sodium oxide content. The molecular sieve has higher relative crystallinity and larger specific surface area when the silicon-aluminum ratio of the molecular sieve is higher, and the structural collapse temperature of the molecular sieve is high, which indicates that the molecular sieve has high thermal stability.
The method for preparing the modified Y-type molecular sieve can carry out new recycling on Si in the part of NaY mother liquor which is produced in NaY synthesis and cannot be completely recycled in NaY synthesis, and Si in the recycled NaY mother liquor is directly used in post-modification production of the NaY molecular sieve, so that the utilization rate of Si sources is greatly improved, and the total recycling rate of Si in the NaY mother liquor can be up to more than 88%, which indicates that the preparation method can further reduce the production cost, reduce the discharge of waste water and waste residues of catalyst production enterprises and protect the environment.
TABLE 2
Figure BDA0003326435640000242
As shown in Table 2, the modified Y-type molecular sieve provided by the invention has higher relative crystallization retention degree after the molecular sieve sample is aged for 17 hours under the severe condition of 800 ℃ and 100% steam in the naked state, which indicates that the modified Y-type molecular sieve provided by the invention has high hydrothermal stability.
TABLE 3 Table 3
Figure BDA0003326435640000251
Table 4 ACE evaluation of raw oil properties
Figure BDA0003326435640000252
TABLE 5
Figure BDA0003326435640000261
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As can be seen from tables 3 and 5, the catalytic cracking catalyst prepared by using the modified Y-type molecular sieve provided by the invention as an active component has very high hydrothermal stability, obviously better coke selectivity, obviously higher liquefied gas yield, gasoline yield, light oil yield and total liquid yield, and shows that the heavy oil conversion activity is higher.
Unless defined otherwise, terms used herein are all 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, since various substitutions, modifications and improvements can be made by those skilled in the art without departing from the true spirit and scope of the invention, and therefore, the present invention is not limited to the above embodiments but only by the claims.

Claims (16)

1. A catalytic cracking catalyst comprising 10 to 50 wt% of a modified Y-type molecular sieve based on the dry weight of the catalyst, 10 to 40 wt% of an alumina binder based on alumina, and 10 to 80 wt% of clay based on the dry weight of the modified Y-type molecular sieve, wherein the modified Y-type molecular sieve comprises 4 to 10 wt%, preferably 4.5 to 9 wt% of RE based on the dry weight of the modified Y-type molecular sieve 2 O 3 0.05 to 6 wt%, preferably 0.5 to 4 wt% of rare earth oxide, based on P 2 O 5 0.1 to 0.5 weight percent of sodium oxide based on phosphorus, and the Si/Al ratio of the framework in the modified Y-type molecular sieve is SiO 2 /Al 2 O 3 The molar ratio is 8.8-19, preferably 9.5-18; the total pore volume of the modified Y-type molecular sieve is 0.35 mL/g-0.40 mL/g, preferablySelecting 0.36-0.39 mL/g; the unit cell constant of the modified Y-type molecular sieve is 2.435 nm-2.450 nm, preferably 2.436 nm-2.448 nm; the lattice collapse temperature of the modified Y-type molecular sieve is not lower than 1070 ℃, and is preferably 1070-1080 ℃; the relative crystallinity of the modified Y-type molecular sieve is 60-80%, preferably 65-75%; the specific surface area of the modified Y-type molecular sieve is 645m 2 /g～670m 2 /g, preferably 650m 2 /g～665m 2 /g。
2. The catalytic cracking catalyst according to claim 1, wherein the modified Y-type molecular sieve has a relative crystal retention of 45% or more, preferably 46% to 52%, after aging at 800 ℃ under normal pressure in a 100% steam atmosphere for 17 hours.
3. The catalytic cracking catalyst of claim 1 or 2, wherein the modified Y-type molecular sieve has a rare earth oxide content of 4.5 to 9 wt%, a sodium oxide content of 0.1 to 0.5 wt%, and a phosphorus content of P 2 O 5 The unit cell constant is 2.436 nm-2.448 nm, and the skeleton silicon-aluminum ratio is 9.5-18.
4. A method of preparing a catalytic cracking catalyst comprising:
preparing a modified Y-type molecular sieve, which comprises the following steps:
(1) Contacting NaY molecular sieve with NaY mother liquor, adding dilute acid solution, mixing to uniformity, and filtering;
(2) Contacting the NaY molecular sieve obtained in the step (1) with a rare earth salt solution for ion exchange reaction, filtering, washing, and optionally drying to obtain a Y-type molecular sieve with reduced sodium oxide content;
(3) Performing mild hydrothermal ultrastable modification treatment on the Y-type molecular sieve with reduced sodium oxide content obtained in the step (2) to obtain the Y-type molecular sieve with reduced unit cell constant;
(4) Carrying out phosphorus modification treatment on the Y-type molecular sieve with the reduced unit cell constant obtained in the step (3) by using a phosphorus compound, and drying to obtain the Y-type molecular sieve with the reduced unit cell constant containing phosphorus;
(5) Contacting the Y-type molecular sieve with the reduced unit cell constant of phosphorus obtained in the step (4) with silicon tetrachloride gas for reaction, and optionally washing and optionally filtering to obtain the modified Y-type molecular sieve;
mixing the modified Y-type molecular sieve with an alumina binder, clay and water to form slurry;
spray drying; and
Optionally, washing and drying the product,
the catalytic cracking catalyst is obtained.
5. The process according to claim 4, wherein in the step (1) of preparing the modified Y-type molecular sieve, the NaY molecular sieve is contacted with the NaY mother liquor while stirring, the mixed slurry is heated to 40 to 90 ℃, preferably 50 to 75 ℃, and the diluted acid aqueous solution is added, and after continuing stirring for 20 to 90 minutes, preferably 30 to 60 minutes, filtration is performed; preferably, the ratio of NaY mother liquor to NaY molecular sieve on a dry basis is from 1 to 1.9ml NaY mother liquor: 1g of NaY molecular sieve.
6. The process according to claim 4 or 5, wherein in the step (1) of preparing the modified Y-type molecular sieve, the NaY molecular sieve is a commercially available NaY molecular sieve or a NaY molecular sieve cake after synthesis of the NaY molecular sieve, which is filtered and washed with industrial water; and/or the NaY mother liquor is the NaY mother liquor which is discharged after the NaY molecular sieve is synthesized, the solid NaY molecular sieve is filtered and separated from the NaY synthetic slurry, and the mother liquor which is remained after the NaY molecular sieve is not recycled in the NaY molecular sieve synthesis process.
7. The process of any one of claims 4 to 6, wherein in step (1) of preparing the modified Y-type molecular sieve, the dilute acid is dilute hydrochloric acid, dilute sulfuric acid, or dilute nitric acid, preferably the concentration of the dilute acid solution is H in solution + The molar concentration of (C) is 0.001 to 0.1mol/L, preferably 0.005 to 0.05mol/L.
8. The method of any one of claims 4 to 7, wherein the modification is made at the time of preparationIn the step (2) of the sex Y-type molecular sieve, the molecular sieve is prepared according to the following steps of NaY: rare earth salt: h 2 O=1: 0.01 to 0.18: 5-15 weight ratio of NaY molecular sieve, rare earth salt and water to form a mixture, stirring to perform ion exchange reaction, wherein the weight of NaY molecular sieve is calculated by dry basis, and the weight of rare earth salt is calculated by rare earth oxide; further preferably, forming the NaY molecular sieve, rare earth salt and water into a mixture is accomplished by mixing the NaY molecular sieve with water, adding the rare earth salt and/or rare earth salt solution with stirring.
9. The process according to any one of claims 4 to 8, wherein in step (2) of preparing a modified Y-type molecular sieve, the conditions of the ion exchange reaction are: the exchange temperature is 15-95 ℃, preferably 65-95 ℃, and the exchange time is 30-120 minutes, preferably 45-90 minutes; preferably, the rare earth salt solution is an aqueous solution of rare earth salt; and preferably the rare earth salt is rare earth chloride and/or rare earth nitrate.
10. The process according to any one of claims 4 to 9, wherein in step (3) of preparing the modified Y-type molecular sieve, the Y-type molecular sieve having a reduced sodium oxide content obtained in step (2) is calcined at a temperature of 350 to 520 ℃, preferably 380 to 480 ℃, in a 30 to 85% by volume, preferably 40 to 80% water vapor atmosphere, for 4.5 to 7 hours, preferably 5 to 6 hours.
11. The process according to any one of claims 4 to 10, wherein in the step (4) of preparing the modified Y-type molecular sieve, the Y-type molecular sieve having a reduced unit cell constant obtained in the step (3) is contacted with an exchange liquid containing a phosphorus compound and water, and subjected to a phosphorus modification treatment by an exchange reaction at 15 to 100 ℃, preferably 30 to 95 ℃ for 10 to 100 minutes; wherein the weight ratio of water in the exchange liquid to the Y-type molecular sieve with reduced unit cell constant on a dry basis is 2-5: 1, preferably 3 to 4:1, a step of; with P 2 O 5 The weight ratio of phosphorus to the Y-type molecular sieve with reduced unit cell constant on a dry basis is 0.0005 to 0.07:1, preferably 0.001 to 0.05:1.
12. the process of any one of claims 4 to 11, wherein in step (4) of preparing the modified Y-type molecular sieve, the phosphorus compound is selected from one or more of phosphoric acid, ammonium phosphate, monoammonium phosphate, diammonium phosphate.
13. The process of any one of claims 4 to 12, wherein in step (4) of preparing the modified Y-type molecular sieve, the water content in the Y-type molecular sieve having a reduced unit cell constant of phosphorus is no more than 1 wt%.
14. The process according to any one of claims 4 to 13, wherein in step (5) of preparing the modified Y-type molecular sieve, siCl 4 : weight ratio of the Y-type molecular sieve with reduced unit cell constant of phosphorus on a dry basis=0.1 to 0.7:1, preferably 0.15 to 0.7:1, a step of; the reaction temperature is 200-600 ℃, preferably 250-550 ℃; the reaction time is 10 minutes to 5 hours, preferably 30 minutes to 4 hours.
15. The catalytic cracking catalyst prepared by the process according to any one of claims 4 to 14, wherein the catalytic cracking catalyst comprises 10 to 50 wt.% modified Y-type molecular sieve based on dry basis, 10 to 40 wt.% alumina binder based on alumina, and 10 to 80 wt.% clay based on dry basis, wherein the modified Y-type molecular sieve comprises 4 to 10 wt.%, preferably 4.5 to 9 wt.% RE based on its dry basis 2 O 3 0.05 to 6 wt%, preferably 0.5 to 4 wt% of rare earth oxide, based on P 2 O 5 0.1 to 0.5 weight percent of sodium oxide based on phosphorus, and the Si/Al ratio of the framework in the modified Y-type molecular sieve is SiO 2 /Al 2 O 3 The molar ratio is 8.8-19, preferably 9.5-18; the total pore volume of the modified Y-type molecular sieve is 0.35-0.40 mL/g, preferably 0.36-0.39 mL/g; the unit cell constant of the modified Y-type molecular sieve is 2.435 nm-2.450 nm, preferably 2.436 nm-2.448 nm; The lattice collapse temperature of the modified Y-type molecular sieve is not lower than 1070 ℃, and 1070-1080 ℃ is preferable; the relative crystallinity of the modified Y-type molecular sieve is 60-80%, preferably 65-75%; the specific surface area of the modified Y-type molecular sieve is 645-670 m 2 Preferably 650-665 m per gram 2 /g。
16. A catalytic cracking process comprising the step of contacting heavy oil with the catalytic cracking catalyst of any one of claims 1 to 3, 15.
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Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040053773A1 (en) * 2002-09-16 2004-03-18 Biswanath Sarkar Process for preparing sodium silicate alkali solution depleted of sodium salt and enriched in silica
CN104743572A (en) * 2013-12-27 2015-07-01 陕西煤化工技术工程中心有限公司 Method for synthesis of high silica-alumina ratio ultrafine NaY molecular sieve
CN107662927A (en) * 2016-07-27 2018-02-06 宁夏大学 A kind of method that NaY molecular sieve is prepared using Si-Al molecular sieve crystallization mother liquor
CN108452834A (en) * 2017-02-22 2018-08-28 中国石油化工股份有限公司 A kind of catalytic cracking catalyst
CN108452827A (en) * 2017-02-21 2018-08-28 中国石油化工股份有限公司 A kind of catalytic cracking catalyst
CN108609633A (en) * 2018-08-16 2018-10-02 于向真 A kind of NaY molecular sieve synthetic method of high-efficiency cleaning
CN110127721A (en) * 2019-05-22 2019-08-16 陕西煤化工技术工程中心有限公司 Cubic nanometer SAPO-34 molecular sieve, preparation method and application
CN110523428A (en) * 2018-05-24 2019-12-03 中国石油天然气股份有限公司 A kind of catalytic cracking catalyst of the composite material containing NaY molecular sieve and preparation method thereof

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040053773A1 (en) * 2002-09-16 2004-03-18 Biswanath Sarkar Process for preparing sodium silicate alkali solution depleted of sodium salt and enriched in silica
CN104743572A (en) * 2013-12-27 2015-07-01 陕西煤化工技术工程中心有限公司 Method for synthesis of high silica-alumina ratio ultrafine NaY molecular sieve
CN107662927A (en) * 2016-07-27 2018-02-06 宁夏大学 A kind of method that NaY molecular sieve is prepared using Si-Al molecular sieve crystallization mother liquor
CN108452827A (en) * 2017-02-21 2018-08-28 中国石油化工股份有限公司 A kind of catalytic cracking catalyst
CN108452834A (en) * 2017-02-22 2018-08-28 中国石油化工股份有限公司 A kind of catalytic cracking catalyst
CN110523428A (en) * 2018-05-24 2019-12-03 中国石油天然气股份有限公司 A kind of catalytic cracking catalyst of the composite material containing NaY molecular sieve and preparation method thereof
CN108609633A (en) * 2018-08-16 2018-10-02 于向真 A kind of NaY molecular sieve synthetic method of high-efficiency cleaning
CN110127721A (en) * 2019-05-22 2019-08-16 陕西煤化工技术工程中心有限公司 Cubic nanometer SAPO-34 molecular sieve, preparation method and application

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