CN114433248A - Catalyst and preparation method thereof - Google Patents

Catalyst and preparation method thereof Download PDF

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Publication number
CN114433248A
CN114433248A CN202011128285.9A CN202011128285A CN114433248A CN 114433248 A CN114433248 A CN 114433248A CN 202011128285 A CN202011128285 A CN 202011128285A CN 114433248 A CN114433248 A CN 114433248A
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carrier
catalyst
impregnation
drying
molecular sieve
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CN114433248B (en
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盛毅
邢瑞思
龙启明
乔晓俊
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China Petroleum and Chemical Corp
Sinopec Catalyst Co
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China Petroleum and Chemical Corp
Sinopec Catalyst Co
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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
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/0201—Impregnation
    • 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
    • B01J29/18—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the mordenite type
    • B01J29/20—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the mordenite type containing iron group metals, noble metals or copper
    • B01J29/22—Noble metals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/30—Catalysts, in general, characterised by their form or physical properties characterised by their physical properties
    • B01J35/391—Physical properties of the active metal ingredient
    • B01J35/394—Metal dispersion value, e.g. percentage or fraction
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/40—Catalysts, in general, characterised by their form or physical properties characterised by dimensions, e.g. grain size
    • 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
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/0009—Use of binding agents; Moulding; Pressing; Powdering; Granulating; Addition of materials ameliorating the mechanical properties of the product catalyst
    • 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
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/0201—Impregnation
    • B01J37/0203—Impregnation the impregnation liquid containing organic compounds
    • 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
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/0236—Drying, e.g. preparing a suspension, adding a soluble salt and drying
    • 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
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/08—Heat treatment
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C6/00—Preparation of hydrocarbons from hydrocarbons containing a different number of carbon atoms by redistribution reactions
    • C07C6/08—Preparation of hydrocarbons from hydrocarbons containing a different number of carbon atoms by redistribution reactions by conversion at a saturated carbon-to-carbon bond
    • C07C6/12—Preparation of hydrocarbons from hydrocarbons containing a different number of carbon atoms by redistribution reactions by conversion at a saturated carbon-to-carbon bond of exclusively hydrocarbons containing a six-membered aromatic ring
    • C07C6/123—Preparation of hydrocarbons from hydrocarbons containing a different number of carbon atoms by redistribution reactions by conversion at a saturated carbon-to-carbon bond of exclusively hydrocarbons containing a six-membered aromatic ring of only one hydrocarbon
    • 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
    • B01J2229/186—After treatment, characterised by the effect to be obtained to introduce other elements into or onto the molecular sieve itself not in framework positions
    • 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
    • B01J2229/24—After treatment, characterised by the effect to be obtained to stabilize the molecular sieve structure
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2529/00—Catalysts comprising molecular sieves
    • C07C2529/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites, pillared clays
    • C07C2529/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • C07C2529/18—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the mordenite type
    • C07C2529/20—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the mordenite type containing iron group metals, noble metals or copper
    • C07C2529/22—Noble metals
    • 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)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
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  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Catalysts (AREA)

Abstract

The invention relates to the field of catalyst preparation, and discloses a catalyst and a preparation method thereof, wherein the method comprises the following steps: 1) contacting the carrier with an impregnation solution containing an active metal component under a first vacuum state; 2) and drying the contacted catalyst in a second vacuum state, wherein the vacuum degree of the first vacuum state is 0.01-0.06 MPa. The method can improve the impregnation uniformity of the catalyst and the activity of the catalyst, the prepared active components of the catalyst are uniformly dispersed, and the problem of carbon deposition and ash generation can be obviously improved. Meanwhile, the impregnation and the drying are completed in the same equipment, so that the labor intensity can be reduced, and the working efficiency can be improved.

Description

Catalyst and preparation method thereof
Technical Field
The invention relates to the field of catalyst preparation, in particular to a catalyst and a preparation method thereof.
Background
The impregnation method is one of the methods commonly used in the preparation of catalysts, and is a method in which a formed carrier is soaked in a soluble compound solution containing an active component, and after contacting for a certain time, a residual liquid is separated to allow the active component to be attached to the carrier. Impregnation and drying are two steps in the impregnation method, and generally, the impregnation is only to simply put the catalyst carrier into a solution containing the active component, which leads to slow drying in the subsequent drying process, and the active component is difficult to be effectively immersed and adsorbed in the carrier after drying due to expansion and contraction with heat and cold, and the influence of the drying rate, the drying temperature and the like. In addition, in the conventional impregnation method, impregnation and drying of the catalyst are respectively completed on an impregnator and a dryer, so that a transfer process is required in the middle, the labor intensity of workers is high, and the working hours are wasted.
On the other hand, even if the component formula of the catalyst is the same, if different impregnation devices and impregnation methods are adopted, the structure and performance of the finally obtained catalyst can be different. The reasons for these differences include mainly the degree of impregnation, the degree of dispersion of the active ingredient, etc. Particularly, in the case of a catalyst having a noble metal as an active component, since the noble metal is expensive and generally used in a small amount in the catalyst, it is more desirable to ensure the uniformity of the noble metal component in the catalyst and to avoid the pulverization and abrasion of the catalyst.
In particular, when the solvent of the impregnation solution is an organic solvent, the organic solvent is oxidized on the surface and in the pores of the support during impregnation and drying to cause a carbon deposition reaction, thereby seriously affecting the performance of the catalyst. And this is especially true when the catalyst support is a relatively active molecular sieve.
Disclosure of Invention
The invention aims to solve the problems of uneven dispersion of active components of a catalyst, ash generation on the surface due to carbon deposition and poor performance of the catalyst in the prior art, and provides the catalyst and the preparation method thereof.
In order to achieve the above object, a first aspect of the present invention provides a method for preparing a catalyst, the method comprising:
1) contacting the carrier with an impregnation solution containing an active metal component under a first vacuum state;
2) drying the contacted catalyst in a second vacuum state,
wherein the vacuum degree of the first vacuum state is 0.01-0.06 MPa.
Preferably, the carrier is subjected to pre-vacuumizing treatment before being contacted with the impregnation liquid; more preferably, the vacuum degree after the pre-vacuumizing treatment is 0.04-0.08 MPa; further preferably, the vacuum degree after the pre-vacuumizing treatment is 0.06-0.08 MPa.
Preferably, the degree of vacuum of the second vacuum state is 0.01-0.04 MPa.
Preferably, the solvent of the impregnation liquid is an organic solvent; more preferably, the solvent of the impregnation liquid is one or more of methanol, ethanol, cyclohexane, isopropanol and butanone.
Preferably, the active metal component is selected from one or more of platinum, tin, rhenium, germanium, palladium and lead; more preferably, the active metal component is selected from one or more of the group consisting of platinum and tin combinations, platinum and rhenium combinations, platinum and germanium combinations, palladium and lead combinations.
Preferably, the carrier is a non-powdered carrier; more preferably, the carrier is one or more of a strip-shaped carrier, a spherical carrier, a columnar carrier and a special-shaped carrier; further preferably, the carrier is a strip-shaped carrier.
Preferably, the length of the support is 1-20 mm.
Preferably, the carrier comprises a molecular sieve; more preferably, the molecular sieve is selected from one or more of the group consisting of ZSM-5 molecular sieve, ZSM-12 molecular sieve, NU-87 molecular sieve, mordenite molecular sieve and zeolite beta molecular sieve.
Preferably, the carrier also contains a binder; more preferably, the binder is selected from Al2O3One or more of alumina sol, polyvinyl alcohol and methyl cellulose.
Preferably, the carrier consists of 30-80 parts molecular sieve and 20-70 parts binder.
Preferably, the weight ratio of the solvent to the carrier in the impregnation liquid is 1: 1 to 6; more preferably, the weight ratio of the solvent to the carrier in the impregnation solution is 1: 2-4.
Preferably, the weight ratio of the active metal component to the carrier in the impregnation liquid is 1: 3-600; more preferably, the weight ratio of the active metal component to the carrier in the impregnation liquid is 1: 8-100.
Preferably, the conditions of the contacting include: the contact time is 1-10min, and the contact temperature is 20-50 ℃; more preferably, the conditions of the contacting include: the contact time is 3-5min, and the contact temperature is 20-35 ℃;
preferably, the contacting is performed in an oxygen-free atmosphere.
Preferably, the drying conditions include: the drying time is 0.5-6h, and the drying temperature is 35-100 ℃; more preferably, the drying conditions include: the drying time is 1-2h, and the drying temperature is 35-50 ℃.
Preferably, step 1) and step 2) are carried out in the same apparatus.
Preferably, the method further comprises: a step of firing after drying, the firing conditions including: the roasting temperature is 200-700 ℃, and the roasting time is 1-8 h; more preferably, the roasting conditions include: the roasting temperature is 450-650 ℃, and the roasting time is 4-6 h.
Preferably, the total content of active metal components in the calcined catalyst is from 1 to 15% by weight.
In a second aspect, the present invention provides a catalyst prepared according to the process of the first aspect of the present invention.
By adopting the technical scheme, the negative pressure impregnation is carried out under a proper vacuum degree, so that the impregnation uniformity and the catalytic performance of the catalyst can be improved.
By impregnating and drying in an oxygen-free atmosphere under the conditions defined by the invention, the carbon deposition and ash formation of the catalyst can be effectively prevented.
On the other hand, the catalyst preparation method provided by the invention can finish impregnation and drying in the same equipment, so that the waste of manpower and the damage to the catalyst caused by a transfer process are avoided. And the active components of the prepared catalyst are uniformly distributed, and the catalyst activity is excellent.
Drawings
FIG. 1 is an appearance diagram of a catalyst prepared in example 1;
fig. 2 is an appearance view of the catalyst prepared in comparative example 2.
Detailed Description
The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.
In a first aspect, the present invention provides a method for preparing a catalyst, the method comprising:
1) contacting the carrier with an impregnation solution containing an active metal component under a first vacuum state;
2) drying the contacted catalyst in a second vacuum state,
wherein the vacuum degree of the first vacuum state is 0.01-0.06 MPa.
In the invention, the vacuum degree refers to the gas rarefied degree in a vacuum state, and the vacuum degree numerical value in the invention represents a numerical value that the actual numerical value of the system pressure is lower than the atmospheric pressure.
According to the present invention, when preparing the impregnation solution containing the active metal component, the amount of the solvent in the impregnation solution may be determined according to the weight of the support. Specifically, the weight ratio of the solvent to the carrier in the impregnation solution may be 1: 1 to 6; preferably, the weight ratio of the solvent to the carrier in the impregnation liquid is 1: 2-4. By limiting the dosage of the solvent in the range, the carrier can be ensured to fully absorb the impregnation liquid, so that the impregnation is better realized, the preparation of the catalyst is finished, the catalytic performance of the catalyst is improved, the dosage of the impregnation liquid can be saved, and the waste is avoided.
The amount of active metal component in the impregnation solution according to the invention may also be determined on the basis of the weight of the support. Specifically, the weight ratio of the active metal component to the carrier in the impregnation liquid may be 1: 3-600; preferably, the weight ratio of the active metal component to the carrier in the impregnation liquid is 1: 8-100 parts of; more preferably, the weight ratio of the active metal component to the carrier in the impregnation liquid is 1: 8-12. By limiting the amount of the active metal component in the impregnation liquid in the above range, the loading amount of the active metal component in the impregnated catalyst can be ensured, the catalyst with high activity and excellent catalytic performance can be prepared, the waste of expensive active metal components can be avoided, and the production cost can be reduced.
According to the present invention, the impregnation solution may be prepared by various methods commonly used in the art for preparing impregnation solutions, for example, the active metal component may be added to the solvent of the impregnation solution, the active metal component may be added first and then the solvent of the impregnation solution, or the solvent of the impregnation solution and the active metal component may be simultaneously added to the impregnation solution preparation apparatus, without particular limitation. In the present invention, it is preferable that the impregnation liquid is obtained by adding the active metal component to the solvent in the above amounts of the solvent and the active metal component. In order to disperse the active metal component in the impregnation liquid rapidly and uniformly, stirring may be performed simultaneously, and the stirring may be performed by various conventional methods for stirring in the art, which will not be described herein.
In the present invention, the solvent of the impregnation solution may be any of various conventional solvents used in the preparation of a catalyst by an impregnation method in the art, and is not particularly limited. Preferably, the solvent of the impregnation liquid is an organic solvent; more preferably, the solvent of the impregnation liquid is one or more of methanol, ethanol, cyclohexane, isopropanol and butanone. By adopting the solvent, the impregnation liquid containing the active metal component can be promoted to enter the pore channel of the carrier, and the loading of the active metal is completed.
In the present invention, the active metal component may be various conventional active metal components that need to be supported when preparing a catalyst in the art, and may be determined according to the kind of the catalyst to be prepared, and is not particularly limited. Preferably, the active metal component is selected from one or more of platinum, tin, rhenium, germanium, palladium and lead; more preferably, the active metal component employs a combination of active metal components, and as such active metal components, for example, one or more of a combination of platinum and tin, a combination of platinum and rhenium, a combination of platinum and germanium, and a combination of palladium and lead may be used.
In the present invention, the carrier may be any of various carriers conventionally used in the preparation of catalysts by impregnation in the art, and may be determined according to the kind of catalyst to be prepared, and is not particularly limited. Preferably, the carrier is a non-powdered carrier; more preferably, the carrier is one or more of a strip-shaped carrier, a spherical carrier, a columnar carrier, and a shaped carrier.
In a preferred embodiment of the present invention, the support is a strip-shaped support, and the length of the support is 1 to 20mm, preferably, the length of the support is 3 to 15 mm. By limiting the length of the carrier within the range, the catalyst can be ensured to be uniformly impregnated, and the phenomenon that when the carrier is too large, multiple layers of active metals are loaded is avoided, and when the carrier is too large, the active metals are loaded unevenly.
In the present invention, preferably, the carrier contains a molecular sieve and a binder. More preferably, the molecular sieve is selected from one or more of ZSM-5 molecular sieve, ZSM-12 molecular sieve, NU-87 molecular sieve, mordenite molecular sieve and beta zeolite molecular sieve; the binder is selected from Al2O3One or more of alumina sol, polyvinyl alcohol and methyl cellulose.
In the present invention, the carrier may be composed of 30 to 80 parts of molecular sieve and 20 to 70 parts of binder. By limiting the weight ratio of the molecular sieve and the binder to the above range, the catalyst strength can be ensured.
In the invention, the carrier can be obtained by kneading, extruding, drying, cutting, molding and roasting the molecular sieve and the adhesive. The preparation process of the carrier is conventional in the field and is not described in detail herein.
According to the invention, before the carrier is contacted with the impregnation liquid, in order to discharge the air inside the pore channels of the molecular sieve in the carrier, the active metal component in the impregnation liquid is better loaded. Preferably, the support is pre-vacuumed. The pre-evacuation treatment may be performed by various conventional methods for evacuation in the art, and is not particularly limited. The vacuum degree after the pre-vacuumizing treatment is 0.04-0.08 MPa; more preferably, the vacuum degree after the pre-vacuumizing treatment is 0.06-0.08 MPa.
According to the invention, the support and the impregnation solution are brought into contact under a first vacuum. Preferably, the degree of vacuum of the first vacuum state is 0.01 to 0.06MPa, and the first vacuum state may be, for example, 0.01MPa, 0.02MPa, 0.03MPa, 0.04MPa, 0.05MPa, or 0.06MPa as long as the degree of vacuum of the present invention is within the range.
In addition, when the solvent in the impregnation liquid is an organic solvent, carbon deposition reaction can occur on the surface of the carrier and in the pore channels in the impregnation and drying processes, so that the performance of the catalyst is greatly influenced, and particularly when the catalyst carrier contains a molecular sieve with high activity, the phenomenon is very serious. Therefore, the inventors of the present invention have made extensive studies and extensive experiments to finally find suitable impregnation and drying conditions. When the carrier is contacted with the impregnation liquid in the vacuum state, the active metal component in the impregnation liquid can be better loaded on the surface of the carrier, and the phenomena of uneven impregnation of the carrier and graying of the surface due to carbon deposition are avoided; but also can prevent the active metal component from entering deeper carrier pore channels due to overhigh vacuum degree to cause the reduction of the activity of the catalyst.
In the present invention, in order to further improve the impregnation effect, it is preferable that the contacting conditions include: the contact time is 1-10min, and the contact temperature is 20-50 ℃; more preferably, the conditions of the contacting include: the contact time is 3-5min, and the contact temperature is 25-35 ℃.
In the present invention, in order to prevent the oxygen in the air from contacting with the catalyst, which causes the active metal component to be oxidized and the carbon deposition reaction to occur, thereby causing the activity of the catalyst to be reduced, it is preferable that the contacting is performed in an oxygen-free atmosphere. The oxygen-free atmosphere may be achieved by various conventional methods in the art, for example, air in the contact system of the support and the impregnation solution may be replaced with an inert gas. As the inert gas, for example, one or more of nitrogen, helium, neon, and argon may be used.
In the present invention, in order to accelerate the progress of impregnation and improve the impregnation effect, it is preferable that the contact is performed under a dynamic state. To achieve the above-described contacting under dynamic conditions, various methods conventional in the art may be employed. For example, the support and the impregnation solution may be contacted under conditions of stirring, shaking, rotation, and the like.
According to the invention, after the contact is completed, the contacted catalyst is dried in a second vacuum state, and the vacuum degree of the second vacuum state is preferably 0.01-0.04 MPa. By drying the catalyst after contact in the second vacuum state, the solvent in the pore channels can be promoted to be discharged as soon as possible.
In the present invention, the drying conditions may include: the drying time is 0.5-6h, and the drying temperature is 35-100 ℃; preferably, the drying conditions include: the drying time is 1-2h, and the drying temperature is 35-50 ℃. The inventors of the present invention have found that by performing the drying within the above temperature and time ranges, not only can the excess solvent be removed and the drying be completed, but also the prepared catalyst can have higher conversion rate and selectivity.
According to the present invention, by the above-mentioned contact and drying, the active metal component in the impregnation liquid can be supported on the carrier to prepare the active metal component-supported catalyst.
In the present invention, the above steps 1) and 2) are preferably carried out in the same apparatus, and the apparatus for carrying out the steps 1) and 2) may be any of various apparatuses capable of impregnation and drying, which are conventional in the art, and is not particularly limited as long as the sealing and heatable functions can be satisfied. Therefore, the impregnation and the drying are carried out in the same equipment, so that the labor cost in the material transfer process can be saved, and the pulverization and the abrasion of the catalyst in the transfer process can be avoided, thereby reducing the labor intensity and improving the working efficiency.
In the present invention, the dried catalyst is further calcined in order to remove the organic silicon component contained in the catalyst and to improve the stability of the catalyst. The calcination may be carried out by a method generally used in the art for calcination, and is not particularly limited. For example, the conditions of the firing may include: the roasting temperature is 200-700 ℃, and the roasting time is 1-8 h; preferably, the conditions of the calcination include: the roasting temperature is 450-650 ℃, and the roasting time is 4-6 h.
In the present invention, the total content of active metal components in the calcined catalyst is 1 to 15% by weight.
Hereinafter, the catalyst preparation method of the present invention will be further described by way of a preferred embodiment of the present invention.
In a preferred embodiment of the present invention, the impregnation and drying of the catalyst are both performed in a vacuum rotary impregnation vessel, and the preparation method of the catalyst mainly comprises the following steps: 1) adding the weighed carrier into a vacuum rotary impregnation kettle, sealing, and pre-vacuumizing the carrier to ensure that the vacuum degree after pre-vacuumizing is within the range; 2) calculating the dosage of the solvent and the active metal component in the impregnation liquid according to the method of the invention, and preparing the impregnation liquid; 3) adding the impregnation liquid into a vacuum rotary impregnation kettle, replacing residual air in the kettle with inert gas, adjusting the vacuum degree in the kettle to a first vacuum state, and impregnating according to the conditions of the invention; 4) after the impregnation is finished, adjusting the vacuum degree in the kettle to the second vacuum state, introducing steam into a jacket of the vacuum rotary impregnation kettle, and drying under the conditions of the invention; 5) the dried catalyst is calcined according to the calcination conditions provided by the invention.
In a second aspect, the present invention provides a catalyst prepared by the preparation method provided in the first aspect of the present invention. The catalyst can be used for transalkylation and toluene disproportionation reactions, and its basic properties are the same as those described in the first aspect of the present invention, and will not be described herein.
The present invention will be described in detail below by way of examples, but the present invention is not limited to the following examples.
In the following examples and comparative examples, the support consisted of 40 parts molecular sieve, mordenite molecular sieve, and 60 parts binder, Al2O3The carrier is a strip-shaped carrier, and the length of the carrier is 3-15 mm.
In the following examples and comparative examples, the above molecular sieve and binder were kneaded, extruded, dried, cut into a shape, and calcined at 500 ℃ for 4 hours to obtain a carrier.
In the following examples and comparative examples, the solvent of the impregnation liquid was ethanol (concentration of 80% by weight).
In the following examples and comparative examples, the content of the active metal component in the catalyst was measured by the ICP method.
In the following examples and comparative examples, the catalytic performance of the resulting catalyst was tested by conducting the toluene disproportionation reaction on a fixed bed reaction evaluation apparatus. Specifically, the catalyst loading was 5.0 grams and the weight space velocity was 4.0 hours-1The reaction temperature is 425 ℃, the reaction pressure is 2.1MPa, and the molar ratio of hydrogen to aromatic hydrocarbon is 2: 1. the toluene conversion and para-selectivity were then calculated using the following formulas:
Figure BDA0002734279500000091
Figure BDA0002734279500000092
example 1
1) Carrying out pre-vacuum treatment on the carrier, wherein the vacuum degree of the treated carrier is 0.05 MPa;
2) uniformly mixing 200g of ethanol, 25g of platinum and 50g of tin to prepare an impregnation liquid;
3) contacting the impregnation liquid prepared in the step 2) with the carrier subjected to the pre-vacuumizing in the step 1), wherein the weight ratio of the solvent to the carrier is 1: 3.5, the weight ratio of the active metal component to the carrier is 1: 9.3, replacing residual air in the impregnation system with nitrogen, adjusting the vacuum degree of the impregnation system to be 0.03MPa, adjusting the temperature of the impregnation system to be 25 ℃, and impregnating for 5min under the conditions;
4) drying at 50 deg.C for 1h under the condition of vacuum degree of 0.03 MPa;
5) the dried catalyst was calcined at 500 ℃ for 5 h.
As a result, the content of platinum in the obtained catalyst was 3.02% by weight, and the content of tin was 6.03% by weight; the appearance of the obtained catalyst is shown in FIG. 1, and the white product ratio and the reaction performance of the obtained catalyst are shown in Table 1.
Example 2
The procedure was followed as in example 1, except that in step 3), the degree of vacuum of impregnation was 0.01 MPa.
As a result, the content of platinum in the obtained catalyst was 2.91 wt%, and the content of tin was 5.96 wt%; the white product ratio in the obtained catalyst and the reaction properties of the catalyst are shown in Table 1.
Example 3
The procedure was followed as in example 1, except that in step 3), the degree of vacuum of impregnation was 0.06 MPa.
As a result, the content of platinum in the obtained catalyst was 3.11 wt%, and the content of tin was 5.95 wt%; the white product ratio in the obtained catalyst and the reaction properties of the catalyst are shown in Table 1.
Example 4
The procedure is as in example 1, except that in step 3), the solvent to carrier weight ratio is 1:2.
as a result, the content of platinum in the obtained catalyst was 3.30% by weight, and the content of tin was 6.25% by weight; the white product ratio in the obtained catalyst and the reaction properties of the catalyst are shown in Table 1.
Example 5
The procedure is as in example 1, except that in step 3) the weight ratio of solvent to carrier is 1: 2.5.
As a result, the content of platinum in the obtained catalyst was 3.23 wt%, and the content of tin was 6.30 wt%; the white product ratio in the obtained catalyst and the reaction properties of the catalyst are shown in Table 1.
Example 6
The procedure is as in example 1, except that in step 3) the weight ratio of solvent to carrier is 1: 3.
As a result, the content of platinum in the obtained catalyst was 3.12 wt%, and the content of tin was 6.07 wt%; the white product ratio in the obtained catalyst and the reaction properties of the catalyst are shown in Table 1.
Example 7
The procedure is as in example 1, except that in step 3) the weight ratio of solvent to carrier is 1: 4.
As a result, the content of platinum in the obtained catalyst was 2.67 wt%, and the content of tin was 4.89 wt%; the white product ratio in the obtained catalyst and the reaction properties of the catalyst are shown in Table 1.
Example 8
The procedure is as in example 1, except that in step 4), the drying time is 2 h.
As a result, the content of platinum in the obtained catalyst was 3.06% by weight, and the content of tin was 5.09% by weight; the white product ratio in the obtained catalyst and the reaction properties of the catalyst are shown in Table 1.
Example 9
The procedure is as in example 1, except that in step 4), the drying time is 3 h.
As a result, the content of platinum in the obtained catalyst was 2.99% by weight, and the content of tin was 5.84% by weight; the white product ratio in the obtained catalyst and the reaction properties of the catalyst are shown in Table 1.
Example 10
The procedure is as in example 1, except that in step 4), the drying time is 4 h.
As a result, the content of platinum in the obtained catalyst was 2.99% by weight, and the content of tin was 5.86% by weight; the white product ratio in the obtained catalyst and the reaction properties of the catalyst are shown in Table 1.
Comparative example 1
The procedure was followed as in example 1, except that in step 3), the degree of vacuum of impregnation was 0.005 MPa.
As a result, the content of platinum in the obtained catalyst was 3.09% by weight, and the content of tin was 5.75% by weight; the white product ratio in the obtained catalyst and the reaction properties of the catalyst are shown in Table 1.
Comparative example 2
The procedure was followed as in example 1, except that in step 3), the degree of vacuum of impregnation was 0.08 MPa.
As a result, the content of platinum in the obtained catalyst was 2.99% by weight, and the content of tin was 5.91% by weight; the appearance of the obtained catalyst is shown in FIG. 2, and the white product ratio and the reaction performance of the catalyst are shown in Table 1.
Comparative example 3
The procedure is as in example 1, except that:
step 1) is not performed;
in the step 3), air in the impregnation system is replaced without nitrogen, and the impregnation is directly carried out without adjusting the vacuum degree of the impregnation system;
in step 4), drying is directly carried out without adjusting the vacuum degree.
As a result, the content of platinum in the obtained catalyst was 3.09% by weight, and the content of tin was 5.7% by weight; the white product ratio in the obtained catalyst and the reaction properties of the catalyst are shown in Table 1.
TABLE 1
Figure BDA0002734279500000131
Note: the white product proportion refers to the proportion of white products in the prepared catalyst in the total weight of the product.
It can be seen from the results of table 1 that when the degree of vacuum during impregnation is 0.01 to 0.06MPa (examples 1 to 3), the carbon deposition and ash formation phenomenon in the prepared catalyst is significantly improved, and the prepared catalyst has higher toluene conversion rate and para-selectivity and excellent catalytic performance, compared with comparative examples 1 to 2.
As can be seen from the figures 1 and 2, the catalyst prepared by the method can completely avoid the occurrence of carbon deposition and ash formation, and the prepared products are all white. And when the vacuum degree of impregnation is beyond the range defined by the invention, the carbon deposition and ash formation phenomenon in the obtained product are serious.
The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

Claims (10)

1. A method of preparing a catalyst, the method comprising:
1) contacting the carrier with an impregnation solution containing an active metal component under a first vacuum state;
2) drying the contacted catalyst in a second vacuum state,
wherein the vacuum degree of the first vacuum state is 0.01-0.06 MPa.
2. The method according to claim 1, wherein the carrier is subjected to a pre-evacuation treatment before being contacted with the impregnation solution;
preferably, the vacuum degree after the pre-vacuumizing treatment is 0.04-0.08 MPa;
more preferably, the vacuum degree after the pre-vacuumizing treatment is 0.06-0.08 MPa;
preferably, the degree of vacuum of the second vacuum state is 0.01-0.04 MPa.
3. The method according to claim 1 or 2, wherein the solvent of the impregnation liquid is an organic solvent,
preferably, the solvent of the impregnation liquid is one or more of methanol, ethanol, cyclohexane, isopropanol and butanone;
preferably, the active metal component is selected from one or more of platinum, tin, rhenium, germanium, palladium and lead;
preferably, the active metal component is selected from one or more of the group consisting of a platinum and tin combination, a platinum and rhenium combination, a platinum and germanium combination, palladium and lead combination.
4. The method of any one of claims 1-3, wherein the carrier is a non-powdered carrier;
preferably, the carrier is one or more of a strip-shaped carrier, a spherical carrier, a columnar carrier and a special-shaped carrier;
more preferably, the carrier is a strip-shaped carrier;
preferably, the length of the support is 1-20 mm.
5. The method according to any one of claims 1 to 3, wherein the carrier contains a molecular sieve,
preferably, the molecular sieve is selected from one or more of ZSM-5 molecular sieve, ZSM-12 molecular sieve, NU-87 molecular sieve, mordenite molecular sieve and beta zeolite molecular sieve;
preferably, the carrier also contains a binder;
more preferably, the binder is selected from Al2O3One or more of aluminum sol, polyvinyl alcohol and methyl cellulose;
preferably, the carrier consists of 30-80 parts molecular sieve and 20-70 parts binder.
6. A method according to any one of claims 1 to 3, wherein the weight ratio of solvent to carrier in the impregnation solution is from 1: 1 to 6;
preferably, the weight ratio of the solvent to the carrier in the impregnation liquid is 1: 2-4;
preferably, the weight ratio of the active metal component to the carrier in the impregnation liquid is 1: 3-600;
more preferably, the weight ratio of the active metal component to the carrier in the impregnation liquid is 1: 8-100.
7. The method of any one of claims 1-3, wherein the conditions of the contacting comprise: the contact time is 1-10min, and the contact temperature is 20-50 ℃;
preferably, the conditions of the contacting include: the contact time is 3-5min, and the contact temperature is 20-35 ℃;
preferably, the contacting is performed in an oxygen-free atmosphere.
8. The method of any of claims 1-3, wherein the drying conditions comprise: the drying time is 0.5-6h, and the drying temperature is 35-100 ℃;
preferably, the drying conditions include: the drying time is 1-2h, and the drying temperature is 35-50 ℃.
9. The method according to any one of claims 1-3, wherein step 1) and step 2) are performed in the same device;
preferably, the method further comprises: a step of firing after drying, the firing conditions including: the roasting temperature is 200-700 ℃, and the roasting time is 1-8 h;
more preferably, the roasting conditions include: the roasting temperature is 450-650 ℃, and the roasting time is 4-6 h;
preferably, the total content of active metal components in the calcined catalyst is from 1 to 15% by weight.
10. A catalyst prepared by the method of any one of claims 1 to 9.
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102716739A (en) * 2011-11-28 2012-10-10 江苏索普（集团）有限公司 Use of catalyst prepared by vacuum method in synthesis of vinyl acetate
CN103769125A (en) * 2012-10-24 2014-05-07 中国石油化工股份有限公司 Preparation method of hydro-treatment catalyst
CN106622269A (en) * 2015-10-29 2017-05-10 中国石油化工股份有限公司 Hydrodenitrogenation catalyst as well as preparation method and application thereof
CN110090654A (en) * 2018-01-30 2019-08-06 中国石油化工股份有限公司 Hydrotreating catalyst and its preparation method and application

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102716739A (en) * 2011-11-28 2012-10-10 江苏索普（集团）有限公司 Use of catalyst prepared by vacuum method in synthesis of vinyl acetate
CN103769125A (en) * 2012-10-24 2014-05-07 中国石油化工股份有限公司 Preparation method of hydro-treatment catalyst
CN106622269A (en) * 2015-10-29 2017-05-10 中国石油化工股份有限公司 Hydrodenitrogenation catalyst as well as preparation method and application thereof
CN110090654A (en) * 2018-01-30 2019-08-06 中国石油化工股份有限公司 Hydrotreating catalyst and its preparation method and application

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