CN109746030B - Propane dehydrogenation catalyst, preparation method thereof and method for preparing propylene by propane dehydrogenation - Google Patents
Propane dehydrogenation catalyst, preparation method thereof and method for preparing propylene by propane dehydrogenation Download PDFInfo
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Abstract
The invention relates to the field of catalysts, and discloses a propane dehydrogenation catalyst, a preparation method thereof and a method for preparing propylene by propane dehydrogenation. The propane dehydrogenation catalyst comprises a carrier, and a Pt component, a Sn component and a Na component which are loaded on the carrier, wherein the carrier is a spherical double mesoporous molecular sieve silica gel composite material, the spherical double mesoporous molecular sieve silica gel composite material contains silica gel and a mesoporous molecular sieve with a three-dimensional cubic cage-shaped pore distribution structure, the compressive strength of the spherical double mesoporous molecular sieve silica gel composite material is 12-16MPa, the average particle size is 40-60 mu m, and the specific surface area is 200-300m2The pore volume is 0.5-1.5mL/g, the pore size distribution is bimodal, and the most probable pore sizes corresponding to the bimodal are 5-15nm and 30-50nm respectively. The propane dehydrogenation catalyst shows good catalytic performance when used for preparing propylene by propane dehydrogenation, and has the advantages of high propane conversion rate, high propylene selectivity, good catalyst stability and strong poisoning resistance.
Description
Technical Field
The invention relates to the field of catalysts, in particular to a propane dehydrogenation catalyst, a preparation method thereof and a method for preparing propylene by propane dehydrogenation.
Background
Propylene is a basic raw material of petrochemical industry and is mainly used for producing polypropylene, acrylonitrile, acetone, propylene oxide, acrylic acid, butanol and octanol and the like. Half of the propylene supply comes from refinery by-products and about 45% from steam cracking, a few other alternative technologies. In recent years, the demand of propylene is increasing year by year, and the traditional propylene production can not meet the demand of the chemical industry for propylene, so that the propylene yield increase becomes a great hot point for research. The dehydrogenation of propane to propylene is one of the main technologies for increasing the yield of propylene. For more than 10 years, the dehydrogenation of propane to prepare propylene has become an important process for the industrial production of propylene. The main catalysts for propane dehydrogenation are the chromium oxide/alumina catalyst in the CYLofin process from ABB Lummus and the platinum tin/alumina catalyst in the Oleflex process from UOP. The chromium catalyst has lower requirements on raw material impurities and lower price compared with noble metals; however, the catalyst is easy to deposit carbon and deactivate, and is regenerated every 15 to 30 minutes, and the chromium in the catalyst is heavy metal, so that the environmental pollution is serious. The platinum-tin catalyst has high activity and good selectivity, the reaction period can reach several days, and the catalyst can bear harsh process conditions and is more environment-friendly; however, the noble metal platinum is expensive, so that the cost of the catalyst is high. The industrial production of the process for preparing propylene by propane dehydrogenation is over twenty years, and the research on dehydrogenation catalysts is more, but the current catalysts still have the defects of low propane conversion rate, easy inactivation and the like, and further improvement and perfection are needed. Therefore, it is of practical significance to develop a propane dehydrogenation catalyst having excellent performance. Much work has been done by researchers to improve the reaction performance of propane dehydrogenation catalysts. Such as: the molecular sieve carrier is adopted to replace the traditional gamma-Al 2O3 carrier, and the carrier has good effect and comprises MFI type microporous molecular sieves (CN104307555A, CN101066532A, CN101380587A and CN101513613A), mesoporous MCM-41 molecular sieves (CN102389831A), mesoporous SBA-15 molecular sieves (CN101972664A and CN101972664B) and the like. However, the pore diameter of the commonly used mesoporous material is small (average pore diameter is 6-9 nm), and if macromolecule catalytic reaction is carried out, the macromolecule is difficult to enter the pore channel, so that the catalytic effect is influenced. Therefore, the selection of a good carrier is an urgent problem to be solved in the field of propane dehydrogenation.
Disclosure of Invention
The propane dehydrogenation catalyst in the prior art usually takes Pt as a main metal active component and takes gamma-Al2O3As carrier, the catalyst has poor dispersion of active components, and poor catalytic activity and stabilityThe defect of (2). The invention aims to overcome the defects that in the prior art, the mesoporous structure is unstable, the conversion rate of propane and the selectivity of propylene are not high, the catalyst is easy to inactivate and the like, and provides a propane dehydrogenation catalyst, a preparation method thereof and a method for preparing propylene by propane dehydrogenation.
In order to achieve the above object, the present invention provides a propane dehydrogenation catalyst, which comprises a carrier and a Pt component, a Sn component and a Na component supported on the carrier, wherein the carrier is a spherical double mesoporous molecular sieve silica gel composite material, the spherical double mesoporous molecular sieve silica gel composite material contains silica gel and a mesoporous molecular sieve having a three-dimensional cubic cage-shaped pore channel distribution structure, the compressive strength of the spherical double mesoporous molecular sieve silica gel composite material is 12-16MPa, the average particle size is 40-60 μm, and the specific surface area is 200-300m2The pore volume is 0.5-1.5mL/g, the pore size distribution is bimodal, and the most probable pore sizes corresponding to the bimodal are 5-15nm and 30-50nm respectively.
The second aspect of the present invention provides a method for preparing the above propane dehydrogenation catalyst, comprising: carrying out heat activation on a carrier, then carrying out impregnation treatment in a mixed solution containing a Pt component precursor, a Sn component precursor and a Na component precursor, and then sequentially carrying out solvent removal treatment, drying and roasting, wherein the carrier is a spherical double mesoporous molecular sieve silica gel composite material, the spherical double mesoporous molecular sieve silica gel composite material contains silica gel and a mesoporous molecular sieve with a three-dimensional cubic cage-shaped pore channel distribution structure, the compressive strength of the spherical double mesoporous molecular sieve silica gel composite material is 12-16MPa, the average particle size is 40-60 mu m, and the specific surface area is 200-300 m-2The pore volume is 0.5-1.5mL/g, the pore size distribution is bimodal, and the most probable pore sizes corresponding to the bimodal are 5-15nm and 30-50nm respectively.
In a third aspect, the present invention provides a propane dehydrogenation catalyst prepared by the above process.
In a fourth aspect of the present invention, there is provided a method for producing propylene by dehydrogenation of propane, the method comprising: and carrying out dehydrogenation reaction on propane in the presence of a catalyst and hydrogen, wherein the catalyst is the propane dehydrogenation catalyst provided by the invention or the propane dehydrogenation catalyst prepared by the method provided by the invention.
According to the spherical double-mesoporous molecular sieve silica gel composite material, the mesoporous molecular sieve with a three-dimensional cage-shaped pore channel distribution structure, the regular ordered mesoporous space characteristic of silica gel and the spherical shape advantage are combined, and the good dispersion of metal components in the pore channels is facilitated, so that the spherical double-mesoporous molecular sieve silica gel composite material is suitable for being used as a carrier of a supported catalyst, and is particularly suitable for being used as a carrier of a supported catalyst used in the reaction of preparing propylene by propane dehydrogenation.
In the propane dehydrogenation catalyst, the spherical double mesoporous molecular sieve silica gel composite material is used as a carrier, and a Pt component, a Sn component and a Na component are loaded, so that the supported catalyst has the advantages of the supported catalyst, such as high catalytic activity, less side reaction, simple post-treatment and the like, and has stronger catalytic activity, the supported catalyst has better dehydrogenation activity and selectivity when being used in the propane dehydrogenation reaction, and the conversion rate of reaction raw materials is obviously improved, specifically, in the reaction of preparing propylene by using the supported catalyst for propane dehydrogenation, the conversion rate of propane can reach 24%, and the selectivity of propylene can reach 80%.
In addition, the co-impregnation method is adopted to replace the conventional step-by-step impregnation method, the preparation process is simple, the conditions are easy to control, and the product repeatability is good.
And, when the propane dehydrogenation catalyst is prepared by a spray-drying method, the propane dehydrogenation catalyst can be recycled, and a high conversion rate of reaction raw materials can be still obtained during recycling.
Furthermore, the invention adds the binder when preparing the spherical double mesoporous molecular sieve silica gel composite material, so that the prepared spherical double mesoporous molecular sieve silica gel composite material has higher compressive strength, can prevent powder segregation after ball milling, and can effectively improve the stability of the spherical double mesoporous molecular sieve silica gel composite material, thereby prolonging the service life of the propane dehydrogenation catalyst prepared by taking the spherical double mesoporous molecular sieve silica gel composite material as a carrier.
Additional features and advantages of the invention will be set forth in the detailed description which follows.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
FIG. 1 is an X-ray diffraction pattern of a spherical double mesoporous molecular sieve silica gel composite of example 1;
FIG. 2 is an SEM scanning electron micrograph of the microstructure of the spherical double mesoporous molecular sieve silica gel composite of example 1;
fig. 3 is a pore size distribution diagram of the spherical double mesoporous molecular sieve silica gel composite of example 1.
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.
The invention provides a propane dehydrogenation catalyst which comprises a carrier, and a Pt component, a Sn component and a Na component which are loaded on the carrier, wherein the carrier is a spherical double mesoporous molecular sieve silica gel composite material, the spherical double mesoporous molecular sieve silica gel composite material contains silica gel and a mesoporous molecular sieve with a three-dimensional cubic cage-shaped pore channel distribution structure, the compressive strength of the spherical double mesoporous molecular sieve silica gel composite material is 12-16MPa, the average particle size is 40-60 mu m, and the specific surface area is 200-300m2The pore volume is 0.5-1.5mL/g, the pore size distribution is bimodal, and the most probable pore sizes corresponding to the bimodal are 5-15nm and 30-50nm respectively.
According to the invention, the carrier has a special three-dimensional cage-shaped pore channel distribution structure, the limitation of one-dimensional pore channels on molecular transmission is broken through, the carrier is combined with the special three-dimensional cage-shaped ordered mesoporous channel distribution structure and the pore channel structure of silica gel, so that the metal components can be well dispersed in the pore channels of the carrier, the spherical double mesoporous molecular sieve silica gel composite material is used as the carrier, and the supported catalyst obtained by loading the Pt component, the Sn component and the Na component has the advantages of the supported catalyst, such as high catalytic activity, less side reaction, simple post-treatment and the like, and has stronger catalytic activity, so that the supported catalyst has better dehydrogenation activity and selectivity when being used in propane dehydrogenation reaction, and the conversion rate of reaction raw materials is obviously improved.
According to the invention, the average particle diameter of the particles of the support is determined using a laser particle size distribution instrument, and the specific surface area, pore volume and most probable pore diameter are determined according to a nitrogen adsorption method.
According to the invention, the structural parameters of the spherical double mesoporous molecular sieve silica gel composite material are controlled within the range, so that the spherical double mesoporous molecular sieve silica gel composite material is ensured not to be easily agglomerated, and the conversion rate of reaction raw materials in the reaction process of preparing propylene by propane dehydrogenation can be improved by using the supported catalyst prepared by the spherical double mesoporous molecular sieve silica gel composite material as a carrier. When the specific surface area of the spherical double mesoporous molecular sieve silica gel composite material is less than 200m2When the volume/g and/or pore volume is less than 0.5mL/g, the catalytic activity of the supported catalyst prepared by using the supported catalyst is remarkably reduced; when the specific surface area of the spherical double mesoporous molecular sieve silica gel composite material is more than 300m2When the volume/g and/or the pore volume is more than 1.5mL/g, the supported catalyst prepared by using the supported catalyst as the carrier is easy to agglomerate in the reaction process of preparing propylene by propane dehydrogenation, thereby influencing the conversion rate of the reaction raw materials in the reaction process of preparing propylene by propane dehydrogenation.
Preferably, the compressive strength of the carrier is 14-16MPa, the average particle diameter is 45-55 μm, and the specific surface area is 210-250m2Pore volume of 0.8-1.4mL/g, and the most probable pore diameters corresponding to bimodal distribution of 6-12nm and 35-45nm, respectively.
According to the present invention, the propane dehydrogenation catalyst comprises a carrier, and a Pt component, a Sn component, and a Na component supported on the carrier, wherein the Pt component is an active metal component, and the Sn component and the Na component are metal promoters.
According to the present invention, the carrier has a content of 97.5 to 99.3 wt%, the Pt component has a content of 0.2 to 0.5 wt% in terms of Pt element, the Sn component has a content of 0.2 to 1.2 wt% in terms of Sn element, and the Na component has a content of 0.3 to 0.8 wt% in terms of Na element, with respect to 100 parts by weight of the propane dehydrogenation catalyst.
Preferably, the compressive strength of the propane dehydrogenation catalyst is 14-16MPa, the average particle diameter is 45-55 μm, and the specific surface area is 150-220m2The pore volume is 0.5-1.2mL/g, the pore size distribution is bimodal, and the most probable pore sizes corresponding to the bimodal are 6-12nm and 35-45nm respectively.
According to the invention, in the spherical double mesoporous molecular sieve silica gel composite material, the weight ratio of the contents of the mesoporous molecular sieve to the silica gel is 1: 0.5-1.5.
The present invention also provides a method for preparing a propane dehydrogenation catalyst, the method comprising: carrying out heat activation on a carrier, then carrying out impregnation treatment in a mixed solution containing a Pt component precursor, a Sn component precursor and a Na component precursor, and then sequentially carrying out solvent removal treatment, drying and roasting, wherein the carrier is a spherical double mesoporous molecular sieve silica gel composite material, the spherical double mesoporous molecular sieve silica gel composite material contains silica gel and a mesoporous molecular sieve with a three-dimensional cubic cage-shaped pore channel distribution structure, the compressive strength of the spherical double mesoporous molecular sieve silica gel composite material is 12-16MPa, the average particle size is 40-60 mu m, and the specific surface area is 200-300 m-2The pore volume is 0.5-1.5mL/g, the pore size distribution is bimodal, and the most probable pore sizes corresponding to the bimodal are 5-15nm and 30-50nm respectively.
According to the present invention, in order to remove hydroxyl groups and residual moisture from the spherical double mesoporous molecular sieve silica gel composite material, a thermal activation treatment is first required before the spherical double mesoporous molecular sieve silica gel composite material is loaded with metal components, and the conditions of the thermal activation treatment may include: in the presence of nitrogen, the carrier is calcined at the temperature of 300-900 ℃ for 7-10 h.
According to the invention, the metal component loaded on the spherical double mesoporous molecular sieve silica gel composite material can adopt an impregnation mode, the metal component enters the pore channel of the spherical double mesoporous molecular sieve silica gel composite material by virtue of the capillary pressure of the pore channel structure of the spherical double mesoporous molecular sieve silica gel composite material, and meanwhile, the metal component can be adsorbed on the surface of the spherical double mesoporous molecular sieve silica gel composite material until the metal component reaches adsorption balance on the surface of the spherical double mesoporous molecular sieve silica gel composite material. Preferably, the impregnation treatment is performed after the spherical double mesoporous molecular sieve silica gel composite material is subjected to thermal activation treatment, and the impregnation treatment can be co-impregnation treatment or step-by-step impregnation treatment. In order to save the preparation cost and simplify the experimental process, the dipping treatment is preferably co-dipping treatment; further preferably, the conditions of the co-impregnation treatment include: the spherical double mesoporous molecular sieve silica gel composite material after thermal activation is mixed and contacted with a solution containing a Pt component precursor, a Sn component precursor and a Na component precursor, the dipping temperature can be 25-50 ℃, and the dipping time can be 2-6 h.
According to the present invention, the solutions of the Pt component precursor, the Sn component precursor, and the Na component precursor are not particularly limited as long as they are water-soluble, and may be conventionally selected in the art. For example, the Pt component precursor can be H2PtCl6The Sn component precursor may be SnCl4The Na component precursor can be NaNO3。
The concentration of the solution containing the Pt component precursor, the Sn component precursor, and the Na component precursor is not particularly limited in the present invention and may be conventionally selected in the art, for example, the concentration of the Pt component precursor may be 0.1 to 0.3mol/L, the concentration of the Sn component precursor may be 0.15 to 1mol/L, and the concentration of the Na component precursor may be 1 to 3.5 mol/L.
According to the present invention, the carrier, the Pt component precursor, the Sn component precursor, and the Na component precursor may be used in amounts such that the carrier has a content of 97.5 to 99.3 wt%, the Pt component has a content of 0.2 to 0.5 wt% in terms of Pt element, the Sn component has a content of 0.2 to 1.2 wt% in terms of Sn element, and the Na component has a content of 0.3 to 0.8 wt% in terms of Na element in the prepared propane dehydrogenation catalyst, based on the total weight of the propane dehydrogenation catalyst.
According to the present invention, the solvent removal treatment can be carried out by a method conventional in the art, for example, a rotary evaporator can be used to remove the solvent in the system.
According to the invention, the drying can be carried out in a drying oven and the baking can be carried out in a muffle furnace. The conditions for the drying and firing are also not particularly limited in the present invention, and may be conventionally selected in the art, for example, the conditions for the drying may include: the temperature is 110-150 ℃ and the time is 3-6 h; the conditions for the firing may include: the temperature is 600 ℃ and 650 ℃, and the time is 5-8 h.
According to the present invention, the method of forming the carrier includes the steps of:
(a) mixing and contacting a template agent, potassium sulfate, an acid agent and a silicon source, and crystallizing and filtering the obtained mixture to obtain a filter cake of the mesoporous molecular sieve;
(b) contacting water glass, inorganic acid and glycerol, and filtering a product obtained after the contact to obtain a silica gel filter cake;
(c) and mixing the spherical double mesoporous molecular sieve filter cake and the silica gel filter cake, adding a binder for ball milling, pulping solid powder obtained after ball milling by using water, then carrying out spray drying, and removing the template agent and the binder in the obtained product.
In the forming process of the carrier, the filter cake of the mesoporous molecular sieve is the filter cake of the mesoporous molecular sieve with a three-dimensional cubic cage-shaped pore channel distribution structure.
In the forming process of the carrier, the pore size distribution of the carrier is controlled to be bimodal distribution mainly by controlling the composition of the mesoporous molecular sieve filter cake and the silica gel filter cake, so that the spherical double mesoporous molecular sieve silica gel composite material has a double-pore distribution structure, and the micro-morphology of the spherical double mesoporous molecular sieve silica gel composite material is controlled to be spherical by controlling a forming method (namely, firstly mixing the mesoporous molecular sieve filter cake and the silica gel filter cake, adding a binder for ball milling, then pulping the obtained solid powder with water and then carrying out spray drying).
According to the present invention, in the step (a), the process for preparing the mesoporous molecular sieve filter cake may comprise: mixing and contacting a template agent, potassium sulfate, an acid agent and a silicon source, and crystallizing and filtering the obtained mixture. The order of the mixing and contacting is not particularly limited, and the template agent, the potassium sulfate, the acid agent and the silicon source may be mixed at the same time, or any two or three of them may be mixed, and then the other components may be added and mixed uniformly. According to a preferred embodiment, the template agent, the potassium sulfate and the acid agent are mixed uniformly, and then the silicon source is added and mixed uniformly.
According to the present invention, the amount of each substance used in the preparation of the mesoporous molecular sieve filter cake can be selected and adjusted within a wide range. For example, the molar ratio of the templating agent, potassium sulfate, and silicon source may be 1: 100-800: 20-200, preferably 1: 150-700: 80-180, more preferably 1: 200-400: 100-150.
According to the present invention, the template agent may be any template agent conventional in the art as long as the obtained mesoporous molecular sieve filter cake can have the aforementioned three-dimensional cubic cage-shaped pore channel distribution structure, and preferably, the template agent may be a triblock copolymer polyoxyethylene-polyoxypropylene-polyoxyethylene. The templating agent may be prepared by methods known to those skilled in the art or may be obtained commercially, for example, from Fuka under the trade designation Synperonic F108, formula EO132PO60EO132Average molecular weight Mn14600. Wherein the number of moles of polyoxyethylene-polyoxypropylene-polyoxyethylene is calculated from the average molecular weight of polyoxyethylene-polyoxypropylene-polyoxyethylene.
In the present invention, the silicon source may be various silicon sources conventionally used in the art, and preferably the silicon source is at least one of tetraethoxysilane, methyl orthosilicate, propyl orthosilicate, sodium orthosilicate and silica sol, and more preferably tetraethoxysilane.
In the present invention, the acid agent may be various acidic aqueous solutions conventionally used in the art, and for example, may be at least one aqueous solution of hydrochloric acid, sulfuric acid, nitric acid and hydrobromic acid, preferably an aqueous hydrochloric acid solution.
The amount of the acid agent is not particularly limited, and may be varied within a wide range, and it is preferable that the pH value of the mixing contact is 1 to 7.
The conditions of the mixing and contacting are not particularly limited in the present invention, and for example, the conditions of the mixing and contacting may include: the temperature is 25-60 deg.C, the time is 10-72h, and the pH value is 1-7. In order to further facilitate uniform mixing between the substances, according to a preferred embodiment of the invention, the mixing contact is carried out under stirring conditions.
In the present invention, the crystallization conditions are not particularly limited, and for example, the crystallization conditions may include: the temperature is 30-150 ℃, preferably 90-150 ℃; the time is 10-72h, preferably 10-40 h. According to a preferred embodiment, the crystallization is carried out by hydrothermal crystallization.
The conditions under which the water glass, the inorganic acid and the glycerol are contacted are not particularly limited in the present invention, and for example, in the step (b), the conditions under which the water glass, the inorganic acid and the glycerol are contacted generally include: the temperature can be 10-60 ℃, preferably 20-40 ℃; the time may be 1 to 5 hours, preferably 1.5 to 3 hours, and the pH value is 2 to 4. In order to increase the pore size of the prepared silica gel, preferably, the amount of water glass, inorganic acid and glycerin may be used in a weight ratio of 3 to 6:1: 1. In order to further facilitate uniform mixing between the substances, the contact of the water glass, the inorganic acid and the glycerol is preferably carried out under stirring conditions.
According to the invention, the water glass is an aqueous solution of sodium silicate conventional in the art, and its concentration may be 10 to 50% by weight, preferably 12 to 30% by weight.
According to the present invention, the kind of the inorganic acid may be conventionally selected in the art, and for example, may be one or more of sulfuric acid, nitric acid and hydrochloric acid. The inorganic acid may be used in a pure form or in the form of an aqueous solution thereof. The inorganic acid is preferably used in such an amount that the reaction system has a pH of 2 to 4 under the contact conditions of the water glass and the inorganic acid.
Further, in the above-described process for preparing the mesoporous molecular sieve cake and the silica gel cake, the process for obtaining the cake by filtration may include: after filtration, washing with distilled water was repeated (the number of washing may be 2 to 10), followed by suction filtration. Preferably, the washing during the preparation of the mesoporous molecular sieve filter cake results in a filter cake PH of 7 and the washing during the preparation of the silica gel filter cake results in a sodium ion content of less than 0.02 wt.%.
According to the present invention, in order to improve the mechanical strength of the finally prepared spherical double mesoporous molecular sieve silica gel composite material and prevent powder segregation after ball milling, in step (c), a binder is added before ball milling after mixing the mesoporous molecular sieve filter cake and the silica gel filter cake. The amount of the mesoporous molecular sieve filter cake, the silica gel filter cake and the binder can be selected according to the components of the spherical double mesoporous molecular sieve silica gel composite material expected to be obtained, and preferably, the weight ratio of the amount of the mesoporous molecular sieve filter cake, the silica gel filter cake and the binder is 1: (0.5-1.5): (0.5-1.5).
According to the present invention, the kind of the binder is not particularly limited as long as it can improve the strength of the finally prepared spherical double mesoporous molecular sieve silica gel composite material, prevent powder segregation after ball milling, and can be removed before or during sintering, and preferably, the binder may be polyvinyl alcohol (PVA).
According to the present invention, the specific operation method and conditions of the ball milling are not particularly limited, subject to not destroying or substantially not destroying the structure of the mesoporous molecular sieve and allowing the silica gel to enter the pores of the mesoporous molecular sieve. One skilled in the art can select various suitable conditions to implement the present invention based on the above principles. Specifically, the ball milling is carried out in a ball mill, wherein the diameter of the milling balls in the ball mill can be 2-3 mm; the number of the grinding balls can be reasonably selected according to the size of the ball milling tank, and for the ball milling tank with the size of 50-150mL, 1 grinding ball can be generally used; the material of the grinding ball can be agate, polytetrafluoroethylene and the like, and agate is preferred. The ball milling conditions include: the rotation speed of the grinding ball can be 300-500r/min, the temperature in the ball milling tank can be 15-100 ℃, and the ball milling time can be 0.1-100 hours.
In the present invention, the specific operation method and conditions of the spray drying are conventional in the art. Specifically, a slurry prepared from the solid powder and water is added into an atomizer and rotated at a high speed to realize spray drying. Wherein the spray drying conditions comprise: the temperature can be 100-300 ℃, and the rotating speed can be 10000-15000 r/min; preferably, the spray drying conditions include: the temperature is 150-250 ℃, and the rotating speed is 11000-13000 r/min; most preferably, the spray drying conditions include: the temperature is 200 ℃, and the rotating speed is 12000 r/min.
The method of removing the templating agent and binder according to the present invention is typically a calcination process. The conditions for removing the templating agent and the binder may be selected conventionally in the art, for example, the conditions for removing the templating agent and the binder include: the temperature can be 300-600 ℃, preferably 350-550 ℃, and most preferably 500 ℃; the time may be 10 to 80 hours, preferably 20 to 30 hours, most preferably 24 hours.
The invention also provides a propane dehydrogenation catalyst prepared by the method.
The invention also provides a method for preparing propylene by propane dehydrogenation, which comprises the following steps: carrying out dehydrogenation reaction on propane in the presence of a catalyst and hydrogen, wherein the catalyst is the propane dehydrogenation catalyst.
According to the present invention, in order to improve the propane conversion and prevent the catalyst from coking, it is preferable that the molar ratio of the amount of propane to the amount of hydrogen is from 0.5 to 1.5: 1.
the conditions for the dehydrogenation reaction in the present invention are not particularly limited and may be conventionally selected in the art, and for example, the conditions for the dehydrogenation reaction may include: the reaction temperature is600 ℃ at 650 ℃, the reaction pressure of 0.05-0.2MPa, the reaction time of 40-60h and the mass space velocity of propane of 2-5h-1。
The present invention will be described in detail below by way of examples.
In the following examples and comparative examples, polyoxyethylene-polyoxypropylene-polyoxyethylene was obtained from Fuka under the trade name Synperonic F108 and the formula EO132PO60EO132Average molecular weight Mn＝14600。
In the following examples and comparative examples, polyvinyl alcohol (PVA) was obtained from carbofuran and had an average molecular weight of 16000.
In the following examples and comparative examples, X-ray diffraction analysis was carried out on an X-ray diffractometer, model D8Advance, available from Bruker AXS, Germany; scanning electron microscopy analysis was performed on a scanning electron microscope, model XL-30, available from FEI, USA; pore structure parameter analysis was performed on an ASAP2020-M + C type adsorber, available from Micromeritics, USA, and BET method was used for the specific surface area and pore volume calculation of the sample; the particle size distribution of the sample is carried out on a Malvern laser particle sizer; the rotary evaporator is produced by German IKA company, and the model is RV10 digital; the active component loading of the propane dehydrogenation catalyst was measured on a wavelength dispersive X-ray fluorescence spectrometer, model Axios-Advanced, available from parnacco, netherlands; analysis of the reaction product composition was performed on a gas chromatograph available from Agilent under model 7890A.
In the following experimental examples and experimental comparative examples, the conversion (%) of propane is ═ amount of propane-content of propane in the reaction product ÷ amount of propane used × 100%;
selectivity (%) of propylene ÷ actual yield of propylene ÷ theoretical yield of propylene × 100%.
Example 1
This example illustrates a propane dehydrogenation catalyst and a method for its preparation.
(1) Preparation of the support
2g (1.4X 10)-4mol) template F108, 5.24g (0.03mol) of K2SO4With 60g of hydrochloric acid with 2(2N) equivalent concentrationStirring the solution at 38 ℃ until F108 is completely dissolved;
adding 4.2g (0.02mol) of tetraethoxysilane into the solution, stirring at 38 ℃ for 15min, and standing at 38 ℃ for 24 h;
then transferring the mixture into a reaction kettle with an agate inner lining, crystallizing the mixture for 24 hours at the temperature of 100 ℃, then filtering the mixture, washing the mixture for 4 times by using deionized water, and then carrying out suction filtration to obtain a mesoporous molecular sieve filter cake A1.
Mixing 15 wt% of water glass, 12 wt% of sulfuric acid solution and glycerol in a weight ratio of 5: 1:1, then adjusting the pH value to 3 with sulfuric acid with the concentration of 98 weight percent, then carrying out suction filtration on the obtained reaction material, and washing the reaction material with distilled water until the content of sodium ions is 0.02 weight percent to obtain a silica gel filter cake B1.
And (3) putting 10g of the prepared filter cake A1, 10g of the prepared filter cake B1 and 10g of binder polyvinyl alcohol into a 100ml ball milling tank together, wherein the ball milling tank is made of polytetrafluoroethylene, grinding balls are made of agate, the diameter of each grinding ball is 3mm, the number of the grinding balls is 1, and the rotating speed is 400 r/min. Sealing the ball milling tank, and carrying out ball milling for 1 hour in the ball milling tank at the temperature of 60 ℃ to obtain 30g of solid powder; dissolving the solid powder in 25 g of deionized water, and spray-drying at 200 ℃ and 12000 r/min; calcining the product obtained after spray drying in a muffle furnace at 550 ℃ for 10 hours, and removing the template agent and the binder to obtain 30g of the spherical double mesoporous molecular sieve silica gel composite material C1.
(2) Preparation of propane dehydrogenation catalyst
Calcining 30g of the spherical double mesoporous molecular sieve silica gel composite material C1 obtained in the step (1) at 400 ℃ for 10h under the protection of nitrogen to carry out thermal activation treatment, and removing hydroxyl and residual moisture of the spherical double mesoporous molecular sieve silica gel composite material C1;
0.08g H2PtCl6·6H2O、0.207g SnCl4·5H2O and 0.185g NaNO3Dissolving in 100ml deionized water to obtain mixture solution, soaking the spherical double mesoporous molecular sieve silica gel composite material subjected to thermal activation treatment in the mixture solution at 25 ℃ for 5hThen, the solvent water in the system was distilled off by a rotary evaporator to obtain a solid product, and the solid product was placed in a drying oven at a temperature of 120 ℃ to be dried for 3 hours and then placed in a muffle furnace at a temperature of 600 ℃ to be calcined for 6 hours to obtain a propane dehydrogenation catalyst Cat-1 (based on the total weight of the propane dehydrogenation catalyst Cat-1, the content of the Pt component calculated as the Pt element was 0.3 wt%, the content of the Sn component calculated as the Sn element was 0.7 wt%, the content of the Na component calculated as the Na element was 0.5 wt%, and the remainder was a carrier).
The spherical double mesoporous molecular sieve silica gel composite material C1 and the propane dehydrogenation catalyst Cat-1 are characterized by an XRD, a scanning electron microscope and an ASAP2020-M + C type adsorption instrument;
fig. 1 is an X-ray diffraction pattern of the spherical double mesoporous molecular sieve silica gel composite material C1, wherein the abscissa is 2 θ and the ordinate is intensity, and the XRD spectrum of the spherical double mesoporous molecular sieve silica gel composite material C1 has a three-dimensional cubic cage-shaped pore structure specific to a mesoporous material, as can be seen from a small-angle spectrum peak appearing in the XRD spectrum;
fig. 2 is an SEM scanning electron microscope image of the spherical double mesoporous molecular sieve silica gel composite material C1, from which it can be seen that the microscopic morphology of the spherical double mesoporous molecular sieve silica gel composite material C1 is microspheres with a particle size of 40-60 μm, and the monodispersity thereof is good;
fig. 3 is a pore size distribution diagram of the spherical double mesoporous molecular sieve silica gel composite material C1, the abscissa is the pore size (unit is 0.1nm), and the ordinate is the pore volume (unit is mL/g), it can be seen from the diagram that the pore size distribution of the spherical double mesoporous molecular sieve silica gel composite material C1 is a bimodal distribution, and the most probable pore sizes corresponding to the bimodal distribution are 8nm and 40nm, respectively.
Table 1 shows the pore structure parameters of the spherical double mesoporous molecular sieve silica gel composite material C1 and the propane dehydrogenation catalyst Cat-1.
TABLE 1
*: the first most probable aperture and the second most probable aperture are separated by a comma: the first most probable aperture and the second most probable aperture are arranged in the order from left to right.
As can be seen from the data of table 1, the specific surface area and pore volume of the spherical double mesoporous molecular sieve silica gel composite material C1 as a carrier were reduced after the main active Pt component, the auxiliary Sn component and the auxiliary Na component were supported, which indicates that the main active Pt component, the auxiliary Sn component and the auxiliary Na component entered the interior of the spherical double mesoporous molecular sieve silica gel composite material C1 during the supporting reaction.
Comparative example 1
This comparative example serves to illustrate a reference propane dehydrogenation catalyst and a method of making the same.
The carrier and the propane dehydrogenation catalyst were prepared according to the method of example 1, except that a mesoporous molecular sieve having a three-dimensional cubic cage-shaped pore distribution structure was not added in the process of preparing the carrier, thereby preparing the carrier D1 and the propane dehydrogenation catalyst Cat-D-1, respectively.
Comparative example 2
This comparative example serves to illustrate a reference propane dehydrogenation catalyst and a method of making the same.
A carrier and a propane dehydrogenation catalyst were prepared according to the method of example 1, except that no silica gel was added during the preparation of the carrier, thereby preparing a carrier D2 and a propane dehydrogenation catalyst Cat-D-2, respectively.
Comparative example 3
This comparative example serves to illustrate a reference propane dehydrogenation catalyst and a method of making the same.
A carrier and a propane dehydrogenation catalyst were prepared according to the method of example 1, except that polyvinyl alcohol was not added as a binder in the preparation of the carrier, thereby preparing a carrier D3 and a propane dehydrogenation catalyst Cat-D-3, respectively.
Comparative example 4
This comparative example serves to illustrate a reference propane dehydrogenation catalyst and a method of making the same.
A carrier and a propane dehydrogenation catalyst were prepared according to the method of example 1, except that during the impregnation process for preparing the propane dehydrogenation catalyst, NaNO was not added3Adding only 0.133gH2PtCl6·6H2O and 0.295g SnCl4·5H2And O, loading an active component Pt and a metal auxiliary agent Sn on the spherical double mesoporous molecular sieve silica gel composite material which is taken as a carrier after thermal activation by a co-impregnation method, thereby preparing the propane dehydrogenation catalyst Cat-D-4, wherein the content of the Pt component calculated by Pt element is 0.5 weight percent, the content of the Sn component calculated by Sn element is 1 weight percent and the rest is the carrier based on the total weight of the propane dehydrogenation catalyst Cat-D-4).
Comparative example 5
A carrier and a propane dehydrogenation catalyst were prepared according to the method of example 1, except that there was no spray-drying step in the preparation of the carrier, and a Pt component, a Sn component, and a Na component were supported on a spherical double mesoporous molecular sieve silica gel composite as a carrier only by the impregnation method, thereby preparing a propane dehydrogenation catalyst Cat-D-5.
Example 2
This example illustrates a propane dehydrogenation catalyst and a method for its preparation.
(1) Preparation of the support
1.46g (1X 10)-4mol) template F108, 6.96g (0.04mol) of K2SO4Stirring with 60g hydrochloric acid solution with 2(2N) equivalent concentration at 38 deg.C until F108 is completely dissolved;
adding 3.1g (0.014mol) of ethyl orthosilicate into the solution, stirring at 38 ℃ for 15min, and standing at 38 ℃ for 24 h;
then transferring the mixture into a reaction kettle with an agate inner lining, crystallizing the mixture for 30 hours at the temperature of 120 ℃, then filtering the mixture, washing the mixture for 4 times by using deionized water, and then carrying out suction filtration to obtain a mesoporous molecular sieve filter cake A2.
Mixing 15 wt% of water glass, 12 wt% of sulfuric acid solution and glycerol in a weight ratio of 4: 1:1, then adjusting the pH value to 2 with sulfuric acid with the concentration of 98 weight percent, then carrying out suction filtration on the obtained reaction material, and washing the reaction material with distilled water until the content of sodium ions is 0.02 weight percent to obtain a silica gel filter cake B2.
And (3) putting 20g of the prepared filter cake A2, 10g of the prepared filter cake B2 and 10g of binder polyvinyl alcohol into a 100ml ball milling tank together, wherein the ball milling tank is made of polytetrafluoroethylene, grinding balls are made of agate, the diameter of each grinding ball is 3mm, the number of the grinding balls is 1, and the rotating speed is 300 r/min. Sealing the ball milling tank, and carrying out ball milling for 0.5 hour in the ball milling tank at the temperature of 80 ℃ to obtain 38g of solid powder; dissolving the solid powder in 12 g of deionized water, and spray-drying at 250 ℃ at the rotating speed of 11000 r/min; calcining the product obtained after spray drying in a muffle furnace at 600 ℃ for 12 hours, and removing the template agent and the binder to obtain 35g of the spherical double mesoporous molecular sieve silica gel composite material C2.
(2) Preparation of propane dehydrogenation catalyst
Calcining 35g of the spherical double mesoporous molecular sieve silica gel composite material C2 obtained in the step (1) at 400 ℃ for 10h under the protection of nitrogen for thermal activation treatment, and removing hydroxyl and residual moisture of the spherical double mesoporous molecular sieve silica gel composite material C2;
0.08g H2PtCl6·6H2O、0.207g SnCl4·5H2O and 0.185g NaNO3Dissolving the spherical double mesoporous molecular sieve silica gel composite material subjected to thermal activation treatment in 100ml of deionized water to obtain a mixture solution, soaking the mixture solution at 25 ℃ for 5 hours, evaporating solvent water in a system by using a rotary evaporator to obtain a solid product, placing the solid product in a drying box at the temperature of 120 ℃, drying the solid product for 3 hours, then placing the dried solid product in a muffle furnace at the temperature of 600 ℃, and roasting the dried solid product for 6 hours to obtain the propane dehydrogenation catalyst Cat-2 (based on the total weight of the propane dehydrogenation catalyst Cat-2, the content of the Pt component in terms of the Pt element is 0.3 wt%, the content of the Sn component in terms of the Sn element is 0.7 wt%, the content of the Na component in terms of the Na element is 0.5 wt%, and the balance is a carrier).
Table 2 shows the pore structure parameters of the spherical double mesoporous molecular sieve silica gel composite material C2 and the propane dehydrogenation catalyst Cat-2.
TABLE 2
*: the first most probable aperture and the second most probable aperture are separated by a comma: the first most probable aperture and the second most probable aperture are arranged in the order from left to right.
As can be seen from the data of table 2, the specific surface area and pore volume of the spherical double mesoporous molecular sieve silica gel composite material C2 as a carrier were reduced after the main active Pt component, the auxiliary Sn component and the auxiliary Na component were supported, which indicates that the main active Pt component, the auxiliary Sn component and the auxiliary Na component entered the interior of the spherical double mesoporous molecular sieve silica gel composite material C2 during the supporting reaction.
Example 3
This example illustrates a propane dehydrogenation catalyst and a method for its preparation.
(1) Preparation of the support
1.46g (1X 10)-4mol) template F108, 3.48g (0.02mol) of K2SO4Stirring with 60g hydrochloric acid solution with 2(2N) equivalent concentration at 38 deg.C until F108 is completely dissolved;
adding 2.1g (0.01mol) of tetraethoxysilane into the solution, stirring at 35 ℃ for 15min, and standing at 35 ℃ for 20 h;
then transferring the mixture into a reaction kettle with an agate inner lining, crystallizing the mixture for 20 hours at 90 ℃, then filtering the mixture, washing the mixture for 4 times by using deionized water, and then carrying out suction filtration to obtain a mesoporous molecular sieve filter cake A3.
Mixing 15 wt% of water glass, 12 wt% of sulfuric acid solution and glycerol in a weight ratio of 6:1:1, and then the reaction mixture was subjected to a contact reaction at 20 ℃ for 3 hours, followed by adjusting the pH to 4 with sulfuric acid having a concentration of 98% by weight, and then the resulting reaction mass was subjected to suction filtration and washed with distilled water until the sodium ion content was 0.02% by weight, to obtain a silica gel cake B3.
And (3) putting 20g of the prepared filter cake A3, 30g of the prepared filter cake B3 and 10g of binder polyvinyl alcohol into a 100ml ball milling tank together, wherein the ball milling tank is made of polytetrafluoroethylene, grinding balls are made of agate, the diameter of each grinding ball is 3mm, the number of the grinding balls is 1, and the rotating speed is 550 r/min. Sealing the ball milling tank, and carrying out ball milling for 10 hours in the ball milling tank at the temperature of 40 ℃ to obtain 55g of solid powder; dissolving the solid powder in 30g of deionized water, and spray-drying at 150 ℃ at the rotating speed of 13000 r/min; calcining the product obtained after spray drying in a muffle furnace at 450 ℃ for 7 hours, and removing the template agent and the binder to obtain 53g of spherical double mesoporous molecular sieve silica gel composite material C3.
(2) Preparation of propane dehydrogenation catalyst
Calcining 53g of spherical double mesoporous molecular sieve silica gel composite material C3 obtained in the step (1) at 400 ℃ for 10h under the protection of nitrogen to carry out thermal activation treatment, and removing hydroxyl and residual moisture of the spherical double mesoporous molecular sieve silica gel composite material C3;
0.08g H2PtCl6·6H2O、0.207g SnCl4·5H2O and 0.185g NaNO3Dissolving the spherical double mesoporous molecular sieve silica gel composite material subjected to thermal activation treatment in 100ml of deionized water to obtain a mixture solution, soaking the mixture solution at 30 ℃ for 5 hours, evaporating solvent water in a system by using a rotary evaporator to obtain a solid product, placing the solid product in a drying box at the temperature of 150 ℃, drying the solid product for 3 hours, then placing the dried solid product in a muffle furnace at the temperature of 650 ℃, and roasting the dried solid product for 5 hours to obtain the propane dehydrogenation catalyst Cat-3 (based on the total weight of the propane dehydrogenation catalyst Cat-3, the content of the Pt component in terms of Pt is 0.3 wt%, the content of the Sn component in terms of Sn element is 0.7 wt%, the content of the Na component in terms of Na element is 0.5 wt%, and the balance is a carrier).
Table 3 shows the pore structure parameters of the spherical double mesoporous molecular sieve silica gel composite material C3 and the propane dehydrogenation catalyst Cat-3.
TABLE 3
*: the first most probable aperture and the second most probable aperture are separated by a comma: the first most probable aperture and the second most probable aperture are arranged in the order from left to right.
As can be seen from the data of table 3, the specific surface area and pore volume of the spherical double mesoporous molecular sieve silica gel composite material C3 as a carrier were reduced after the main active Pt component, the auxiliary Sn component and the auxiliary Na component were supported, which indicates that the main active Pt component, the auxiliary Sn component and the auxiliary Na component entered the interior of the spherical double mesoporous molecular sieve silica gel composite material C3 during the supporting reaction.
Experimental example 1
This example is intended to illustrate the preparation of propylene using the propane dehydrogenation catalyst of the present invention
0.5g of propane dehydrogenation catalyst Cat-1 was charged into a fixed bed quartz reactor, the reaction temperature was controlled at 610 ℃, the reaction pressure was 0.1MPa, and the molar ratio of propane: the molar ratio of hydrogen is 1:1, the reaction time is 50h, and the mass space velocity of propane is 3h-1. Propane conversion and propylene selectivity are shown in table 4.
Experimental examples 2 to 3
Propane dehydrogenation was carried out to produce propylene in accordance with the procedure of experimental example 1, except that the propane dehydrogenation catalyst Cat-1 was replaced with the propane dehydrogenation catalyst Cat-2 and the propane dehydrogenation catalyst Cat-3, respectively. Propane conversion and propylene selectivity are shown in table 4.
Experimental comparative examples 1 to 5
Propane dehydrogenation was carried out to produce propylene in accordance with the procedure of Experimental example 1, except that the propane dehydrogenation catalyst Cat-D-1, the propane dehydrogenation catalyst Cat-D-2, the propane dehydrogenation catalyst Cat-D-3, the propane dehydrogenation catalyst Cat-D-4 and the propane dehydrogenation catalyst Cat-D-5 were used in place of the propane dehydrogenation catalyst Cat-1, respectively. Propane conversion and propylene selectivity are shown in table 4.
TABLE 4
It can be seen from table 4 that the propane dehydrogenation catalyst prepared by using the spherical double mesoporous molecular sieve silica gel composite material of the present invention has high compressive strength, and when the catalyst is used in a reaction for preparing propylene by propane dehydrogenation, a high propane conversion rate and propylene selectivity can be obtained after 50 hours of reaction, which indicates that the propane dehydrogenation catalyst of the present invention not only has good catalytic performance, but also has excellent stability.
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. The propane dehydrogenation catalyst is characterized by comprising a carrier, and a Pt component, a Sn component and a Na component which are loaded on the carrier, wherein the carrier is a spherical double mesoporous molecular sieve silica gel composite material, the spherical double mesoporous molecular sieve silica gel composite material contains silica gel and a mesoporous molecular sieve with a three-dimensional cubic cage-shaped pore distribution structure, the compressive strength of the spherical double mesoporous molecular sieve silica gel composite material is 12-16MPa, the average particle size is 40-60 mu m, and the specific surface area is 200-300m2The pore volume is 0.5-1.5mL/g, the pore size distribution is bimodal distribution, and the most probable pore sizes corresponding to the bimodal distribution are 5-15nm and 30-50nm respectively;
wherein the forming method of the carrier comprises the following steps:
(a) mixing and contacting a template agent, potassium sulfate, an acid agent and a silicon source, and crystallizing and filtering the obtained mixture to obtain a filter cake of the mesoporous molecular sieve;
(b) contacting water glass, inorganic acid and glycerol, and filtering a product obtained after the contact to obtain a silica gel filter cake;
(c) mixing the mesoporous molecular sieve filter cake and the silica gel filter cake, adding a binder for ball milling, pulping solid powder obtained after ball milling by using water, then carrying out spray drying, and removing the template agent and the binder in the obtained product.
2. The propane dehydrogenation catalyst of claim 1, wherein the support is present in an amount of 97.5 to 99.3 wt.%, the Pt component is present in an amount of 0.2 to 0.5 wt.% as Pt element, the Sn component is present in an amount of 0.2 to 1.2 wt.% as Sn element, and the Na component is present in an amount of 0.3 to 0.8 wt.% as Na element, based on the total weight of the propane dehydrogenation catalyst;
and/or the compressive strength of the carrier is 14-16MPa, the average particle size is 45-55 mu m, and the specific surface area is 210-250m2Pore volume of 0.8-1.4mL/g, and the most probable pore diameters corresponding to bimodal distribution of 6-12nm and 35-45nm, respectively.
3. The propane dehydrogenation catalyst of claim 1, wherein the weight ratio of the content of the mesoporous molecular sieve and the silica gel is 1: 0.5-1.5.
4. A process for preparing a propane dehydrogenation catalyst, the process comprising: carrying out heat activation on a carrier, then carrying out immersion treatment in a mixed solution containing a Pt component precursor, a Sn component precursor and a Na component precursor, and then sequentially carrying out solvent removal treatment, drying and roasting, wherein the carrier is a spherical double mesoporous molecular sieve silica gel composite material, the spherical double mesoporous molecular sieve silica gel composite material contains silica gel and mesoporous molecular sieves with a three-dimensional cubic cage-shaped pore channel distribution structure, the compressive strength of the spherical double mesoporous molecular sieve silica gel composite material is 12-16MPa, the average particle size is 40-60 mu m, and the specific surface area is 200-300m2The pore volume is 0.5-1.5mL/g, the pore size distribution is bimodal, and the most probable pore sizes corresponding to the bimodal are 5-15nm and 30-50nm respectively;
wherein the forming method of the carrier comprises the following steps:
(a) mixing and contacting a template agent, potassium sulfate, an acid agent and a silicon source, and crystallizing and filtering the obtained mixture to obtain a filter cake of the mesoporous molecular sieve;
(b) contacting water glass, inorganic acid and glycerol, and filtering a product obtained after the contact to obtain a silica gel filter cake;
(c) mixing the mesoporous molecular sieve filter cake and the silica gel filter cake, adding a binder for ball milling, pulping solid powder obtained after ball milling by using water, then carrying out spray drying, and removing the template agent and the binder in the obtained product.
5. The method according to claim 4, wherein the support, the Pt component precursor, the Sn component precursor and the Na component precursor are used in amounts such that the propane dehydrogenation catalyst is prepared in which the support is contained in an amount of 97.5 to 99.3% by weight, the Pt component is contained in an amount of 0.2 to 0.5% by weight in terms of Pt element, the Sn component is contained in an amount of 0.2 to 1.2% by weight in terms of Sn element, and the Na component is contained in an amount of 0.3 to 0.8% by weight in terms of Na element, based on the total weight of the propane dehydrogenation catalyst;
and/or the compressive strength of the carrier is 14-16MPa, the average particle size is 45-55 mu m, and the specific surface area is 210-250m2The pore volume is 0.8-1.4mL/g, and the most probable pore diameters corresponding to the bimodal distribution are 6-12nm and 35-45nm respectively;
and/or, the conditions of thermal activation include: the temperature is 300-900 ℃ and the time is 7-10 h; the conditions of the impregnation treatment include: the temperature is 25-50 ℃ and the time is 2-6 h.
6. The method of claim 4, wherein in step (a), the molar ratio of the templating agent, potassium sulfate, and silicon source is 1: 100-800: 20-200 parts of;
and/or the template agent is triblock copolymer polyoxyethylene-polyoxypropylene-polyoxyethylene, the acid agent is hydrochloric acid, and the silicon source is at least one of ethyl orthosilicate, methyl orthosilicate, propyl orthosilicate, sodium orthosilicate and silica sol;
and/or, the conditions of the mixing contact comprise: the temperature is 25-60 ℃, the time is 10-72h, the pH value is 1-7, and the crystallization conditions comprise: the temperature is 30-150 ℃ and the time is 10-72 h.
7. The production method according to claim 4 or 6, wherein in step (b), the conditions under which the water glass, the inorganic acid and the glycerin are contacted include: the weight ratio of the water glass, the inorganic acid and the glycerol is 3-6:1:1, the temperature is 10-60 ℃, the time is 1-5 hours, and the pH value is 2-4; the inorganic acid is one or more of sulfuric acid, nitric acid and hydrochloric acid;
and/or, in the step (c), the weight ratio of the used amount of the spherical mesoporous molecular sieve filter cake, the used amount of the silica gel filter cake and the used amount of the binder is 1: (0.5-1.5): (0.5-1.5);
and/or, the binder is polyvinyl alcohol;
and/or the template agent and binder removal process comprises the following steps: calcining at 600 ℃ for 8-20 h.
8. A propane dehydrogenation catalyst prepared by the process of any of claims 4-7.
9. A method for producing propylene by propane dehydrogenation, comprising: the dehydrogenation of propane in the presence of a catalyst and hydrogen, characterized in that the catalyst is a propane dehydrogenation catalyst according to any one of claims 1 to 3 and 8.
10. The process according to claim 9, wherein the molar ratio of the amount of propane to the amount of hydrogen is between 0.5 and 1.5: 1;
and/or, the dehydrogenation reaction conditions include: the reaction temperature is 600-650 ℃, the reaction pressure is 0.05-0.2MPa, the reaction time is 40-60h, and the propane mass space velocity is 2-5h-1。
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