CN111085208A - Non-noble metal low-carbon alkane dehydrogenation catalyst with spherical double-mesoporous composite carrier and preparation method and application thereof - Google Patents

Non-noble metal low-carbon alkane dehydrogenation catalyst with spherical double-mesoporous composite carrier and preparation method and application thereof Download PDF

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CN111085208A
CN111085208A CN201811246808.2A CN201811246808A CN111085208A CN 111085208 A CN111085208 A CN 111085208A CN 201811246808 A CN201811246808 A CN 201811246808A CN 111085208 A CN111085208 A CN 111085208A
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noble metal
low
dehydrogenation catalyst
alkane dehydrogenation
mesoporous composite
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亢宇
刘红梅
薛琳
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Sinopec Beijing Research Institute of Chemical Industry
China Petroleum and Chemical Corp
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Sinopec Beijing Research Institute of Chemical Industry
China Petroleum and Chemical Corp
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/74—Iron group metals
    • B01J23/745—Iron
    • 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
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/06—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of zinc, cadmium or mercury
    • 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
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/74—Iron group metals
    • B01J23/755—Nickel
    • B01J35/615—
    • B01J35/635—
    • B01J35/638—
    • B01J35/69—
    • 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
    • B01J37/0018—Addition of a binding agent or of material, later completely removed among others as result of heat treatment, leaching or washing,(e.g. forming of pores; protective layer, desintegrating by heat)
    • 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
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C5/00—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms
    • C07C5/32—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by dehydrogenation with formation of free hydrogen
    • C07C5/327—Formation of non-aromatic carbon-to-carbon double bonds only
    • C07C5/333—Catalytic processes
    • C07C5/3335—Catalytic processes with 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

Abstract

The invention relates to the field of catalysts, and discloses a non-noble metal low-carbon alkane dehydrogenation catalyst, and a preparation method and application thereof. The method for preparing the non-noble metal low-carbon alkane dehydrogenation catalyst comprises the following steps: (a) providing a mesoporous material filter cake; (b) providing a silica gel filter cake; (c) mixing and ball-milling the mesoporous material filter cake and the silica gel filter cake, pulping solid powder obtained after ball-milling with water, then carrying out spray drying, and removing the template agent in the obtained product to obtain a spherical double-mesoporous composite material carrier; (d) and (2) dipping the spherical double-mesoporous composite material carrier in a solution containing an active non-noble metal component precursor, and then sequentially carrying out solvent removal treatment, drying and roasting. The non-noble metal low-carbon alkane dehydrogenation catalyst obtained by the invention can achieve better dehydrogenation activity, selectivity and stability in the preparation of low-carbon olefin by low-carbon alkane dehydrogenation.

Description

Non-noble metal low-carbon alkane dehydrogenation catalyst with spherical double-mesoporous composite carrier and preparation method and application thereof
Technical Field
The invention relates to the field of catalysts, in particular to a non-noble metal low-carbon alkane dehydrogenation catalyst with a spherical double-mesoporous composite carrier, a preparation method of the non-noble metal low-carbon alkane dehydrogenation catalyst, a non-noble metal low-carbon alkane dehydrogenation catalyst prepared by the method, and a method for preparing low-carbon olefin by low-carbon alkane dehydrogenation.
Background
The low-carbon olefin (mainly comprising propylene, isobutene and the like) is a very important organic chemical raw material. The propylene can be used for producing chemical products such as polypropylene, acrolein, acrylic acid, glycerol, isopropanol, polyacrylonitrile, butanol and octanol; isobutene is used for preparing various organic raw materials and fine chemicals such as methyl tert-butyl ether, butyl rubber, methyl ethyl ketone, polyisobutylene, methacrylate, isoprene, tert-butyl phenol, tert-butyl amine, 1, 4-butanediol, ABS resin and the like. At present, propylene and isobutene are mainly derived from refinery by-products and steam cracking co-production. Recently, with the rapid development of coal chemical industry, the realization of MTP process has effectively increased the source of propylene. Even so, the gaps in propylene and isobutylene are still not made up. In the above background, dehydrogenation of lower alkanes makes one of the important ways to increase the sources of propylene and isobutylene. The dehydrogenation technology of the low-carbon alkane is mainly divided into direct dehydrogenation and oxidative dehydrogenation, wherein the direct dehydrogenation technology has realized industrial production in 90 years in the 20 th century. The low-carbon alkane direct dehydrogenation catalyst for industrial application mainly comprises a Cr series catalyst and a Pt series catalyst. There are a Catofin process developed by Lummus, a Linde process developed by Linde & BASF, and an FBD process developed by Snamprogetti using Cr-series catalysts, an Oleflex process developed by UOP, and a Star process developed by Phillips using Pt-series catalysts. The Cr-based catalyst is low in price but easy to deactivate, and the heavy metal chromium causes serious environmental pollution. Relatively speaking, the Pt catalyst has high activity, good selectivity and stability, but the noble metal platinum is expensive and the catalyst cost is high. Therefore, until now, the development of non-noble metal based low-carbon alkane dehydrogenation catalysts with higher activity, better stability and environmental friendliness is still the main research direction for producing low-carbon olefins.
In 1998, Zhao Dongyuan et al successfully synthesized the mesoporous silica molecular sieve SBA-15(Science, 1998,279(5350): 548-552). The SBA-15 mesoporous molecular sieve is obtained by hydrothermal synthesis under an acidic condition by using a triblock copolymer as a template agent and tetraethoxysilane as a silicon source. Compared with the common alumina carrier, the SBA-15 has higher specific surface area and is more beneficial to the dispersion of active components. In addition, different from other mesoporous materials, the template used for preparing SBA-15 does not cause environmental pollution. Therefore, the SBA-15 and the modified material thereof are suitable to be used as carriers of non-noble metal series low-carbon alkane dehydrogenation catalysts.
However, the conventional SBA-15 molecular sieve material still has an acid site, and when the material is used as a catalyst carrier, the defects of easy carbon deposition and the like still exist, and the selectivity of a target product is to be further improved.
Therefore, how to select a suitable carrier with excellent performance and cooperatively load a suitable active component, so as to improve the reaction performance of the non-noble metal-based low-carbon alkane dehydrogenation catalyst is an urgent problem in the field of low-carbon olefin preparation by low-carbon alkane dehydrogenation.
Disclosure of Invention
The invention aims to overcome the defects of high cost and environmental pollution easily caused by non-noble metal low-carbon alkane dehydrogenation catalysts in the prior art, and provides a non-noble metal low-carbon alkane dehydrogenation catalyst and a preparation method thereof.
In order to achieve the above object, the present invention provides a method for preparing a non-noble metal-based light alkane dehydrogenation catalyst, comprising the steps of:
(a) in the presence of a template agent, contacting tetraethoxysilane with ammonia water, and filtering a mixture obtained after the contact to obtain a mesoporous material filter cake;
(b) contacting water glass with inorganic acid, and filtering a product obtained after the contact to obtain a silica gel filter cake;
(c) mixing and ball-milling the mesoporous material filter cake and the silica gel filter cake, pulping solid powder obtained after ball-milling with water, then carrying out spray drying, and removing the template agent in the obtained product to obtain a spherical double-mesoporous composite material carrier;
(d) dipping the spherical double-mesoporous composite material carrier obtained in the step (c) in a solution containing an active non-noble metal component precursor, and then sequentially carrying out solvent removal treatment, drying and roasting.
The invention provides a non-noble metal-based low-carbon alkane dehydrogenation catalyst prepared by the method.
The third aspect of the present invention provides an application of the non-noble metal based low carbon alkane dehydrogenation catalyst prepared by the foregoing method in low carbon alkane dehydrogenation to prepare low carbon olefin, wherein the method for preparing low carbon olefin by low carbon alkane dehydrogenation comprises: in the presence of a catalyst, the low-carbon alkane is subjected to dehydrogenation reaction.
The carrier structure of the dehydrogenation catalyst (including physical structures such as specific surface area, pore volume and pore size distribution, and chemical structures such as surface acid sites and electronic properties) not only has an important influence on the dispersion of active components, but also directly influences mass transfer and diffusion in the reaction process. Thus, the catalytic properties of heterogeneous catalysts, such as activity, selectivity and stability, depend both on the catalytic characteristics of the active component and on the characteristics of the catalyst support. Currently, the non-noble metal low-carbon alkane dehydrogenation catalyst used in industry generally uses alumina as a carrier. However, most commercially available activated aluminas have a low specific surface area and are too acidic with too many surface hydroxyl groups. When the aluminum oxide is used as a carrier to prepare the dehydrogenation catalyst, the surface of the catalyst is easy to deposit carbon in the reaction process, and the rapid inactivation is caused.
The inventor of the invention discovers through research that the non-noble metal low-carbon alkane dehydrogenation catalyst with good performance can be obtained by using the spherical double-mesoporous composite material obtained by the method provided by the invention as a carrier and loading a non-noble metal component as an active component.
Compared with the prior art, the technical scheme of the invention has the following advantages:
(1) the non-noble metal low-carbon alkane dehydrogenation catalyst does not contain noble metal, so that the preparation cost of the dehydrogenation catalyst can be effectively reduced;
(2) the non-noble metal low-carbon alkane dehydrogenation catalyst provided by the preferred scheme of the invention does not contain chromium element, and is environment-friendly;
(3) in the non-noble metal low-carbon alkane dehydrogenation catalyst, the main component of the carrier is SiO2The surface has no acid sites, so that the carbon deposition risk in the reaction process of preparing olefin by dehydrogenating low-carbon alkane can be obviously reduced, and the selectivity of a target product is improved;
(4) the dehydrogenation catalyst shows good catalytic performance when used for preparing olefin by directly dehydrogenating low-carbon alkane, and has high alkane conversion rate, high target product selectivity and good catalyst stability;
(5) the preparation method of the non-noble metal low-carbon alkane dehydrogenation catalyst has the advantages of simple process, easily controlled conditions and good product repeatability.
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 the spherical double mesoporous composite material support of example 1;
FIG. 2A is an SEM scanning electron micrograph of the microstructure of the spherical double mesoporous composite support of example 1 at 50 times magnification;
FIG. 2B is an SEM scanning electron micrograph of the microscopic morphology of the spherical mesoporous dual mesoporous composite support of example 1 at a magnification of 100 times;
FIG. 3 is a pore size distribution curve of the spherical dual mesoporous composite support of example 1;
fig. 4 is a particle size distribution curve of the spherical dual mesoporous composite support 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.
As described above, the first aspect of the present invention provides a method for preparing a non-noble metal-based low-carbon alkane dehydrogenation catalyst, which comprises the following steps:
(a) in the presence of a template agent, contacting tetraethoxysilane with ammonia water, and filtering a mixture obtained after the contact to obtain a mesoporous material filter cake;
(b) contacting water glass with inorganic acid, and filtering a product obtained after the contact to obtain a silica gel filter cake;
(c) mixing and ball-milling the mesoporous material filter cake and the silica gel filter cake, pulping solid powder obtained after ball-milling with water, then carrying out spray drying, and removing the template agent in the obtained product to obtain a spherical double-mesoporous composite material carrier;
(d) dipping the spherical double-mesoporous composite material carrier obtained in the step (c) in a solution containing an active non-noble metal component precursor, and then sequentially carrying out solvent removal treatment, drying and roasting.
In the formation process of the non-noble metal low-carbon alkane dehydrogenation catalyst, the mesoporous material filter cake is a mesoporous molecular sieve material with a two-dimensional hexagonal pore channel distribution structure.
In the process of forming the spherical double-mesoporous composite material carrier, the pore size distribution is controlled to be bimodal distribution mainly by controlling the composition of the mesoporous material filter cake and the silica gel filter cake, the spherical double-mesoporous composite material carrier is enabled to have a double-pore distribution structure, the micro-morphology of the spherical double-mesoporous composite material carrier is controlled to be spherical by controlling a forming method (namely, the mesoporous material filter cake and the silica gel filter cake are mixed and ball-milled firstly, then the obtained solid powder is slurried with water and then is spray-dried), so that the mesoporous molecular sieve material with a two-dimensional hexagonal special pore channel distribution structure and the spherical double-mesoporous composite material carrier with the advantages of the spherical carrier can be synthesized by using common and easily-obtained raw materials under simple operation conditions, and the carrier has the porous structure, the large specific surface area and the porous structure of the mesoporous molecular sieve material with a two-dimensional hexagonal pore channel distribution structure, The pore volume is large, and the non-noble metal low-carbon alkane dehydrogenation catalyst with no acidity on the surface, good dehydrogenation activity, high selectivity, strong stability and good carbon deposition resistance can be prepared by impregnating and loading active non-noble metal components.
According to the present invention, the amount of each substance can be selected and adjusted within a wide range in the process of preparing the mesoporous material filter cake. For example, in step (a), the tetraethoxysilane, the template agent, ammonia in ammonia water and water can be used in a molar ratio of 1: 0.1-1: 0.1-5: 100-200, preferably 1: 0.2-0.5: 1.5-3.5: 120-180.
According to the invention, in order to make the obtained mesoporous material filter cake have a two-dimensional hexagonal pore channel distribution structure, the type of the template agent is preferably Cetyl Trimethyl Ammonium Bromide (CTAB).
According to the invention, the conditions for contacting the ethyl orthosilicate with ammonia water may comprise: the temperature is 25-100 ℃, and the time is 10-72 hours; preferably, the conditions for contacting the tetraethoxysilane and the ammonia solution can comprise: the temperature is 30-100 ℃ and the time is 20-40 hours.
The mode of contacting the template agent, the tetraethoxysilane and the ammonia water is not particularly limited, for example, the template agent, the tetraethoxysilane and the ammonia water solution can be simultaneously mixed, or any two of the template agent, the tetraethoxysilane and the ammonia water solution can be mixed, and other components can be added and uniformly mixed. According to a preferred embodiment, the template agent and the tetraethoxysilane are added into the ammonia water solution together and mixed evenly. The contact mode is that the template agent and the tetraethoxysilane are added into an ammonia water solution and mixed evenly, the obtained mixture is placed into a water bath with the temperature of 25-100 ℃ to be stirred until the mixture is dissolved, then the temperature is kept unchanged, and the mixture is stirred and reacts for 20-40 hours.
According to the method for preparing the non-noble metal-based low-carbon alkane dehydrogenation catalyst, in the step (b), the conditions for contacting the water glass with the inorganic acid can comprise: 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 further facilitate uniform mixing between the substances, the contact of the water glass with the mineral acid 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 inorganic acid 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.
In addition, in the above process for preparing the mesoporous material filter cake and the silica gel filter cake, the process for obtaining the filter cake by filtering 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 material 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 the step (c), the amount of the mesoporous material filter cake and the silica gel filter cake may be selected according to the components of the spherical double mesoporous composite material carrier to be obtained, and preferably, the silica gel filter cake may be used in an amount of 1 to 200 parts by weight, preferably 50 to 150 parts by weight, based on 100 parts by weight of the mesoporous material filter cake.
According to the invention, the specific operation method and conditions of the ball milling are based on that the structure of the mesoporous material is not damaged or basically not damaged and the silica gel enters the pore canal of the mesoporous material. 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 invention, the specific operation method and conditions of the spray drying are preferably as follows: adding a slurry prepared from the solid powder and water into an atomizer, and rotating at a high speed to realize spray drying. Wherein the spray drying conditions may include: 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.
According to the invention, the method for removing the template agent is preferably a calcination method. The conditions for removing the template agent may include: the temperature is 300-600 ℃, preferably 350-550 ℃, and most preferably 500 ℃; the time is 10 to 80 hours, preferably 20 to 30 hours, most preferably 24 hours.
According to the invention, in the step (d), the active non-noble metal component loaded on the spherical double-mesoporous composite material carrier can enter the pore channel of the spherical double-mesoporous composite material carrier by adopting an impregnation mode and depending on the capillary pressure of the pore channel structure of the carrier, and meanwhile, the active non-noble metal component can be adsorbed on the surface of the spherical double-mesoporous composite material carrier until the active non-noble metal component reaches adsorption balance on the surface of the carrier. The dipping treatment may be a co-dipping treatment or a stepwise dipping 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 composite material carrier is mixed and contacted with a solution containing an active non-noble metal component precursor, the dipping temperature can be 25-50 ℃, and the dipping time can be 2-6 h.
According to the invention, in the step (d), the spherical double mesoporous composite material carrier and the solution containing the active non-noble metal component precursor are preferably used in such amounts that the content of the active non-noble metal component in the prepared non-noble metal based low-carbon alkane dehydrogenation catalyst is 2-40 wt%, preferably 3-30 wt%, based on the total weight of the non-noble metal based low-carbon alkane dehydrogenation catalyst; the content of the spherical double mesoporous composite material carrier is 60-98 wt%, and preferably 70-97 wt%.
According to the invention, in step (d), the solution containing precursors of active non-noble metal components is preferably at least one of a soluble salt solution of iron, nickel, zinc, molybdenum, tungsten, manganese, tin and copper.
According to the present invention, the concentration of the soluble salt of the active non-noble metal component in the solution containing the precursor of the active non-noble metal component is not particularly limited, and for example, the concentration of the soluble salt of the active non-noble metal component in the solution containing the precursor of the active non-noble metal component may be 0.04 to 0.25 mol/L. The soluble salt in the present invention preferably means a water-soluble salt.
According to the invention, when the concentration of the solution containing the active non-noble metal component precursor is in the above range, the amount of the solution containing the active non-noble metal component precursor can be 50-150 mL.
According to the present invention, in the step (d), the solvent removing treatment may be carried out by a method conventional in the art, for example, a rotary evaporator may be used to remove the solvent in the system.
According to the present invention, in the step (d), the drying may be performed in a drying oven, and the firing may be performed in a muffle furnace. The drying conditions may include: the temperature is 60-160 ℃, preferably 80-130 ℃, and the time is 1-20h, preferably 2-5 h; the conditions for the firing may include: the temperature is 450-700 ℃, preferably 500-650 ℃, and the time is 2-15h, preferably 3-10 h.
According to the invention, in the preparation method of the non-noble metal-based low-carbon alkane dehydrogenation catalyst, due to the introduction of the composite material with the two-dimensional hexagonal special pore channel distribution structure in the preparation process of the carrier, the carrier of the non-noble metal-based low-carbon alkane dehydrogenation catalyst can obtain the characteristics of porous structure, large specific surface area and large pore volume of the mesoporous molecular sieve material, so that the carrier of the non-noble metal-based low-carbon alkane dehydrogenation catalyst is particularly favorable for good dispersion of the active non-noble metal component on the surface of the carrier, the active non-noble metal component is effectively prevented from being deeply reduced and converted into pure metal in the catalytic process, the occurrence of side reactions such as hydrogenolysis and the like in the dehydrogenation process is inhibited, and the catalytic activity of the obtained dehydrogenation catalyst and the selectivity of a target dehydrogenation product are further improved, therefore, in the non-noble metal-based, The nickel, zinc, molybdenum, tungsten, manganese, tin and copper and respective oxide active components thereof can obtain higher catalytic activity, and are particularly suitable for dehydrogenation reaction of low-carbon alkane.
The invention also provides a non-noble metal low-carbon alkane dehydrogenation catalyst prepared by the method.
According to the invention, the non-noble metal series low-carbon alkaneThe dehydrogenation catalyst comprises a carrier and an active non-noble metal component loaded on the carrier, wherein the active non-noble metal component is non-noble metal and/or non-noble metal oxide, the carrier is a spherical double-mesoporous composite material carrier, the spherical double-mesoporous composite material carrier contains a mesoporous molecular sieve material with a two-dimensional hexagonal pore channel distribution structure, the average particle size of the spherical double-mesoporous composite material carrier is 30-60 mu m, and the specific surface area of the spherical double-mesoporous composite material carrier is 200-650m2The 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 1.5-15nm and 16-50nm respectively.
According to the invention, in the non-noble metal low-carbon alkane dehydrogenation catalyst, the spherical double-mesoporous composite material carrier serving as the carrier has a special two-dimensional hexagonal pore channel distribution structure, the average particle size of particles is measured by adopting a laser particle size distribution instrument, and the specific surface area, the pore volume and the most probable pore diameter are measured by a nitrogen adsorption method. In the present invention, the particle size refers to the particle size of the raw material particles, and is expressed by the diameter of the sphere when the raw material particles are spherical, by the side length of the cube when the raw material particles are cubic, and by the mesh size of the screen that can sieve out the raw material particles when the raw material particles are irregularly shaped.
According to the invention, the spherical double-mesoporous composite material carrier can ensure that the spherical double-mesoporous composite material carrier is not easy to agglomerate by controlling the particle size of the spherical double-mesoporous composite material carrier within the range, and the conversion rate of reaction raw materials in the reaction process of preparing low-carbon olefin by dehydrogenating low-carbon alkane can be improved by using the supported catalyst prepared by using the spherical double-mesoporous composite material carrier as the carrier. When the specific surface area of the spherical double mesoporous composite material carrier 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 composite material carrier is more than 650m2When the volume of the catalyst is more than 1.5mL/g, the supported catalyst prepared by using the catalyst as a carrier is easy to agglomerate in the reaction process of preparing low-carbon olefin by dehydrogenating the low-carbon alkane, so that the influence on the low-carbon alkaneThe conversion rate of reaction raw materials in the reaction process of preparing low-carbon olefin by dehydrogenation.
Preferably, the average particle diameter of the spherical double mesoporous composite material carrier is 35-60 μm, and the specific surface area is 200-400m2The pore volume is 0.8-1.4mL/g, the pore size distribution is bimodal, and the most probable pore sizes corresponding to the bimodal are 1.8-12nm and 18-40nm respectively.
According to the invention, the content of the active non-noble metal component calculated by the active metal element oxide is 2-40 wt%, preferably 3-30 wt% based on the total weight of the non-noble metal-based low-carbon alkane dehydrogenation catalyst; the content of the spherical double mesoporous composite material carrier is 60-98 wt%, and preferably 70-97 wt%.
According to the present invention, in the non-noble metal-based low-carbon alkane dehydrogenation catalyst, the active non-noble metal component is at least one of iron, nickel, zinc, molybdenum, tungsten, manganese, tin, copper, and oxides thereof.
More preferably, the average particle size of the non-noble metal-based low-carbon alkane dehydrogenation catalyst is 30-60 μm, and the specific surface area is 180-400m2The pore volume is 0.6-1.2mL/g, the pore size distribution is bimodal, and the most probable pore sizes corresponding to the bimodal are 1.8-12nm and 18-40nm respectively.
According to the present invention, the spherical double mesoporous composite material support may further contain silica introduced through silica gel. The term "silica introduced through silica gel" refers to a silica component which is brought into the finally prepared spherical double-mesoporous composite material carrier by using silica gel as a preparation raw material during the preparation process of the spherical double-mesoporous composite material carrier. In the spherical dual mesoporous composite support, the content of the silica introduced through the silica gel may be 1 to 200 parts by weight, preferably 50 to 150 parts by weight, with respect to 100 parts by weight of the mesoporous molecular sieve material having a two-dimensional hexagonal pore distribution structure.
According to the invention, the mesoporous molecular sieve material with the two-dimensional hexagonal pore channel distribution structure can be prepared according to the method.
As mentioned above, the present invention further provides an application of the non-noble metal based low carbon alkane dehydrogenation catalyst prepared by the foregoing method in low carbon alkane dehydrogenation to prepare low carbon olefin, wherein the method for preparing low carbon olefin by low carbon alkane dehydrogenation comprises: in the presence of a catalyst, the low-carbon alkane is subjected to dehydrogenation reaction.
According to the application of the non-noble metal-based low-carbon alkane dehydrogenation catalyst in the preparation of low-carbon olefin through low-carbon alkane dehydrogenation, the low-carbon alkane refers to straight-chain or branched-chain alkane with the carbon atom number of 2-4, correspondingly, the low-carbon olefin is straight-chain or branched-chain monoolefin with the carbon atom number of 2-4, preferably, the low-carbon alkane is propane or isobutane, and correspondingly, the low-carbon olefin is propylene or isobutene. The conditions for dehydrogenation reaction of the low-carbon alkane preferably comprise: the reaction temperature is 500-650 ℃, the reaction pressure is 0.05-0.2MPa, and the mass space velocity of the low-carbon alkane is 1-10h-1。
According to a preferred embodiment of the present invention, when the lower alkane is propane, it is preferable to add an inert gas as a diluent to the reaction raw material to reduce the partial pressure of propane in the reaction system in order to increase the conversion of propane and prevent coking of the catalyst. Wherein the inert gas comprises at least one of nitrogen, helium and argon. The molar ratio of the amount of propane to the amount of inert gas is 0.2-5: 1. the conditions of the dehydrogenation reaction may 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。
According to another preferred embodiment of the present invention, when the low-carbon alkane is isobutane, in order to increase the isobutane conversion rate and prevent the catalyst from coking, an inert gas is preferably added to the reaction raw material as a diluent to reduce the partial pressure of isobutane in the reaction system. Wherein the inert gas comprises at least one of nitrogen, helium and argon. The molar ratio of the consumption of the isobutane to the consumption of the inert gas is 0.2-5.0: 1. the conditions of the dehydrogenation reaction may include: the reaction temperature is 550-650 ℃, the reaction pressure is 0.05-0.2MPa, the reaction time is 20-40h, and the mass space velocity of isobutane is 2-5h-1。
The present invention will be described in detail below by way of examples.
In the following examples and comparative examples, the 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 adsorption apparatus, available from Micromeritics, USA, and the sample was degassed at 350 ℃ in vacuum for 4 hours before measurement, and the BET method was used to calculate the specific surface area of the sample, and the BJH model was used to calculate the pore volume; the drying box is produced by Shanghai-Hengchun scientific instruments Co., Ltd, and is of a type DHG-9030A; the muffle furnace is manufactured by CARBOLITE corporation, and is of a model CWF 1100; the ultrasonic generator is a KQ-300GTDV high-frequency constant-temperature numerical control ultrasonic cleaner produced by ultrasonic instruments Limited in Kunshan, the ultrasonic frequency is 80kHz, and the working voltage is 220V; the rotary evaporator is produced by German IKA company, and the model is RV10 digital; the active component load capacity of the low-carbon alkane dehydrogenation catalyst is measured on a wavelength dispersion X-ray fluorescence spectrometer which is purchased from Parnacidae, Netherlands and has the model of Axios-Advanced; 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 low-carbon alkane is ═ (amount of low-carbon alkane used-content of low-carbon alkane in the reaction product) ÷ amount of low-carbon alkane used × 100%;
selectivity (%) of the low carbon olefin is the amount of low carbon alkane consumed to produce the low carbon olefin ÷ total consumption of the low carbon alkane × 100%.
Example 1
This example is used to illustrate a non-noble metal based low-carbon alkane dehydrogenation catalyst and a method for preparing the same.
(1) Preparation of spherical double-mesoporous composite material carrier
Adding hexadecyl trimethyl ammonium bromide and ethyl orthosilicate into an ammonia water solution with the concentration of 25 weight percent, wherein the adding amount of the ethyl orthosilicate is 1g, and the mol ratio of ammonia to water in the ethyl orthosilicate, the hexadecyl trimethyl ammonium bromide and the ammonia water is 1: 0.37: 2.8: 142 and stirred at 80 ℃ until dissolved, then the obtained solution is filtered and washed 4 times with deionized water, and then filtered by suction to obtain a filter cake a1 of the mesoporous molecular sieve material with a two-dimensional hexagonal pore structure.
Mixing 15 wt% water glass and 12 wt% sulfuric acid solution in a weight ratio of 5:1, reacting at 30 deg.c for 2 hr, regulating the pH to 3 with 98 wt% sulfuric acid, suction filtering the obtained reaction material, and washing with distilled water to sodium ion content of 0.02 wt% to obtain silica gel filter cake B1.
And (3) putting 20g of the prepared filter cake A1 and 10g of the prepared filter cake B1 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 30g of deionized water, and spray-drying at 200 ℃ at a rotating speed of 12000 r/min; calcining the spray-dried product in a muffle furnace at 500 ℃ for 24 hours, and removing the template agent to obtain 30g of spherical double-mesoporous composite material carrier C1 with a two-dimensional hexagonal pore channel distribution structure.
(2) Preparation of non-noble metal low-carbon alkane dehydrogenation catalyst
3.25g of iron sulfate (Fe)2(SO4)3) Dissolving in 100ml of deionized water, mixing with 10g of the spherical double mesoporous composite material carrier C1 prepared in the step (1), and continuously stirring and reacting for 5 hours at room temperature. And (4) evaporating the solvent water in the system by using a rotary evaporator to obtain a solid product. The solid product was dried in a drying oven at 110 ℃ for 3 hours. And then roasting the mixture for 6 hours in a muffle furnace at the temperature of 550 ℃ to obtain the non-noble metal low-carbon alkane dehydrogenation catalyst Cat-1.
Measured by an X-ray fluorescence spectrometer, in the non-noble metal system low-carbon alkane dehydrogenation catalyst Cat-1, the iron component is iron oxide (Fe) based on the total weight of the Cat-12O3) Calculated content is 11.5 wt%, sphericalThe content of the double mesoporous composite material carrier C1 was 88.5 wt%.
The spherical double mesoporous composite material carrier C1 and the non-noble metal low-carbon alkane 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 C1, wherein a is an XRD pattern of C1 of the spherical double mesoporous composite material carrier, the abscissa is 2 θ, and the ordinate is intensity, and the XRD pattern a of the spherical double mesoporous composite material carrier C1 has a two-dimensional hexagonal channel structure specific to the mesoporous material, as can be seen from a small-angle spectrum peak appearing in the XRD pattern;
fig. 2A is an SEM (50 times magnification) of C1, fig. 2B is an SEM of C1 (100 times magnification), and fig. 2A and 2B show that the spherical mesoporous composite material carrier C1 is a spherical material with good dispersibility and a particle size of 30 to 60 μm;
FIG. 3 is a graph of pore size distribution of C1, the abscissa is pore size, the unit is nm, it can be seen from the graph that the pore size distribution of the spherical double mesoporous composite material carrier C1 is bimodal distribution, and the most probable pore sizes corresponding to the bimodal distribution are 1.5-15nm and 16-50nm, respectively, and the pore canal distribution is uniform;
FIG. 4 is a graph of the particle size distribution of C1, the abscissa is μm, and it can be seen that the spherical mesoporous composite material carrier C1 has a uniform particle size distribution and an average particle size of 56.9 μm.
Table 1 shows the pore structure parameters of the spherical double-mesoporous composite material carrier C1 and the low-carbon alkane dehydrogenation catalyst Cat-1.
TABLE 1
Sample (I) Specific surface area (m)2/g) Pore volume (ml/g) Most probable aperture*(nm) Particle size (. mu.m)
Vector C1 220 1.4 7.2，33.3 56.9
Catalyst Cat-1 202 1.1 6.1，31.1 56.9
*: 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 sequence from left to right.
As can be seen from the data of table 1, the specific surface area and the pore volume of the spherical double mesoporous composite support are reduced after the Fe component is loaded, which indicates that the Fe component enters the inside of the spherical double mesoporous composite support during the loading reaction.
Example 2
This example is used to illustrate a non-noble metal based low-carbon alkane dehydrogenation catalyst and a method for preparing the same.
(1) Preparation of spherical double-mesoporous composite material carrier
Adding hexadecyl trimethyl ammonium bromide and ethyl orthosilicate into an ammonia water solution with the concentration of 25 weight percent, wherein the adding amount of the ethyl orthosilicate is 1g, and the mol ratio of ammonia to water in the ethyl orthosilicate, the hexadecyl trimethyl ammonium bromide and the ammonia water is 1: 0.5: 3.2: 140 and stirred at 90 ℃ until dissolved, then the obtained solution is filtered and washed 4 times with deionized water, and then filtered by suction to obtain a filter cake a2 of the mesoporous molecular sieve material with a two-dimensional hexagonal pore structure.
Mixing 15 wt% water glass and 12 wt% sulfuric acid solution in a weight ratio of 4:1, reacting at 40 deg.c for 1.5 hr, regulating the pH value to 2 with 98 wt% sulfuric acid, suction filtering the obtained reaction material, and washing with distilled water to sodium ion content of 0.02 wt% to obtain silica gel filter cake B2.
28g of the prepared filter cake A2 and 10g of the prepared filter cake B2 are put 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 12g of deionized water, and spray-drying at 250 ℃ at the rotating speed of 11000 r/min; calcining the spray-dried product in a muffle furnace at 500 ℃ for 15 hours, and removing the template agent to obtain 35g of spherical double-mesoporous composite material carrier C2 with a two-dimensional hexagonal pore channel distribution structure.
(2) Preparation of non-noble metal low-carbon alkane dehydrogenation catalyst
Dissolving 1.06g of nickel sulfate hexahydrate in 100ml of deionized water, mixing with 10g of the spherical double-mesoporous composite material carrier C2 prepared in the step (1), and continuously stirring and reacting for 5 hours at room temperature. And (4) evaporating the solvent water in the system by using a rotary evaporator to obtain a solid product. The solid product was placed in a drying oven at 130 ℃ and dried for 2 hours. Then roasting the mixture for 3 hours in a muffle furnace at the temperature of 650 ℃ to obtain the non-noble metal low-carbon alkane dehydrogenation catalyst Cat-2.
According to the determination of an X-ray fluorescence spectrometer, in the non-noble metal-based low-carbon alkane dehydrogenation catalyst Cat-2, the content of a nickel component in terms of nickel oxide (NiO) is 3 wt%, and the content of a spherical double-mesoporous composite material carrier C2 is 97 wt% based on the total weight of the Cat-2.
The spherical double mesoporous composite material carrier C2 and the non-noble metal low-carbon alkane dehydrogenation catalyst Cat-2 are characterized by an XRD, a scanning electron microscope and an ASAP2020-M + C type adsorption instrument.
Table 2 shows the pore structure parameters of the spherical double mesoporous composite material carrier C2 and the low carbon alkane dehydrogenation catalyst Cat-2.
TABLE 2
Sample (I) Specific surface area (m)2/g) Pore volume (ml/g) Most probable aperture*(nm) Particle size (. mu.m)
Vector C2 232 1.2 5.5，31.7 55
Catalyst Cat-2 205 0.8 3.5，28.5 55
*: 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 sequence from left to right.
As can be seen from the data of table 2, the specific surface area and the pore volume of the spherical double mesoporous composite support are reduced after the Ni component is loaded, which indicates that the Ni component enters the inside of the spherical double mesoporous composite support during the loading reaction.
Example 3
This example is used to illustrate a non-noble metal based low-carbon alkane dehydrogenation catalyst and a method for preparing the same.
(1) Preparation of spherical double-mesoporous composite material carrier
Adding hexadecyl trimethyl ammonium bromide and ethyl orthosilicate into an ammonia water solution with the concentration of 25 weight percent, wherein the adding amount of the ethyl orthosilicate is 1g, and the mol ratio of ammonia to water in the ethyl orthosilicate, the hexadecyl trimethyl ammonium bromide and the ammonia water is 1: 0.3: 3: 150, and stirring the mixture at 90 ℃ until the mixture is dissolved, filtering the obtained solution, washing the solution for 4 times by using deionized water, and performing suction filtration to obtain a filter cake A3 of the mesoporous molecular sieve material with the two-dimensional hexagonal pore structure.
Mixing 15 wt% water glass and 12 wt% sulfuric acid solution in the weight ratio of 6:1, contacting and reacting at 20 deg.c for 3 hr, regulating the pH value to 4 with 98 wt% sulfuric acid, suction filtering the obtained reaction material, and washing with distilled water to sodium ion content of 0.02 wt% to obtain silica gel filter cake B3.
32g of the prepared filter cake A3 and 30g of the prepared filter cake B3 are put 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 spray-dried product in a muffle furnace at 450 ℃ for 70 hours, and removing the template agent to obtain 53g of spherical double-mesoporous composite material carrier C3 with a two-dimensional hexagonal pore channel distribution structure.
(2) Preparation of non-noble metal low-carbon alkane dehydrogenation catalyst
Dissolving 7.28g of zinc nitrate hexahydrate in 100ml of deionized water, mixing with 10g of the spherical double-mesoporous composite material carrier C3 prepared in the step (1), and continuously stirring and reacting for 5 hours at room temperature. And (4) evaporating the solvent water in the system by using a rotary evaporator to obtain a solid product. The solid product was dried in a drying oven at 80 ℃ for 5 hours. Then roasting the mixture for 10 hours in a muffle furnace at the temperature of 500 ℃ to obtain the non-noble metal low-carbon alkane dehydrogenation catalyst Cat-3.
According to the determination of an X-ray fluorescence spectrometer, in the non-noble metal-based low-carbon alkane dehydrogenation catalyst Cat-3, the content of a zinc component in terms of zinc oxide (ZnO) is 16.6 wt%, and the content of a spherical double-mesoporous composite material carrier C3 is 83.4 wt%, based on the total weight of the Cat-3.
The spherical double mesoporous composite material carrier C3 and the non-noble metal low-carbon alkane dehydrogenation catalyst Cat-3 are characterized by an XRD, a scanning electron microscope and an ASAP2020-M + C type adsorption instrument.
Table 3 shows the pore structure parameters of the spherical double mesoporous composite material carrier C3 and the low carbon alkane dehydrogenation catalyst Cat-3.
TABLE 3
Sample (I) Specific surface area (m)2/g) Pore volume (ml/g) Most probable aperture*(nm) Particle size (. mu.m)
Vector C3 218 1.3 7，28.5 52.5
Catalyst Cat-3 190 0.7 4.3，25.1 52.5
*: 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 sequence from left to right.
As can be seen from the data of table 3, the specific surface area and the pore volume of the spherical dual mesoporous composite support are reduced after the Zn component is loaded, which indicates that the Zn component enters the interior of the spherical dual mesoporous composite support during the loading reaction.
Example 4
This example is used to illustrate a non-noble metal based low-carbon alkane dehydrogenation catalyst and a method for preparing the same.
A non-noble metal-based low-carbon alkane dehydrogenation catalyst Cat-4 was prepared by the method of example 1 except that the amount of iron sulfate used in step (2) was 13.75 g.
Measured by an X-ray fluorescence spectrometer, in the non-noble metal system low-carbon alkane dehydrogenation catalyst Cat-4, the iron component is iron oxide (Fe) based on the total weight of the Cat-42O3) The content of the spherical double mesoporous composite material carrier C4 is 35.5 wt%, and the content of the spherical double mesoporous composite material carrier C4 is 64.5 wt%.
The spherical double mesoporous composite material carrier C4 and the non-noble metal low-carbon alkane dehydrogenation catalyst Cat-4 are characterized by an XRD, a scanning electron microscope and an ASAP2020-M + C type adsorption instrument.
Table 4 shows the pore structure parameters of the spherical double mesoporous composite material carrier C4 and the light alkane dehydrogenation catalyst Cat-4.
TABLE 4
Sample (I) Specific surface area (m)2/g) Pore volume (ml/g) Most probable aperture*(nm) Particle size (. mu.m)
Vector C4 220 1.4 7.2，33.3 56.9
Catalyst Cat-4 195 0.7 4.8，28.2 56.9
*: 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 sequence from left to right.
As can be seen from the data of table 4, the specific surface area and the pore volume of the spherical double mesoporous composite support are reduced after the Fe component is loaded, which indicates that the Fe component enters the inside of the spherical double mesoporous composite support during the loading reaction.
Comparative example 1
This comparative example is used to illustrate a reference non-noble metal based low carbon alkane dehydrogenation catalyst and a method of making the same.
The carrier and the low-carbon alkane dehydrogenation catalyst were prepared according to the method of example 1, except that the same weight of alumina carrier was used in the preparation of the carrier instead of the spherical double mesoporous composite carrier C1, thereby preparing the carrier D1 and the low-carbon alkane dehydrogenation catalyst Cat-D-1, respectively.
Comparative example 2
This comparative example is used to illustrate a reference non-noble metal based low carbon alkane dehydrogenation catalyst and a method of making the same.
The carrier and the lower alkane dehydrogenation catalyst were prepared according to the method of example 1, except that the spray drying step was not performed in the preparation of the lower alkane dehydrogenation catalyst, and the Fe component was supported on the carrier only by the impregnation method, thereby preparing the lower alkane dehydrogenation catalyst Cat-D-2.
Comparative example 3
This comparative example is used to illustrate a reference non-noble metal based low carbon alkane dehydrogenation catalyst and a method of making the same.
A low carbon alkane dehydrogenation catalyst was prepared according to the method of example 2, except that, in step (2), 0.8g of chromium sulfate (Cr)2(SO4)3) Replacing the nickel sulfate hexahydrate, namely, taking an active component loaded by the spherical double-mesoporous composite material carrier C2 as a noble metal Cr component to obtain the low-carbon alkane dehydrogenation catalyst Cat-D3.
The chromium component is chromium oxide (Cr) in the low-carbon alkane dehydrogenation catalyst Cat-D3 by the determination of an X-ray fluorescence spectrometer, wherein the total weight of the Cat-D3 is taken as a reference2O3) The content is 3 wt%, and the content of the spherical double mesoporous composite material carrier C2 is 97 wt%.
Test example 1
Test of performance of low-carbon alkane dehydrogenation catalyst in reaction for preparing propylene by propane dehydrogenation
0.5g of the low-carbon alkane dehydrogenation catalysts prepared in the above examples and comparative examples were respectively charged into a fixed bed quartz reactor, and the reaction temperature was controlled600 ℃, reaction pressure 0.1MPa, propane: the molar ratio of helium is 1: 1, the mass space velocity of propane is 5.0h-1The reaction time is 6 h. By Al2O3The reaction product separated by the S molecular sieve column directly enters an Agilent 7890A gas chromatograph provided with a hydrogen flame detector (FID) for on-line analysis. And calculating the conversion rate of propane and the selectivity of propylene according to the reaction data, and judging the stability of the catalyst according to the gradual reduction amplitude of the conversion rate of propane and the selectivity of propylene along with the prolonging of the reaction time in the reaction process.
The test results are shown in Table 5.
TABLE 5
Figure BDA0001840721490000211
Test example 2
Test of performance of low-carbon alkane dehydrogenation catalyst in reaction for preparing isobutene through isobutane dehydrogenation
0.5g of the low-carbon alkane dehydrogenation catalysts prepared in the above examples and comparative examples were respectively loaded into a fixed bed quartz reactor, the reaction temperature was controlled to 580 ℃, the reaction pressure was 0.1MPa, and the reaction pressure was controlled to be isobutane: the molar ratio of helium is 1: 1, the mass space velocity of the isobutane is 2.0h-1The reaction time is 6 h. By Al2O3The reaction product separated by the S molecular sieve column directly enters an Agilent 7890A gas chromatograph provided with a hydrogen flame detector (FID) for on-line analysis. And (3) calculating the isobutane conversion rate and the isobutene selectivity according to the reaction data, and judging the stability of the catalyst according to the gradual reduction amplitude of the isobutane conversion rate and the isobutene selectivity along with the prolonging of the reaction time in the reaction process.
The test results are shown in Table 6.
TABLE 6
Figure BDA0001840721490000221
The results in table 5 show that, when the dehydrogenation catalyst Cat-1 prepared by using the spherical double-mesoporous composite material as the carrier is used for propylene preparation through propane dehydrogenation, the catalytic performance of the catalyst Cat-1 is obviously superior to that of the catalyst Cat-D1 prepared by using alumina as the carrier, the propane conversion rate and the propylene selectivity are obviously improved, and the catalyst stability is also obviously improved. The experimental results of the comparative test examples 1-1 and the test examples 1-D2 show that the spherical double-mesoporous composite material carrier with better performance can be obtained by adopting a spray drying method in the preparation process of the low-carbon alkane dehydrogenation catalyst, and the dehydrogenation catalyst with better performance can be further obtained. In addition, the experimental results of the comparative test examples 1 to 1 and 1 to D3 show that the low-carbon alkane dehydrogenation catalyst obtained by loading the non-noble metal active component on the spherical dual-mesoporous composite material carrier has equivalent catalytic performance to the low-carbon alkane dehydrogenation catalyst obtained by loading the toxic metal active component Cr on the spherical dual-mesoporous composite material carrier when catalyzing propane dehydrogenation. In addition, as a result of comparing the experimental results of test examples 1 to 1 and test examples 1 to 4, it was found that when the loading amount of the non-noble metal active component was within the preferred range of the present invention, a dehydrogenation catalyst having more excellent performance could be obtained.
Similarly, it can be seen from the results in table 6 that the method for preparing the non-noble metal-based low-carbon alkane dehydrogenation catalyst provided by the invention can also effectively improve the activity, selectivity and stability of the catalyst in the reaction of preparing isobutene by dehydrogenating isobutane. By comparing the test example 2 with the test example 2-D3, it can be found that the low-carbon alkane dehydrogenation catalyst obtained by loading the non-noble metal active component on the spherical dual-mesoporous composite material carrier has equivalent catalytic performance to the low-carbon alkane dehydrogenation catalyst obtained by loading the toxic metal active component Cr on the spherical dual-mesoporous composite material carrier when catalyzing the dehydrogenation of isobutane. In addition, as a result of comparing the experimental results of test examples 2-1 and 2-4, it was found that when the loading amount of the non-noble metal active component was within the preferred range of the present invention, a dehydrogenation catalyst having more excellent performance could be obtained.
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 (11)

1. A method for preparing a non-noble metal-based low-carbon alkane dehydrogenation catalyst is characterized by comprising the following steps of:
(a) in the presence of a template agent, contacting tetraethoxysilane with ammonia water, and filtering a mixture obtained after the contact to obtain a mesoporous material filter cake;
(b) contacting water glass with inorganic acid, and filtering a product obtained after the contact to obtain a silica gel filter cake;
(c) mixing and ball-milling the mesoporous material filter cake and the silica gel filter cake, pulping solid powder obtained after ball-milling with water, then carrying out spray drying, and removing the template agent in the obtained product to obtain a spherical double-mesoporous composite material carrier;
(d) dipping the spherical double-mesoporous composite material carrier obtained in the step (c) in a solution containing an active non-noble metal component precursor, and then sequentially carrying out solvent removal treatment, drying and roasting.
2. The method of claim 1, wherein in the step (a), the ethyl orthosilicate, the template, ammonia in ammonia water and water are used in a molar ratio of 1: 0.1-1: 0.1-5: 100-200, preferably 1: 0.2-0.5: 1.5-3.5: 120-180;
preferably, the template agent is cetyl trimethyl ammonium bromide;
further preferably, the conditions under which the ethyl orthosilicate is contacted with ammonia water include: the temperature is 25-100 ℃ and the time is 10-72 hours.
3. The method of claim 1, wherein in step (b), the conditions under which the water glass is contacted with the mineral acid comprise: 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.
4. The method according to claim 1, wherein, in the step (c), the silica gel cake is used in an amount of 1 to 200 parts by weight, preferably 50 to 150 parts by weight, based on 100 parts by weight of the mesoporous material cake.
5. The method according to claim 1, wherein, in step (d), the spherical dual mesoporous composite support and the solution containing the active non-noble metal component precursor are used in amounts such that the non-noble metal based light alkane dehydrogenation catalyst is prepared in which the active non-noble metal component is present in an amount of 2 to 40 wt%, preferably 3 to 30 wt%, based on the total weight of the non-noble metal based light alkane dehydrogenation catalyst; the content of the spherical double mesoporous composite material carrier is 60-98 wt%, and preferably 70-97 wt%.
6. The method of claim 1 or 5, wherein the solution containing precursors of active non-noble metal components is at least one of a soluble salt solution of iron, nickel, zinc, molybdenum, tungsten, manganese, tin, and copper.
7. A non-noble metal-based light alkane dehydrogenation catalyst prepared by the process of any of claims 1-6.
8. The non-noble metal-based low-carbon alkane dehydrogenation catalyst according to claim 7, wherein the non-noble metal-based low-carbon alkane dehydrogenation catalyst comprises a carrier and an active non-noble metal component supported on the carrier, wherein the active non-noble metal component is a non-noble metal and/or a non-noble metal oxide, the carrier is a spherical dual-mesoporous composite carrier, the spherical dual-mesoporous composite carrier contains a mesoporous molecular sieve material having a two-dimensional hexagonal pore distribution structure, the average particle size of the spherical dual-mesoporous composite carrier is 30-60 μm, and the specific surface area is 200-650 m-2The pore volume is 0.5-1.5mL/g, the pore diameter distribution is bimodal, and the most probable pore diameters corresponding to the bimodal are respectively 1.5-15nm and 16-50 nm.
9. The non-noble metal-based light alkane dehydrogenation catalyst according to claim 8, wherein the active non-noble metal component is present in an amount of 2 to 40 wt%, preferably 3 to 30 wt%, calculated as the active metal element oxide, based on the total weight of the non-noble metal-based light alkane dehydrogenation catalyst; the content of the spherical double mesoporous composite material carrier is 60-98 wt%, preferably 70-97 wt%;
preferably, the active non-noble metal component is at least one of iron, nickel, zinc, molybdenum, tungsten, manganese, tin, copper and their respective oxides.
10. The use of the non-noble metal-based light alkane dehydrogenation catalyst of any one of claims 7 to 9 in the preparation of light olefins by light alkane dehydrogenation, wherein the method for preparing light olefins by light alkane dehydrogenation comprises: in the presence of a catalyst, the low-carbon alkane is subjected to dehydrogenation reaction.
11. The use of claim 10, wherein the lower alkane is propane and/or isobutane and the dehydrogenation reaction conditions of the lower alkane comprise: the reaction temperature is 500-650 ℃, the reaction pressure is 0.05-0.2MPa, and the mass space velocity of the low-carbon alkane is 1-10h-1。
CN201811246808.2A 2018-10-24 2018-10-24 Non-noble metal low-carbon alkane dehydrogenation catalyst with spherical double-mesoporous composite carrier and preparation method and application thereof Pending CN111085208A (en)

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CN115106118A (en) * 2021-03-19 2022-09-27 中国石油化工股份有限公司 Supported catalyst with function of catalyzing dehydrogenation of low-carbon alkane, preparation method and application thereof, and method for preparing low-carbon alkene
CN115337956A (en) * 2021-05-12 2022-11-15 中国石油化工股份有限公司 Supported catalyst, preparation method thereof and application of supported catalyst in preparation of propylene by propane dehydrogenation

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CN115106118A (en) * 2021-03-19 2022-09-27 中国石油化工股份有限公司 Supported catalyst with function of catalyzing dehydrogenation of low-carbon alkane, preparation method and application thereof, and method for preparing low-carbon alkene
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