Supported non-noble metal dehydrogenation catalyst and preparation method and application thereof
阅读说明：本技术 负载型非贵金属脱氢催化剂及其制备方法和应用 (Supported non-noble metal dehydrogenation catalyst and preparation method and application thereof ) 是由 吴省 缪长喜 洪学思 樊志贵 张新玉 于 2019-10-09 设计创作，主要内容包括：本发明为催化应用领域,具体提供了一种负载型非贵金属脱氢催化剂及其制备方法和应用,以重量百分比计,活性组分锌和/或锌氧化物的含量为0.1～10％,助剂磷和/或磷氧化物的含量为0.3～5％,载体MFI分子筛的含量为85～99.5％,活性组分通过真空浸渍的方法负载到所述载体上。本发明的催化剂用于脱氢反应,具有较好的活性和选择性。在优选的实施方式中,通过水热法合成MFI分子筛,通过碱处理,改善其孔道结构,同时通过真空浸渍,增大活性组分和助剂等物种在分子筛孔道内含量。利用孔道大小的限制作用,可减轻活性组分Zn等的聚集,延长催化剂使用寿命,同时通过助剂加入,改善活性和选择性。(The invention belongs to the field of catalytic application, and particularly provides a supported non-noble metal dehydrogenation catalyst and a preparation method and application thereof, wherein the supported non-noble metal dehydrogenation catalyst comprises, by weight, 0.1-10% of active components of zinc and/or zinc oxide, 0.3-5% of auxiliary agents of phosphorus and/or phosphorus oxide, 85-99.5% of carrier MFI molecular sieve, and active components supported on the carrier by a vacuum impregnation method. The catalyst of the invention is used for dehydrogenation reaction and has better activity and selectivity. In a preferred embodiment, the MFI molecular sieve is synthesized by a hydrothermal method, the pore channel structure of the MFI molecular sieve is improved by alkali treatment, and meanwhile, the content of active components, auxiliary agents and other species in the pore channels of the molecular sieve is increased by vacuum impregnation. By utilizing the restriction effect of pore canal size, the aggregation of active components Zn and the like can be reduced, the service life of the catalyst is prolonged, and simultaneously, the activity and the selectivity are improved by adding the auxiliary agent.)
1. The supported non-noble metal dehydrogenation catalyst is characterized by comprising, by weight, 0.1-10% of active component zinc and/or zinc oxide, 0.3-5% of auxiliary agent phosphorus and/or phosphorus oxide, and 85-99.5% of carrier MFI molecular sieve.
2. The catalyst of claim 1, wherein,
XPS and ICP characterization, (M)Zn/MP)XPS/(MZn/MP)ICP1 to 15, wherein (M)Zn/MP)XPSThe weight ratio of Zn to P of the catalyst, characterized by X-ray photoelectron spectroscopy, (M)Zn/MP)ICPThe weight ratio of the catalyst Zn to the catalyst P is characterized by plasma coupling; preferably, the first and second electrodes are formed of a metal,
(MZn/MP)XPS/(MZn/MP)ICP(M) is 2 to 15, more preferably (M)Zn/MP)XPS/(MZn/MP)ICP＝3～10。
3. The catalyst of claim 1 or 2,
the content of active component zinc and/or zinc oxide is 1-8%, and the content of auxiliary agent phosphorus and/or phosphorus oxide is 0.5-3%; and/or
The MFI molecular sieve is selected from one or more of ZSM-5, ZSM-11 and ZSM-35, and is preferably ZSM-5 and/or ZSM-11; and/or
The active component is loaded on the carrier by a vacuum impregnation method.
4. A process for preparing a supported non-noble metal dehydrogenation catalyst according to any of claims 1-3, comprising:
a) preparing MFI molecular sieve carrier containing phosphorus and/or phosphorus oxide by a hydrothermal synthesis method;
b) the zinc and/or zinc oxide is loaded on the carrier by a vacuum impregnation method.
5. The method of claim 4, wherein,
the preparation method for preparing the MFI molecular sieve carrier containing phosphorus and/or phosphorus oxide by adopting a hydrothermal synthesis method comprises the following steps:
(1) contacting a silicon source, aluminum sulfate, a phosphorus source, deionized water and hexadecyl trimethyl ammonium bromide, and adjusting the pH value to form gel, wherein the molar ratio of the substances is SiO2:Al2O3:P:CTABr:H2O＝(15～500)：1：(5～20)：(10～60)：(500～3000)；
(2) Transferring the gel into a high-pressure reaction kettle, carrying out hydrothermal treatment at 110-190 ℃, and then washing, drying and roasting to obtain the molecular sieve;
(3) adding the molecular sieve obtained in the step (2) into alkali liquor with the mass concentration of 0.1-1.0%, and treating at the temperature of 50-90 ℃ to obtain a carrier;
(4) and (4) adding the carrier obtained in the step (3) into a silicon solution with the mass concentration of 10-30%, uniformly mixing, and forming to obtain a formed carrier.
6. The method of claim 5, wherein,
the water washing in the step (2) is carried out for 3-5 times by using deionized water with the weight 2-5 times that of the molecular sieve in the step (1); and/or
The drying conditions in the step (2) include: drying temperature: drying at 60-120 ℃ for: 4-24 hours; and/or
The roasting condition in the step (2) comprises the following steps: the roasting temperature is 400-700 ℃, and the roasting time is 3-12 hours; and/or
In the step (3), the treatment time is 1-20 hours, and the alkali liquor is a sodium hydroxide solution and/or a potassium hydroxide solution; and/or
In the step (4), the silicon solution is SiO-containing2The solid content of the colloidal solution is 10-40%To (c) to (d); and extruding and forming to obtain a cylinder with the diameter of 1-4 mm and the length of 3-8 cm.
7. The method according to any one of claims 4 to 6, wherein the step of loading the zinc and/or zinc oxide onto the carrier using a vacuum impregnation method comprises:
adding a Zn-containing source solution into a carrier in the same volume, and vacuumizing at 0.01-0.03 MPa, preferably at the vacuum temperature: soaking for 0.5-8 hours at 60-150 ℃, then roasting, preferably,
the roasting conditions include: the temperature is 450-650 ℃, and the preferable time is 2-18 hours; and/or
The Zn source is selected from one or more of zinc nitrate, zinc acetate, zinc chloride and zinc sulfate.
8. The method of any of claims 4-6, wherein the method further comprises:
step c): after the step b) is finished, carrying out activation treatment, wherein the treatment atmosphere is water vapor, the pressure range is 0.1-0.5 MPa, the temperature is 300-600 ℃, and the time is 1-10 hours; preferably further comprising step d): after the end of step c), maintaining the pressure and temperature constant at O2And N2The volume ratio is 0.01-1.0: treating in 100 portions of mixed gas for 0.5-8 hours.
9. Use of a catalyst according to any one of claims 1 to 3 and a catalyst prepared by a process according to any one of claims 4 to 8 in the dehydrogenation of alkanes.
10. Use of a catalyst according to any one of claims 1 to 3 and a catalyst prepared by a process according to any one of claims 4 to 8 in the dehydrogenation of propane.
Technical Field
The invention relates to a supported non-noble metal dehydrogenation catalyst, a preparation method thereof and application thereof in alkane dehydrogenation, particularly propane dehydrogenation.
Background
Propylene is an important organic chemical raw material and is mainly used for producing chemical products such as polypropylene, acrylonitrile, propylene oxide, acrylic acid and the like. With the increasing demand of the global market for propylene downstream products, the propylene yield increase becomes a research hotspot of the petrochemical industry. The traditional method for preparing propylene by adopting ethylene coproduction and light oil (naphtha and light diesel oil) cracking process is limited in petroleum reserve, and the propylene is limited by raw material sources and is difficult to increase on a large scale. Propane with abundant sources and low price is used as a raw material to carry out dehydrogenation reaction to prepare propylene, which is one of the most promising methods.
The propane dehydrogenation technology is currently industrialized, the main dehydrogenation technologies include an Oleflex technology of UOP, a Catofin technology of Lummus, a STAR technology of Uhde, a PDH technology of Linde, an FBD technology developed by Snamprogetti-Yarsintez cooperation and the like, the most industrialized devices are the Oleflex technology and the Catofin technology, and catalysts applied to the Oleflex technology and the Catofin technology are Pt catalysts and Cr catalysts respectively. The Pt dehydrogenation catalyst is used for propane dehydrogenation, has the advantages of environmental friendliness, high activity and the like, but has high price, complex preparation and high requirement on the purity of reaction raw materials. The Cr series catalyst has low price, relatively high activity, low requirement on the purity of raw materials, certain influence on the environment, frequent regeneration in the reaction process, harsh dehydrogenation conditions and the like. Therefore, the development of new non-noble metal catalysts which can replace Pt and Cr is very important, and has great potential market value in the future.
CN103638954 reports a non-noble metal dehydrogenation catalyst, which takes aluminum hydroxide dry gel powder as a catalystMixing Ni (H) with carrier by kneading method or constant-temperature supersaturation immersion method2PO2)2·6H2O is loaded on the carrier to obtain Ni with dehydrogenation active component2P/γ-Al2O3A catalyst. The catalyst is used in3～C20Alkane and cycloalkane dehydrogenation reaction, and has the dehydrogenation activity, selectivity and stability of noble metal platinum catalyst.
CN106311214 reports the preparation and application of a non-noble metal dehydrogenation catalyst, which comprises a carrier, a main catalyst and an auxiliary catalyst, wherein the carrier is Mg-Al-O composite oxide, the main catalyst is at least one of copper, zinc, chromium, vanadium, molybdenum and gallium, and the auxiliary catalyst is at least one of tin, indium and gallium. The above samples are calcined in a microwave field to obtain dehydrogenation catalysts for cycloalkanes and alkanes with high selectivity of the target product and better reaction stability.
US20120116143a1 reports a catalyst for preparing lower olefins and a method for preparing lower olefins, which is a solid catalyst containing MFI zeolite, can efficiently prepare olefins, and at the same time, has a long service life. In addition to commonly used molecular sieves, alumina, and the like, diamond is also utilized as a dehydrogenation catalyst support or a primary dehydrogenation component. Wang et al (R WANG, X SUN, B ZHANG, et al. hybrid Nanocarbon as a Catalyst for direct reduction of Panel: Formation of an Active and Selective Core-Shell sp2/sp3 Nanocomposite Structure[J]Chemistry-A European Journal, 2014, 20 (21): 6324-3) Graphite outer shell (sp)2) The propane dehydrogenation performance of the ND @ G composite nano carbon material with different proportions is researched, and the performance of the material is found to be superior to that of single nano diamond and graphite.
Among the propane dehydrogenation catalysts, there has been a great progress made in the China university of Petroleum (Shandong) fluidized bed process, and no relevant reports have been made on the active components and carriers of the catalysts. KBR also claimed to be successful in the development of a fluidized bed process suitable for dehydrogenation of lower alkanes such as propane, and similarly, the catalyst composition and the like are not reported in detail. However, the development of non-Pt and non-Cr propane dehydrogenation catalyst systems has become a hot spot for the next research.
Disclosure of Invention
The invention aims to provide a non-noble metal propane dehydrogenation catalyst with better activity and selectivity as well as a preparation method and application thereof.
In order to achieve the above purpose, in a first aspect, the present invention provides a supported non-noble metal dehydrogenation catalyst, wherein the content of an active component zinc and/or zinc oxide is 0.1 to 10 wt%, the content of an auxiliary agent phosphorus and/or phosphorus oxide is 0.3 to 5 wt%, and the content of a carrier MFI molecular sieve is 85 to 99.5 wt%.
Preferably, the catalyst is characterized by XPS and ICP, (M)Zn/MP)XPS/(MZn/MP)ICP1 to 15, wherein (M)Zn/MP)XPSThe weight ratio of Zn to P of the catalyst, characterized by X-ray photoelectron spectroscopy, (M)Zn/MP)ICPThe catalyst Zn to P weight ratio is characterized by plasma coupling.
Preferably, (M)Zn/MP)XPS/(MZn/MP)ICPThe content is 2.0 to 15.0, and the more preferable range is (M)Zn/MP)XPS/(MZn/MP)ICP＝3～10。
Preferably, the Zn-P/MFI catalyst has 1-8% of active component zinc and/or zinc oxide and 0.5-3% of auxiliary agent phosphorus and/or phosphorus oxide; and/or the MFI molecular sieve is selected from one or more of ZSM-5, ZSM-11 and ZSM-35, preferably ZSM-5 and/or ZSM-11.
Preferably, the active ingredient is loaded onto the support by means of vacuum impregnation.
In a second aspect, the present invention provides a method for preparing a supported non-noble metal dehydrogenation catalyst according to the present invention, the method comprising:
a) preparing MFI molecular sieve carrier containing phosphorus and/or phosphorus oxide by a hydrothermal synthesis method;
b) the zinc and/or zinc oxide is loaded on the carrier by a vacuum impregnation method.
Preferably, the preparation steps of the MFI molecular sieve support containing phosphorus and/or phosphorus oxide by using the hydrothermal synthesis method comprise:
(1) contacting a silicon source, aluminum sulfate, a phosphorus source, deionized water and hexadecyl trimethyl ammonium bromide, and adjusting the pH value to form gel, wherein the molar ratio of the substances is SiO2:Al2O3:P:CTABr:H2O＝(15～500)：1：(5～20)：(10～60)：(500～3000)；
(2) Transferring the gel into a high-pressure reaction kettle, carrying out hydrothermal treatment at 110-190 ℃, and then washing, drying and roasting to obtain the required molecular sieve;
(3) adding the molecular sieve obtained in the step (2) into 0.1-1.0% alkali liquor, and treating at 50-90 ℃ for 1-20 hours to obtain a molecular sieve carrier with hierarchical pores;
(4) and (4) adding the carrier obtained in the step (3) into 10-30% of silicon solution, uniformly mixing, and forming to obtain a formed carrier.
Preferably, the water washing in the step (2) is carried out for 3-5 times by using deionized water which is 2-5 times of the weight of the molecular sieve in the step (1); and/or
The drying conditions in the step (2) include: drying temperature: drying at 60-120 ℃ for: 4-24 hours; and/or
The roasting condition in the step (2) comprises the following steps: the roasting temperature is 400-700 ℃, and the roasting time is 3-12 hours; and/or
And (4) extruding and forming to obtain a cylinder with the diameter of 1-4 mm and the length of 3-8 cm.
Preferably, the step of loading zinc and/or zinc oxide onto the carrier using a vacuum impregnation method comprises:
adding a Zn source solution into a carrier in the same volume, vacuumizing at 0.01-0.03 MPa, wherein the vacuum temperature is as follows: dipping for 0.5-8 hours at 60-150 ℃, then roasting, preferably,
the roasting conditions include: the temperature is 450-650 ℃, and the time is 2-18 hours; and/or
The Zn source is selected from one or more of zinc nitrate, zinc acetate, zinc chloride and zinc sulfate.
Preferably, the method further comprises:
step c): after the step b) is finished, carrying out activation treatment, wherein the treatment atmosphere is water vapor, the pressure range is 0.1-0.5 MPa, the temperature is 300-600 ℃, and the time is 1-10 hours; preferably further comprising step d): after the end of step c), maintaining the pressure and temperature constant at O2/N2Treating for 0.5-8 hours in mixed gas with the volume ratio of 0.01-1.0%.
In a third aspect, the invention provides the use of a catalyst as described herein and a catalyst prepared by a process as described herein for the dehydrogenation of alkanes.
In a fourth aspect, the present invention provides the use of a catalyst according to the present invention and a catalyst prepared by a process according to the present invention for the dehydrogenation of propane.
The catalyst of the invention is used for dehydrogenation reaction and has better activity and selectivity. In a preferred embodiment, the MFI molecular sieve is synthesized by a hydrothermal method, the pore channel structure of the MFI molecular sieve is improved by alkali treatment, and meanwhile, the content of active components, auxiliary agents and other species in the pore channels of the molecular sieve is increased by vacuum impregnation. By utilizing the restriction effect of pore canal size, the aggregation of active components Zn and the like can be reduced, the service life of the catalyst is prolonged, and simultaneously, the activity and the selectivity are improved by adding the auxiliary agent.
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 supported non-noble metal dehydrogenation catalyst, which comprises, by weight, 0.1-10% of active component zinc and/or zinc oxide, 0.3-5% of auxiliary agent phosphorus and/or phosphorus oxide, and 85-99.5% of carrier MFI molecular sieve. The catalyst of the invention is used for dehydrogenation reaction and has better activity and selectivity.
According to the invention, XPS and ICP characterization of (M) in the catalystZn/MP)XPS/(MZn/MP)ICP1 to 15, wherein (M)Zn/MP)XPSThe weight ratio of Zn to P of the catalyst, characterized by X-ray photoelectron spectroscopy, (M)Zn/MP)ICPThe weight ratio of the catalyst Zn to the catalyst P is characterized by plasma coupling; preferably, (M)Zn/MP)XPS/(MZn/MP)ICPThe content is 2 to 15, and the preferable range is (M)Zn/MP)XPS/(MZn/MP)ICP3-10. Catalysts with the aforementioned characteristics enable better activity and selectivity.
According to the invention, the content of the active component zinc and/or zinc oxide is preferably 1-8% by weight.
According to the invention, the content of the auxiliary agent phosphorus and/or phosphorus oxide is preferably 0.5-3% by weight.
According to the invention, the molecular sieve with the MFI structure can be selected from a wide range, the existing molecular sieve with the MFI structure can be used in the invention, and in the invention, the MFI molecular sieve is preferably selected from one or more of ZSM-5, ZSM-11 and ZSM-35, and is preferably selected from ZSM-5 and/or ZSM-11. The selection of the foregoing molecular sieves can further enhance the dehydrogenation activity, particularly propane dehydrogenation activity, of the supported non-noble metal dehydrogenation catalyst.
According to the present invention, preferably, the active ingredient is loaded onto the support by means of vacuum impregnation.
The catalysts having the aforementioned composition and properties all achieve the object of the present invention, and the preparation process thereof is not particularly restricted and may be prepared, for example, by the following steps:
1) preparing an MFI molecular sieve carrier by adopting a hydrothermal synthesis method;
2) and loading the active component and the auxiliary agent to the carrier by adopting vacuum impregnation to obtain a required catalyst sample.
For the purposes of the present invention, preference is given to preparing the catalyst by a process which comprises:
a) preparing MFI molecular sieve carrier containing phosphorus and/or phosphorus oxide by a hydrothermal synthesis method;
b) the zinc and/or zinc oxide is loaded on the carrier by a vacuum impregnation method.
According to the method of the invention, the preparation steps of the MFI molecular sieve carrier containing phosphorus and/or phosphorus oxide by using a hydrothermal synthesis method preferably comprise the following steps:
the preparation method for preparing the MFI molecular sieve carrier containing phosphorus and/or phosphorus oxide by adopting a hydrothermal synthesis method comprises the following steps:
(1) contacting a silicon source, aluminum sulfate, a phosphorus source, deionized water and hexadecyl trimethyl ammonium bromide, and adjusting the pH value to form gel, wherein the molar ratio of the substances is SiO2:Al2O3:P:CTABr:H2O＝(15～500)：1：(5～20)：(10～60)：(500～3000)；
(2) Transferring the gel into a high-pressure reaction kettle, carrying out hydrothermal treatment at 110-190 ℃, and then washing, drying and roasting to obtain the molecular sieve;
(3) adding the molecular sieve obtained in the step (2) into alkali liquor with the mass concentration of 0.1-1.0%, and treating at the temperature of 50-90 ℃ to obtain a carrier;
(4) and (4) adding the carrier obtained in the step (3) into a silicon solution with the mass concentration of 10-30%, uniformly mixing, and forming to obtain a formed carrier.
More preferably, the preparation method of the MFI molecular sieve carrier containing phosphorus and/or phosphorus oxide by using a hydrothermal synthesis method comprises the following steps:
(1) contacting a silicon source, aluminum sulfate, a phosphorus source, deionized water and hexadecyl trimethyl ammonium bromide, and adjusting the pH value to form gel, wherein the molar ratio of the substances is SiO2:Al2O3:P:CTABr:H2O＝(15～500)：1：(5～20)：(10～60)：(500～3000)；
(2) Transferring the gel into a high-pressure reaction kettle, carrying out hydrothermal treatment at 110-190 ℃, and then washing, drying and roasting to obtain the required molecular sieve;
(3) adding the molecular sieve obtained in the step (2) into alkali liquor with the mass concentration of 0.1-1.0%, and treating at the temperature of 50-90 ℃ for 1-20 hours to obtain a molecular sieve carrier with hierarchical pores;
(4) and (4) adding the carrier obtained in the step (3) into a silicon solution with the mass concentration of 10-30%, uniformly mixing, and forming to obtain a formed carrier. The catalyst prepared by the method has high catalyst activity, and particularly the activity for propane dehydrogenation can be greatly improved.
According to the method, the water washing in the step (2) is preferably carried out 3-5 times by using deionized water which is 2-5 times of the weight of the molecular sieve in the step (1).
According to the method of the present invention, it is preferable that the conditions for drying in step (2) include: drying temperature: the drying time is determined according to the drying temperature at 60-120 ℃, wherein the preferable drying time is as follows: 4-24 hours.
According to the method of the present invention, it is preferable that the conditions for the calcination in the step (2) include: the roasting temperature is 400-700 ℃, and the roasting time is more preferably 3-12 hours.
According to the method of the invention, the lye is, for example, a sodium hydroxide solution and/or a potassium hydroxide solution, preferably a sodium hydroxide solution, more preferably a sodium hydroxide solution having a mass concentration of 0.1 to 10%.
According to the method, the extrusion molding is preferably carried out in the step (4) to obtain the cylinder with the diameter of 1-4 mm and the length of 3-8 cm.
According to the method of the invention, the silicon solution is SiO-containing2The solid content of the colloidal solution is 10-40%.
According to the process of the present invention, the step of loading zinc and/or zinc oxide onto a support, preferably by vacuum impregnation, comprises: adding a Zn-containing source solution into a carrier in the same volume, and vacuumizing at 0.01-0.03 MPa, preferably at the vacuum temperature: 60-150 ℃; preferably, the dipping time is 0.5-8 hours, and then roasting is carried out, wherein the preferable roasting conditions comprise: the temperature is 450-650 ℃, and the roasting time is more preferably 2-18 hours.
According to the method of the present invention, the variety of the Zn source can be widely selected, soluble zinc salts can be used in the present invention, and for the present invention, it is preferable that the Zn source is selected from one or more of zinc nitrate, zinc acetate, zinc chloride and zinc sulfate.
According to the method of the present invention, the phosphorus source can be selected from a wide variety of sources, and can be, for example, a soluble phosphorus salt.
According to the method of the present invention, preferably the method further comprises:
step c): after the step b) is finished, carrying out activation treatment, preferably, the atmosphere of the activation treatment is steam; the optimized treatment pressure range is 0.1-0.5 MPa; more preferably, the temperature of the treatment is 300 to 600 ℃, and the time of the treatment is 1 to 10 hours. The dehydrogenation activity of the catalyst can be improved by the aforementioned activation treatment.
The process according to the invention preferably also comprises a step d): after the end of step c), maintaining the pressure and temperature constant at O2/N2The volume ratio is 0.01-1.0: 100, preferably for 0.5 to 8 hours.
The invention provides application of the catalyst prepared by the method in alkane dehydrogenation. The catalyst of the invention has good dehydrogenation activity.
The catalyst of the invention is particularly suitable for propane dehydrogenation, and the invention provides the catalyst of the invention and the use of the catalyst prepared by the method of the invention in propane dehydrogenation.
The catalyst of the invention can be evaluated in an isothermal fixed bed reactor, and the evaluation conditions of the catalyst in the isothermal fixed bed reactor are as follows: about 10 g of catalyst and 10 g of magnetic ring are uniformly mixed and loaded into a quartz tube reactor with the inner diameter of phi 22 mm-phi 18mm, the reaction pressure is normal pressure, the gas mass space velocity is 1.0 h-1, and the reaction temperature is 550 ℃. The conversion rate of the propane is obtained by multiplying the content of the propane which accounts for the sum of the contents of all gas-phase products after the reaction by 100 percent; the selectivity to olefin is the percentage of propylene content in the gaseous components other than propane after reaction, i.e. the percentage of propylene content divided by the sum of the C1, C2, C4 and propylene contents.
The following examples are given to illustrate the technical aspects of the present invention in detail, but the present invention is not limited to the following examples.
Various substitutions and alterations can be made without departing from the technical idea of the invention, based on the common technical knowledge in the field and the similar means.
Example 1
Preparing a ZSM-5 molecular sieve by using a hydrothermal synthesis method: 180.25 g of silica sol having a solid content of 20% was dissolved in 180 g of deionized water, 72.89 g of cetyltrimethylammonium bromide (hereinafter abbreviated as CTABr), 6.66 g of aluminum sulfate and 0.76 g of ammonium phosphate were added, and the above sample was stirred at room temperature for 3 hours to form a uniform gel. The materials in the gel are calculated by molar ratio: SiO 22:Al2O3:CTABr:H2O300: 1: 20: 1000. and transferring the sample into a high-pressure reaction kettle, crystallizing for 60 hours at 170 ℃, performing suction filtration and washing on a crystallized product to be neutral, drying at 120 ℃, and roasting at 500 ℃ for 4 hours to obtain MFI type molecular sieve raw powder. The prepared sample was added to 1.0% sodium hydroxide solution, and treated for 5 hours while maintaining the temperature at 70 ℃. And (4) carrying out suction filtration, drying and roasting on the sample treated by the alkali liquor for later use, and recording the sample as D-MFI. Weighing 10 g of D-MFI sample, adding 3 g of silica gel solution with the solid content of 10%, uniformly mixing, extruding and forming to obtain a cylinder with the diameter of 3mm and the length of 4-6 cm, and recording as Y-MFI.
Impregnating active components: 3.62 g of zinc nitrate is weighed, dissolved in 10 ml of deionized water and fully stirred to be dissolved uniformly. Then 20 g of the formed Y-MFI molecular sieve is weighed and added into the solution, and the solution is put into a vacuum drying oven at 60 ℃, the degree of vacuum pumping is 0.01MPa, and the dipping time is kept for 2 hours. Transferring the dried sample into a muffle furnace at 500 ℃, and roasting for 4 hours to obtain the required dehydrogenation catalyst 5% Zn-1% P/MFI, wherein (M)Zn/MP)XPS/(MZn/MP)ICP4.5, and is denoted as catalyst a.
The flow of propane gas is regulated by a mass flow meter, the propane gas enters a preheating zone for preheating, and then enters a reaction zone, a heating section and a reaction section of the reactor are heated by electric heating wires to reach a preset temperature, and the reactor is a quartz tube with the internal diameter of phi 20mm and the length of 400 mm. The reacted gas was passed through a condensing pot and then analyzed for composition by gas chromatography.
The catalyst evaluation conditions in the isothermal fixed bed reactor were as follows: mixing 10 g of the catalyst and 10 g of a magnetic ring with the diameter of 3mm uniformly, and loading the mixture into the isothermal fixed bed reactor, wherein the reaction pressure is normal pressure, and the gas mass space velocity is 1.0 hour-1And the reaction temperature was 550 ℃. The results after 3 days of reaction are shown in Table 1.
Comparative example 1
The preparation method of the catalyst carrier is the same as that of example 1, except that the impregnation of the active component is carried out under normal pressure, the composition content, the evaluation method and the like of each component after the impregnation are the same as those of example 1, the catalyst is marked as B1, and the results after 3 days of reaction are shown in Table 1.
Comparative example 2
The preparation method of the catalyst carrier is the same as that in example 1, except that no ammonium phosphate is added during the preparation of the MFI molecular sieve, only 5% of ZnO is dipped in vacuum, and the dipped catalyst is a 5% Zn/MFI catalyst, the evaluation method and the like are the same as those in example 1, the catalyst is marked as B2, and the results after 3 days of reaction are shown in Table 1.
Comparative example 3
The preparation method of the catalyst carrier is the same as that in example 1, except that after the Y-MFI molecular sieve is prepared, 5% ZnO is not subjected to vacuum impregnation to obtain a 1% P/MFI catalyst, the evaluation method and the like are the same as those in example 1, the catalyst is marked as B3, and the results after 3 days of reaction are shown in Table 1.
Example 2
Preparing a ZSM-5 molecular sieve by using a hydrothermal synthesis method: 90.13 g of silica sol having a solid content of 20% was dissolved in 180 g of deionized water, and then 36.50 g of cetyltrimethylammonium bromide (hereinafter abbreviated as CTABr), 6.66 g of aluminum sulfate and 0.2.27 g of ammonium phosphate were added, and the above sample was stirred at room temperature for 3 hours to form a uniform gel. The materials in the gel are calculated by molar ratio: SiO 22:Al2O3:CTABr:H2O150: 1: 10: 1000. transferring the sample into a high-pressure reaction kettle, crystallizing at 170 ℃ for 48 hours, filtering and washing the crystallized product to be neutral, drying at 100 ℃, and roasting at 500 DEG CAnd 4 hours, obtaining MFI type molecular sieve raw powder. The prepared sample was added to 0.5% sodium hydroxide solution, and treated for 3 hours while maintaining the temperature at 70 ℃. And (4) carrying out suction filtration, drying and roasting on the sample treated by the alkali liquor for later use, and recording the sample as D-MFI. Weighing 10 g of D-MFI sample, adding 3 g of silica gel solution with the solid content of 10%, uniformly mixing, extruding and forming to obtain a cylinder with the diameter of 3mm and the length of 4-6 cm, and recording as Y-MFI.
Dipping active components and auxiliary agents: 5.79 g of zinc nitrate is weighed and dissolved in 10 ml of deionized water, and the mixture is fully stirred to be dissolved uniformly. Then 20 g of the formed Y-MFI molecular sieve is weighed and added into the solution, and the solution is put into a vacuum drying oven at 60 ℃, the degree of vacuum pumping is 0.01MPa, and the dipping time is kept for 4 hours. Transferring the dried sample into a muffle furnace at 500 ℃, and roasting for 6 hours to obtain the required dehydrogenation catalyst C, wherein (M) isZn/MP)XPS/(MZn/MP)ICPThe results after 3 days of reaction are shown in table 1.
Example 3
Preparing a ZSM-5 molecular sieve by using a hydrothermal synthesis method: 1802.5 g of silica sol having a solid content of 20% was dissolved in 90 g of deionized water, 364.45 g of cetyltrimethylammonium bromide (hereinafter abbreviated as CTABr), 6.66 g of aluminum sulfate and 0.38 g of ammonium phosphate were added, and the above sample was stirred at room temperature for 3 hours to form a uniform gel. The materials in the gel are calculated by molar ratio: SiO 22:Al2O3:CTABr:H2O-30: 1: 10: 500. and transferring the sample into a high-pressure reaction kettle, crystallizing for 60 hours at 170 ℃, performing suction filtration and washing on a crystallized product to be neutral, drying at 120 ℃, and roasting at 500 ℃ for 6 hours to obtain MFI type molecular sieve raw powder. The prepared sample was added to 0.1% sodium hydroxide solution, and treated for 3 hours while maintaining the temperature at 70 ℃. And (4) carrying out suction filtration, drying and roasting on the sample treated by the alkali liquor for later use, and recording the sample as D-MFI. Weighing 10 g of D-MFI sample, adding 3 g of silica gel solution with the solid content of 10%, uniformly mixing, extruding and forming to obtain a cylinder with the diameter of 3mm and the length of 4-6 cm, and recording as Y-MFI.
Dipping active components and auxiliary agents: 0.73 g of zinc nitrate is weighed and dissolved in 10 ml of deionized water, and the mixture is fully stirredStirring to dissolve uniformly. Then 20 g of the formed Y-MFI molecular sieve is weighed and added into the solution, and the solution is put into a vacuum drying oven at 80 ℃, the vacuum degree is 0.01MPa, and the dipping time is kept for 1 hour. Transferring the dried sample into a muffle furnace at 500 ℃, and roasting for 4 hours to obtain the required dehydrogenation catalyst D, wherein (M)Zn/MP)XPS/(MZn/MP)ICPThe results after 3 days of reaction are shown in table 1.
Example 4
Preparing a ZSM-5 molecular sieve by using a hydrothermal synthesis method: 300.42 g of silica sol having a solid content of 20% was dissolved in 360 g of deionized water, and 72.89 g of cetyltrimethylammonium bromide (hereinafter abbreviated as CTABr), 6.66 g of aluminum sulfate and 1.38 g of ammonium phosphate were added thereto, and the above sample was stirred at room temperature for 3 hours to form a uniform gel. The materials in the gel are calculated by molar ratio: SiO 22:Al2O3:CTABr:H2O500: 1: 20: 3000. and transferring the sample into a high-pressure reaction kettle, crystallizing for 60 hours at 170 ℃, performing suction filtration and washing on a crystallized product to be neutral, drying at 100 ℃, and roasting at 500 ℃ for 8 hours to obtain MFI type molecular sieve raw powder. The prepared sample was added to 1.0% sodium hydroxide solution, and treated for 8 hours while maintaining the temperature at 40 ℃. And (4) carrying out suction filtration, drying and roasting on the sample treated by the alkali liquor for later use, and recording the sample as D-MFI. Weighing 10 g of D-MFI sample, adding 3 g of silica gel solution with the solid content of 10%, uniformly mixing, extruding and forming to obtain a cylinder with the diameter of 3mm and the length of 4-6 cm, and recording as Y-MFI.
Dipping active components and auxiliary agents: 2.70 g of zinc acetate is weighed, dissolved in 10 ml of deionized water and fully stirred to be dissolved uniformly. Then 20 g of the formed Y-MFI molecular sieve is weighed and added into the solution, and the solution is put into a vacuum drying oven at 80 ℃, the vacuum degree is 0.01MPa, and the dipping time is kept for 1 hour. Transferring the dried sample into a muffle furnace at 500 ℃, and roasting for 4 hours to obtain the required dehydrogenation catalyst E, wherein (M)Zn/MP)XPS/(MZn/MP)ICPThe results after 3 days of reaction are shown in table 1.
Example 5
By hydrothermal synthesisPreparing a ZSM-5 molecular sieve by a formation method: 180.25 g of silica sol having a solid content of 20% was dissolved in 540 g of deionized water, and then 145.78 g of cetyltrimethylammonium bromide (hereinafter abbreviated as CTABr), 6.66 g of aluminum sulfate and 0.35 g of ammonium phosphate were added, and the above sample was stirred at room temperature for 3 hours to form a uniform gel. The materials in the gel are calculated by molar ratio: SiO 22:Al2O3:CTABr:H2O300: 1: 60: 3000. and transferring the sample into a high-pressure reaction kettle, crystallizing for 50 hours at 170 ℃, performing suction filtration and washing on a crystallized product to be neutral, drying at 110 ℃, and roasting for 6 hours at 500 ℃ to obtain MFI type molecular sieve raw powder. The prepared sample was added to 1.0% sodium hydroxide solution, and treated for 4 hours while maintaining the temperature at 40 ℃. And (4) carrying out suction filtration, drying and roasting on the sample treated by the alkali liquor for later use, and recording the sample as D-MFI. Weighing 10 g of D-MFI sample, adding 3 g of silica gel solution with the solid content of 10%, uniformly mixing, extruding and forming to obtain a cylinder with the diameter of 3mm and the length of 4-6 cm, and recording as Y-MFI.
Dipping active components and auxiliary agents: 1.62 g of zinc acetate is weighed, dissolved in 10 ml of deionized water and fully stirred to be dissolved uniformly. Then 20 g of the formed Y-MFI molecular sieve is weighed and added into the solution, and the solution is put into a vacuum drying oven with the temperature of 80 ℃, the vacuum degree is 0.01MPa, and the dipping time is kept for 2 hours. Transferring the dried sample into a muffle furnace at 500 ℃, and roasting for 4 hours to obtain the required dehydrogenation catalyst F, wherein (M)Zn/MP)XPS/(MZn/MP)ICPThe results after 3 days of reaction are shown in table 1.
Example 6
Preparing a ZSM-5 molecular sieve by using a hydrothermal synthesis method: 300.42 g of silica sol having a solid content of 20% was dissolved in 360 g of deionized water, and then 48.59 g of cetyltrimethylammonium bromide (hereinafter abbreviated as CTABr), 6.66 g of aluminum sulfate and 2.07 g of ammonium phosphate were added, and the above sample was stirred at room temperature for 5 hours to form a uniform gel. The materials in the gel are calculated by molar ratio: SiO 22:Al2O3:CTABr:H2O500: 1: 20: 2000. transferring the sample into a high-pressure reaction kettle, crystallizing at 150 ℃ for 72 hours, and filtering and washing the crystallized product to be neutralAnd drying at 110 ℃, and roasting at 500 ℃ for 5 hours to obtain MFI type molecular sieve raw powder. The prepared sample was added to 1.0% sodium hydroxide solution, and treated for 6 hours while maintaining the temperature at 40 ℃. And (4) carrying out suction filtration, drying and roasting on the sample treated by the alkali liquor for later use, and recording the sample as D-MFI. Weighing 10 g of D-MFI sample, adding 3 g of silica gel solution with the solid content of 10%, uniformly mixing, extruding and forming to obtain a cylinder with the diameter of 3mm and the length of 4-6 cm, and recording as Y-MFI.
Dipping active components and auxiliary agents: 2.41 g of zinc nitrate is weighed, dissolved in 10 ml of deionized water and fully stirred to be dissolved uniformly. Then 20 g of the formed Y-MFI molecular sieve is weighed and added into the solution, and the solution is put into a vacuum drying oven at 80 ℃, the vacuum degree is 0.01MPa, and the dipping time is kept for 1 hour. Transferring the dried sample into a muffle furnace at 530 ℃, and roasting for 6 hours to obtain the required dehydrogenation catalyst G, wherein (M)Zn/MP)XPS/(MZn/MP)ICPThe results after 3 days of reaction are shown in table 1.
Example 7
Preparing a ZSM-5 molecular sieve by using a hydrothermal synthesis method: 9.01 g of silica sol having a solid content of 20% was dissolved in 540 g of deionized water, and 48.59 g of cetyltrimethylammonium bromide (hereinafter abbreviated as CTABr), 6.66 g of aluminum sulfate and 0.69 g of ammonium phosphate were added thereto, and the above sample was stirred at room temperature for 3 hours to form a uniform gel. The materials in the gel are calculated by molar ratio: SiO 22:Al2O3:CTABr:H2O15: 1: 20: 3000. and transferring the sample into a high-pressure reaction kettle, crystallizing for 48 hours at 170 ℃, performing suction filtration and washing on a crystallized product to be neutral, drying at 120 ℃, and roasting at 550 ℃ for 4 hours to obtain MFI type molecular sieve raw powder. The prepared sample was added to 1.0% sodium hydroxide solution, and treated for 6 hours while maintaining the temperature at 50 ℃. And (4) carrying out suction filtration, drying and roasting on the sample treated by the alkali liquor for later use, and recording the sample as D-MFI. Weighing 10 g of D-MFI sample, adding 3 g of silica gel solution with the solid content of 10%, uniformly mixing, extruding and forming to obtain a cylinder with the diameter of 3mm and the length of 4-6 cm, and recording as Y-MFI.
Dipping active components and auxiliary agents: 5.79 g of zinc nitrate are weighed out and dissolved inIn 10 ml of deionized water, the solution was stirred sufficiently to dissolve uniformly. Then 20 g of the formed Y-MFI molecular sieve is weighed and added into the solution, and the solution is put into a vacuum drying oven at 80 ℃, the vacuum degree is 0.01MPa, and the dipping time is kept for 3 hours. Transferring the dried sample into a muffle furnace at 520 ℃, and roasting for 6 hours to obtain the required dehydrogenation catalyst H, wherein (M)Zn/MP)XPS/(MZn/MP)ICPThe results after 3 days of reaction are shown in table 1.
Example 8
Preparing a ZSM-5 molecular sieve by using a hydrothermal synthesis method: 180.25 g of silica sol having a solid content of 20% was dissolved in 180 g of deionized water, 48.59 g of cetyltrimethylammonium bromide (hereinafter abbreviated as CTABr), 6.66 g of aluminum sulfate and 0.35 g of ammonium phosphate were added, and the above sample was stirred at room temperature for 5 hours to form a uniform gel. The materials in the gel are calculated by molar ratio: SiO 22:Al2O3:CTABr:H2O300: 1: 20: 1000. and transferring the sample into a high-pressure reaction kettle, crystallizing for 72 hours at 170 ℃, performing suction filtration and washing on a crystallized product to be neutral, drying at 120 ℃, and roasting for 4 hours at 500 ℃ to obtain MFI type molecular sieve raw powder. The prepared sample was added to 1.0% sodium hydroxide solution, and treated for 5 hours while maintaining the temperature at 40 ℃. And (4) carrying out suction filtration, drying and roasting on the sample treated by the alkali liquor for later use, and recording the sample as D-MFI. Weighing 10 g of D-MFI sample, adding 3 g of silica gel solution with the solid content of 20%, uniformly mixing, extruding and forming to obtain a cylinder with the diameter of 3mm and the length of 4-6 cm, and recording as Y-MFI.
Dipping active components and auxiliary agents: 3.62 g of zinc nitrate is weighed, dissolved in 10 ml of deionized water and fully stirred to be dissolved uniformly. Then 20 g of the formed Y-MFI molecular sieve is weighed and added into the solution, and the solution is put into a vacuum drying oven at 60 ℃, the degree of vacuum pumping is 0.01MPa, and the dipping time is kept for 3 hours. Transferring the dried sample into a muffle furnace at 500 ℃, and roasting for 6 hours to obtain the required dehydrogenation catalyst I, wherein (M)Zn/MP)XPS/(MZn/MP)ICPThe results after 3 days of reaction are shown in table 1.
Example 9
The preparation method of the catalyst carrier is the same as that in example 1, except that the MFI obtained by hydrothermal synthesis is directly extruded and formed without alkali liquor treatment, the impregnation of the active components is the same as that in example 1, vacuum impregnation is adopted, the composition content, the evaluation method and the like of each component after the impregnation are the same as those in example 1, the catalyst is marked as B2, and the results after 3 days of reaction are shown in Table 1.
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.
TABLE 1
Catalyst and process for preparing same
Conversion rate%
Selectively, according to
A
25.6
91.8
B1
20.5
86.1
B3
19.2
85.1
B4
11.9
83.6
C
25.2
91.0
D
24.8
91.4
E
24.9
91.6
F
25.1
91.5
G
25.0
91.2
H
24.9
91.3
I
25.0
91.1
J
19.7
88.2
As can be seen from the above table results, the catalyst of the present invention has excellent propane dehydrogenation activity and selectivity.