Supported catalyst for preparing propylene by propane dehydrogenation and preparation method and application thereof
阅读说明：本技术 负载型丙烷脱氢制丙烯的催化剂及其制备方法和应用 (Supported catalyst for preparing propylene by propane dehydrogenation and preparation method and application thereof ) 是由 吴省 缪长喜 洪学思 曾铁强 张磊 于 2019-10-09 设计创作，主要内容包括：本发明涉及催化剂领域,具体提供一种负载型丙烷脱氢制丙烯的催化剂及其制备方法和应用,以重量百分比计,包括以下成分,活性组分的含量为0.05～1％,所述活性组分元素为Pt、Pd、Ru和Rh中的一种或多种；过渡金属的含量为0.05～3％,所述过渡金属为Sn、Zn、Fe、Ni和Co中的一种或多种；碱金属的含量为0.05～2％；载体MFI分子筛的含量为94～99.5％；所述活性组分、所述碱金属、所述过渡金属中的一种或多种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,本发明的催化剂用于丙烷脱氢具有很高的丙烯选择性。(The invention relates to the field of catalysts, and particularly provides a supported catalyst for preparing propylene by propane dehydrogenation and a preparation method and application thereof, wherein the supported catalyst comprises the following components in percentage by weight, the content of an active component is 0.05-1%, and the active component element is one or more of Pt, Pd, Ru and Rh; the content of transition metal is 0.05-3%, and the transition metal is one or more of Sn, Zn, Fe, Ni and Co; the content of alkali metal is 0.05-2%; the content of the carrier MFI molecular sieve is 94-99.5%; one or more of the active component, the alkali metal and the transition metal is loaded on the carrier by a vacuum impregnation method. The catalyst of the invention is used for dehydrogenation reaction, has better activity and selectivity, and has very high propylene selectivity when being used for propane dehydrogenation.)
1. A supported catalyst for preparing propylene by propane dehydrogenation is characterized by comprising the following components in percentage by weight,
a) the content of an active component is 0.05-1%, and the active component element is one or more of Pt, Pd, Ru and Rh;
b) the content of transition metal is 0.05-3%, and the transition metal is one or more of Sn, Zn, Fe, Ni and Co;
c) the content of alkali metal is 0.05-2%;
d) the content of the carrier MFI molecular sieve is 94-99.5%.
2. The catalyst of claim 1, wherein,
the active component is Pt and/or Pd; and/or
The alkali metal is one or more of Li, Na, K and Cs, and is preferably Na and/or K; and/or
The transition metal is one or more of Sn, Fe and Zn; and/or
The carrier MFI molecular sieve is one or more of ZSM-5, ZSM-11 and ZSM-35, preferably ZSM-5 and/or ZSM-11; and/or
The catalyst is distributed in a multi-stage pore mode, and the mesoporous volume is 0.18-0.40 cm3The pore size distribution of the mesopores is 2-10 nm, and the proportion of the mesopores is 15-50%.
3. The catalyst of claim 1, wherein,
the content of the active component is 0.1-0.6%; and/or
The content of the transition metal is 0.1-2%; and/or
The content of alkali metal is 0.1-1%.
4. The catalyst according to any one of claims 1 to 3,
one or more of the active component, the alkali metal and the transition metal is/are loaded on the carrier by a vacuum impregnation method, preferably the active component, the alkali metal and the transition metal are loaded on the carrier by a vacuum impregnation method.
5. A process for preparing the catalyst of any one of claims 1 to 4, comprising:
a) preparing an MFI molecular sieve carrier by adopting a hydrothermal synthesis method;
b) one or more of the active component, the alkali metal and the transition metal are loaded on the carrier by a vacuum impregnation method.
6. The method of claim 5, wherein,
the preparation method for preparing the MFI molecular sieve carrier by adopting the hydrothermal synthesis method comprises the following steps:
(1) contacting a silicon source, aluminum sulfate, 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:CTABr:H2O＝(15～500)：1：(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.
7. The method of claim 6, 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%; and extruding and forming to obtain a cylinder with the diameter of 1-4 mm and the length of 3-8 cm.
8. The method according to any one of claims 5 to 7, wherein the step of loading the active component, the alkali metal and the transition metal on the carrier using a vacuum impregnation method comprises:
adding a solution containing an active component source, an auxiliary alkali metal source and a transition metal source into a carrier, vacuumizing at 0.01-0.05 MPa, wherein the vacuum temperature is as follows: dipping at 80-150 ℃ for 0.5-8 hours, and roasting at 300-500 ℃ for 3-12 hours.
9. The method of claim 8, wherein,
the transition metal source is transition metal chloride and/or transition metal nitrate; and/or
The alkali metal source is selected from one or more of alkali metal nitrate, alkali metal chloride and alkali metal sulfate; and/or
The active ingredient source is selected from a salt containing an active ingredient element and/or a complex containing an active ingredient element.
10. Use of a catalyst according to any one of claims 1 to 4 and a catalyst prepared by a process according to any one of claims 5 to 9 in the dehydrogenation of propane to produce propylene.
Technical Field
The invention relates to a supported catalyst for preparing propylene by propane dehydrogenation and a preparation method and application thereof.
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 co-production and light oil (naphtha and light diesel oil) cracking process is one of the most promising methods, but the petroleum reserves are limited, the propylene is limited by the raw material sources, and the large-scale increase is difficult, so that the new routes for preparing low-carbon olefins such as propylene and the like are vigorously developed in various countries, and particularly, the propane with rich sources and low price is used as the raw material to perform dehydrogenation reaction to prepare the propylene. The propane dehydrogenation reaction is a strong endothermic reaction and is limited by thermodynamic equilibrium, so that a relatively ideal propylene yield can be obtained under the conditions of low pressure and high temperature, and the problems of poor catalyst performance, low selectivity and the like caused by the aggravation of propane cracking reaction and deep dehydrogenation due to excessively high reaction temperature are solved, so that the preparation of a dehydrogenation catalyst with excellent performance is required, and the conversion rate of propane and the selectivity of propylene are improved.
In the catalyst commonly used in the field of direct dehydrogenation, Pt is used as an active component, so that the catalyst is environment-friendly and has wide application. In the preparation process of Pt-based catalyst, chloroplatinic acid is generally adopted as precursor of Pt to cause catalysisIn the preparation process of the catalyst, Cl is contained-And introducing ions. In order to control the content of chloride ions in the catalyst, the catalyst needs to be subjected to high-temperature hydrothermal treatment, and the process can cause Pt active components to aggregate and grow, even cause sintering of Pt, so that the catalyst is permanently inactivated.
The carrier of dehydrogenation catalyst is active alumina and zinc aluminate spinel, and besides, molecular sieve, zirconia, carbon material and other carrier are also used for dehydrogenation reaction. In the catalysis taking a molecular sieve as a carrier, a ZSM series molecular sieve with ten-membered rings is mainly selected to obtain the dehydrogenation catalyst by an impregnation method.
Many techniques such as those disclosed in application nos. 201010292066.4, 201010588617.1, and 200810042177.2 have been reported. Because the Pt nano particles obtained by conventional impregnation have relatively large diameters, and orifices of MFI type molecular sieves such as ZSM-5 and the like are 0.54-0.56 nm, active components cannot enter internal pore channels of the MFI type molecular sieves such as ZSM-5 and the like when the conventional impregnation method is used for loading Pt, and therefore the active components need to be modified, and the corresponding impregnation method needs to be improved.
Article [ Huangli, Wangxianghua, Xuan, etc., Pt-Sn-Na propane dehydrogenation propylene preparation catalyst using ZSM-5 molecular sieve treated by alkali liquor as carrier, petrochemical technology and application, 2015, 33 (3): 216-220 ] the ZSM-5 molecular sieve generates a mesoporous structure through alkali liquor treatment, the external specific surface area and the total pore volume of the carrier are increased, the dispersion of active components of the catalyst and the diffusion and desorption of hydrocarbon molecules are facilitated, and meanwhile, the strong acid center of the molecular sieve is weakened, and the carbon deposition resistance is increased. And then, the molecular sieve after alkali treatment is used as a carrier to prepare the propane dehydrogenation catalyst, after 7 hours of reaction, the propane conversion rate is still kept at 29.6%, the Pt dispersion degree is high, the deactivation rate and the carbon deposition mass fraction are low, and the dehydrogenation reaction stability is better. In addition, the performance of the dehydrogenation catalyst is improved by adopting a method of modifying molecular sieve pore paths.
In the propane dehydrogenation reaction, the profit space for obtaining each ton of propylene is determined by the price difference between propane and propylene, and the propylene selectivity is provided under the condition of similar conversion rate, so that the loss of propane can be reduced undoubtedly, and the influence on improving the economic benefit of propane dehydrogenation enterprises is great.
CN107303497 reports a hierarchical pore dehydrogenation catalyst and a preparation method thereof, and discloses a catalyst which takes hierarchical pore ZSM-5 and alumina as carriers, Pt as an active component and Sn and Na as auxiliary agents. After the multi-stage hole ZSM-5 is treated by ammonium, the content of mesopores is increased, the specific surface area of a molecular sieve in the multi-stage hole is high, the pore volume of the mesopores is 0.2-0.55 cm3/g, the pore diameters of the mesopores are distributed in a range of 5-12 nm, and the volume of the mesopores accounts for 60-85% of the total pore volume. The catalyst prepared by the method is prepared at the temperature of 620 ℃, and the hydrogen: under the condition that the volume ratio of the propane is 0.8:1, the conversion rate of the propane is up to 38 percent, and the selectivity is up to 96.7 percent.
CN104307555 adopts a molecular sieve containing hetero atoms as a carrier, and obtains an MFI molecular sieve catalyst for converting propane dehydrogenation into propylene by soaking Pt active components and the like, but the reaction temperature of the dehydrogenation catalyst is higher, and the propylene selectivity is 95% at most under the condition that hydrogen is used as diluent gas.
Disclosure of Invention
The invention aims to provide a propane dehydrogenation catalyst with high selectivity, and a preparation method and application thereof.
In order to achieve the above object, the present invention provides a supported catalyst for propylene production by propane dehydrogenation, which comprises the following components in percentage by weight,
a) the content of an active component is 0.05-1%, and the active component element is one or more of Pt, Pd, Ru and Rh;
b) the content of transition metal is 0.05-3%, and the transition metal is one or more of Sn, Zn, Fe, Ni and Co;
c) the content of alkali metal is 0.05-2%;
d) the content of the carrier MFI molecular sieve is 94-99.5%.
Preferably, the active component is Pt and/or Pd; and/or
The alkali metal is one or more of Li, Na, K and Cs, and is preferably Na and/or K; and/or
The transition metal is one or more of Sn, Fe and Zn; and/or
The carrier MFI molecular sieve is one or more of ZSM-5, ZSM-11 and ZSM-35, preferably ZSM-5 and/or ZSM-11; and/or
The catalyst is distributed in a multi-stage pore mode, and the mesoporous volume is 0.18-0.40 cm3The pore size distribution of the mesopores is 2-10 nm, and the proportion of the mesopores is 15-50%.
Preferably, the content of the active component is 0.1-0.6%.
Preferably, the content of the transition metal is 0.1-2%.
Preferably, the content of alkali metal is 0.1-1%.
Preferably, one or more of the active component, the alkali metal and the transition metal is/are loaded on the carrier by a vacuum impregnation method.
Preferably the active component, the alkali metal and the transition metal are supported on the support by means of vacuum impregnation.
Preferably, the method of preparing the catalyst of the present invention comprises:
a) preparing an MFI molecular sieve carrier by adopting a hydrothermal synthesis method;
b) and loading the active component, the alkali metal and the transition metal on the carrier by adopting a vacuum impregnation method.
Preferably, the preparation method for preparing the MFI molecular sieve carrier by using the hydrothermal synthesis method comprises the following steps:
(1) contacting a silicon source, aluminum sulfate, 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:CTABr:H2O＝(15～500)：1：(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.
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
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%; and 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 the active component, the alkali metal and the transition metal on the carrier using a vacuum impregnation method comprises:
adding a solution containing an active component source, an auxiliary alkali metal source and a transition metal source into a carrier, vacuumizing at 0.01-0.05 MPa, wherein the vacuum temperature is as follows: dipping at 80-150 ℃ for 0.5-8 hours, and roasting at 300-500 ℃ for 3-12 hours.
Preferably, the transition metal source is a transition metal chloride and/or a transition metal nitrate; and/or
The alkali metal source is selected from one or more of alkali metal nitrate, alkali metal chloride and alkali metal sulfate; and/or
The active ingredient source is selected from a salt containing an active ingredient element and/or a complex containing an active ingredient element.
The invention provides the catalyst and the application of the catalyst prepared by the method in the preparation of propylene by propane dehydrogenation.
The catalyst of the invention is used for dehydrogenation reaction, has better activity and selectivity, and has very high propylene selectivity when being used for propane dehydrogenation.
According to the preferred embodiment of the invention, 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, additives and other species in the pore channels of the molecular sieve is increased by vacuum impregnation. The limit effect of the pore canal size is utilized, the aggregation of active components such as Pt and the like can be reduced, the service life of the catalyst is prolonged, meanwhile, the addition of the auxiliary agent and the alkali metal improves the acidity of the catalyst, reduces carbon deposition and improves the selectivity of the catalyst.
Drawings
FIG. 1 is a graph showing adsorption and desorption curves of a sample of the dehydrogenation catalyst obtained in example 1 of the present invention.
Detailed Description
The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.
In order to achieve the above object, the present invention provides a supported catalyst for propylene production by propane dehydrogenation, which comprises the following components in percentage by weight,
a) the content of an active component is 0.05-1%, and the active component element is one or more of Pt, Pd, Ru and Rh;
b) the content of transition metal is 0.05-3%, and the transition metal is one or more of Sn, Zn, Fe, Ni and Co;
c) the content of alkali metal is 0.05-2%;
d) the content of the carrier MFI molecular sieve is 94-99.5%.
The catalyst of the invention has higher dehydrogenation activity, and particularly has high propylene selectivity when being used for propane dehydrogenation to propylene.
According to a preferred embodiment of the present invention, the content of the active ingredient is preferably 0.1 to 0.6%.
According to a preferred embodiment of the present invention, the content of the transition metal is preferably 0.1 to 2%.
According to a preferred embodiment of the present invention, the content of the alkali metal is preferably 0.1 to 1%.
According to a preferred embodiment of the present invention, preferably, one or more of the active component, the alkali metal and the transition metal are loaded on the carrier by a vacuum impregnation method, and more preferably, the active component, the alkali metal and the transition metal are loaded on the carrier by a vacuum impregnation method.
According to a preferred embodiment of the present invention, it is preferred that the active component is Pt and/or Pd.
According to a preferred embodiment of the invention, the alkali metal is one or more of Li, Na, K and Cs, preferably Na and/or K.
According to a preferred embodiment of the present invention, the transition metal is one or more of Sn, Fe and Zn.
According to a preferred embodiment of the present invention, the carrier MFI molecular sieve is one or more of ZSM-5, ZSM-11 and ZSM-35, preferably ZSM-5 and/or ZSM-11.
According to a preferred embodiment of the invention, the catalyst is distributed in a multi-stage pore distribution, and the mesoporous volume is 0.18-0.40 cm3The pore size distribution of the mesopores is 2-10 nm, and the proportion of the mesopores is 15-50%.
According to a preferred embodiment of the present invention, a molecular sieve catalyst for propane dehydrogenation to produce propylene comprises the following components by weight percentage:
a) any one of main active components Pt, Pd, Ru and Rh with the content of 0.05-1.0%;
b) any one or two of transition metals Sn, Zn, Fe, Ni and Co, the content of which is 0.05-3.0%;
c) any one of alkali metals Li, Na, K and Cs, wherein the content of the alkali metals Li, Na, K and Cs is 0.05-2.0%;
d) the carrier is an MFI type molecular sieve, and the content of the carrier is 94-99.5%.
According to a preferred embodiment of the present invention, the MFI carrier is preferably a hierarchical pore distribution, with mesopores0.18-0.40 cm3The pore diameter distribution of the mesopores is 2-10 nm, and the proportion of the mesopores is 15-50%.
According to a preferred embodiment of the present invention, the active component is preferably Pt or Pd, or a mixture thereof, in weight percentage of the propane dehydrogenation catalyst, and the content of the active component is preferably in the range of 0.1 to 0.6%.
According to a preferred embodiment of the present invention, the transition metal is any one or a mixture of two of Sn, Fe and Zn, preferably in the range of 0.1 to 2% by weight of the propane dehydrogenation catalyst.
According to a preferred embodiment of the present invention, the alkali metal is any one of Li, Na, K and Cs, preferably Na or K, in a preferred range of 0.1 to 1.0% by weight of the propane dehydrogenation catalyst.
According to a preferred embodiment of the present invention, the MFI support is selected from one or more of ZSM-5, ZSM-11, ZSM-35, preferably any one of ZSM-5 or ZSM-11.
The catalyst has the composition, so that the purpose of the invention can be realized, no special requirement is required on the preparation method of the catalyst, and aiming at the invention, the preparation method of the molecular sieve catalyst for preparing propylene by propane dehydrogenation is provided, and the steps comprise: 1) preparing an MFI molecular sieve carrier by adopting a hydrothermal synthesis method; 2) and loading the active component, the auxiliary agent alkali metal and the transition metal to the carrier by adopting vacuum impregnation to obtain a required catalyst sample.
Preferably, the method of preparing the catalyst of the present invention comprises:
a) preparing an MFI molecular sieve carrier by adopting a hydrothermal synthesis method;
b) one or more of the active component, the alkali metal and the transition metal are loaded on the carrier by a vacuum impregnation method.
Preferably, the preparation method for preparing the MFI molecular sieve carrier by using the hydrothermal synthesis method comprises the following steps:
(1) contacting a silicon source, aluminum sulfate, 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:CTABr:H2O＝(15～500)：1：(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.
According to a preferred embodiment of the invention, the water washing in the step (2) is performed 3-5 times by using deionized water 2-5 times the weight of the molecular sieve in the step (1).
According to a preferred embodiment of the present invention, the conditions for drying in step (2) include: drying temperature: 60-120 ℃, the drying time is determined according to the temperature, and the preferable drying time is as follows: 4-24 hours.
According to a preferred embodiment of the present invention, the conditions for the calcination in step (2) include: the roasting temperature is 400-700 ℃, the roasting time is determined according to the temperature, and the roasting time is preferably 3-12 hours.
According to a preferred embodiment of the present invention, in the step (3), the treatment time is 1 to 20 hours.
According to a preferred embodiment of the invention, the lye may be a conventional lye, for which the sodium hydroxide solution and/or the potassium hydroxide solution is preferred. The sodium hydroxide solution is preferred, and the mass concentration of the sodium hydroxide solution is more preferably 0.1 to 10%.
According to a preferred embodiment of the present invention, in the step (4), the silicon solution is SiO-containing2The solid content of the colloidal solution is 10-40%.
According to a preferred embodiment of the invention, the extrusion molding is carried out, and preferably the extrusion molding is carried out to obtain a cylinder with the diameter of 1-4 mm and the length of 3-8 cm.
According to a preferred embodiment of the present invention, the step of loading the active component, the alkali metal and the transition metal on the carrier using a vacuum impregnation method comprises:
adding a solution containing an active component source, an auxiliary alkali metal source and a transition metal source into a carrier, vacuumizing at 0.01-0.05 MPa, preferably at a vacuum temperature: the dipping time is preferably 0.5 to 8 hours at 80 to 150 ℃, and then the roasting time is preferably 300 to 500 ℃, and more preferably 3 to 12 hours.
According to the invention, the transition metal source is a transition metal chloride and/or a transition metal nitrate.
According to the invention, the alkali metal source is selected from one or more of the group consisting of alkali metal nitrates, alkali metal chlorides and alkali metal sulfates.
According to the invention, the source of the active ingredient is selected from salts containing the active ingredient element and/or complexes containing the active ingredient element.
According to a preferred embodiment of the invention, a preparation method of a molecular sieve catalyst for preparing propylene by propane dehydrogenation is provided, which comprises the preparation and post-treatment methods of carrier MFI type molecular sieve, and comprises the following steps:
(1) preparing an MFI type molecular sieve by using a hydrothermal synthesis method: contacting silicon solution, aluminum sulfate, deionized water and hexadecyl trimethyl ammonium bromide, and adjusting the pH value to form gel, wherein the molar ratio of each substance is SiO2:Al2O3:CTABr:H2O＝(15～500)：1：(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 second step into 0.1-1.0% alkali liquor, and treating for 1-20 hours at 50-90 ℃ to obtain a molecular sieve carrier with multilevel pores;
(4) and (3) adding the carrier obtained in the third step into a 10-30% silicon solution, uniformly mixing, extruding and forming to obtain a cylinder with the diameter of 1-4 mm and the length of 3-8 cm.
In the preparation method of the MFI type molecular sieve catalyst for propylene preparation by propane dehydrogenation, the method further comprises the step (2) of washing 3-5 times of deionized water which is 2-5 times of the weight of the molecular sieve in the step (1); the drying temperature is as follows: drying at 60-120 ℃ for: 4-24 hours; the roasting temperature is 400-700 ℃, and the roasting time is 3-12 hours.
In the preparation method of the molecular sieve catalyst for preparing propylene by propane dehydrogenation, the main active components are noble metals Pt and Pd, the auxiliary agent is selected from transition metals and alkali metals, and the catalyst is obtained by adopting a vacuum impregnation method and comprises the following specific steps:
adding a solution containing an active component source, an auxiliary transition metal source and an alkali metal source into a carrier, vacuumizing at 0.01-0.05 MPa, wherein the vacuum temperature is as follows: dipping at 80-150 ℃ for 0.5-8 hours, and roasting at 300-500 ℃ for 3-12 hours.
According to a preferred embodiment of the invention, the active components Pt, Pd, Ru, Rh are derived from platinum-containing substances which are chloroplatinic acid, platinum acetylacetonate, platinous chloride and compounds or complexes containing palladium, rhodium, ruthenium.
In the auxiliary agent, the transition metal is Sn, Zn, Fe, Ni and Co source selected from chlorides or nitrates thereof; the source of the alkali metals Li, Na, K and Cs is selected from nitrate, chloride or sulfate thereof.
The invention provides the catalyst and the application of the catalyst prepared by the method in the preparation of propylene by propane dehydrogenation.
In the invention, a catalyst sample is carried out by adopting a Micromeritic ASAP2020M + C full-automatic specific surface and micropore physical adsorption instrument of American Mike instruments, can carry out full-automatic specific surface area and mesopore/micropore analysis, and has a high-precision pressure sensor; different adsorption media may also be used.
The test conditions were as follows:
degassing conditions set degassing stage values: the temperature rise speed is 10 ℃/min, the target temperature is 90 ℃, the degassing rate is 5.0mmHg/s, the vacuum degree end point is 10 mu mHg, and the degassing time is 60 min. Heating stage value: heating rate 10 ℃/min, keeping temperature 200 ℃, keeping time 240min, keeping pressure: 100 mmHg.
Analysis conditions set values: the vacuum pumping rate is 5.0mmHg/s, the final vacuum degree is 10 μmHg, the degassing time is 60min, and the pressure P is0And T, selection1, detection interval time 120 min. Nitrogen was chosen as the fill gas for analysis.
The detection range of the instrument is as follows: specific surface analysis from 0.0005m2(ii) g to no upper limit, pore diameter measurement range ofThe resolution of the microporous section isPore volume minimum measurement was 0.0001cm3/g。
The catalyst evaluation conditions in the isothermal fixed bed reactor were as follows: about 10 grams of catalyst and 10 grams of magnetic rings are uniformly mixed and are filled into a quartz tube reactor with the inner diameter of phi 22 mm-phi 18mm, the reaction pressure is normal pressure, and the gas mass space velocity is 1.0 hour-1And the reaction temperature was 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; selectivity of olefin as a percentage of propylene content in other gas components than propane after reaction, i.e. propylene content divided by C1、C2、C4And the percentage of the sum of the 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) and 6.66 g of aluminum sulfate 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. transferring the sample into a high-pressure reaction kettle, crystallizing at 170 ℃ for 60 hours, and filtering and washing the crystallized product toAfter neutralization, drying at 120 ℃, and roasting at 500 ℃ for 4 hours to obtain MFI type molecular sieve raw powder. The prepared sample was added to a 1.0% sodium hydroxide solution (hereinafter, mass concentration), and treated at 70 ℃ for 5 hours. 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: 0.21 g of chloroplatinic acid, 0.28 g of sodium nitrate and 0.13 g of stannous chloride are weighed and dissolved in 50 ml of deionized water, and the mixture is fully stirred to be dissolved uniformly. Then 10 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 the temperature of 90 ℃, the vacuum degree is 0.01MPa, and the dipping time is kept for 2 hours. And transferring the dried sample into a muffle furnace at 500 ℃, and roasting for 4 hours to obtain the required dehydrogenation 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 mesoporous volume is 0.20cm by a Micromeritic ASAP2020M + C instrument3(g), mesoporous pore diameter: 3.9nm, mesopore ratio: 34 percent.
Fig. 1 is an adsorption and desorption curve of a dehydrogenation catalyst sample obtained in example 1 of the present invention, and it can be seen from fig. 1 that an adsorption and desorption hysteresis loop exists at higher and lower relative pressures, which indicates that the catalyst sample has both macroporous and mesoporous structures.
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 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 and the auxiliary agents of alkali metal and noble metal adopts normal pressure impregnation, the composition content, the evaluation method and the like of each component after the impregnation are the same as those of example 1, and the catalyst is marked as B1. Analysis was performed by a Micromeritic ASAP2020M + C instrument, wherein the mesopore volume: 0.53cm3(g), mesoporous pore diameter: 14.1nm, mesopore ratio: 13 percent. The catalyst performance was evaluated by the same method as in example 1, and the results 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, 36.50 g of cetyltrimethylammonium bromide (hereinafter abbreviated as CTABr) and 6.66 g of aluminum sulfate 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. 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 100 ℃, and roasting at 500 ℃ for 4 hours to obtain 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: 0.32 g of chloroplatinic acid, 0.06 g of sodium nitrate and 0.26 g of stannous chloride are weighed, dissolved in 50 ml of deionized water, and fully stirred to be dissolved uniformly. Then 10 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 4 hours. And transferring the dried sample into a muffle furnace at 500 ℃, and roasting for 6 hours to obtain the required dehydrogenation catalyst C. Analysis was performed by a Micromeritic ASAP2020M + C instrument, wherein the mesopore volume: 0.39cm3(g), mesoporous pore diameter: 8.5nm, mesopore ratio: 48 percent. By comparison with example 1The catalyst performance was evaluated in the same manner, and the results 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 900 g of deionized water, 364.45 g of cetyltrimethylammonium bromide (hereinafter abbreviated as CTABr) and 6.66 g of aluminum sulfate 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: 0.11 g of chloroplatinic acid, 0.56 g of sodium nitrate and 0.13 g of stannous chloride are weighed, dissolved in 50 ml of deionized water, and fully stirred to be dissolved uniformly. Then 10 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 120 ℃, the degree of vacuum pumping is 0.01MPa, and the dipping time is kept for 1 hour. And transferring the dried sample into a muffle furnace at 500 ℃, and roasting for 4 hours to obtain the required dehydrogenation catalyst D. Analysis was performed by a Micromeritic ASAP2020M + C instrument, wherein the mesopore volume: 0.29cm3(g), mesoporous pore diameter: 5.6nm, mesopore ratio: 42 percent. The catalyst performance was evaluated by the same method as in example 1, and the results 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 540 g of deionized water, 72.89 g of cetyltrimethylammonium bromide (hereinafter abbreviated as CTABr) and 6.66 g of aluminum sulfate 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: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: 0.04 g of chloroplatinic acid, 0.28 g of sodium nitrate and 0.03 g of stannous chloride are weighed, dissolved in 50 ml of deionized water, and fully stirred to be dissolved uniformly. Then 10 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. And transferring the dried sample into a muffle furnace at 500 ℃, and roasting for 4 hours to obtain the required dehydrogenation catalyst E. The mesoporous volume is 0.18cm by a Micromeritic ASAP2020M + C instrument3(g), mesoporous pore diameter: 3.6nm, mesopore ratio: 20 percent. The catalyst performance was evaluated by the same method as in example 1, and the results are shown in Table 1.
Example 5
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 540 g of deionized water, 109.34 g of cetyltrimethylammonium bromide (hereinafter abbreviated as CTABr) and 6.66 g of aluminum sulfate 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:H2O500: 1: 30: 3000. 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 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 6 hours while maintaining the temperature at 50 ℃. Mixing the alkali liquorAnd carrying out suction filtration, drying and roasting on the treated sample for later use, wherein the sample is marked 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: 0.13 g of palladium chloride, 0.28 g of sodium nitrate and 0.03 g of stannous chloride are weighed and dissolved in 50 ml of deionized water, and the mixture is fully stirred to be dissolved uniformly. Then 10 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 70 ℃, the vacuum degree is 0.01MPa, and the dipping time is kept for 2 hours. And transferring the dried sample into a muffle furnace at 500 ℃, and roasting for 6 hours to obtain the required dehydrogenation catalyst F. The mesoporous volume is 0.27cm by a Micromeritic ASAP2020M + C instrument3(g), mesoporous pore diameter: 4.9nm, mesopore ratio: 41 percent. The catalyst performance was evaluated by the same method as in example 1, and the results are shown in Table 1.
Example 6
Preparing a ZSM-5 molecular sieve by using a hydrothermal synthesis method: 60.08 g of silica sol having a solid content of 20% was dissolved in 540 g of deionized water, and 218.67 g of cetyltrimethylammonium bromide (hereinafter abbreviated as CTABr) and 6.66 g of aluminum sulfate 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:H2O100: 1: 60: 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 80 ℃, 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 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: 0.11 g of chloroplatinic acid, 0.28 g of sodium nitrate and 0.46 g of zinc nitrate are weighed, dissolved in 50 ml of deionized water and stirred sufficiently to ensure thatThe dissolution is uniform. Then 10 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 4 hours. And transferring the dried sample into a muffle furnace at 550 ℃, and roasting for 4 hours to obtain the required dehydrogenation catalyst G. The mesoporous volume is 0.21cm by a Micromeritic ASAP2020M + C instrument3(g), mesoporous pore diameter: 4.2nm, mesoporous ratio: 36 percent. The catalyst performance was evaluated by the same method as in example 1, and the results 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 72.89 g of cetyltrimethylammonium bromide (hereinafter abbreviated as CTABr) and 19.98 g of aluminum sulfate 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 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 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 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: 0.21 g of chloroplatinic acid, 0.26 g of potassium nitrate and 0.43 g of ferric nitrate were weighed out and dissolved in 50 ml of deionized water, and the mixture was stirred sufficiently to dissolve the components uniformly. Then 10 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 degree of vacuum pumping is 0.01MPa, and the dipping time is kept for 3 hours. And transferring the dried sample into a muffle furnace at 500 ℃, and roasting for 6 hours to obtain the required dehydrogenation catalyst H. The mesoporous volume is 0.23cm by a Micromeritic ASAP2020M + C instrument3(g), mesoporous pore diameter: 4.6nm, mesopore ratio: 39 percent. By way of example1 the catalyst performance was evaluated in the same manner, and the results 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 360 g of deionized water, 72.89 g of cetyltrimethylammonium bromide (hereinafter abbreviated as CTABr) and 6.66 g of aluminum sulfate 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: 2000. 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 90 ℃, 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 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: 0.21 g of chloroplatinic acid, 0.10 g of potassium nitrate and 0.03 g of stannous chloride are weighed, dissolved in 50 ml of deionized water, and sufficiently stirred to be uniformly dissolved. Then 10 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 1 hour. And transferring the dried sample into a muffle furnace at 500 ℃, and roasting for 3 hours to obtain the required dehydrogenation catalyst I. The mesoporous volume is 0.20cm by a Micromeritic ASAP2020M + C instrument3(g), mesoporous pore diameter: 4.0nm, mesopore ratio: 37 percent. The catalyst performance was evaluated by the same method as in example 1, and the results are shown in Table 1.
Example 9
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 180 g of deionized water, 36.25 g of cetyltrimethylammonium bromide (hereinafter abbreviated as CTABr) and 6.66 g of aluminum sulfate were added, and the above sample was stirred at room temperature for 3 hours to form a uniform gel. GelThe materials in the composition are as follows in molar ratio: SiO 22:Al2O3:CTABr:H2O500: 1: 10: 1000. 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 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 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: 0.26 g of chloroplatinic acid, 0.28 g of sodium nitrate and 0.03 g of stannous chloride are weighed, dissolved in 50 ml of deionized water, and fully stirred to be dissolved uniformly. Then 10 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. And transferring the dried sample into a muffle furnace at 500 ℃, and roasting for 4 hours to obtain the required dehydrogenation catalyst J. The mesoporous volume is 0.29cm by a Micromeritic ASAP2020M + C instrument3(g), mesoporous pore diameter: 5.3nm, mesopore ratio: and 43 percent. The catalyst performance was evaluated by the same method as in example 1, and the results are shown in Table 1.
Example 10
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, 72.89 g of cetyltrimethylammonium bromide (hereinafter abbreviated as CTABr) and 6.66 g of aluminum sulfate 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:H2O500: 1: 20: 2000. 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 110 ℃, 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 8 hours while maintaining the temperature at 60 ℃. Treating the alkaline solutionAnd carrying out suction filtration, drying and roasting on the obtained sample 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: 0.16 g of chloroplatinic acid, 0.28 g of sodium nitrate and 0.09 g of stannous chloride are weighed and dissolved in 50 ml of deionized water, and the mixture is fully stirred to be dissolved uniformly. Then 10 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 100 ℃, the degree of vacuum pumping is 0.01MPa, and the dipping time is kept for 2 hours. And transferring the dried sample into a muffle furnace at 500 ℃, and roasting for 5 hours to obtain the required dehydrogenation catalyst K. The mesoporous volume is 0.31cm by a Micromeritic ASAP2020M + C instrument3(g), mesoporous pore diameter: 5.8nm, mesopore ratio: 45 percent. The catalyst performance was evaluated by the same method as in example 1, and the results are shown in Table 1.
Example 11
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 without being treated by alkali liquor, the impregnation of active components, auxiliaries and the like is the same as that in example 1, the 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, and the catalyst is marked as L. The mesoporous volume is 0.72cm by a Micromeritic ASAP2020M + C instrument3(g), mesoporous pore diameter: 19.3nm, mesopore ratio: 10 percent. The catalyst performance was evaluated by the same method as in example 1, and the results are shown in Table 1.
Comparative example 2
The catalyst carrier was prepared in the same manner as in example 1, except that the binder used in the extrusion molding was boehmite, etc., the amount of the binder added was the same as that used in the silicon solution, the impregnation of the active component and the auxiliary agent, etc. was the same as in example 1, the impregnation was performed in vacuum, the composition contents and evaluation methods of the components after the impregnation were the same as in example 1, and the catalyst was designated as B2. Analysis was performed by a Micromeritic ASAP2020M + C instrument, wherein the mesopore volume: 0.66cm3(g), mesoporous pore diameter: 15.8nm, mesopore ratio: 14 percent. By comparison with example 1The catalyst performance was evaluated in the same manner, and the results are shown in Table 1.
TABLE 1