CN111054381B

CN111054381B - Catalyst for dehydrogenation of light alkane

Info

Publication number: CN111054381B
Application number: CN201811201405.6A
Authority: CN
Inventors: 柯俊; 缪长喜; 吴文海
Original assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Current assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Priority date: 2018-10-16
Filing date: 2018-10-16
Publication date: 2023-05-02
Anticipated expiration: 2038-10-16
Also published as: CN111054381A

Abstract

The invention discloses a catalyst for light alkane dehydrogenation, wherein the dispersion degree of Pt is 12-33%; the coating comprises the following components in parts by weight: a) 0.1 to 6.5 parts of Pt-Co nano particles or oxides thereof; b) 0.1-9.2 parts of M or an oxide thereof, wherein M is selected from Cs and/or La; c) 0.1 to 9.5 parts of Zn-Ga-O or Y-Ga-O binary metal oxide; d) 80-99 parts of carrier S, S is selected from at least one of alumina, silica and titanium oxide. The invention aims to solve the technical problem that the catalyst is easy to deactivate in the prior art, and the provided catalyst and the preparation method thereof have the advantage of difficult deactivation when being used in the reaction of preparing unsaturated hydrocarbon products by dehydrogenating light chain alkane and naphthene.

Description

Catalyst for dehydrogenation of light alkane

Technical Field

The invention discloses a catalyst with higher activity for light alkane dehydrogenation reaction and a preparation method thereof.

Background

Light unsaturated hydrocarbons, such as propylene, butene and isobutylene, are very important organic chemical feedstocks which, together with ethylene, are considered the basis of modern petrochemical industry for the production of polymers, gasoline, detergents and other chemical feedstocks, and the like. The conventional method for preparing propylene, butene and isobutene adopts ethylene co-production and light oil (naphtha and light diesel) cracking processes, but petroleum reserves are limited, and propylene, butene and isobutene are limited by target products and are difficult to increase in large scale, so that various countries in the world are devoted to developing new routes for preparing propylene, butene and isobutene. The method for preparing the corresponding olefin by using light alkane (such as propane, n-butane, isobutane and the like) in petrochemical byproducts or natural gas and the like as raw materials through a direct dehydrogenation process is greatly paid attention. In recent years, the demand of human beings for petrochemical raw materials and petrochemical products in the world is continuously increased, the demand of propylene, butylene and isobutene serving as petrochemical basic raw materials is continuously increased, the increasing demand of the propylene, butylene and isobutene cannot be met by the traditional conventional method, and the global shortage is caused. Along with the increasing shortage of petroleum resources, the production of light unsaturated hydrocarbons has been converted from a technical route which simply depends on petroleum as a raw material to diversification of the raw material, in particular to a technical route for preparing unsaturated hydrocarbons by taking light alkane as the raw material, and the dehydrogenation of light alkane with abundant sources and low price is one of the most promising methods for preparing corresponding unsaturated hydrocarbons. At present, tens of propane, n-butane or isobutane dehydrogenation devices are operated in the world, and main dehydrogenation technologies include an Oleflex process of UOP, a Catofin process of Lummus, a STAR process of Uhde, a PDH process of Linde, and an FBD process cooperatively developed by Snamprogetti-Yarstez.

Due to simple preparation method and low cost, pt/Al ₂ O ₃ Catalysts are widely used as dehydrogenation catalysts for light alkanes, but the catalysts require high temperature calcination and reduction with hydrogen during the preparation process due to Pt and Al ₂ O ₃ The interaction between the two is weaker, pt atoms are easy to gather in the preparation process, the size is enlarged, and the activity of the catalyst in the catalysis process is reduced finally; plus Al ₂ O ₃ The weak acidity of the surface can quickly generate coking after the catalytic reaction starts, so that the activity of the catalyst is easy to be reduced in the catalytic process, thus Pt/Al ₂ O ₃ Not ideal dehydrogenation catalyst for light alkane, and research on dehydrogenation catalyst which is difficult to deactivate is urgently needed. Because the dehydrogenation effect of Pt is best in all metals, in the research of light alkane dehydrogenation catalysts, the important point is to select proper auxiliary agents to change the carrier or regulate the surface property of the carrier, play a role in regulating the size of Pt, the specific surface area of the carrier, the acidity and alkalinity of the carrier and the like, or generate other beneficial effects, so that the activity of the catalyst can be kept stable for a long time.

Regarding alkane dehydrogenation catalysts containing noble metals as active components, part of elements of group IVA and IIIA represented by Sn are commonly used modification aids, and patent CN106607021A, CN106588544A, CN107537485A and other patents disclose dehydrogenation catalysts containing Pt, sn and other aids, respectively, for improving the reactivity of the catalysts for catalyzing the dehydrogenation reaction of light alkanes such as propane, isobutane, isopentane and the like. CN107008260A, CN105642264A discloses a pass-through carrier A method for regulating the performance of a low paraffin dehydrogenation catalyst. CN105102120A discloses a dehydrogenation catalyst for naphthenes by reacting with Pt/Al ₂ O ₃ Group 3 metals are introduced into the catalyst as auxiliary agents. CN103443060B discloses a method for catalyzing dehydrogenation of saturated cyclic hydrocarbons and five membered ring compounds with Pt-Sn dehydrogenation catalyst.

The light alkane dehydrogenation catalyst has been greatly developed at present, but the performance of the catalyst has room for further improvement, so that the light alkane dehydrogenation catalyst, particularly an auxiliary agent in the light alkane dehydrogenation catalyst, needs to be subjected to fine design and regulation.

Disclosure of Invention

One of the technical problems to be solved by the invention is that the light alkane dehydrogenation catalyst is easy to deactivate in the prior art, and a novel catalyst for light alkane dehydrogenation reaction is provided. The second technical problem to be solved by the invention is to provide a catalyst preparation method corresponding to one of the technical problems to be solved.

In order to solve one of the technical problems, the invention adopts the following technical scheme:

A catalyst for dehydrogenation of light alkane, wherein the dispersity of Pt of the catalyst is 12-33%.

In the technical scheme, the catalyst comprises the following components in parts by weight:

a) 0.1 to 6.5 parts of Pt-Co nano particles or oxides thereof;

b) 0.1-9.2 parts of M or an oxide thereof, wherein M is selected from Cs and/or La;

c) 0.1 to 9.5 parts of Zn-Ga-O or Y-Ga-O binary metal oxide;

d) 80-99 parts of carrier S, S is selected from at least one of alumina, silica and titanium oxide.

In the above technical scheme, preferably, the part of the Pt-Co nano particles or the oxides thereof in the component a) is 0.1-3.6 parts by weight.

In the above-mentioned technical scheme, it is preferable that Co-Pt in the component a) is (0.06-0.94): 1 in terms of mole ratio.

In the above-mentioned embodiments, it is more preferable that Co-Pt in the component a) is (0.25 to 0.68): 1 in terms of molar ratio.

In the above technical scheme, preferably, M is selected from Cs and La.

In the above technical scheme, preferably, the part of M or the oxide thereof is 1.2-4.2 parts by weight.

In the above technical scheme, preferably, the parts by weight of Zn-Ga-O or Y-Ga-O binary metal oxide is 1.2-5.8 parts.

In the above technical scheme, preferably, in the component d), zn, ga or Y, ga is (0.05-0.6) 1 in terms of mole ratio.

In the above technical scheme, preferably, the component d) is selected from Y-Ga-O binary metal oxides.

In the above technical scheme, preferably, the carrier is selected from gamma-Al ₂ O ₃ Or SiO ₂ One of them.

In the above technical scheme, more preferably, the carrier is selected from gamma-Al ₂ O ₃ 。

In the above technical scheme, preferably, the dispersity of Pt is 17% -26%. The method for measuring the dispersity of Pt is as follows: the dispersity of Pt is the percentage of Pt on the surface of the catalyst to all Pt in the catalyst, and the testing method comprises the following steps: and (3) taking a proper amount of catalyst, reducing the catalyst by hydrogen at 300 ℃ on a chemical adsorption and desorption instrument, and obtaining the dispersity of Pt by a carbon monoxide chemical adsorption method at 25 ℃.

In order to solve the second technical problem, the technical scheme adopted by the invention is as follows:

a method for preparing a catalyst corresponding to one of the technical problems to be solved for a light alkane dehydrogenation catalyst, comprising the steps of:

1) Dissolving soluble compounds of Pt and Co, adding a reducing agent and soluble halides, reacting for several hours, and processing to obtain Pt-Co nano particles;

2) Mixing Ga and Zn or Ga and Y soluble salt, adding a carrier S, and regulating pH to be alkaline to obtain a catalyst precursor I;

3) Dissolving soluble salt of M, and adding the dissolved salt into the catalyst precursor I to obtain a catalyst precursor II;

4) Dispersing the Pt-Co nano particles obtained in the steps in a solvent, and adding the Pt-Co nano particles into a catalyst precursor II to obtain a light alkane dehydrogenation catalyst;

5) Preferably, the preparation process also comprises the steps of dipping, drying and roasting;

the dispersity of the Pt catalyst is 12-33%; the coating comprises the following components in parts by weight: a) 0.1 to 6.5 parts of Pt-Co nano particles or oxides thereof; b) 0.1-9.2 parts of M or an oxide thereof, wherein M is selected from Cs and/or La; c) 0.1 to 9.5 parts of Zn-Ga-O or Y-Ga-O binary metal oxide; d) 80-99 parts of carrier S, S is selected from at least one of alumina, silica and titanium oxide.

In the above technical solution, preferably, the soluble salt of Pt is preferably selected from one of chloroplatinic acid or potassium chloroplatinite, and the soluble salt of Co, cs, la, ga, Y, zn element is preferably selected from one of chloride or nitrate.

In the above technical solution, preferably, in step a), the reducing agent is selected from one of polyvinylpyrrolidone or sodium borohydride, and the soluble halide is preferably selected from one of potassium chloride or potassium bromide.

In the above technical scheme, preferably, the dipping temperature in the dipping process is 10-80 ℃, the dipping time is 1-24 hours, the drying temperature is 80-150 ℃, and the drying time is 4-24 hours. The roasting process is to roast for 4-24 hours at the temperature of 450-650 ℃.

The light alkane dehydrogenation catalyst prepared by the method is subjected to activity evaluation in an isothermal fixed bed reactor, and the reaction conditions are as follows: the reaction pressure is 0-1 MPa, the temperature is 300-600 ℃, and the mass airspeed is 0.1-10 h ^-1 The method comprises the steps of carrying out a first treatment on the surface of the The light alkane or the mixture of the light alkane and the hydrogen is contacted and reacted with the catalyst to generate the corresponding unsaturated hydrocarbon.

In the above technical scheme, preferably, the light alkane is at least one of saturated chain alkane or saturated cycloalkane with a boiling point not higher than 110 ℃ under normal pressure.

In the above technical scheme, preferably, the light alkane is at least one selected from propane, n-butane, isobutane, cyclohexane and methylcyclohexane.

In the above technical scheme, preferably, the activation conditions before the reaction of the catalyst are as follows: the reduction temperature is 300-500 ℃, preferably 300-400 ℃, and the hydrogen flow rate in the reduction process is 100-500 mL.min ^-1 Preferably 200 to 400 mL/min ^-1 The reduction time is 2 to 8 hours, preferably 3 to 6 hours.

In the dehydrogenation catalytic process of light alkane, pt is used as an active site of the catalyst, the activity of the Pt is limited by the electronic structure of the Pt, the problem of easy deactivation is solved, and the catalytic activity of the Pt catalyst can be improved by adding a proper auxiliary agent and selecting a proper carrier. The catalyst provided by the invention has the advantages of difficult inactivation compared with other catalysts taking Pt as active sites in the dehydrogenation catalytic reaction of light alkane by adopting Pt-Co nano particles or oxides thereof and utilizing the synergistic effect between the Pt-Co nano particles or oxides thereof and Cs, la, ga, zn, Y and other elements and a corresponding catalyst preparation method, and has better technical effect.

The present invention is further illustrated by the following examples, but the present invention is not limited to the following examples.

Detailed Description

[ example 1 ]

192mg of potassium chloroplatinite, 44mg of cobalt chloride, 500mg of polyvinylpyrrolidone and 5.0g of potassium bromide are dissolved in 300mL of deionized water in a 500mL hydrothermal kettle and uniformly mixed, the mixture is reacted for 1h in a 160 ℃ oven, and Pt-Co nano particles are obtained after centrifugal separation and washing, and are dispersed in ethanol.

283mg of yttrium nitrate, 92.8mg of gallium nitrate were weighed into 50mL of deionized water, and 3.0g of gamma-Al was added ₂ O ₃ After stirring the support for 1h, aqueous ammonia was added dropwise with continued stirring until the pH was 8.5. The product was aged for 2h, suction filtered, washed three times with 500mL of water, dried in an oven at 90 ℃ for 16h, and then put in a muffle furnace for calcination at 450 ℃ for 16h to obtain the catalyst precursor I.

62.2mg of cesium nitrate and 132mg of lanthanum nitrate are weighed and dissolved in 5mL of water, 3.0g of the catalyst precursor I is added into the mixture under stirring, the mixture is immersed for 4 hours at room temperature, and the mixture is dried for 4 hours in a baking oven at 90 ℃ and then is put into a muffle furnace for roasting for 4 hours at 650 ℃ to obtain a catalyst precursor II.

2.0g of the catalyst precursor II was added to ethanol in which 13.0mg of Pt-Co nanoparticles were dispersed with stirring, stirred for 2 hours, dried in an oven at 50℃for 4 hours, and then put into a muffle furnace for calcination at 650℃for 4 hours to obtain a catalyst.

Grinding the obtained catalyst into particles with the particle size of 12-20 meshes, taking 0.1g of the particles, measuring the dispersity of Pt in the catalyst by a carbon monoxide chemisorption method on a chemical absorption and desorption instrument according to the measuring method, taking 1.2g of the particles, mixing and diluting the particles with a proper amount of non-catalytic 20 meshes of quartz sand, and then evaluating the particles in an isothermal fixed bed reactor with the flow of 300 mL.min before evaluation ^-1 Reducing the catalyst for 4 hours at the normal pressure and 350 ℃, and reducing the temperature, and then reducing the catalyst for 2 hours at the normal pressure and 520 ℃ at the airspeed ^-1 The catalyst was used as a representative raw material for light paraffins, hydrogen was mixed with n-butane in a molar ratio of 1.1:1, and the conversion at 1h and 56h of the catalytic reaction was recorded, and the results are shown in Table 1.

[ example 2 ]

192mg of potassium chloroplatinite, 27.5mg of cobalt chloride, 500mg of polyvinylpyrrolidone and 5.0g of potassium bromide are dissolved in 300mL of deionized water in a 500mL hydrothermal kettle and uniformly mixed, reacted for 1h in a 160 ℃ oven, centrifugally separated and washed to obtain Pt-Co nano particles, and the nano particles are dispersed in ethanol.

The catalyst obtained was ground to particles having a particle size of 12 to 20 mesh, the method for measuring the dispersion degree of Pt in the catalyst was the same as in example 1, 1.2g of the catalyst was additionally mixed and diluted with an appropriate amount of catalytically inactive 20 mesh silica sand, and then the mixture was evaluated in an isothermal fixed bed reactor, and hydrogen was used for reduction before the evaluation, and the reduction conditions and the evaluation conditions were the same as in example 1, and the results are shown in table 1.

[ example 3 ]

192mg of potassium chloroplatinite, 74.8mg of cobalt chloride, 500mg of polyvinylpyrrolidone and 5.0g of potassium bromide are dissolved in 300mL of deionized water in a 500mL hydrothermal kettle and uniformly mixed, the mixture is reacted for 1h in a 160 ℃ oven, and Pt-Co nano particles are obtained after centrifugal separation and washing, and are dispersed in ethanol.

[ example 4 ]

192mg of potassium chloroplatinite, 6.6mg of cobalt chloride, 500mg of polyvinylpyrrolidone and 5.0g of potassium bromide are dissolved in 300mL of deionized water in a 500mL hydrothermal kettle and uniformly mixed, the mixture is reacted for 1h in a 160 ℃ oven, and Pt-Co nano particles are obtained after centrifugal separation and washing, and are dispersed in ethanol.

[ example 5 ]

192mg of potassium chloroplatinite, 103mg of cobalt chloride, 500mg of polyvinylpyrrolidone and 5.0g of potassium bromide are dissolved in 300mL of deionized water in a 500mL hydrothermal kettle and uniformly mixed, the mixture is reacted for 1h in a 160 ℃ oven, and Pt-Co nano particles are obtained after centrifugal separation and washing, and are dispersed in ethanol.

[ example 6 ]

2.0g of the catalyst precursor II was added to ethanol in which 2.2mg of Pt-Co nanoparticles were dispersed with stirring, stirred for 2 hours, dried in an oven at 50℃for 4 hours, and then put into a muffle furnace for calcination at 650℃for 4 hours to obtain a catalyst.

[ example 7 ]

2.0g of the catalyst precursor II was added to ethanol in which 26.1mg of Pt-Co nanoparticles were dispersed with stirring, stirred for 2 hours, dried in an oven at 50℃for 4 hours, and then put into a muffle furnace for calcination at 650℃for 4 hours to obtain a catalyst.

[ example 8 ]

2.0g of the catalyst precursor II was added to ethanol in which 52.2mg of Pt-Co nanoparticles were dispersed with stirring, stirred for 2 hours, dried in an oven at 50℃for 4 hours, and then put into a muffle furnace for calcination at 650℃for 4 hours to obtain a catalyst.

[ example 9 ]

2.0g of the above catalyst precursor II was added to ethanol in which 78.3mg of Pt-Co nanoparticles were dispersed with stirring, stirred for 2 hours, dried in an oven at 50℃for 4 hours, and then put into a muffle furnace for calcination at 650℃for 4 hours to obtain a catalyst.

[ example 10 ]

283mg of yttrium nitrate, 92.8mg of gallium nitrate were weighed into 50mL of deionized water, and 3.0g of gamma-Al was added ₂ O ₃ After stirring the support for 1h, aqueous ammonia was added dropwise with continued stirring until the pH was 8.5. Aging the product for 2h, suction filtering, washing with 500mL water three times, drying in a 90 deg.C oven for 16h, and placing into a muffle furnaceRoasting for 16h at 450 ℃ in a furnace to obtain the catalyst precursor I.

To ethanol in which 141mg of Pt-Co nanoparticles were dispersed, 2.0g of the above catalyst precursor II was added under stirring, stirred for 2 hours, dried in an oven at 50 ℃ for 4 hours, and then put into a muffle furnace for calcination at 650 ℃ for 4 hours to obtain a catalyst.

[ example 11 ]

126mg of cesium nitrate was weighed and dissolved in 5mL of water, 3.0g of the above-mentioned catalyst precursor I was added thereto with stirring, immersed for 4 hours at room temperature, dried for 4 hours in an oven at 90℃and then put into a muffle furnace to be calcined for 4 hours at 650℃to obtain a catalyst precursor II.

[ example 12 ]

264mg of lanthanum nitrate is weighed and dissolved in 5mL of water, 3.0g of the catalyst precursor I is added into the solution under stirring, the solution is immersed for 4 hours at room temperature, and after the solution is dried for 4 hours in a 90 ℃ oven, the solution is put into a muffle furnace and baked for 4 hours at 650 ℃ to obtain a catalyst precursor II.

[ example 13 ]

28.7mg of cesium nitrate and 61mg of lanthanum nitrate are weighed and dissolved in 5mL of water, 3.0g of the catalyst precursor I is added into the mixture under stirring, the mixture is immersed for 4 hours at room temperature, and the mixture is dried for 4 hours in a baking oven at 90 ℃ and then is put into a muffle furnace for roasting for 4 hours at 650 ℃ to obtain a catalyst precursor II.

[ example 14 ]

283mg of yttrium nitrate, 92.8mg of gallium nitrate were weighed into 50mL of deionized water, and 3.0g of gamma-Al was added ₂ O ₃ After stirring the support for 1h, aqueous ammonia was added dropwise with continued stirring until the pH was 8.5. Aging the productAfter 2h, the catalyst was suction filtered, washed three times with 500mL of water, dried in an oven at 90℃for 16h, and then calcined in a muffle furnace at 450℃for 16h to give the catalyst precursor I.

100mg of cesium nitrate and 213mg of lanthanum nitrate are weighed and dissolved in 5mL of water, 3.0g of the catalyst precursor I is added into the mixture under stirring, the mixture is immersed for 4 hours at room temperature, and the mixture is dried for 4 hours in a 90 ℃ oven and then is put into a muffle furnace for roasting for 4 hours at 650 ℃ to obtain a catalyst precursor II.

[ example 15 ]

2.4mg of cesium nitrate and 5.1mg of lanthanum nitrate are weighed and dissolved in 5mL of water, 3.0g of the catalyst precursor I is added into the mixture under stirring, the mixture is immersed for 4 hours at room temperature, and after the mixture is dried for 4 hours in a 90 ℃ oven, the mixture is put into a muffle furnace and baked for 4 hours at 650 ℃ to obtain a catalyst precursor II.

[ example 16 ]

220mg of cesium nitrate and 468mg of lanthanum nitrate are weighed and dissolved in 5mL of water, 3.0g of the catalyst precursor I is added into the mixture under stirring, the mixture is immersed for 4 hours at room temperature, and the mixture is dried for 4 hours in a 90 ℃ oven and then is put into a muffle furnace for roasting for 4 hours at 650 ℃ to obtain a catalyst precursor II.

[ example 17 ]

283mg of zinc nitrate and 119mg of gallium nitrate are weighed and dissolved in 50mL of deionized water, and 3.0g of gamma-Al is added ₂ O ₃ After stirring the support for 1h, aqueous ammonia was added dropwise with continued stirring until the pH was 8.5. The product was aged for 2h, suction filtered, washed three times with 500mL of water, dried in an oven at 90 ℃ for 16h, and then put in a muffle furnace for calcination at 450 ℃ for 16h to obtain the catalyst precursor I.

Example 18

340mg of yttrium nitrate and 18.5mg of gallium nitrate are weighed and dissolved in 50mL of deionized water, and 3.0g of gamma is added-Al ₂ O ₃ After stirring the support for 1h, aqueous ammonia was added dropwise with continued stirring until the pH was 8.5. The product was aged for 2h, suction filtered, washed three times with 500mL of water, dried in an oven at 90 ℃ for 16h, and then put in a muffle furnace for calcination at 450 ℃ for 16h to obtain the catalyst precursor I.

[ example 19 ]

312mg of yttrium nitrate and 54.5mg of gallium nitrate are weighed and dissolved in 50mL of deionized water, and 3.0g of gamma-Al is added ₂ O ₃ After stirring the support for 1h, aqueous ammonia was added dropwise with continued stirring until the pH was 8.5. The product was aged for 2h, suction filtered, washed three times with 500mL of water, dried in an oven at 90 ℃ for 16h, and then put in a muffle furnace for calcination at 450 ℃ for 16h to obtain the catalyst precursor I.

[ example 20 ]

259mg of yttrium nitrate and 124mg of gallium nitrate are weighed and dissolved in 50mL of deionized water, and 3.0g of gamma-Al is added ₂ O ₃ After stirring the support for 1h, aqueous ammonia was added dropwise with continued stirring until the pH was 8.5. The product was aged for 2h, suction filtered, washed three times with 500mL of water, dried in an oven at 90 ℃ for 16h, and then put in a muffle furnace for calcination at 450 ℃ for 16h to obtain the catalyst precursor I.

[ example 21 ]

236mg of yttrium nitrate and 155mg of gallium nitrate are weighed and dissolved in 50mL of deionized water, and 3.0g of gamma-Al is added ₂ O ₃ After stirring the support for 1h, aqueous ammonia was added dropwise with continued stirring until the pH was 8.5. The product was aged for 2h, suction filtered, washed three times with 500mL of water, dried in an oven at 90 ℃ for 16h, and then put in a muffle furnace for calcination at 450 ℃ for 16h to obtain the catalyst precursor I.

[ example 22 ]

106mg of yttrium nitrate and 34.8mg of gallium nitrate are weighed and dissolved in 50mL of deionized water, and 3.0g of gamma-Al is added ₂ O ₃ After stirring the support for 1h, aqueous ammonia was added dropwise with continued stirring until the pH was 8.5. The product was aged for 2h, suction filtered, washed three times with 500mL of water, dried in an oven at 90 ℃ for 16h, and then put in a muffle furnace for calcination at 450 ℃ for 16h to obtain the catalyst precursor I.

Example 23

514mg of yttrium nitrate and 168mg of gallium nitrate are weighed and dissolved in 50mL of deionized water, and 3.0g of gamma-Al is added ₂ O ₃ After stirring the support for 1h, aqueous ammonia was added dropwise with continued stirring until the pH was 8.5. The product was aged for 2h, suction filtered, washed three times with 500mL of water, dried in an oven at 90 ℃ for 16h, and then put in a muffle furnace for calcination at 450 ℃ for 16h to obtain the catalyst precursor I.

[ example 24 ]

8.9mg of yttrium nitrate and 2.9mg of gallium nitrate are weighed and dissolved in 50mL of deionized water, and 3.0g of gamma-Al is added ₂ O ₃ After stirring the support for 1h, aqueous ammonia was added dropwise with continued stirring until the pH was 8.5. The product was aged for 2h, suction filtered, washed three times with 500mL of water, dried in an oven at 90 ℃ for 16h, and then put in a muffle furnace for calcination at 450 ℃ for 16h to obtain the catalyst precursor I.

[ example 25 ]

841mg of yttrium nitrate and 275mg of gallium nitrate are weighed and dissolved in 50mL of deionized water, and 3.0g of gamma-Al is added ₂ O ₃ After stirring the support for 1h, aqueous ammonia was added dropwise with continued stirring until the pH was 8.5. The product was aged for 2h, suction filtered, washed three times with 500mL of water, dried in an oven at 90 ℃ for 16h, and then put in a muffle furnace for calcination at 450 ℃ for 16h to obtain the catalyst precursor I.

[ example 26 ]

283mg of yttrium nitrate and 92.8mg of gallium nitrate were weighed into 50mL of deionized water, and 3.0g of SiO was added ₂ After stirring the support for 1h, aqueous ammonia was added dropwise with continued stirring until the pH was 8.5. The product was aged for 2h, suction filtered, washed three times with 500mL of water, dried in an oven at 90 ℃ for 16h, and then put in a muffle furnace for calcination at 450 ℃ for 16h to obtain the catalyst precursor I.

[ example 27 ]

283mg of yttrium nitrate and 92.8mg of gallium nitrate were weighed into 50mL of deionized water, and 3.0g of TiO was added ₂ After stirring the support for 1h, aqueous ammonia was added dropwise with continued stirring until the pH was 8.5. The product was aged for 2h, suction filtered, washed three times with 500mL of water, dried in an oven at 90 ℃ for 16h, and then put in a muffle furnace for calcination at 450 ℃ for 16h to obtain the catalyst precursor I.

Comparative example 1

27.8mg of potassium chloroplatinite was weighed out and dissolved in 3mL of water, and 2.0g of gamma-Al was stirred ₂ O ₃ The carrier is added into the catalyst, immersed for 4 hours at room temperature, dried for 4 hours in a 90 ℃ oven, and then put into a muffle furnace to be roasted for 4 hours at 650 ℃ to obtain the catalyst.

Comparative example 2

24.7mg of potassium chloroplatinite and 5.7mg of cobalt chloride are weighed and dissolved in 3mL of water, 2.0g of the catalyst precursor II is added into the mixture under stirring, the mixture is immersed for 4 hours at room temperature, and the mixture is dried for 4 hours in a 90 ℃ oven and then is put into a muffle furnace for roasting for 4 hours at 650 ℃ to obtain the catalyst.

[ comparative example 3 ]

192mg of potassium chloroplatinite, 500mg of polyvinylpyrrolidone and 5.0g of potassium bromide are dissolved in 300mL of deionized water in a 500mL hydrothermal kettle and uniformly mixed, reacted for 1h in a 160 ℃ oven, centrifugally separated and washed to obtain Pt-Co nano particles, and the nano particles are dispersed in ethanol.

[ comparative example 4 ]

192mg of potassium chloroplatinite, 275mg of cobalt chloride, 500mg of polyvinylpyrrolidone and 5.0g of potassium bromide are dissolved in 300mL of deionized water in a 500mL hydrothermal kettle and uniformly mixed, the mixture is reacted for 1h in a 160 ℃ oven, and Pt-Co nano particles are obtained after centrifugal separation and washing, and are dispersed in ethanol.

Comparative example 5

2.0g of the above catalyst precursor I was added to ethanol in which 13.0mg of Pt-Co nanoparticles were dispersed with stirring, stirred for 2 hours, dried in an oven at 50℃for 4 hours, and then put into a muffle furnace for calcination at 650℃for 4 hours to obtain a catalyst.

[ comparative example 6 ]

354mg of yttrium nitrate was weighed into 50mL of deionized water, and 3.0g of gamma-Al was added ₂ O ₃ After stirring the support for 1h, aqueous ammonia was added dropwise with continued stirring until the pH was 8.5. The product was aged for 2h, suction filtered, washed three times with 500mL of water, dried in an oven at 90 ℃ for 16h, and then put in a muffle furnace for calcination at 450 ℃ for 16h to obtain the catalyst precursor I.

[ comparative example 7 ]

465mg of gallium nitrate was weighed into 50mL of deionized water and 3.0g of gamma-Al was added ₂ O ₃ After stirring the support for 1h, aqueous ammonia was added dropwise with continued stirring until the pH was 8.5. The product was aged for 2h, suction filtered, washed three times with 500mL of water, dried in an oven at 90 ℃ for 16h, and then put in a muffle furnace for calcination at 450 ℃ for 16h to obtain the catalyst precursor I.

Comparative example 8

115mg of yttrium nitrate and 314mg of gallium nitrate are weighed and dissolved in 50mL of deionized water, and 3.0g of gamma-Al is added ₂ O ₃ After stirring the support for 1h, aqueous ammonia was added dropwise with continued stirring until the pH was 8.5. The product was aged for 2h, suction filtered, washed three times with 500mL of water, dried in an oven at 90 ℃ for 16h, and then put in a muffle furnace for calcination at 450 ℃ for 16h to obtain the catalyst precursor I.

TABLE 1

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Examples 28 to 31

The catalyst prepared in example 1 was used for performance evaluation of light alkane dehydrogenation reaction, and the results are shown in table 2.

TABLE 2

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Claims

1. A catalyst for dehydrogenation of light alkane, wherein the dispersity of Pt of the catalyst is 12-33%;

the catalyst comprises the following components in parts by weight:

a) 0.1 to 6.5 parts of Pt-Co nano particles or oxides thereof;

c) 0.1 to 9.5 parts of Y-Ga-O binary metal oxide;

2. The catalyst for dehydrogenation of light alkane according to claim 1, wherein the fraction of Pt-Co nanoparticles or oxides thereof in component a) is 0.1 to 3.6 parts by weight.

3. The catalyst for the dehydrogenation of light alkanes according to claim 1, characterized in that the molar ratio of Co to Pt in component a) is (0.06-0.94): 1.

4. The catalyst for dehydrogenation of light alkanes according to claim 1, characterized in that M is selected from Cs and La, the fraction of element M or its oxide being between 0.6 and 2.6 parts by weight.

5. The catalyst for dehydrogenating light alkane according to claim 1, wherein the fraction of the binary metal oxide of Y-Ga-O is 1.2 to 6 parts by weight, and the molar ratio of Y-Ga in the component c) is (0.05 to 0.6): 1.

6. The catalyst for dehydrogenating light alkane of claim 1, wherein the carrier is S is gamma-Al ₂ O ₃ Or SiO ₂ At least one of them.

7. The catalyst for dehydrogenation of light alkanes according to claim 1, characterized in that the dispersity of Pt is 17% to 26%.

8. A method for preparing a light alkane dehydrogenation catalyst, which comprises the following steps:

9. A method for dehydrogenating light alkane, which comprises the following reaction conditions: the reaction pressure is 0-1 MPa, the temperature is 300-600 ℃, and the mass airspeed is 0.1-10 h ⁻¹ The method comprises the steps of carrying out a first treatment on the surface of the Contacting a light alkane or a mixture of light alkane and hydrogen with the catalyst of any one of claims 1 to 7 to produce the corresponding unsaturated hydrocarbon.

10. The method for dehydrogenating a light alkane according to claim 9, characterized in that the light alkane is selected from at least one of saturated chain alkanes or saturated cycloalkanes having a boiling point of not more than 110 degrees celsius at normal pressure.

11. The method for dehydrogenating light alkane according to claim 9, wherein the light alkane is at least one selected from the group consisting of propane, n-butane, isobutane, cyclohexane and methylcyclohexane.