CoCe composite oxide catalyst, preparation method thereof and method for preparing propylene by catalyzing propane dehydrogenation

Abstract

The invention belongs to the technical field of supported catalysts, and discloses a CoCe composite oxide catalyst, a preparation method thereof and a method for preparing propylene by catalyzing propane dehydrogenation. According to the catalyst, a CoCe composite oxide is loaded on a gamma-Al2O3 carrier, the mass ratio of Ce to gamma-Al2O3 is 10%-40%, and the mass ratio of Co to CeO2 / gamma-Al2O3 is 0.5%-2%; the preparation method comprises the following steps: impregnating the gamma-Al2O3 carrier with cerous nitrate by adopting a step-by-step impregnation method, drying a precursor, and pyrolyzing in air to obtain the gamma-Al2O3 loaded Ce oxide catalyst. And dipping cobalt nitrate on the CeO2 / gamma-Al2O3, drying the CeO2 / gamma-Al2O3, and carrying out air pyrolysis on the CeO2 / gamma-Al2O3 to obtain the CoO-CeO2 / gamma-Al2O3 catalyst. According to the invention, through the interaction of oxide carriers between CoO and CeO2, the reaction performance is improved; the catalyst takes a non-noble metal oxide as an active center, and is simple in preparation method, low in price and low in toxicity; the catalyst is used for catalyzing propane dehydrogenation to prepare propylene and has excellent performance.

Description

Technical Field

[0001] The invention belongs to the technical field of supported catalysts, and in particular relates to a CoCe composite oxide catalyst and a preparation method thereof, and a method for catalyzing propane dehydrogenation to produce propylene. Background Art

[0002] As an important basic raw material in the petrochemical industry, propylene is industrially used in the preparation of a variety of high value-added products, including polypropylene, propylene oxide, isopropyl alcohol, ethyl acrylate, and acrylonitrile. In industrial production and daily life, the above-mentioned propylene derivatives have a wide range of applications. For example, compared with polyethylene, polypropylene has good mechanical properties and better heat resistance, so it is widely used in food packaging and optical fiber fields. Propylene oxide can be used in the production of polyether polyols and further synthesized into polyurethane foam materials, which are important basic materials for thermal insulation, sound insulation and waterproofing. Acrylonitrile can be polymerized with butadiene through polymerization reaction to form nitrile rubber, which has excellent elasticity, weather resistance and chemical resistance, and is widely used in the automotive industry and other fields.

[0003] Compared with traditional fluidized catalytic cracking and naphtha steam cracking, which are constrained by fossil raw material consumption, methanol to olefins has low propylene selectivity, and propane dehydrogenation to propylene is particularly important due to the transformation of the refining industry to the production of chemical raw materials and the development of shale gas, which has abundant raw materials and directional production of propylene. The propane dehydrogenation process is to selectively break the CH bond of propane molecules under the action of catalysts to generate a single product propylene, so this process can achieve a relatively high propylene yield. At the same time, with the advancement of technologies such as hydraulic fracturing, the efficient development of shale gas resources has been achieved. The rich propane components in it have greatly reduced the raw material cost required for propane dehydrogenation technology, making the market price gap between propane and propylene gradually widen, and greatly improving the economic efficiency of propane dehydrogenation to produce propylene, a product with higher added value. Therefore, propane dehydrogenation to propylene technology is considered to be the most promising propylene production technology and has received widespread attention in the fields of industrial application and basic research.

[0004] Propane dehydrogenation plants based on oleflex and catofin processes have been widely deployed around the world, but the Pt-based and CrO x The basic catalysts are either expensive or highly toxic, and it is urgent to find cheap, low-toxic and high-performance alternative catalysts. Summary of the invention

[0005] The purpose of the present invention is to solve the technical problem that the existing propane dehydrogenation catalysts are expensive or highly toxic, and to provide a CoO-CeO catalyst with low price, low toxicity and excellent performance. 2 / γ-Al 2 O 3A catalyst and a preparation method thereof, and a method for preparing propylene by catalyzing propane dehydrogenation using the catalyst.

[0006] In order to solve the above technical problems, the present invention is implemented by the following technical solutions:

[0007] According to one aspect of the present invention, a CoCe composite oxide catalyst is provided. 2 O 3 As carrier, γ-Al 2 O 3 The carrier is loaded with CoCe composite oxide, expressed as CoO-CeO 2 / γ-Al 2 O 3 ; Among them, Ce and γ-Al 2 O 3 The mass ratio of Co and CeO is 10% to 40%. 2 / γ-Al 2 O 3 The mass ratio is 0.5% to 2%.

[0008] Preferably, Ce and γ-Al 2 O 3 The mass ratio is 10% to 20%.

[0009] Preferably, Co and CeO 2 / γ-Al 2 O 3 The mass ratio is 0.5% to 1%.

[0010] According to another aspect of the present invention, there is provided a method for preparing the above-mentioned CoCe composite oxide catalyst, comprising the following steps:

[0011] (1) Using Ce(NO 3 ) 3 6H 2 O is configured into a Ce precursor solution A, and the precursor solution A is added dropwise to the γ-Al 2 O 3 The powder is vibrated and ultrasonicated to obtain a slurry mixture; the obtained slurry mixture is dried and ground into powder, and calcined at 400℃~700℃ for 1~6h; the obtained product is recorded as CeO 2 / γ-Al 2 O 3 ;

[0012] Here, solution A is added dropwise to γ-Al 2 O 3 When the volume of solution A in mL is controlled, the volume of carrier γ-Al in g is controlled. 2 O 3The numerical ratio of the mass is 1:1 to 4:1;

[0013] (2) Using Co(NO 3 ) 2 6H 2 O is configured into a precursor solution B of Co, and the precursor solution B is added dropwise to the CeO obtained in step (1). 2 / γ-Al 2 O 3 The powder is vibrated and ultrasonicated to obtain a slurry mixture; the obtained slurry mixture is dried and ground into powder, and calcined at 400-700°C for 1-6h; the obtained catalyst is recorded as CoO-CeO 2 / γ-Al 2 O 3 ;

[0014] In which, solution B was added dropwise to CeO 2 / γ-Al 2 O 3 When the volume of solution B in mL is controlled, the volume of CeO in g is controlled. 2 / γ-Al 2 O 3 The numerical ratio of the mass is 1:1 to 4:1.

[0015] Furthermore, in step (1) and step (2), drying is performed in flowing air at 50° C. to 110° C. for 6 to 18 hours.

[0016] Preferably, in step (1) and step (2), the calcination temperature is 500° C. to 600° C. and the calcination time is 2 to 4 hours.

[0017] Preferably, in step (1), solution A is added dropwise to γ-Al 2 O 3 When the volume of solution A in mL is controlled, the volume of carrier γ-Al in g is controlled. 2 O 3 The numerical ratio of the mass is 2:1 to 3:1.

[0018] Preferably, in step (2), solution B is added dropwise to CeO 2 / γ-Al 2 O 3 When the volume of solution B in mL is controlled, the volume of CeO in g is controlled. 2 / γ-Al 2 O 3 The numerical ratio of the mass is 1.2:1 to 2:1.

[0019] According to another aspect of the present invention, a method for catalytic dehydrogenation of propane to produce propylene is provided, wherein the CoO-CeO2 / γ-Al 2 O 3 The catalyst is placed in a fixed bed reactor and heated at 0.1-0.14 MPa total pressure, 10-50 kPa propane atmosphere, 550-620 °C, 0.5-4 h -1 Propylene is obtained at a weight hourly space velocity.

[0020] Further, at a total pressure of 0.1 to 0.12 MPa, a propane atmosphere of 15 to 30 kPa, 570 to 590 ° C, 1 to 2 h -1 Reaction under weight space-time velocity.

[0021] The beneficial effects of the present invention are:

[0022] The CoCe composite oxide catalyst of the present invention utilizes CoO and CeO 2 The interaction between the oxide support and the 2+ And further inhibited Co 2+ The active sites of propane dehydrogenation are deeply reduced, which improves the reaction performance. It uses non-precious metal oxides as active centers, has a simple preparation method, is low in price, and has low toxicity. The catalyst is used for catalyzing propane dehydrogenation to produce propylene, and has excellent performance, a propane conversion rate of 31.3-51.8%, and a propylene selectivity of 67.2-87.5%. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Different loading amounts of xCoO-yCeO 2 / γ-Al 2 O 3 Conversion rate result chart;

[0024] Figure 2 Different loading amounts of xCoO-yCeO 2 / γ-Al 2 O 3 Selective result graph of

[0025] Figure 3 1CoO-yCeO with different Ce loading 2 / γ-Al 2 O 3 The conversion rate and selectivity result diagram;

[0026] Figure 4 1CoO-20CeO 2 / γ-Al 2 O 3 The conversion rate and selectivity results of the reaction at different temperatures;

[0027] Figure 5 1CoO-20CeO 2 / γ-Al 2 O 3 The conversion and selectivity results of the reaction at different weight space-time velocities are shown in the figure;

[0028] Figure 6 1CoO-20CeO 2 / γ-Al 2 O 3 The stability test results of 20 cycles of catalytic propane dehydrogenation to propylene in a fixed bed reactor;

[0029] Figure 7 It is 20CeO 2 / γ-Al 2 O 3 At 18 vol.% H 2 / Ar in-situ diffuse reflectance infrared images of reduction at different temperatures;

[0030] Figure 8 1CoO-20CeO 2 / γ-Al 2 O 3 At 18 vol.% H 2 / Ar in-situ diffuse reflectance infrared images of reduction at different temperatures;

[0031] Fig. 9 Different loading amounts of xCoO-yCeO 2 / γ-Al 2 O 3 Ex situ XPS pattern of Co 2p;

[0032] Fig.10 1CoO-20CeO 2 / γ-Al 2 O 3 Quasi-in-situ XPS patterns of Co 2p before and after reaction in 20 kPa propane for 20 min. DETAILED DESCRIPTION

[0033] The present invention provides a CoCe composite oxide catalyst with γ-Al 2 O 3 As carrier, γ-Al 2 O 3 The carrier is loaded with CoCe composite oxide, expressed as CoO-CeO 2 / γ-Al 2 O 3 ; Among them, Ce and γ-Al 2 O 3 The mass ratio of Co and CeO is 10% to 40%. 2 / γ-Al 2 O 3The mass ratio is 0.5% to 2%.

[0034] In some preferred embodiments of the present invention, Ce and γ-Al 2 O 3 The mass ratio is 10% to 20%.

[0035] In some preferred embodiments of the present invention, Co and CeO 2 / γ-Al 2 O 3 The mass ratio is 0.5% to 1%.

[0036] The present invention also provides a method for preparing the CoCe composite oxide catalyst, comprising the following steps:

[0037] Weigh a certain amount of Ce(NO 3 ) 3 6H 2 O is used as a precursor of Ce and dissolved in a certain amount of ultrapure water to form a precursor solution A; a certain amount of γ-Al 2 O 3 The powder was used as a carrier and solution A was added dropwise to the γ-Al 2 O 3 The powder is vibrated and ultrasonicated to obtain a slurry mixture; the slurry mixture is transferred to an oven and dried in flowing air at 50°C to 110°C for 6 to 18 hours, and then the dried mixture is ground into powder and calcined in a muffle furnace at 400°C to 700°C for 1 to 6 hours; the obtained catalyst is recorded as yCeO 2 / γ-Al 2 O 3 , where y represents Ce and γ-Al 2 O 3 The mass ratio of

[0038] Then weigh a certain amount of Co(NO 3 ) 2 6H 2 O is used as a precursor of Co and dissolved in a certain amount of ultrapure water to form a precursor solution B. A certain amount of yCeO 2 / γ-Al 2 O 3 Powder, add solution B dropwise to yCeO 2 / γ-Al 2 O 3 The powder is vibrated and ultrasonicated to obtain a slurry mixture; the slurry mixture is transferred to an oven and dried in flowing air at 50°C to 110°C for 6 to 18 hours, and then the dried mixture is ground into powder and calcined in a muffle furnace at 400°C to 700°C for 1 to 6 hours; the obtained catalyst is recorded as xCoO-yCeO2 / γ-Al 2 O 3 , where x represents Co and yCeO 2 / γ-Al 2 O 3 The mass ratio of

[0039] Solution A was added dropwise to the carrier γ-Al 2 O 3 When the volume of solution A in mL is controlled, the volume of carrier γ-Al in g is controlled. 2 O 3 The mass ratio of yCeO is 1:1 to 4:1; add solution B dropwise to yCeO 2 / γ-Al 2 O 3 When the volume of solution B in mL is controlled, the volume of yCeO in g is controlled. 2 / γ-Al 2 O 3 The numerical ratio of the mass is 1:1 to 4:1.

[0040] In some preferred embodiments of the present invention, solution A is added dropwise to the carrier γ-Al 2 O 3 When the volume of solution A in mL is controlled, the volume of carrier γ-Al in g is controlled. 2 O 3 The numerical ratio of the mass is 2:1 to 3:1.

[0041] In some preferred embodiments of the present invention, solution B is added dropwise to yCeO 2 / γ-Al 2 O 3 When the volume of solution B in mL is controlled, the volume of yCeO in g is controlled. 2 / γ-Al 2 O 3 The numerical ratio of the mass is 1.2:1 to 2:1.

[0042] In some preferred embodiments of the present invention, both loadings are performed by drying the obtained slurry mixture at 80°C-90°C in flowing air for 8-12 hours, and then calcining the dried mixture at 500°C-600°C for 2-4 hours.

[0043] The present invention also provides a method for preparing propylene by dehydrogenating propane using the CoCe composite oxide catalyst, wherein the CoO-CeO 2 / γ-Al 2 O 3The catalyst is placed in a fixed bed reactor and heated at 0.1-0.14 MPa total pressure, 10-50 kPa propane atmosphere, 550-620 °C, 0.5-4 h -1 Propylene is obtained at a weight hourly space velocity.

[0044] In some preferred embodiments of the present invention, the total pressure is 0.1-0.12 MPa, the propane atmosphere is 15-30 kPa, the temperature is 570-590°C, and the temperature is 1-2 hours. -1 Reaction under weight space-time velocity.

[0045] The present invention is further described in detail below through specific examples. The following examples can enable those skilled in the art to more fully understand the present invention, but do not limit the present invention in any way.

[0046] Example 1

[0047] According to the Ce and γ-Al 2 O 3 The mass ratio of Co to CeO is 0%, 2 / γ-Al 2 O 3 The mass ratio is 1%.

[0048] Weigh 0.050 g Co(NO 3 ) 2 6H 2 O was dissolved in 2 mL of ultrapure water to obtain solution B; 1 g of γ-Al 2 O 3 ; Add solution B dropwise to γ-Al 2 O 3 The slurry mixture was transferred to an oven and dried in flowing air at 80°C for 12 h, and then the dried mixture was ground into powder and calcined in a muffle furnace at 600°C for 2 h to obtain a composite metal oxide catalyst 1Co / Al.

[0049] Example 2

[0050] According to the Ce and γ-Al 2 O 3 The mass ratio of Co to 20CeO is 20%. 2 / γ-Al 2 O 3 The mass ratio is 0.5%.

[0051] Weigh 0.620 g Ce(NO 3 ) 3 6H 2 O was dissolved in 2 mL of ultrapure water to obtain solution A; 1 g of γ-Al 2O 3 ; Add solution A dropwise to γ-Al 2 O 3 The slurry mixture was transferred to an oven and dried in flowing air at 80°C for 12 h, and then the dried mixture was ground into powder and calcined in a muffle furnace at 600°C for 2 h to obtain 20CeAl.

[0052] Weigh 0.025 g Co(NO 3 ) 2 6H 2 O was dissolved in 1.3 mL of ultrapure water to obtain solution B; 1 g of 20CeAl was weighed; solution B was added dropwise to 20CeAl to obtain a slurry mixture after oscillation and ultrasound; the obtained slurry mixture was transferred to an oven and dried in flowing air at 80°C for 12 h, and then the dried mixture was ground into powder and placed in a muffle furnace and calcined at 600°C for 4 h to obtain 0.5Co / 20CeAl.

[0053] Example 3

[0054] The preparation was carried out according to the steps of Example 2, except that Co and 20CeO 2 / γ-Al 2 O 3 The mass ratio of Co(NO 3 ) 2 6H 2 O was dissolved in 1.3 mL of ultrapure water to obtain solution B; and finally 1Co / 20CeAl was obtained.

[0055] Example 4

[0056] The preparation was carried out according to the steps of Example 2, except that Co and 20CeO 2 / γ-Al 2 O 3 The mass ratio of Co(NO 3 ) 2 6H 2 O was dissolved in 1.3 mL of ultrapure water to obtain solution B; and finally 2Co / 20CeAl was obtained.

[0057] Example 5

[0058] According to the Ce and γ-Al 2 O 3 The mass ratio of Co to 20CeO is 20%. 2 / γ-Al 2 O 3 The mass ratio is 0%.

[0059] Weigh 0.620 g Ce(NO 3 ) 3 6H 2 O was dissolved in 2 mL of ultrapure water to obtain solution A; 1 g of γ-Al 2 O 3 ; Add solution A dropwise to γ-Al 2 O 3 The slurry mixture was transferred to an oven and dried in flowing air at 80°C for 12 h, and then the dried mixture was ground into powder and calcined in a muffle furnace at 600°C for 2 h to obtain 20CeAl.

[0060] Example 6

[0061] The preparation was carried out according to the steps of Example 2, except that Ce and γ-Al 2 O 3 The mass ratio of Co to CeO is 10% 2 / γ-Al 2 O 3 The mass ratio of Ce(NO 3 ) 3 6H 2 O was dissolved in 2 mL of ultrapure water to obtain solution A; 0.050 g Co(NO 3 ) 2 6H 2 O was dissolved in 1.3 mL of ultrapure water to obtain solution B; and finally 1Co / 10CeAl was obtained.

[0062] Example 7

[0063] The preparation was carried out according to the steps of Example 2, except that Ce and γ-Al 2 O 3 The mass ratio of Co to CeO is 40% 2 / γ-Al 2 O 3 The mass ratio of Ce(NO 3 ) 3 6H 2 O was dissolved in 2 mL of ultrapure water to obtain solution A; 0.050 g Co(NO 3 ) 2 6H 2 O was dissolved in 1.3 mL of ultrapure water to obtain solution B; finally 1Co / 40CeAl was obtained.

[0064] The catalyst prepared in Examples 1 to 5 is used to catalyze the dehydrogenation of propane to produce propylene. The specific method is as follows:

[0065] 0.5 g of catalyst was placed in a fixed bed reactor and heated at 0.1 MPa total pressure, 19 kPa propane atmosphere, 590 °C, for 1 h. -1 The reaction was carried out at a weight hourly space velocity and the product was detected by GC. Figure 1 and Figure 2 .

[0066] Depend on Figure 1 and Figure 2 It can be seen that the catalysts prepared in Examples 1 to 5 have excellent performance in catalyzing propane dehydrogenation to propylene, among which 1Co / 20CeAl has the best performance, achieving the best performance of 46.9% propane conversion and 86.6% propylene selectivity in 5 min.

[0067] The inventors used the catalysts prepared in Examples 6 and 7 to catalyze the dehydrogenation of propane to produce propylene. 0.5 g of the catalyst was placed in a fixed bed reactor and heated at 0.1 MPa total pressure, 19 kPa propane atmosphere, 590°C, for 1 h. -1 The reaction was carried out at a weight hourly space velocity and the product was detected by GC. Figure 3 .

[0068] Depend on Figure 3 It can be seen that as the Ce content increases from 10% to 40%, the conversion gradually increases to 49.8% of 1Co / 40CeAl, but the selectivity of 1Co / 40CeAl decreases to 68.2%, so the optimal performance is achieved in 1Co / 20CeAl.

[0069] The inventors placed 0.5 g of the composite oxide catalyst of Example 3 in a fixed bed reactor and heated it at 550-590° C. for 1 h under a total pressure of 0.1 MPa and a propane atmosphere of 19 kPa. -1 The reaction was carried out at a weight hourly space velocity and the product was detected by GC. Figure 4 .

[0070] Depend on Figure 4 It can be seen that as the reaction temperature gradually increases from 550°C to 590°C, the reaction performance of 1Co / 20CeAl gradually improves, and the optimal reaction performance is achieved at 590°C.

[0071] The inventors placed 0.5 g of the composite oxide catalyst of Example 3 in a fixed bed reactor and heated the reactor at 0.1 MPa total pressure, 19 kPa propane atmosphere, 590°C, for 1 to 4 h. -1 The reaction was carried out at a weight hourly space velocity and the product was detected by GC. Figure 5 .

[0072] Depend on Figure 5 It can be seen that as the weight space-time speed increases from 4h -1 Until 1h-1 The reaction performance of 1Co / 20CeAl gradually improved. -1 Get the best response performance.

[0073] The inventor used the composite oxide catalyst of Example 3 to catalyze the dehydrogenation of propane to produce propylene, and then heated the catalyst to 10 vol.% O 2 / N 2 Regeneration 15min, recycling, recycling effect see Figure 6 .

[0074] Depend on Figure 6 It can be seen that the catalyst of the present invention can be recycled and has good cycle stability.

[0075] The catalysts prepared in Examples 3 and 5 above were measured at 18 vol.% H 2 / Ar reduced in situ diffuse reflectance infrared at different temperatures, the results are shown in Figure 7 and Figure 8 .Depend on Figure 7 and Figure 8 It can be seen that the surface CeO of 20CeAl 2 The oxygen vacancy starting temperature is 450℃, and the surface CeO of 1Co / 20CeAl 2 The onset temperature of oxygen vacancies is 400°C, indicating the presence of 2 Oxygen supply to CoO leads to the formation of surface CeO at lower temperatures 2 The oxygen vacancies help maintain the partial oxidation state of CoO. 2 There is an oxide-support interaction between them.

[0076] The catalysts prepared in Examples 1 to 4 were characterized by ex situ XPS. Fig. 9 .Depend on Fig. 9 Calculated Co 2+ The contents are shown in Table 1.

[0077] Table 1 Co in different catalysts 2+ content

[0078]

[0079] As can be seen from Table 1, compared with 1Co / Al, 1Co / 20CeAl has 2+ The content of CoO and CeO is improved. 2 The interaction between the oxide support and the 2+ content.

[0080] The catalyst prepared in Example 3 was tested at 20 vol.% C. 3 H8 / N 2 Quasi-in-situ XPS was performed before and after 20 minutes of reduction. The results are shown in Fig.10 .Depend on Fig.10 It can be seen that no Co was produced after reduction. 0 , CoO and CeO 2 The oxide-support interaction between the two groups inhibits the 2+ Deep reduction of active sites for propane dehydrogenation.

[0081] In summary, the CoCe composite oxide catalyst prepared in the present invention uses non-noble metal oxides as active centers, and 2 The interaction between the oxide support and the 2+ And further inhibited Co 2+ The propane dehydrogenation active site is deeply reduced, and the reaction performance is improved. The propane conversion rate is 31.3-51.8%, and the propylene selectivity is 67.2-87.5%. In the preferred range, the propane conversion rate is 31.3-46.9%, and the propylene selectivity is 83.4-87.5%.

[0082] Although the preferred embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments, which are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms of specific changes without departing from the scope of protection of the present invention and the claims, all of which fall within the scope of protection of the present invention.

Claims

1. A CoCe composite oxide catalyst, characterized in that: γ-Al2O3 is used as a carrier, and the γ-Al2O3 carrier loads CoCe composite oxide, which is expressed as CoO-CeO2 / γ-Al2O3; wherein the mass ratio of Ce to γ-Al2O3 is 10% to 40%, and the mass ratio of Co to CeO2 / γ-Al2O3 is 0.5% to 2%.

2. A CoCe composite oxide catalyst according to claim 1, characterized in that: The mass ratio of Ce to γ-Al2O3 is 10% to 20%.

3. A CoCe composite oxide catalyst according to claim 1, characterized in that: The mass ratio of Co to CeO2 / γ-Al2O3 is 0.5% to 1%.

4. A method for preparing the CoCe composite oxide catalyst according to any one of claims 1 to 3, characterized in that: The steps include: (1) Ce(NO3)3·6H2O is used to prepare a Ce precursor solution A, and the precursor solution A is added dropwise to γ-Al2O3 powder, and a slurry mixture is obtained after oscillation and ultrasound; the obtained slurry mixture is dried and then ground into powder, and calcined at 400°C to 700°C for 1 to 6 hours; the obtained product is recorded as CeO2 / γ-Al2O3; When solution A is added dropwise to γ-Al2O3, the numerical ratio of the volume of solution A in mL to the mass of carrier γ-Al2O3 in g is controlled to be 1:1 to 4:1; (2) using Co(NO3)2·6H2O to prepare a Co precursor solution B, and adding the precursor solution B dropwise to the CeO2 / γ-Al2O3 powder obtained in step (1), and obtaining a slurry mixture after oscillation and ultrasound; drying the obtained slurry mixture, grinding it into powder, and calcining it at 400-700°C for 1-6h; the obtained catalyst is recorded as CoO-CeO2 / γ-Al2O3; When solution B is added dropwise to CeO2 / γ-Al2O3, the numerical ratio of the volume of solution B in mL to the mass of CeO2 / γ-Al2O3 in g is controlled to be 1:1 to 4:

1.

5. The method for preparing a CoCe composite oxide catalyst according to claim 4, characterized in that: In step (1) and step (2), drying is performed in flowing air at 50°C to 110°C for 6 to 18 hours.

6. The method for preparing a CoCe composite oxide catalyst according to claim 4, characterized in that: In step (1) and step (2), the calcination temperature is 500° C. to 600° C. and the calcination time is 2 to 4 hours.

7. The method for preparing a CoCe composite oxide catalyst according to claim 4, characterized in that: In step (1), when solution A is added dropwise to γ-Al2O3, the numerical ratio of the volume of solution A in mL to the mass of carrier γ-Al2O3 in g is controlled to be 2:1 to 3:

1.

8. The method for preparing a CoCe composite oxide catalyst according to claim 4, characterized in that: In step (2), when solution B is added dropwise to CeO2 / γ-Al2O3, the numerical ratio of the volume of solution B in mL to the mass of CeO2 / γ-Al2O3 in g is controlled to be 1.2:1 to 2:

1.

9. A method for preparing propylene by catalytic dehydrogenation of propane, characterized in that: The CoO-CeO2 / γ-Al2O3 catalyst according to any one of claims 1 to 3 is placed in a fixed bed reactor, heated at a total pressure of 0.1 to 0.14 MPa, a propane atmosphere of 10 to 50 kPa, and a temperature of 550 to 620°C for 0.5 to 4 hours. -1 Propylene is obtained at a weight hourly space velocity.

10. The method for preparing propylene by catalytic dehydrogenation of propane according to claim 9, characterized in that: At 0.1-0.12MPa total pressure, 15-30kPa propane atmosphere, 570-590℃, 1-2h -1 Reaction under weight space-time velocity.

Images