CN113134386A

CN113134386A - Gallium-zirconium composite oxide-molecular sieve catalyst, and preparation method and application thereof

Info

Publication number: CN113134386A
Application number: CN202110446402.4A
Authority: CN
Inventors: 王森; 樊卫斌; 董梅; 秦张峰; 王建国
Original assignee: Shanxi Institute of Coal Chemistry of CAS
Current assignee: Shanxi Institute of Coal Chemistry of CAS
Priority date: 2021-04-25
Filing date: 2021-04-25
Publication date: 2021-07-20
Anticipated expiration: 2041-04-25
Also published as: CN113134386B

Abstract

The invention provides a gallium-zirconium composite oxide-molecular sieve catalyst, belonging to the technical field of catalysts. The catalyst provided by the invention comprises mixed gallium-zirconium composite oxide and a hydrogen H-SSZ-13 molecular sieve; the chemical formula of the gallium-zirconium composite oxide is Ga_aZr_bO_c. In the invention, the gallium-zirconium composite oxide has larger surface oxygen hole concentration and can promote CO₂Adsorption activation and CO increase₂Conversion rate, and simultaneously the gallium-zirconium composite oxide has moderate CO₂The adsorption strength can effectively avoid excessive dissociation of C-O bonds and reduce the generation of by-products CO; the H-SSZ-13 molecular sieve has an eight-membered ring pore structure, is favorable for limiting the generation of long-chain hydrocarbons, and simultaneously has stronger acid strength and high content of strong acid sites, which is favorable for high selectionPropane is selectively produced.

Description

Gallium-zirconium composite oxide-molecular sieve catalyst, and preparation method and application thereof

Technical Field

The invention relates to the technical field of catalysts, in particular to a gallium-zirconium composite oxide-molecular sieve catalyst and a preparation method and application thereof.

Background

CO₂Is a non-toxic and rich carbon-containing resource. By means of hydrogenation, CO is introduced₂The method for preparing the high value-added chemicals by directly converting the raw materials can not only slow down the greenhouse effect and adjust the carbon balance in the atmosphere, but also open up a new way for preparing clean fuels. Among them, propane is an important basic raw material in modern chemical industry, and is also a main component of Liquefied Petroleum Gas (LPG). Therefore, the direct conversion of CO with high activity and high selectivity is realized₂The preparation of propane has important practical significance.

At present, direct conversion of CO₂The preparation of hydrocarbons, such as propane, can be achieved by the Fischer-Tropsch synthesis route and the methanol-intermediate based (methanol-intermediate) synthesis route. Fischer-Tropsch synthesis routes using Fe, Co or Rh based catalysts generally have higher Co₂The conversion rate is limited by Anderson-Schultz-Flory (ASF for short), the generation of hydrocarbon becomes uncontrollable, a large amount of methane by-products are generated in the reaction process, and the selectivity of the target product is seriously reduced. ZnZrO used based on methanol intermediate synthesis route_x/SAPO-34、ZnAl₂O₄/SAPO-34、ZnGa₂O₄SAPO-34 and InZrO_xSAPO-34 and other bifunctional catalysts in CO₂The ASF regulation limit can be effectively broken through in the hydrogenation process, but the main product is low-carbon olefin, and the propane selectivity does not exceed 10%.

There are studies indicating the use of CuZnZrO_xcatalyst/Pd-Beta composite in CO₂The selectivity of propane can be improved to 21.1 percent in the hydrogenation process, and CO can be improved₂The conversion rate is 21.2%, but a large amount of by-product CO is generated in the reaction process, and the selectivity of CO reaches 64.5%. Further use of In₂O₃SAPO-34 composite catalyst, albeit in CO₂The selectivity of propane can be further improved to 30% in the hydrogenation process, but the selectivity of CO as a byproduct is as high as 85%.

Disclosure of Invention

In view of the above, the present invention aims to provide a gallium zirconium composite oxide-molecular sieve catalyst, and a preparation method and an application thereof. The gallium-zirconium composite oxide-molecular sieve catalyst provided by the invention catalyzes CO₂High CO content in the preparation of propane by hydrogenation₂Conversion rate and propane selectivity, good catalytic stability, and effective inhibition of CO byproduct generation.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides a gallium-zirconium composite oxide-molecular sieve catalyst, which comprises a mixed gallium-zirconium composite oxide and a hydrogen type H-SSZ-13 molecular sieve; the chemical formula of the gallium-zirconium composite oxide is Ga_aZr_bO_cWherein a, b and c are the atomic ratio of Ga, Zr and O, and a, b and c are Ga_aZr_bO_cHas a valence of 0.

Preferably, the mass ratio of the gallium-zirconium composite oxide to the hydrogen H-SSZ-13 molecular sieve is (0.2-5): 1.

preferably, the ratio of a to b is (0.01-1.0): (0.1-5.0).

Preferably, the silicon-aluminum ratio of the hydrogen type H-SSZ-13 molecular sieve is (3.0-30): 1.

Preferably, the particle size of the gallium-zirconium composite oxide-molecular sieve catalyst is 10-60 meshes.

The invention provides a preparation method of the gallium-zirconium composite oxide-molecular sieve catalyst, which comprises the following steps:

(1) mixing water-soluble gallium salt, water-soluble zirconium salt and a complexing agent with water, and carrying out a complexing reaction to obtain a gallium-zirconium complex;

(2) roasting the gallium-zirconium complex to obtain a gallium-zirconium composite oxide;

(3) and mixing the gallium-zirconium composite oxide with a hydrogen H-SSZ-13 molecular sieve to obtain the gallium-zirconium composite oxide-molecular sieve catalyst.

Preferably, the complexing agent is one or more of glucose, citric acid, tartaric acid, salicylic acid and adipic acid;

the ratio of the sum of the amount of the substances of gallium ions and zirconium ions to the amount of the substance of the complexing agent in the mixture obtained by mixing in the step (1) is 1: (0.5-5).

Preferably, the temperature of the complexation reaction is 60-95 ℃ and the time is 1-15 h.

Preferably, the roasting temperature is 400-700 ℃, and the roasting time is 1-20 h.

The invention provides the application of the gallium-zirconium composite oxide-molecular sieve catalyst in catalyzing CO₂Application in preparing propane by hydrogenation.

The invention provides a gallium-zirconium composite oxide-molecular sieve catalyst, which comprises a gallium-zirconium composite oxide and a hydrogen type H-SSZ-13 molecular sieve; the chemical formula of the gallium-zirconium composite oxide is Ga_aZr_bO_cWherein a, b and c are the atomic ratio of Ga, Zr and O, and a, b and c are Ga_aZr_bO_cHas a valence of 0. In the invention, the gallium-zirconium composite oxide has larger surface oxygen hole concentration and can promote CO₂Adsorption activation and CO increase₂Conversion rate while the gallium zirconium composite oxide has proper CO₂The adsorption strength can effectively avoid excessive dissociation of C-O bonds, and the generation of by-products CO is reduced; the H-SSZ-13 molecular sieve has an eight-membered ring pore structure, is favorable for limiting the generation of long-chain hydrocarbons, and simultaneously has stronger acid strength and high strong acid site content, which is favorable for generating propane with high selectivity. The invention adopts gallium-zirconium composite oxide as an active component, and simultaneously combines and uses a hydrogen H-SSZ-13 molecular sieve for catalyzing CO₂The hydrogenation for preparing propane can obviously improve CO₂Conversion rate, propane selectivity and yield, and can effectively reduce the generation of a byproduct CO. The results of the examples show that the gallium zirconium composite oxide-molecular sieve catalyst provided by the invention is used for catalyzing CO₂When propane is produced by hydrogenation, the conversion of carbon dioxide is 32.6%, the selectivity and yield of propane are 80.0% and 18.5%, respectively, and the selectivity of CO as a by-product is 29.0%.

The invention provides a preparation method of the gallium-zirconium composite oxide-molecular sieve catalyst, which comprises the steps of complexing water-soluble gallium salt and water-soluble zirconium salt in water, and roasting a complex product to obtain the gallium-zirconium composite oxide; and finally, mixing the gallium-zirconium composite oxide with a hydrogen H-SSZ-13 molecular sieve to obtain the gallium-zirconium composite oxide-molecular sieve catalyst. The preparation method provided by the invention is simple, has no secondary pollution, and is suitable for industrial production.

Drawings

FIG. 1 is a nitrogen adsorption diagram of an H-SSZ-13 molecular sieve;

FIG. 2 is an SEM image of a gallium zirconium composite oxide-molecular sieve catalyst obtained in example 1;

FIG. 3 is an XRD spectrum of a gallium zirconium composite oxide obtained in example 1;

FIG. 4 shows the molecular sieve-composite gallium-zirconium oxide catalyst prepared in example 7 in CO₂CH in reaction for preparing propane by hydrogenation₄Propane, LPG, Other-HC, oxygenate and CO selectivities and CO₂Graph of the conversion over time;

FIG. 5 shows the molecular sieve-composite gallium-zirconium oxide catalyst prepared in example 7 in CO₂Selectivity of different hydrocarbon compounds in the reaction of hydrogenation to propane and yield of propane and LPG as a function of time are plotted.

Detailed Description

In the invention, the ratio of a to b is preferably (0.01-1.0): (0.1 to 5.0), more preferably (0.05 to 0.8): (0.2-2.0). In the present invention, the ratio of the amounts of Ga and Zr is controlled to the above range, which is advantageous for improving the activity of the catalyst.

In the present invention, the Ga is_aZr_bO_cPreferably Ga_8.0Zr_2.0O_16.0、Ga_4.0Zr_2.0O_10.0、Ga_2.0Zr_2.0O_7.0、Ga_1.0Zr_2.0O_5.5、Ga_0.7Zr_2.0O_5.05、Ga_0.5Zr_2.0O_4.75、Ga_0.4Zr_2.0O_4.6、Ga_0.3Zr_2.0O_4.45And Ga_0.2Zr_2.0O_4.3One or more of them.

In the invention, the silicon-aluminum ratio of the hydrogen type H-SSZ-13 molecular sieve is preferably 3.0-30, more preferably 5.0-20.0, and further preferably 6.0-10.0. In the invention, the silicon-aluminum ratio of the hydrogen type H-SSZ-13 molecular sieve is too low, so that a large amount of Al atoms cannot effectively enter a framework of SSZ-13, non-framework aluminum is induced to form, and the crystallinity and catalytic activity of the molecular sieve are reduced; and the silicon-aluminum ratio is too high, so that the acid amount and the acid strength are reduced, and the generation of propane is not facilitated. In the invention, the total specific surface area of the hydrogen type H-SSZ-13 molecular sieve is preferably 270.3-616.4 m²(ii)/g, more preferably 527.5 to 598.9m²(ii)/g; the total pore volume of the hydrogen type H-SSZ-13 molecular sieve is preferably 0.16-0.45 cm³A more preferable range is 0.2 to 0.35 m/g²(ii) in terms of/g. The invention has no special requirements on the source of the hydrogen type H-SSZ-13 molecular sieve, and the hydrogen type H-SSZ-13 molecular sieve can be synthesized by self in a laboratory by adopting a method disclosed and reported by a literature or can be used as a hydrogen type H-SSZ-13 molecular sieve sold in the field; as a specific example of the invention, the hydrogen H-SSZ-13 molecular sieve is synthesized by laboratory self-made method, and the preparation method is preferably as follows: respectively taking aluminum sulfate as an aluminum source, silica sol as a silicon source, N, N, N-trimethyl-1-adamantane ammonium hydroxide as a template agent and potassium hydroxide as an alkali source, and adopting a dynamic hydrothermal synthesis method to prepare the SSZ-13 molecular sieve, wherein the specific synthesis conditions can be found in the reference [ Journal of catalysis 393(2021) 190-]. The hydrogen type H-SSZ-13 molecular sieve has an eight-membered ring pore structure, is favorable for limiting the generation of long-chain hydrocarbons, and simultaneously has stronger acid strength and high strong acid site content, which is favorable for promoting the formation of propane with high selectivity.

In the invention, the mass ratio of the gallium-zirconium composite oxide to the hydrogen H-SSZ-13 molecular sieve is preferably (0.2-5): 1, more preferably (0.3-4): 1, and still more preferably (0.5-2): 1.

In the invention, the particle size of the gallium zirconium composite oxide-molecular sieve catalyst is preferably 10-60 meshes, more preferably 20-50 meshes, and further preferably 30-40 meshes. In the present invention, the particle size of the catalyst is preferably controlled within the above range, which is advantageous for the full exertion of the catalytic performance of the catalyst.

The gallium-zirconium composite oxide-molecular sieve catalyst provided by the invention uses gallium-zirconium composite oxide as an active component and uses a hydrogen H-SSZ-13 molecular sieve for CO in a combined manner₂The reaction for preparing propane by hydrogenation can obviously improve CO₂Conversion rate, propane selectivity and yield, and can effectively reduce the generation of a byproduct CO.

The invention mixes water-soluble gallium salt, water-soluble zirconium salt, complexing agent and water to carry out complex reaction, and dry colloidal gallium-zirconium complex can be obtained through complex reaction. In the present invention, the water-soluble gallium salt is preferably gallium nitrate and/or gallium chloride; the water-soluble zirconium salt is preferably zirconium nitrate and/or zirconium chloride. In the invention, the complexing agent is one or more of glucose, citric acid, tartaric acid, salicylic acid and adipic acid, and when the complexing agent is two or more, the mass ratio of the complexing agent is not particularly limited, and the complexing agent can be added in any proportion.

In the present invention, the water is preferably deionized water.

The invention does not require any particular mixing means, such as stirring, known to the person skilled in the art. In the present invention, the ratio of the sum of the amounts of the gallium ion and zirconium ion species to the amount of the complexing agent species in the mixture obtained after mixing is preferably 1: (0.5 to 5), more preferably 1: (2-4). In the present invention, the ratio of the sum of the amounts of the gallium ion and zirconium ion substances to the amount of the complexing agent substance in the mixed solution obtained by mixing is preferably controlled to be within the above range, so that the reaction can be sufficiently carried out, and the raw materials are not wasted.

In the invention, the concentration of gallium ions in the mixed solution obtained after mixing is preferably 0.01-1.0 mol/L, more preferably 0.05-0.8 mol/L, and most preferably 0.06-0.6 mol/L; the concentration of zirconium ions in the mixed solution is preferably 0.1 to 5.0mol/L, more preferably 0.2 to 2.0mol/L, and most preferably 0.3 to 1.0 mol/L.

In the invention, the temperature of the complexation reaction is preferably 60-95 ℃, more preferably 65-85 ℃, and most preferably 70-80 ℃; the time of the complexation reaction is preferably 1-15 h, and more preferably 4-10 h. According to the invention, through the complexing reaction, abundant surface hydroxyl groups of the complexing agent and metal ions are utilized to perform coordination complexing action, so that the metal ions can be tightly bound around the complexing agent. Meanwhile, a dry colloidal complex can be obtained through a complexation reaction.

After the complexing reaction, the complex obtained is preferably dried in the present invention. In the invention, the drying temperature is preferably 80-120 ℃, more preferably 90-110 ℃, and most preferably 100 ℃; the drying time is preferably 2-15 h, more preferably 3-10 h, and most preferably 5-9 h; the means for drying is preferably an oven.

After the gallium-zirconium complex is obtained, the gallium-zirconium complex is roasted to obtain the gallium-zirconium composite oxide. In the invention, the roasting temperature is preferably 400-700 ℃, more preferably 450-650 ℃, and most preferably 500-600 ℃; the roasting time is preferably 1-20 h, more preferably 5-15 h, and most preferably 6-10 h; the roasting atmosphere is preferably air; the means for calcining is preferably a muffle furnace. According to the invention, the gallium-zirconium composite oxide precursor is oxidized by roasting to form the gallium-zirconium composite oxide.

After the gallium-zirconium composite oxide is obtained, the gallium-zirconium composite oxide is mixed with a hydrogen H-SSZ-13 molecular sieve to obtain the gallium-zirconium composite oxide-molecular sieve catalyst. In the present invention, the mixing is preferably performed by grinding. The grinding mode is not particularly limited in the present invention, and a grinding technical scheme known to those skilled in the art can be adopted. In an embodiment of the invention, the grinding is preferably mechanical grinding.

After the mixing, the mixed product is preferably subjected to tabletting, crushing and screening in sequence to obtain the gallium-zirconium composite oxide-molecular sieve catalyst. The tabletting, crushing and sieving operations are not particularly limited in the present invention, and the technical solutions of tabletting, crushing and sieving known to those skilled in the art can be adopted. In the invention, the particle size of the screened catalyst is preferably 10-60 meshes, and more preferably 20-50 meshes. In the present invention, the pressure of the tablet is preferably 15.0 MPa.

The invention provides the application of the gallium-zirconium composite oxide-molecular sieve catalyst in catalyzing CO₂Application in preparing propane by hydrogenation. In the present invention, the catalytic CO₂The process for producing propane by hydrogenation preferably comprises the steps of:

(1) carrying out reduction pretreatment on the gallium-zirconium composite oxide-molecular sieve catalyst to obtain a pre-reduction catalyst;

(2) introducing CO₂And H₂And introducing the mixed gas into the pre-reduction catalyst to carry out hydrogenation reaction to obtain propane.

The invention preferably carries out reduction pretreatment on the gallium-zirconium composite oxide-molecular sieve catalyst to obtain the pre-reduction catalyst. In the invention, the reduction pretreatment is preferably carried out in a hydrogen atmosphere, and the temperature of the reduction pretreatment is preferably 300-500 ℃, and more preferably 400 ℃; the time is preferably 1 to 4 hours, and more preferably 2 to 3 hours.

After obtaining the pre-reduction catalyst, the invention preferably adds CO₂And H₂And introducing the mixed gas into the pre-reduction catalyst to carry out hydrogenation reaction to obtain propane. In the present invention, said H₂And CO₂The volume ratio of (C) is preferably (1-9))1, more preferably (2-8): 1, and most preferably (3-6): 1. Said H₂And CO₂The space velocity of the mixed gas is preferably 500 to 10000 mL/(h.g), more preferably 800 to 6000 mL/(h.g), and still more preferably 1000 to 4000 mL/(h.g).

In the invention, the temperature of the hydrogenation reaction is preferably 260-400 ℃, more preferably 300-380 ℃, and further preferably 330-370 ℃; the pressure of the hydrogenation reaction is preferably 0.1-5 MPa, more preferably 1-4 MPa, and further preferably 2-3 MPa; the time of the hydrogenation reaction is preferably 10-1000 h, more preferably 20-500 h, and further preferably 50-200 h.

The gallium zirconium composite oxide-molecular sieve catalyst provided by the present invention, the preparation method and the application thereof are described in detail with reference to the following examples, but they should not be construed as limiting the scope of the present invention.

In the following examples, the hydrogen form of the H-SSZ-13 molecular sieve used was synthesized in-house by the laboratory. The nitrogen adsorption profile of the H-SSZ-13 molecular sieve with different Si/Al ratios is shown in FIG. 1, and the specific surface area and pore volume results are shown in Table 1.

TABLE 1 specific surface area and pore volume results for H-SSZ-13 molecular sieves of varying Si/Al ratios

Example 1

25.5730g of gallium nitrate and 85.8640g of zirconium nitrate are dissolved in 1500mL of deionized water, 178.3530g of glucose is added, the mixture is uniformly mixed (wherein the ratio of the total metal ions in the composite metal ion salt solution to the glucose is 1: 3, the concentration of gallium ions is 0.067mol/L, and the concentration of zirconium ions is 0.133mol/L), the complex reaction is carried out for 8 hours at 80 ℃ under the stirring condition, then the mixture is placed in a 100 ℃ oven for drying for 12 hours, then the mixture is roasted for 3 hours at 500 ℃ in a muffle furnace under the air atmosphere, and the natural cooling is carried out to obtain the gallium-zirconium composite oxide Ga_1.0Zr_2.0O_5.5。

The gallium zirconium composite oxide Ga obtained above_1.0Zr_2.0O_5.5And mechanically grinding and mixing the hydrogen type H-SSZ-13 molecular sieve with the silicon-aluminum ratio of 6.0 according to the mass ratio of 0.5:1, then tabletting under 15.0MPa, and finally crushing and screening to obtain the gallium-zirconium composite oxide-molecular sieve catalyst with the granularity of 20-40 meshes.

The SEM image of the obtained gallium zirconium composite oxide-molecular sieve catalyst is shown in fig. 2. In fig. 2, the bead structure is a molecular sieve, and the bulk structure is a stacked agglomerate of metal oxides, both of which are in close physical contact.

The XRD spectrum of the obtained gallium-zirconium composite oxide is shown in fig. 3, and it can be seen from fig. 3 that (011), (002), (112) and (121) crystal planes are present at diffraction angles of 30.5 °, 35.5 °, 50.6 ° and 60.2 °, indicating that gallium and zirconium are fused with each other to form a gallium-zirconium solid solution structure.

Example 2

12.7865g of gallium nitrate and 85.8640g of zirconium nitrate were dissolved in 1500mL of deionized water; adding 148.6275g glucose into the composite metal ion salt solution, uniformly mixing (the mass ratio of total metal ions to glucose in the composite metal ion salt solution is 1: 3, the concentration of gallium ions is 0.033mol/L, and the concentration of zirconium ions is 0.133mol/L), carrying out complex reaction for 6h at 90 ℃ under the condition of stirring, then placing the obtained product in a 100 ℃ drying oven for drying for 12h, then roasting the obtained product for 3h at 500 ℃ in a muffle furnace under the air atmosphere, and naturally cooling to obtain the gallium-zirconium composite oxide Ga_0.5Zr_2.0O_4.75。

The gallium zirconium composite oxide Ga obtained above_0.5Zr_2.0O_4.75And mechanically grinding and mixing the hydrogen type H-SSZ-13 molecular sieve with the aluminum-silicon ratio of 6.0 according to the mass ratio of 0.5:1, then tabletting under 15.0MPa, and finally crushing and screening to obtain the gallium-zirconium composite oxide-molecular sieve catalyst with the granularity of 20-40 meshes.

Example 3

5.1146g of gallium nitrate and 85.8640g of zirconium nitrate were dissolved in 1500mL of deionized water; 130.7922g of glucose is added into the composite metal ion salt solution and uniformly mixed (the ratio of the total metal ions in the composite metal ion salt solution to the glucose is 1:3, the concentration of gallium ions is 0.013mol/L, the concentration of zirconium ions is 0.133mol/L), carrying out complex reaction for 10h at 70 ℃ under the stirring condition, then placing the obtained product in a drying oven at 100 ℃ for drying for 12h, then roasting the obtained product for 5h in a muffle furnace at 600 ℃ under the air atmosphere, and naturally cooling to obtain the gallium-zirconium composite oxide Ga_0.2Zr_2.0O_4.3。

The gallium zirconium composite oxide Ga obtained above_0.2Zr_2.0O_4.3And mechanically grinding and mixing the hydrogen type H-SSZ-13 molecular sieve with the aluminum-silicon ratio of 6.0 according to the mass ratio of 0.5:1, then tabletting under 15.0MPa, and finally crushing and screening to obtain the gallium-zirconium composite oxide-molecular sieve catalyst with the granularity of 20-40 meshes.

Example 4

51.1460g of gallium nitrate and 85.8640g of zirconium nitrate were dissolved in 1500mL of deionized water; adding 237.8040g glucose into the composite metal ion salt solution, uniformly mixing (the mass ratio of total metal ions to glucose in the composite metal ion salt solution is 1: 3, the concentration of gallium ions is 0.133mol/L, and the concentration of zirconium ions is 0.133mol/L), carrying out complex reaction for 8h at 80 ℃ under the condition of stirring, then placing the obtained product in a 100 ℃ oven for drying for 12h, then roasting the obtained product for 6h at 400 ℃ in a muffle furnace under the air atmosphere, and naturally cooling to obtain the gallium-zirconium composite oxide Ga_2.0Zr_2.0O_7.0。

The gallium zirconium composite oxide Ga obtained above_2.0Zr_2.0O_7.0And mechanically grinding and mixing the hydrogen type H-SSZ-13 molecular sieve with the aluminum-silicon ratio of 6.0 according to the mass ratio of 0.5:1, then tabletting under 15.0MPa, and finally crushing and screening to obtain the gallium-zirconium composite oxide-molecular sieve catalyst with the granularity of 20-40 meshes.

Example 5

25.5730g of gallium nitrate and 85.8640g of zirconium nitrate were dissolved in 1500mL of deionized water; adding 178.3530g glucose into the above composite metal ion salt solution, mixing well (the ratio of total metal ions to glucose in the composite metal ion salt solution is 1: 3, the concentration of gallium ions is 0.067mol/L, the concentration of zirconium ions is 0.133mol/L), stirring at 80 deg.CPerforming complexation reaction for 8 hours, then placing the mixture in a drying oven at 100 ℃ for drying for 12 hours, then roasting the mixture in a muffle furnace at 500 ℃ for 3 hours in air atmosphere, and naturally cooling to obtain the Ga-Zr composite oxide Ga_1.0Zr_2.0O_5.5。

The gallium zirconium composite oxide Ga obtained above_1.0Zr_2.0O_5.5And mechanically grinding and mixing the hydrogen type H-SSZ-13 molecular sieve with the aluminum-silicon ratio of 9.6 according to the mass ratio of 0.5:1, then tabletting under 15.0MPa, and finally crushing and screening to obtain the gallium-zirconium composite oxide-molecular sieve catalyst with the granularity of 20-40 meshes.

Example 6

25.5730g of gallium nitrate and 85.8640g of zirconium nitrate were dissolved in 1500mL of deionized water; adding 178.3530g glucose into the composite metal ion salt solution, uniformly mixing (the mass ratio of total metal ions to glucose in the composite metal ion salt solution is 1: 3, the concentration of gallium ions is 0.067mol/L, and the concentration of zirconium ions is 0.133mol/L), carrying out complex reaction for 8h at 80 ℃ under the condition of stirring, then placing in a 100 ℃ oven for drying for 12h, then roasting for 3h at 500 ℃ in a muffle furnace under the atmosphere of air, and naturally cooling to obtain the gallium-zirconium composite oxide Ga_1.0Zr_2.0O_5.5。

The gallium zirconium composite oxide Ga obtained above_1.0Zr_2.0O_5.5And mechanically grinding and mixing the hydrogen type H-SSZ-13 molecular sieve with the aluminum-silicon ratio of 22.0 according to the mass ratio of 0.5:1, then tabletting under 15.0MPa, and finally crushing and screening to obtain the gallium-zirconium composite oxide-molecular sieve catalyst with the granularity of 20-40 meshes.

Example 7

25.5730g of gallium nitrate and 85.8640g of zirconium nitrate were dissolved in 1500mL of deionized water; adding 178.3530g glucose into the composite metal ion salt solution, uniformly mixing (the mass ratio of total metal ions to glucose in the composite metal ion salt solution is 1: 3, the concentration of gallium ions is 0.067mol/L, and the concentration of zirconium ions is 0.133mol/L), carrying out complex reaction for 8h at 80 ℃ under the condition of stirring, then placing in a 100 ℃ oven for drying for 12h, then placing in a muffle furnace at 500 ℃ to,Roasting for 3h in air atmosphere, and naturally cooling to obtain gallium zirconium composite oxide Ga_1.0Zr_2.0O_5.5。

The gallium zirconium composite oxide Ga obtained above_1.0Zr_2.0O_5.5And mechanically grinding and mixing the hydrogen type H-SSZ-13 molecular sieve with the aluminum-silicon ratio of 6.0 according to the mass ratio of 0.4:1, then tabletting under 15.0MPa, and finally crushing and screening to obtain the gallium-zirconium composite oxide-molecular sieve catalyst with the granularity of 20-40 meshes.

Comparative example 1

51.1460g of gallium nitrate was dissolved in 1500mL of deionized water; adding 118.9020g of glucose into the metal ion salt solution, uniformly mixing (the mass ratio of total metal ions to glucose in the metal ion salt solution is 1: 3, and the concentration of gallium ions is 0.133mol/L), carrying out a complexing reaction for 8h under the conditions of stirring at 80 ℃, then placing the solution in a 100 ℃ oven for drying for 12h, then roasting the solution in a muffle furnace at 500 ℃ for 3h under the air atmosphere, and naturally cooling to obtain a metal oxide Ga₂O₃。

The metal oxide Ga obtained above₂O₃And mechanically grinding and mixing the hydrogen type H-SSZ-13 molecular sieve with the aluminum-silicon ratio of 6.0 according to the mass ratio of 0.5:1, then tabletting under 15.0MPa, and finally crushing and screening to obtain the metal oxide-molecular sieve catalyst with the granularity of 20-40 meshes.

Comparative example 2

85.8640g of zirconium nitrate was dissolved in 1500mL of deionized water; adding 118.9020g of glucose into the metal ion salt solution, uniformly mixing (the mass ratio of total metal ions to glucose in the metal ion salt solution is 1: 3, and the concentration of zirconium ions is 0.133mol/L), carrying out a complexing reaction for 8h under the conditions of stirring at 80 ℃, then placing the mixture in a 100 ℃ oven for drying for 12h, then roasting the mixture in a muffle furnace at 500 ℃ for 3h under the air atmosphere, and naturally cooling to obtain a metal oxide ZrO₂。

The metal oxide ZrO obtained above₂Mechanically grinding and mixing the hydrogen type H-SSZ-13 molecular sieve with the aluminum-silicon ratio of 6.0 according to the mass ratio of 0.5:1, and tabletting under the pressure of 15.0MPaAnd finally, crushing and screening to obtain the metal oxide-molecular sieve catalyst with the granularity of 20-40 meshes.

Comparative example 3

31.8830g of indium nitrate and 85.8640g of zirconium nitrate were dissolved in 1500mL of deionized water; adding 178.3530g glucose into the metal ion salt solution, uniformly mixing (the mass ratio of total metal ions to glucose In the metal ion salt solution is 1: 3, the concentration of indium ions is 0.067mol/L, and the concentration of zirconium ions is 0.133mol/L), carrying out complex reaction for 8h at 80 ℃ under stirring, then placing In a 100 ℃ oven for drying for 12h, then roasting In a muffle furnace at 500 ℃ for 3h under air atmosphere, and naturally cooling to obtain the metal oxide In_1.0Zr_2.0O_5.5。

The metal oxide In obtained above_1.0Zr_2.0O_5.5And mechanically grinding and mixing the hydrogen type H-SSZ-13 molecular sieve with the aluminum-silicon ratio of 6.0 according to the mass ratio of 0.5:1, then tabletting under 15.0MPa, and finally crushing and screening to obtain the metal oxide-molecular sieve catalyst with the granularity of 20-40 meshes.

Comparative example 4

The gallium zirconium composite oxide Ga obtained above_1.0Zr_2.0O_5.5And mechanically grinding and mixing the molecular sieve with a hydrogen type H-SAPO-34 molecular sieve with the aluminum-silicon ratio of 0.15 according to the mass ratio of 0.5:1, tabletting under 15.0MPa, and finally crushing and screening to obtain the gallium-zirconium composite oxide-molecular sieve catalyst with the granularity of 20-40 meshes.

Comparative example 5

The gallium zirconium composite oxide Ga obtained above_1.0Zr_2.0O_5.5And mechanically grinding and mixing the hydrogen type H-ZSM-35 molecular sieve with the aluminum-silicon ratio of 10.0 according to the mass ratio of 0.5:1, tabletting under 15.0MPa, and finally crushing and screening to obtain the gallium-zirconium composite oxide-molecular sieve catalyst with the granularity of 20-40 meshes.

Comparative example 6

The gallium zirconium composite oxide Ga obtained above_1.0Zr_2.0O_5.5And mechanically grinding and mixing the molecular sieve with a hydrogen type H-ZSM-11 molecular sieve with the aluminum-silicon ratio of 9.0 according to the mass ratio of 0.5:1, tabletting under 15.0MPa, and finally crushing and screening to obtain the gallium-zirconium composite oxide-molecular sieve catalyst with the granularity of 20-40 meshes.

Application example

The gallium-zirconium composites prepared in examples 1 to 7 were compoundedThe oxide-molecular sieve catalyst and the metal oxide-molecular sieve catalyst prepared in comparative examples 1 to 6 were respectively in H₂Reducing and pretreating for 2h at 400 ℃ in atmosphere, and then applying to CO₂In the catalytic reaction of hydrogenation to prepare propane;

wherein, the reaction conditions of the gallium zirconium composite oxide-molecular sieve catalyst prepared in the examples 1-6 and the metal oxide-molecular sieve catalyst prepared in the proportions 1-6 are as follows: the reaction temperature is 350 ℃, the reaction pressure is 3.0MPa, and H₂With CO₂The volume ratio of (A) is 3:1, and the space velocity is 2400 mL/(h.g);

the reaction conditions of the gallium zirconium composite oxide-molecular sieve catalyst prepared in example 7 were: the reaction temperature is 350 ℃, the reaction pressure is 3.0MPa, and H₂With CO₂The volume ratio of (A) to (B) is 6:1, and the space velocity is 1000 mL/(h.g).

The catalytic performances of the gallium zirconium composite oxide-molecular sieve catalysts prepared in examples 1 to 7 and the metal oxide-molecular sieve catalysts prepared in comparative examples 1 to 6 are shown in tables 2 and 3.

Wherein, the gallium zirconium composite oxide-molecular sieve catalyst prepared in example 7 is used in CO₂CH in reaction for preparing propane by hydrogenation₄Propane, LPG, Other-HC, oxygenate and CO selectivities and CO₂The graph of the conversion rate with time is shown in FIG. 4;

gallium zirconium composite oxide-molecular sieve catalyst prepared in example 7 in CO₂The selectivity of the different hydrocarbon compounds in the hydrogenation to propane reaction and the propane and LPG yields as a function of time are plotted in figure 5.

TABLE 2 catalytic Properties of the gallium zirconium composite oxide-molecular sieve catalysts prepared in examples 1 to 7 and the metal oxide-molecular sieve catalysts prepared in comparative examples 1 to 6

TABLE 3 catalytic Properties of the gallium zirconium composite oxide-molecular sieve catalysts prepared in examples 1 to 7 and the metal oxide-molecular sieve catalysts prepared in comparative examples 1 to 6

In tables 2 and 3, CH₄Is methane, C₃ ⁰For propane, LPG is a liquefied petroleum gas, representing the sum of propane and butane, and Other-HC represents the sum of hydrocarbons Other than methane, propane and butane, oxygenates, including methanol and dimethyl ether.

As can be seen from the catalytic results of tables 2 and 3, and FIGS. 4 and 5, the gallium zirconium composite oxide-molecular sieve catalyst provided by the present invention has excellent CO₂The catalytic performance of the hydrogenation for preparing propane is high, and the selectivity of the propane reaches 75.8-80.0%; CO 2₂The conversion rate can reach 32.6 percent, and the selectivity of the byproduct CO is as low as 29.0 percent. The maximum yield of the propane reaches 18.50 percent. Compared with comparative examples 1-6, the propane selectivity is reduced to 59.6% and 73.5%, and CO is reduced by using other metal oxides such as gallium oxide or zirconium oxide₂The conversion was only 12.9% and 5.3%, and the propane yield did not exceed 3.2%, although In was used_1.0Zr_2.0O_5.5Oxide, CO₂The conversion can be improved to 17.9%, but a large amount of CO and methane byproducts are generated simultaneously, the selectivity is 52.0% and 6.0%, and the selectivity and the yield of propane are reduced to 73.4% and 6.30%; the selectivity and yield of propane are only 17.9-38.0% and 1.64-3.81% by using other acidic molecular sieves such as commercial hydrogen type H-SAPO-34, H-ZSM-35 or H-ZSM-11 molecular sieves.

From the above examples, it can be seen that the gallium zirconium composite oxide-molecular sieve catalyst provided by the present invention is used for catalyzing a reaction of producing propane from carbon dioxide, and has the performances of high carbon dioxide conversion rate, high propane selectivity and yield, and low selectivity of byproduct carbon monoxide.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. A gallium zirconium composite oxide-molecular sieve catalyst, comprising mixed gallium zirconium composite oxide and hydrogen H-SSZ-13 molecular sieve; the chemical formula of the gallium-zirconium composite oxide is Ga_aZr_bO_cWherein a, b and c are the atomic ratio of Ga, Zr and O, and a, b and c are Ga_aZr_bO_cHas a valence of 0.

2. The gallium-zirconium composite oxide-molecular sieve catalyst according to claim 1, wherein the mass ratio of the gallium-zirconium composite oxide to the hydrogen H-SSZ-13 molecular sieve is (0.2-5): 1.

3. the gallium-zirconium composite oxide-molecular sieve catalyst according to claim 1, wherein the ratio of a to b is (0.01 to 1.0): (0.1-5.0).

4. The gallium-zirconium composite oxide-molecular sieve catalyst of claim 1, wherein the hydrogen H-SSZ-13 molecular sieve has a silica to alumina ratio of (3.0-30): 1.

5. The gallium-zirconium composite oxide-molecular sieve catalyst according to claim 1, wherein the particle size of the gallium-zirconium composite oxide-molecular sieve catalyst is 10 to 60 mesh.

6. The method for preparing a gallium zirconium composite oxide-molecular sieve catalyst according to any one of claims 1 to 5, comprising the steps of:

7. The preparation method of claim 6, wherein the complexing agent is one or more of glucose, citric acid, tartaric acid, salicylic acid and adipic acid;

8. The preparation method according to claim 6 or 7, wherein the temperature of the complexation reaction is 60-95 ℃ and the time is 1-15 h.

9. The preparation method according to claim 6, wherein the roasting temperature is 400-700 ℃ and the roasting time is 1-20 h.

10. The gallium zirconium composite oxide-molecular sieve catalyst of any one of claims 1 to 5 or the gallium zirconium composite oxide-molecular sieve catalyst prepared by the preparation method of any one of claims 6 to 9 in CO catalysis₂Application in preparing propane by hydrogenation.