WO2019218488A1 - Catalyst for aromatic hydrocarbon synthesis, preparation method therefor, and application thereof - Google Patents

Abstract

Disclosed are a catalyst for aromatic hydrocarbon synthesis, a preparation method therefor, and an application thereof. The catalyst comprises a zinc-aluminum spinel oxide and an acidic molecular sieve having a mass ratio of 1:5-5:1, wherein the zinc-aluminum spinel oxide optionally contains at least one other element selected from chromium, zirconium, copper, manganese, indium, gallium, and silicon, and the acidic molecular sieve is selected from an acidic ZSM-5 molecular sieve, an acidic ZSM-11 molecular sieve, and the mixture thereof. When the catalyst is applied in a method for directly preparing an aromatic hydrocarbon by means of carbon dioxide hydrogenation, the catalyst can enable the highly selective generation of the aromatic hydrocarbon by means of carbon dioxide hydrogenation, and has good stability. The method of the present invention implements the one-step generation of an aromatic hydrocarbon by means of carbon dioxide hydrogenation, thereby reducing great energy consumption resulting from stepwise production.

Description

Catalyst for aromatic hydrocarbon synthesis, preparation method and application thereof Technical field

The invention relates to a catalyst for synthesizing aromatic hydrocarbons, a preparation method and application thereof.

Background technique

In the past two centuries, the large-scale development and utilization of petrochemical resources represented by oil, coal and natural gas has provided abundant energy and raw materials for human society and promoted the unprecedented prosperity and development of economy and civilization. However, it also caused a lot of carbon dioxide emissions. As we all know, carbon dioxide is a typical greenhouse gas, and large-scale industrial emissions pose a serious threat to human living environment. Clean energy, represented by solar energy, wind energy, tidal energy, geothermal energy, etc., has a large amount of energy and does not generate additional carbon dioxide emissions. However, due to low energy density and high volatility, it is difficult to use it efficiently. If you use the energy generated by clean energy to electrolyze water, obtain hydrogen, and then react with carbon dioxide produced by petrochemical resources to produce bulk fuel or chemicals, you can effectively solve the above two problems.

Aromatic hydrocarbons are an important basic organic chemical raw material, and their derivatives are widely used in chemical products and fine chemicals such as fuel, petrochemical, chemical fiber, plastic and rubber. At present, aromatics are mainly produced from petroleum as raw materials, mainly from the catalytic reforming process unit of the refinery. In addition, the aromatics production process of the petroleum route includes aromatics extraction technology, heavy aromatics lightening technology, and light hydrocarbon aromatization technology. For countries with “rich coal-poor” energy structures, such as China, aromatics can also be produced through coal chemical routes. In the aromatics technology of coal chemical industry, the research on the preparation of aromatic hydrocarbons from methanol as the raw material of coal chemical platform is the most extensive. The methanol-based aromatics technology generally adopts acidic ZSM-5 molecular sieve catalyst modified by metal zinc, gallium, silver and the like. However, the rapid decline of aromatic hydrocarbons and short catalyst life restrict the large-scale industrial application of methanol aromatics technology.

Because aromatics have large unsaturation and complex molecular structure, it is difficult to prepare in a strong reduction reaction environment. There have been no reports on the direct and highly selective production of aromatic hydrocarbons by carbon dioxide hydrogenation.

Summary of the invention

In order to overcome the problems existing in the prior art, the inventors conducted diligent research. As a result, it has been found that a catalyst comprising zinc aluminum spinel oxide and an acidic molecular sieve is very suitable for a method of producing aromatic hydrocarbons by hydrogenation of carbon dioxide, thereby completing the present invention.

Accordingly, it is an object of the present invention to provide a catalyst for aromatic hydrocarbon synthesis comprising a zinc aluminum spinel oxide and an acidic molecular sieve in a mass ratio of 1:5 to 5:1, wherein the zinc aluminum spinel is oxidized Optionally containing at least one other element selected from the group consisting of chromium, zirconium, copper, manganese, indium, gallium, and silicon, and the acidic molecules are selected from acidic ZSM-5 molecular sieves, acidic ZSM-11 molecular sieves, and mixtures thereof .

Another object of the present invention is to provide a process for preparing the above catalyst.

It is still another object of the present invention to provide a process for producing aromatic hydrocarbons by hydrogenation of carbon dioxide using the above catalyst.

Description of the preferred embodiment

In a first aspect, the present invention provides a catalyst for aromatic hydrocarbon synthesis comprising a zinc aluminum spinel oxide and an acidic molecular sieve in a mass ratio of 1:5 to 5:1, wherein the zinc aluminum spinel oxide Optionally, at least one other element selected from the group consisting of chromium, zirconium, copper, manganese, indium, gallium, and silicon is selected, and the acidic molecules are selected from acidic ZSM-5 molecular sieves, acidic ZSM-11 molecular sieves, and mixtures thereof.

In one embodiment, the aromatic hydrocarbon synthesis catalyst is composed of a zinc aluminum spinel oxide having a mass ratio of 1:5 to 5:1 and an acidic molecular sieve, wherein the zinc aluminum spinel oxide is optionally contained At least one other element selected from the group consisting of chromium, zirconium, copper, manganese, indium, gallium, and silicon, and the acidic molecules are selected from acidic ZSM-5 molecular sieves, acidic ZSM-11 molecular sieves, and mixtures thereof.

In the catalyst of the present invention, the mass ratio of the zinc aluminum spinel oxide to the acidic molecular sieve is from 1:5 to 5:1, such as 1:1, 1:5, 2:1 or 5:1.

The Zn/Al molar ratio in the zinc aluminum spinel oxide in the catalyst of the present invention is any ratio, preferably Zn/Al = 1:9 to 1:1, such as 1:1, 1:2, 1:4.5 or 1: 9.

In some embodiments, the zinc aluminum spinel oxide has a zinc aluminum spinel crystal size of less than or equal to 30 nm.

In some embodiments, the zinc aluminum spinel oxide further contains at least one other element selected from the group consisting of chromium, zirconium, copper, manganese, indium, gallium, and silicon. The other elements may be added to the zinc aluminum spinel oxide by one or both of impregnation or coprecipitation methods. Preferably, the mass fraction of the other element in the zinc aluminum spinel oxide is less than or equal to 10%, such as 1%, 3%, 5%, 7%, 9% or 10%.

The acidic molecules in the catalyst of the invention are screened from acidic ZSM-5 molecular sieves, acidic ZSM-11 molecular sieves, and mixtures thereof.

In some embodiments, the atomic ratio of silicon to aluminum in the acidic ZSM-5 and ZSM-11 molecular sieves is Si/Al = 3 to 200, preferably Si/Al = 100 to 150.

In some embodiments, the crystals of the acidic ZSM-5 and ZSM-11 molecular sieves are microscale or nanoscale, and the crystals contain a microporous structure or a mesoporous-microporous structure.

The acidic molecular sieves useful in the present invention are either commercially available or can be prepared by methods known per se.

The catalyst of the present invention can have any shape and size known in the art to be suitable for use in fixed bed reactor applications. For example, the shape of the catalyst may be spherical, cylindrical, semi-cylindrical, prismatic, clover, annular, pellet, regular or irregular particles or flakes. In a second aspect, the present invention provides a method of preparing the above catalyst, the method comprising the steps of:

(1) providing a zinc aluminum spinel oxide, wherein the zinc aluminum spinel oxide optionally contains at least one other element selected from the group consisting of chromium, zirconium, copper, manganese, indium, gallium, and silicon;

(2) providing an acidic molecular sieve selected from an acidic ZSM-5 molecular sieve, an acidic ZSM-11 molecular sieve, and a mixture thereof;

(3) mixing the zinc aluminum spinel oxide obtained in the step (1) and the acidic molecular sieve obtained in the step (2), and molding the resulting mixture.

In one embodiment, the zinc aluminum spinel oxide that can be used to prepare the catalyst of the present invention is prepared by a precipitation-calcination process, and optionally at least one other element is added. For example, the zinc aluminum spinel oxide is prepared by a method comprising the steps of: formulating a zinc salt and an aluminum salt into a mixed metal salt aqueous solution; contacting the mixed metal salt aqueous solution with an aqueous solution of a precipitating agent to make Co-precipitation of metal ions in a mixed metal salt aqueous solution; aging; and washing the precipitate, drying and calcining to obtain the zinc aluminum spinel oxide; and optionally, at least one by impregnation and/or coprecipitation A brine solution of other elements is added to add the at least one other element. Examples of such precipitating agents include, but are not limited to, sodium carbonate, potassium carbonate, ammonium carbonate, sodium hydrogencarbonate, potassium hydrogencarbonate, ammonium hydrogencarbonate, aqueous ammonia, sodium hydroxide, potassium hydroxide, and mixtures thereof.

In one embodiment, the temperature during the coprecipitation is from 20 ° C to 95 ° C, the pH during the coprecipitation is from 7.0 to 9.0, the aging time is not less than 1 hour, and the calcination temperature is from 450 ° C to 800 ° C.

In a specific embodiment, the zinc aluminum spinel oxide is prepared by dissolving a zinc salt and an aluminum salt in any ratio in deionized water to prepare a mixed metal salt aqueous solution having a concentration of the mixed metal salt aqueous solution. The room temperature can be completely dissolved in any concentration of deionized water; the precipitating agent is dissolved in deionized water to prepare an aqueous solution of a precipitating agent, and the concentration of the aqueous solution of the precipitating agent is completely soluble in any concentration of deionized water at room temperature; The mixed metal salt aqueous solution is contacted with the aqueous solution of the precipitating agent, and coprecipitated at 20 to 95 ° C. The pH of the mixed metal salt aqueous solution and the aqueous solution of the precipitating agent is controlled during the precipitation to control the pH between 7.0 and 9.0. After the coprecipitation is completed, the mixture is aged at 20 to 95 ° C for 1 to 24 hours, then centrifuged, washed with deionized water, dried at 100 ° C for 24 hours, and finally calcined at 450 to 800 ° C for 2 to 10 hours to obtain zinc aluminum spinel oxide.

In the present invention, the kinds of the salts of the zinc salt, the aluminum salt and at least one other element are not particularly limited as long as they are water-soluble, for example, have a water solubility of more than 1 g/L at 25 °C. Examples of salts of the zinc salt, aluminum salt, and at least one other element include, but are not limited to, hydrochloride, sulfate, and nitrate.

In the method of the present invention, the manner of contacting the mixed metal salt aqueous solution with the aqueous solution of the precipitating agent is not particularly limited. In a particular embodiment, the contacting can be accomplished by cocurrent, feed or reverse feed.

The acidic molecules useful in the catalyst preparation process of the present invention are screened from acidic ZSM-5 molecular sieves, acidic ZSM-11 molecular sieves, and mixtures thereof. The acidic molecular sieves are either commercially available or can be prepared by methods known per se.

The molding method employed in the step (3) of the catalyst preparation method of the present invention is not particularly limited. For example, the mixture can be molded into a catalyst shape suitable for fixed bed reactor applications using an extrusion process or a molding process.

In a third aspect, the present invention provides a method for hydrogenating carbon dioxide to produce aromatic hydrocarbons, the method comprising:

a) passing a feed gas comprising carbon dioxide and hydrogen through a reaction zone carrying the catalyst, reacting under reaction conditions sufficient to convert at least a portion of the feed to obtain a reaction effluent comprising an aromatic hydrocarbon;

b) separating the aromatic hydrocarbon from the reaction effluent.

It is believed that the reactions taking place in the reaction zone are very complex and involve a series of reaction processes such as:

1) Methanol synthesis reaction:

CO ₂ +3H ₂ =CH ₃ OH+H ₂ O

2) Methanol to aromatics reaction:

CH ₃ OH→aromatics+H ₂ O

3) Reverse water gas shift reaction (RWGS):

CO ₂ +H ₂ =CO+H ₂ O

The catalyst in the method of the present invention comprises a zinc aluminum spinel oxide and an acidic molecular sieve in a mass ratio of 1:5 to 5:1, wherein the zinc aluminum spinel oxide optionally contains a chromium or zirconium selected from the group consisting of chromium and zirconium. At least one other element of copper, manganese, indium, gallium, and silicon, and the acidic molecules are selected from acidic ZSM-5 molecular sieves, acidic ZSM-11 molecular sieves, and mixtures thereof. The details of the catalyst are as described in the first aspect of the invention.

In the process of the invention, carbon dioxide and hydrogen are used as feed gases. In the feed gas, the molar ratio of hydrogen to carbon dioxide is from 1:9 to 9:1, preferably from 1:9 to 1:1.

The main side reaction in the reaction of carbon dioxide hydrogenation to aromatics is the reverse water gas shift reaction. This reaction is a typical equilibrium reaction. The addition of carbon monoxide is beneficial to suppress the reverse water gas shift reaction and improve the utilization efficiency of carbon dioxide. Therefore, the raw material gas in the method of the present invention may further contain carbon monoxide, and the molar concentration of carbon monoxide in the raw material gas is 1.0 to 20.0%, for example, 1%, 3%, 5%, 8%, 10%, 13%. , 15%, 17% and 20%.

In the process of the invention, the reaction zone may be one or more fixed bed reactors. The fixed bed reactor can be operated in a continuous mode. When multiple fixed bed reactors are employed, the plurality of reactors can be in series, parallel, or a combination of series and parallel.

In the method of the present invention, the reaction conditions include: a reaction temperature of 300 to 450 ° C, a reaction pressure of 0.5 to 10.0 MPa, a molar ratio of hydrogen to carbon dioxide in a feed gas of 1:9 to 9:1, and 1000 to Syngas volume hourly space velocity in the standard state of 20000 h ^-1 .

In a preferred embodiment, the reaction conditions include: a reaction temperature of 310 to 360 ° C, a reaction pressure of 1.0 to 4.0 MPa, a molar ratio of hydrogen to carbon dioxide in the feed gas of 3:1 to 6:1, and 3000. Syngas volume hourly space velocity in the standard state of ~8000h ^-1 .

In the present invention, the aromatic hydrocarbon is at least one selected from the group consisting of monocyclic aromatic hydrocarbons having 6 to 11 carbon atoms. Examples of the monocyclic aromatic hydrocarbon having 6 to 11 carbon atoms include, but are not limited to, benzene, toluene, ethylbenzene, p-xylene, m-xylene, o-xylene, mesitylene, and tetramethylbenzene.

The beneficial effects that can be produced by the present invention include:

1) The catalyst used in the present invention enables hydrogenation of carbon dioxide to be highly selective to produce aromatic hydrocarbons, and the catalyst has good stability.

2) By adding carbon monoxide, the reverse water gas shift reaction can be effectively suppressed, and the carbon dioxide utilization efficiency is high.

3) The method of the invention realizes the hydrogenation of carbon dioxide in one step to generate aromatic hydrocarbons, which reduces the problem of large energy consumption caused by stepwise production.

DRAWINGS

1 is an XRD chart of material A in Example 1 of the present application.

2 is a TEM image of material A in Example 1 of the present application.

Detailed ways

The invention will be described in detail below with reference to examples, but the invention is not limited to the examples.

The raw materials in the examples of the present invention are all commercially available unless otherwise indicated.

In the examples, automated analysis was performed using two Agilent 7890 gas chromatographs with a gas autosampler, a TCD detector coupled to a TDX-1 packed column, and an FID detector coupled to an FFAP and PLOT-Q capillary column.

In the examples, the conversion and selectivity are calculated based on the number of moles of carbon:

Carbon dioxide conversion = [(mole carbon dioxide carbon in feed) - (molar carbon dioxide carbon in the discharge)] ÷ (molar carbon dioxide carbon in the feed) × 100%

Aromatic hydrocarbon selectivity = (molar moles of aromatic hydrocarbons in the discharge) ÷ (sum of all hydrocarbon products in the discharge, carbon moles of methanol, dimethyl ether) × 100%

Carbon monoxide selectivity = (moles of carbon monoxide carbon produced by the reaction) ÷ (moles of converted carbon dioxide carbon) × 100%

Preparation of zinc aluminum spinel oxide

Example 1

95 g of Zn(NO ₃ ) ₂ 6H ₂ O and 80 g of Al(NO ₃ ) ₃ 9H ₂ O were dissolved in 200 ml of deionized water to prepare a salt solution. 25 g of ammonium carbonate was dissolved in 200 ml of deionized water to prepare an alkali solution. The salt solution and the alkali solution were co-precipitated by two peristaltic pumps, and the precipitation reaction temperature was controlled at 60 ° C, pH 7.2, and aged at this temperature for 4 h, filtered, washed and dried at 100 ° C for 24 h, 500 ° C. Calcination for 4 h gave a zinc aluminum spinel oxide numbered A. X-ray fluorescence spectrometry (XRF) showed that Zn/Al (molar ratio) in A was 1:1, the XRD pattern is shown in Fig. 1, and the TEM image is shown in Fig. 2.

Example 2

48 g of Zn(NO ₃ ) ₂ 6H ₂ O and 80 g of Al(NO ₃ ) ₃ 9H ₂ O were dissolved in 200 ml of deionized water to prepare a salt solution. 25 g of aqueous ammonia (containing 25% NH ₃ ) was dissolved in 200 ml of deionized water to prepare an alkali solution. The salt solution and the alkali solution were co-precipitated by two peristaltic pumps, and the precipitation reaction temperature was controlled at 70 ° C, pH 7.5, and aged at this temperature for 6 h, filtered, washed and dried at 100 ° C for 24 h, 500 ° C. Calcination for 4 h gave a zinc aluminum spinel oxide numbered B. XRF shows Zn/Al (molar ratio) in B = 1:2.

Example 3

10.6 g of Zn(NO ₃ ) ₂ 6H ₂ O and 80 g of Al(NO ₃ ) ₃ 9H ₂ O were dissolved in 200 ml of deionized water to prepare a salt solution. 25 g of sodium carbonate was dissolved in 200 ml of deionized water to prepare an alkali solution. The salt solution and the alkali solution were co-precipitated by two peristaltic pumps, and the precipitation reaction temperature was controlled at 80 ° C, pH 7.8, and aged at this temperature for 6 h, filtered, washed and dried at 100 ° C for 24 h, 500 ° C. Calcination for 6 h gave a zinc aluminum spinel oxide numbered C. XRF shows Zn/Al (molar ratio) in C = 1:9.

Example 4

10.6 g of Zn(NO ₃ ) ₂ 6H ₂ O and 40 g of Al(NO ₃ ) ₃ 9H ₂ O were dissolved in 200 ml of deionized water to prepare a salt solution. 15 g of potassium carbonate was dissolved in 200 ml of deionized water to prepare an alkali solution. The salt solution and the alkali solution were co-precipitated by two peristaltic pumps, and the precipitation reaction temperature was controlled at 70 ° C, pH 7.1, and aged at this temperature for 6 h, filtered, washed and dried at 100 ° C for 24 h, 500 ° C. Calcination for 4 h gave a zinc aluminum spinel oxide numbered D. XRF showed Zn/Al (molar ratio) in D = 1:4.5.

Example 5

7.7 g of Cr(NO ₃ ) ₃ 9H ₂ O was dissolved in 15 ml of deionized water, then 20 g of catalyst B was immersed at room temperature for 24 h, dried at 100 ° C for 24 h, and calcined at 500 ° C for 4 h to obtain 5% (mass fraction) chromium-modified zinc aluminum. Spinel oxide, numbered E.

Example 6

4.7 g of Zr(NO ₃ ) ₄ 5H ₂ O was dissolved in 15 ml of deionized water, then 20 g of catalyst B was immersed at room temperature for 24 h, dried at 100 ° C for 24 h, and calcined at 500 ° C for 4 h to obtain 5% (mass fraction) zirconium modified zinc aluminum. Spinel oxide, numbered F.

Catalyst preparation

Example 7

Zinc-aluminum spinel oxide A and H-ZSM-5 (Si/Al=200) (Nankai University Catalyst Factory) were uniformly mixed at a mass ratio of 1:1, ground with agate grind for 10 minutes, and then used with a tablet press. The sheet was compressed at 40 MPa to prepare a physically mixed catalyst G.

Example 8

Zinc-aluminum spinel oxide B and H-ZSM-5 (Si/Al=150) (Nankai University Catalyst Factory) were uniformly mixed at a mass ratio of 2:1, ground with agate grind for 10 minutes, and then used with a tablet press. The sheet was compressed at 40 MPa to prepare a physically mixed catalyst H.

Example 9

Zinc-aluminum spinel oxide C and H-ZSM-11 (Si/Al=40) (Aoco) are uniformly mixed at a mass ratio of 5:1, ground with agate grind for 10 minutes, and then used in a tablet press. The sheet was compressed at 40 MPa to prepare a physically mixed catalyst I.

Example 10

Zinc-aluminum spinel oxide D and H-ZSM-5 (Si/Al=3) (Aoco) are uniformly mixed at a mass ratio of 1:5, ground with agate grind for 10 minutes, and then pressed by a tablet press. The sheet was compressed at 40 MPa to prepare a physically mixed catalyst J.

Example 11

Zinc-aluminum spinel oxide E and H-ZSM-5 (Si/Al=150) (Nankai University Catalyst Factory) were uniformly mixed at a mass ratio of 2:1, ground with agate grind for 10 minutes, and then used with a tablet press. The sheet was compressed at 40 MPa to prepare a physically mixed catalyst K.

Example 12

Zinc-aluminum spinel oxide G and H-ZSM-5 (Si/Al=150) (Nankai University Catalyst Factory) were uniformly mixed at a mass ratio of 2:1, ground with agate grind for 10 minutes, and then used with a tablet press. The sheet was compressed at 40 MPa to prepare a physically mixed catalyst L.

Catalyst performance test

Example 13

The catalyst G crushing sieve was divided into 0.4 to 0.8 mm pellets, 2 g was placed in a stainless steel reaction tube having an inner diameter of 8 mm, and activated by using 50 ml/min of hydrogen at 300 ° C for 1 h, and the reaction was carried out under the following conditions: reaction temperature (T) = 320 ° C , the reaction pressure (P) = 4.0 MPa, the molar ratio of hydrogen to carbon dioxide in the feed gas is (H ₂ : CO ₂ ) = 3:1; the raw material gas volume hourly space velocity (GHSV) = 6000 h ^-1 under standard conditions. After reacting for 500 hours, the product was analyzed by gas chromatography, and the results are shown in Table 1.

Example 14-18

The reaction conditions and reaction results are shown in Table 1. The other operations are the same as those in the embodiment 13.

Example 19

The catalyst G crushing sieve was divided into 0.4 to 0.8 mm pellets, 2 g was placed in a stainless steel reaction tube having an inner diameter of 8 mm, and activated by using 50 ml/min of hydrogen at 300 ° C for 1 h, and the reaction was carried out under the following conditions: reaction temperature (T) = 320 ° C , the reaction pressure (P) = 4.0 MPa, the molar ratio of hydrogen, carbon dioxide, carbon monoxide in the feed gas is (H ₂ : CO ₂ : CO) = ₃ : ₁ : 0.04 (ie, the content of CO in the feed gas is 1%); The raw material gas volume hourly space velocity (GHSV) = 6000h ^-1 under standard conditions. After reacting for 500 hours, the product was analyzed by gas chromatography, and the results are shown in Table 1.

Example 20

The catalyst G crushing sieve was divided into 0.4 to 0.8 mm pellets, 2 g was placed in a stainless steel reaction tube having an inner diameter of 8 mm, and activated by using 50 ml/min of hydrogen at 300 ° C for 1 h, and the reaction was carried out under the following conditions: reaction temperature (T) = 320 ° C , the reaction pressure (P) = 4.0 MPa, the molar ratio of hydrogen, carbon dioxide, carbon monoxide in the feed gas is (H ₂ : CO ₂ : CO) = ₃ : ₁ : 0.2 (ie, the content of CO in the feed gas is 4.8%); The raw material gas volume hourly space velocity (GHSV) = 6000h ^-1 under standard conditions. After reacting for 500 hours, the product was analyzed by gas chromatography, and the results are shown in Table 1.

Example 21

The catalyst G crushing sieve was divided into 0.4-0.8 mm pellets, 2 g was placed in a stainless steel reaction tube having an inner diameter of 8 mm, and activated by using 50 ml/min of hydrogen at 300 ° C for 1 h, and the reaction was carried out under the following conditions: reaction temperature (T) = 320 ° C , the reaction pressure (P) = 4.0 MPa, the molar ratio of hydrogen, carbon dioxide, carbon monoxide in the feed gas is (H ₂ : CO ₂ : CO) = 3: 1:1 (ie, the content of CO in the feed gas is 20%); The raw material gas volume hourly space velocity (GHSV) = 6000h ^-1 under standard conditions. After reacting for 500 hours, the product was analyzed by gas chromatography, and the results are shown in Table 1.

Table 1 Results of catalytic reactions in Examples 13-21

Catalyst regeneration test

Example 22

The catalyst deactivated in Example 13 was treated with a mixture of a volume fraction of 2% oxygen and 98% nitrogen at 550 ° C for 10 h to allow the catalyst to regenerate for one round and reacted under the conditions of Example 13. Five rounds were regenerated in the same manner, and the catalytic activity data after 500 hours of each reaction was selected for comparison. The results are shown in Table 2.

Table 2 Results of the catalytic reaction in Example 22

The above is only a few embodiments of the present invention, and is not intended to limit the present invention. The present invention is disclosed by the preferred embodiments, but is not intended to limit the present invention. It is within the scope of the technical solution to make a slight change or modification with the technical content disclosed above, which is equivalent to the equivalent embodiment, without departing from the scope of the present invention.

Claims (10)

A catalyst for synthesizing aromatic hydrocarbons, comprising: a zinc-aluminum spinel oxide and an acidic molecular sieve having a mass ratio of 1:5 to 5:1, wherein the zinc-aluminum spinel oxide optionally contains a metal selected from the group consisting of chromium, At least one other element of zirconium, copper, manganese, indium, gallium, and silicon, and the acidic molecules are screened from acidic ZSM-5 molecular sieves, acidic ZSM-11 molecular sieves, and mixtures thereof. The catalyst of claim 1 having at least one of the following characteristics: - the atomic ratio of silicon to aluminum in the acidic ZSM-5 and ZSM-11 molecular sieves is Si / Al = 3 ~ 200, preferably Si / Al = 100 ~ 150; - the Zn/Al molar ratio in the zinc-aluminum spinel oxide is Zn/Al = 1:9 to 1:1; - the mass fraction of the other elements in the zinc aluminum spinel oxide is less than or equal to 10%. A method of preparing the catalyst of any of claims 1-2, the method comprising the steps of: (1) providing a zinc aluminum spinel oxide, wherein the zinc aluminum spinel oxide optionally contains at least one other element selected from the group consisting of chromium, zirconium, copper, manganese, steel, gallium, and silicon; (2) providing an acidic molecular sieve selected from an acidic ZSM-5 molecular sieve, an acidic ZSM-11 molecular sieve, and a mixture thereof; (3) mixing the zinc aluminum spinel oxide obtained in the step (1) and the acidic molecular sieve obtained in the step (2), and molding the resulting mixture. The method of claim 3 having at least one of the following features: - in step (1), preparing the zinc aluminum spinel oxide by a precipitation-calcination method, and optionally adding at least one other element; - In the step (3), the mixture is molded into catalyst particles by an extrusion method or a molding method. The method of claim 4, wherein in the step (1), the zinc aluminum spinel oxide is prepared by a method comprising the steps of: formulating a zinc salt and an aluminum salt into a mixed metal salt aqueous solution; and making the mixed metal salt Contacting the aqueous solution with an aqueous solution of the precipitating agent to coprecipitate the metal ions in the mixed metal salt aqueous solution; aging; and washing the precipitate, drying and calcining to obtain the zinc aluminum spinel oxide; and optionally The at least one other element is added by impregnation and/or coprecipitation of a brine solution of at least one other element. The method of claim 5 having at least one of the following features: a salt of said zinc salt, aluminum salt and at least one other element selected from the group consisting of hydrochlorides, sulfates and nitrates; The precipitating agent is selected from the group consisting of sodium carbonate, potassium carbonate, ammonium carbonate, sodium hydrogencarbonate, potassium hydrogencarbonate, ammonium hydrogencarbonate, aqueous ammonia, sodium hydroxide, potassium hydroxide and mixtures thereof; - the coprecipitation is carried out at 20 ° C to 95 ° C; - the pH value during the coprecipitation is 7.0 to 9.0; - the aging time is not less than 1 hour; - the calcination is carried out at 450 ° C to 800 ° C. A method for producing aromatic hydrocarbons by hydrogenation of carbon dioxide, the method comprising: a) passing a feed gas comprising carbon dioxide and hydrogen through a reaction zone carrying the catalyst, reacting under reaction conditions sufficient to convert at least a portion of the feed to obtain a reaction effluent comprising an aromatic hydrocarbon; b) separating the aromatic hydrocarbon from the reaction effluent, Wherein the catalyst comprises a zinc aluminum spinel oxide and an acidic molecular sieve in a mass ratio of 1:5 to 5:1, wherein the zinc aluminum spinel oxide optionally contains a selected from the group consisting of chromium, zirconium, copper, and manganese. At least one other element of indium, gallium, and silicon, and the acidic molecules are screened from acidic ZSM-5 molecular sieves, acidic ZSM-11 molecular sieves, and mixtures thereof. The method of claim 7 having at least one of the following features: The reaction zone comprises a fixed bed reactor or a plurality of fixed bed reactors connected in series and / or in parallel; - the reaction conditions include: a reaction temperature of 300 to 450 ° C, a reaction pressure of 0.5 to 10.0 MPa, a molar ratio of hydrogen to carbon dioxide in a feed gas of 1:9 to 9:1, and a standard state of 1000 to 20000 h ^-1 Lower syngas volume hourly space velocity; The aromatic hydrocarbon is at least one selected from the group consisting of monocyclic aromatic hydrocarbons having 6 to 11 carbon atoms; - the atomic ratio of silicon to aluminum in the acidic ZSM-5 and ZSM-11 molecular sieves is Si / Al = 3 ~ 200, preferably Si / Al = 100 ~ 150; - the Zn/Al molar ratio in the zinc-aluminum spinel oxide is Zn/Al = 1:9 to 1:1; - the mass fraction of the other elements in the zinc aluminum spinel oxide is less than or equal to 10%. The method of claim 7 or 8, wherein the feed gas further contains carbon monoxide, and the molar concentration of carbon monoxide in the feed gas is from 1.0 to 20.0%. The method according to claim 8, wherein the reaction conditions are: a reaction temperature of 310 to 360 ° C, a reaction pressure of 1.0 to 4.0 MPa, and a molar ratio of hydrogen to carbon dioxide in the raw material gas of 3:1 to 6:1. And the standard gas volume hourly space velocity in the standard state of 3000 to 8000 h ^-1 .

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