A catalyst for synthesizing aramatics from syngas, a preparation method and application thereof

Abstract

The application discloses a catalyst for synthesizing aromatic hydrocarbons from synthesis gas and a preparation method and application thereof. The catalyst comprises a Mn-based metal oxide and a metal M supported on the surface of the metal oxide, and the metal M is selected from at least one of Ce, Zr, Ti, Fe and Ni. The catalyst can significantly improve the conversion rate of CO and the yield of aromatic hydrocarbons.

Description

Technical Field

[0001] This invention relates to the field of syngas-to-aromatics technology, and particularly to a catalyst for syngas-to-aromatics production, its preparation method, and its application. Background Technology

[0002] Aromatics (especially BTX) are important basic chemical raw materials. Currently, aromatics production mainly comes from naphtha catalytic reforming. With the increasing demand for aromatics and the increasing depletion of petroleum resources, exploring non-petroleum routes for the highly selective preparation of aromatics is of great significance. Syngas can be derived from coal, biomass, and solid waste, and the production of aromatics from syngas has received widespread attention in recent years. Its production processes can be divided into two types: indirect and direct methods. The direct method has the advantages of a shorter process flow, reduced costs, and lower equipment investment. One-step syngas synthesis processes can be divided into two main categories based on the intermediates: one is based on Fischer-Tropsch components + molecular sieves, using C... 2-4 Alkenes are used as reaction intermediates, while another type uses metal oxides and molecular sieves, with methanol or ketene as intermediates.

[0003] CN112295597A discloses a catalyst for the direct conversion of syngas into BTX-rich aromatics and its applications. This catalyst is a composite catalyst comprising components I+II+III. Component I and component II are mechanically mixed to form I+II, while component III is layered with I+II at the bottom, forming a dual-bed catalyst. The active component of component I is a metal oxide, component II is a ZSM-5 molecular sieve, and component III is one or more molecular sieves with two-dimensional (2D) or three-dimensional (3D) twelve-membered ring channels. This catalyst achieves an aromatic selectivity of 40%–80%, with benzene, toluene, and xylene accounting for 50%–90% of the aromatics, while the selectivity for the byproduct methane is less than 15%.

[0004] CN110368984A discloses an Fe-based catalyst, its preparation method, and its application in the one-step synthesis of aromatics from syngas. The catalyst is composed of Fe-based spinel material, molecular sieve zeolite, and metal oxides, wherein the Fe-based spinel content is 9.95%–79.95%, the zeolite molecular sieve content is 20%–90%, and the oxide promoter content is 0.05%–20%. This catalyst couples the synthesis of olefins from syngas with the aromatization reaction of olefins to produce aromatics; however, it exhibits high methane selectivity but low aromatic selectivity, around 60%. Summary of the Invention

[0005] To address the problems of low CO conversion and aromatics yield in existing technologies, this invention provides a catalyst for the synthesis of aromatics from syngas, its preparation method, and its applications. The catalyst of this invention can significantly improve CO conversion and aromatics yield.

[0006] The first aspect of the present invention provides a catalyst for the synthesis of aromatics from syngas, comprising a Mn-based metal oxide and a metal M supported on its surface, wherein the metal M is selected from at least one of Ce, Zr, Ti, Fe and Ni, preferably Ce.

[0007] Furthermore, the Mn-based metal oxide is manganese oxide.

[0008] Furthermore, in addition to Mn, the Mn-based metal oxide preferably includes metal N, which is selected from at least one of Ce, Zr, Ti, Fe, and Ni, with Ce being preferred. The metal M and the metal N can be the same metal or can be different metals.

[0009] Furthermore, in the Mn-based metal oxide, the molar ratio of Mn to N, calculated by metal element, is 1 to 300, preferably 10 to 160, and more preferably 20 to 100.

[0010] Furthermore, in the Mn-based metal oxide and the metal M supported on its surface, the molar ratio of Mn to the sum of metal M and metal N, in terms of elements, is 5 to 50, preferably 10 to 35, and more preferably 10 to 25.

[0011] Furthermore, in the Mn-based metal oxide and the metal M supported on its surface, the metal element distribution coefficient q is 0 to 1, and q does not include 1, preferably 0 to 0.2; wherein, q is the molar ratio of Mn to the sum of metal M and N measured by XPS in terms of elements / the molar ratio of Mn to the sum of metal M and N measured by ICP-OES in terms of elements.

[0012] Furthermore, the catalyst also includes a molecular sieve. The molecular sieve is at least one of HZSM-5, HZSM-11, and HZSM-12 molecular sieves, preferably HZSM-5 and / or HZSM-11.

[0013] Furthermore, the Mn-based oxide and the metal M and molecular sieve supported on its surface exist independently of each other. For example, they can be individually packaged or mechanically mixed, preferably mechanically mixed.

[0014] Furthermore, the weight ratio of Mn-based metal oxides and the metal M supported on their surface, calculated as oxides, to the molecular sieve is 0.05–10, preferably 1–5.

[0015] A second aspect of the present invention provides a method for preparing the above-mentioned catalyst, comprising:

[0016] (1) Preparation of Mn-based metal oxides;

[0017] (2) The Mn-based metal oxide from step (1) is mixed with the metal M precursor, ethanol, urea and water, and subjected to a hydrothermal reaction. Then it is dried and calcined to obtain the catalyst.

[0018] Furthermore, in step (1), the Mn-based metal oxide can be prepared by co-precipitation. For example, the precursor of Mn, optionally the precursor of metal N, precipitant, and water can be co-precipitated, followed by aging, solid-liquid separation, washing, drying, and calcination to obtain the Mn-based metal oxide.

[0019] Further, in step (1), the precursor of Mn is an Mn salt. The Mn salt can be at least one of the nitrate, acetate, and sulfate of Mn; the precursor of metallic N can be at least one of the nitrate, acetate, and sulfate of metallic N.

[0020] Further, in step (1), the precursor of Mn and optionally the precursor of metal N in the Mn-based metal oxide, based on the metal element, have a molar ratio of 1 to 300, preferably 10 to 160, and more preferably 20 to 100.

[0021] Further, in step (1), the precipitation method of the Mn precursor and optionally the metal N precursor with the precipitant is co-precipitation in parallel flow, and the pH value of the precipitation process is controlled at 7.0 to 10.0, preferably 8.0 to 9.0.

[0022] Further, in step (1), the precipitant can be at least one of sodium hydroxide, sodium carbonate, sodium bicarbonate, ammonium carbonate, ammonium bicarbonate, and ammonia.

[0023] Furthermore, in step (1), precipitation can be carried out in accordance with conventional methods in the art, and the precipitation temperature can be 40 to 80°C.

[0024] Furthermore, in step (1), the aging temperature is 40-80℃, preferably 50-75℃, and the aging time is 1-7h, preferably 2-5h.

[0025] Furthermore, in step (1), filtration and washing can be performed in accordance with conventional methods in the art.

[0026] Furthermore, in step (1), the drying temperature is 50-120°C, preferably 70-100°C, and the drying time is 8-20h, preferably 12-18h.

[0027] Furthermore, in step (1), the calcination temperature is 400–800°C, preferably 450–650°C, and the calcination time is 1–8 hours, preferably 1–4 hours. The calcination atmosphere is an oxygen-containing gas, such as air.

[0028] Further, in step (2), the molar ratio of Mn-based metal oxide to metal M precursor, calculated by metal element, is Mn:(N+M) 5 to 50, preferably 10 to 35, and more preferably 10 to 25.

[0029] Further, in step (2), the mass ratio of Mn-based metal oxide to ethanol is 1 to 20; the mass ratio of Mn-based metal oxide to urea is 1 to 15.

[0030] Furthermore, in step (2), the mixing method is to stir at 20-40°C for 0.5-3 hours.

[0031] Furthermore, in step (2), the hydrothermal reaction temperature is 100-200℃, preferably 140-180℃, and the hydrothermal reaction time is 12-36h.

[0032] Furthermore, in step (2), after the hydrothermal reaction, the mixture undergoes solid-liquid separation, washing, and then drying. The solid-liquid separation can be performed by filtration. Filtration and washing can be carried out according to conventional methods in the art.

[0033] Furthermore, in step (2), the drying temperature is 50-120°C, preferably 70-100°C, and the drying time is 8-20h, preferably 12-18h.

[0034] Furthermore, in step (2), the calcination temperature is 400–800℃, preferably 450–650℃, and the calcination time is 1–8h, preferably 1–4h. The calcination atmosphere is air.

[0035] Furthermore, the preparation method further includes mixing the Mn-based metal oxide prepared in step (2) with a catalyst of metal M supported on its surface and a molecular sieve. The mixing method can be mechanical mixing, such as grinding mixing.

[0036] A third aspect of the present invention provides the application of the above-described catalyst in the preparation of aromatics using syngas as a feedstock.

[0037] Furthermore, the syngas is a mixture of carbon monoxide / hydrogen or carbon monoxide / carbon dioxide / hydrogen.

[0038] Furthermore, the preparation of aromatics is preferably carried out in a fixed bed reaction.

[0039] Furthermore, the reaction temperature for preparing aromatics is 350-450℃, the reaction pressure is 1-10MPa, and the space velocity is 800-10000h.-1 The hydrogen-to-carbon ratio is 0.5-5.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] The catalyst of this invention, by designing a specific catalyst structure and loading a specific metal on the surface of a Mn-based metal oxide, increases the synergistic effect between the metal oxides, improves the CO activation capacity, and can significantly improve the CO conversion rate and aromatic yield.

[0042] The method of this invention is simple to prepare and easy to industrially produce. Detailed Implementation

[0043] The present invention will be further described below through specific embodiments, but the scope of protection of the present invention is not limited to these embodiments.

[0044] This invention uses inductively coupled plasma optical emission spectrometry (ICP-OES) to measure the bulk elemental composition of Mn-based metal oxides and X-ray photoelectron spectroscopy (XPS) to measure the surface elemental composition of Mn-based metal oxides.

[0045] The catalysts in the following examples use HZSM-5 molecular sieve.

[0046] HZSM-5 molecular sieve was prepared as follows: TEOS, aluminum isopropoxide, and tetrapropylammonium hydroxide (TPAOH) were used as the silicon source, aluminum source, and template agent, respectively. The silicon source was calculated as SiO2, and the aluminum source as Al2O3. The molar ratio of TEOS:aluminum isopropoxide:TPAOH:H2O:Na2O:EtOH was 1:SiO2:0.01:Al2O3:0.2:TPAOH:50:H2O:0.05:Na2O:4.0:EtOH. 25g of TEOS, 40g of deionized water, and 9.8g of TPAOH were stirred at room temperature for 10h to form solution A. Then, 0.5 g of aluminum isopropoxide, 9.8 g of TPAOH, 22.1 g of ethanol, and 0.48 g of NaOH were stirred for 4 h to form solution B. The two solutions were mixed and stirred for another 12 h. The mixture was then stirred at 180 °C for 48 h to crystallize. The resulting solid was washed with deionized water until neutral, separated, dried, and calcined in a muffle furnace at 550 °C for 5 h to obtain Na-type ZSM-5 molecular sieve. These Na-type molecular sieves were then subjected to ion exchange with 0.1 M NH4NO3 at 80 °C for 3 h, followed by calcination in a muffle furnace at 550 °C for 5 h to obtain HZSM-5 molecular sieve.

[0047]

Example 1

[0048] Weigh 0.15 mol of manganese nitrate and 0.002 mol of cerium nitrate, dissolve them in 150 mL of distilled water, then dissolve 0.34 mol of sodium hydroxide in 300 mL of water. Run the two aqueous solutions in parallel at 70 °C to co-precipitate, then age at 80 °C for 2 h, filter, wash, dry at 100 °C overnight, and calcine at 500 °C in air atmosphere for 1 h to obtain CeMn oxide.

[0049] The obtained CeMn oxide, 0.008 mol of cerium nitrate, 20 ml of ethanol, and 2 g of urea were added to 100 ml of deionized water and stirred at room temperature for 2 h. The mixture was then transferred to a polytetrafluoroethylene liner and hydrothermally reacted at 120 °C for 5 h. After cooling to room temperature, the mixture was filtered, washed, and dried overnight at 100 °C. Finally, it was calcined at 500 °C in air atmosphere for 1 h to obtain CeMn metal oxide with Ce-loaded surface. The molar ratio of Mn to metallic M in the CeMn metal oxide with Ce-loaded surface obtained in this example was tested by XPS and ICP-OES, respectively.

[0050] 1.0 g of the prepared CeMn oxide with surface-loaded Ce and 1.0 g of the prepared HZSM-5 were ground and mixed, granulated, and loaded into a quartz reaction tube with an inner diameter of 6 mm. Before the reaction, the mixture was reduced with hydrogen at 400 °C for 3 hours. After the reduction was completed, a mixture of (n hydrogen:n carbon monoxide = 50:50) was introduced into the reaction tube and placed into a catalytic bed for reaction. The reaction temperature was 400 °C, the reaction system pressure was 5 MPa, and the gas hourly space velocity was 2000 h⁻¹. -1 The synthesis of aromatics from syngas was carried out under the specified conditions. The activity evaluation results are shown in Table 1.

[0051]

Example 2

[0052] Weigh 0.15 mol of manganese nitrate and 0.003 mol of cerium nitrate, dissolve them in 150 mL of distilled water, then dissolve 0.34 mol of sodium hydroxide in 300 mL of water. Run the two aqueous solutions in parallel at 70 °C to co-precipitate, then age at 80 °C for 2 h, filter, wash, dry at 100 °C overnight, and calcine at 500 °C in air atmosphere for 1 h to obtain CeMn oxide.

[0053] The obtained CeMn oxide, 0.007 mol of cerium nitrate, 20 ml of ethanol, and 2 g of urea were added to 100 ml of deionized water. After stirring at room temperature for 2 h, the mixture was transferred to a polytetrafluoroethylene liner and hydrothermally reacted at 120 °C for 5 h. After cooling to room temperature, the mixture was filtered, washed, dried at 100 °C overnight, and calcined at 500 °C in air atmosphere for 1 h to obtain CeMn metal oxide with Ce loaded on the surface. The molar ratio of Mn to metallic M in the CeMn metal oxide with Ce loaded on the surface obtained in this example was tested by XPS and ICP-OES, respectively.

[0054] 1.0 g of the prepared Ce-loaded CeMn metal oxide and 1.0 g of the prepared HZSM-5 were ground and mixed, granulated, and packed into a quartz reaction tube with an inner diameter of 6 mm. Before the reaction, the mixture was reduced with hydrogen at 400 °C for 3 hours. After the reduction was completed, a mixture of (n hydrogen:n carbon monoxide = 50:50) was introduced into the reaction tube and placed into a catalytic bed for reaction. The reaction temperature was 400 °C, the reaction system pressure was 5 MPa, and the gas hourly space velocity was 2000 h⁻¹. -1 The synthesis of aromatics from syngas was carried out under the specified conditions. The activity evaluation results are shown in Table 1.

[0055]

Example 3

[0056] Weigh 0.15 mol of manganese nitrate and 0.005 mol of cerium nitrate, dissolve them in 150 mL of distilled water, then dissolve 0.34 mol of sodium hydroxide in 300 mL of water. Run the two aqueous solutions in parallel at 70 °C to co-precipitate, then age at 80 °C for 2 h, filter, wash, dry at 100 °C overnight, and calcine at 500 °C in air atmosphere for 1 h to obtain CeMn oxide.

[0057] The obtained CeMn oxide, 0.005 mol of cerium nitrate, 20 ml of ethanol, and 2 g of urea were added to 100 ml of deionized water and stirred at room temperature for 2 h. The mixture was then transferred to a polytetrafluoroethylene liner and hydrothermally reacted at 120 °C for 5 h. After cooling to room temperature, the mixture was filtered, washed, dried at 100 °C overnight, and calcined at 500 °C in air atmosphere for 1 h to obtain CeMn metal with Ce-loaded surface. The molar ratio of Mn to metal M in the CeMn metal oxide with Ce-loaded surface obtained in this example was tested by XPS and ICP-OES, respectively.

[0058] 1.0 g of the prepared CeMn oxide with surface-loaded Ce and 1.0 g of the prepared HZSM-5 were ground and mixed, granulated, and loaded into a quartz reaction tube with an inner diameter of 6 mm. Before the reaction, the mixture was reduced with hydrogen at 400 °C for 3 hours. After the reduction was completed, a mixture of (n hydrogen:n carbon monoxide = 50:50) was introduced into the reaction tube and placed into a catalytic bed for reaction. The reaction temperature was 400 °C, the reaction system pressure was 5 MPa, and the gas hourly space velocity was 2000 h⁻¹. -1 The synthesis of aromatics from syngas was carried out under the specified conditions. The activity evaluation results are shown in Table 1.

[0059]

Example 4

[0060] Weigh 0.15 mol of manganese nitrate and 0.007 mol of cerium nitrate, dissolve them in 150 mL of distilled water, then dissolve 0.34 mol of sodium hydroxide in 300 mL of water. Run the two aqueous solutions in parallel at 70 °C to co-precipitate, then age at 80 °C for 2 h, filter, wash, dry at 100 °C overnight, and calcine at 500 °C in air atmosphere for 1 h to obtain CeMn oxide.

[0061] The obtained CeMn oxide, 0.003 mol of cerium nitrate, 20 ml of ethanol, and 2 g of urea were added to 100 ml of deionized water and stirred at room temperature for 2 h. The mixture was then transferred to a polytetrafluoroethylene liner and hydrothermally reacted at 120 °C for 5 h. After cooling to room temperature, the mixture was filtered, washed, and dried overnight at 100 °C. Finally, it was calcined at 500 °C in air atmosphere for 1 h to obtain CeMn metal with Ce-loaded surface. The molar ratio of Mn to metal M in the CeMn metal oxide with Ce-loaded surface obtained in this example was tested by XPS and ICP-OES, respectively.

[0062] 1.0 g of the prepared CeMn oxide with surface-loaded Ce and 1.0 g of the prepared HZSM-5 were ground and mixed, granulated, and loaded into a quartz reaction tube with an inner diameter of 6 mm. Before the reaction, the mixture was reduced with hydrogen at 400 °C for 3 hours. After the reduction was completed, a mixture of (n hydrogen:n carbon monoxide = 50:50) was introduced into the reaction tube and placed into a catalytic bed for reaction. The reaction temperature was 400 °C, the reaction system pressure was 5 MPa, and the gas hourly space velocity was 2000 h⁻¹. -1 The synthesis of aromatics from syngas was carried out under the specified conditions. The activity evaluation results are shown in Table 1.

[0063]

Example 5

[0064] Weigh 0.15 mol of manganese nitrate and 0.008 mol of cerium nitrate, dissolve them in 150 mL of distilled water, then dissolve 0.34 mol of sodium hydroxide in 300 mL of water. Run the two aqueous solutions in parallel at 70 °C to co-precipitate, then age at 80 °C for 2 h, filter, wash, dry at 100 °C overnight, and calcine at 500 °C in air atmosphere for 1 h to obtain CeMn oxide.

[0065] The obtained CeMn oxide, 0.002 mol of cerium nitrate, 20 ml of ethanol, and 2 g of urea were added to 100 ml of deionized water and stirred at room temperature for 2 h. The mixture was then transferred to a polytetrafluoroethylene liner and hydrothermally reacted at 120 °C for 5 h. After cooling to room temperature, the mixture was filtered, washed, and dried overnight at 100 °C. Finally, it was calcined at 500 °C in air atmosphere for 1 h to obtain CeMn metal with Ce-loaded surface. The molar ratio of Mn to metal M in the CeMn metal oxide with Ce-loaded surface obtained in this example was tested by XPS and ICP-OES, respectively.

[0066] 1.0 g of the prepared CeMn oxide with surface-loaded Ce and 1.0 g of the prepared HZSM-5 were ground and mixed, granulated, and loaded into a quartz reaction tube with an inner diameter of 6 mm. Before the reaction, the mixture was reduced with hydrogen at 400 °C for 3 hours. After the reduction was completed, a mixture of (n hydrogen:n carbon monoxide = 50:50) was introduced into the reaction tube and placed into a catalytic bed for reaction. The reaction temperature was 400 °C, the reaction system pressure was 5 MPa, and the gas hourly space velocity was 2000 h⁻¹. -1 The synthesis of aromatics from syngas was carried out under the specified conditions. The activity evaluation results are shown in Table 1.

[0067]

Example 6

[0068] Weigh 0.15 mol of manganese nitrate and 0.009 mol of cerium nitrate, dissolve them in 150 mL of distilled water, then dissolve 0.34 mol of sodium hydroxide in 300 mL of water. Run the two aqueous solutions in parallel at 70 °C to co-precipitate, then age at 80 °C for 2 h, filter, wash, dry at 100 °C overnight, and calcine at 500 °C in air atmosphere for 1 h to obtain CeMn oxide.

[0069] The obtained CeMn oxide, 0.001 mol of cerium nitrate, 20 ml of ethanol, and 2 g of urea were added to 100 ml of deionized water and stirred at room temperature for 2 h. The mixture was then transferred to a polytetrafluoroethylene liner and hydrothermally reacted at 120 °C for 5 h. After cooling to room temperature, the mixture was filtered, washed, and dried overnight at 100 °C. Finally, it was calcined at 500 °C in air atmosphere for 1 h to obtain CeMn metal with Ce-loaded surface. The molar ratio of Mn to metal M in the CeMn metal oxide with Ce-loaded surface obtained in this example was tested by XPS and ICP-OES, respectively.

[0070] 1.0 g of the prepared CeMn oxide with surface-loaded Ce and 1.0 g of the prepared HZSM-5 were ground and mixed, granulated, and loaded into a quartz reaction tube with an inner diameter of 6 mm. Before the reaction, the mixture was reduced with hydrogen at 400 °C for 3 hours. After the reduction was completed, a mixture of (n hydrogen:n carbon monoxide = 50:50) was introduced into the reaction tube and placed into a catalytic bed for reaction. The reaction temperature was 400 °C, the reaction system pressure was 5 MPa, and the gas hourly space velocity was 2000 h⁻¹. -1 The synthesis of aromatics from syngas was carried out under the specified conditions. The activity evaluation results are shown in Table 1.

[0071]

Example 7

[0072] Weigh 0.2 mol of manganese nitrate and 0.002 mol of cerium nitrate, dissolve them in 200 mL of distilled water, then dissolve 0.44 mol of sodium hydroxide in 400 mL of water. After co-precipitating the two aqueous solutions in parallel streams, age them at 80 °C for 2 h, filter them, dry them at 100 °C overnight, and calcine them at 500 °C in air atmosphere for 1 h to obtain CeMn oxide.

[0073] The obtained CeMn oxide, 0.008 mol of cerium nitrate, 20 ml of ethanol, and 2 g of urea were added to 100 ml of deionized water and stirred at room temperature for 2 h. The mixture was then transferred to a polytetrafluoroethylene liner and hydrothermally reacted at 120 °C for 5 h. After cooling to room temperature, the mixture was filtered, washed, and dried overnight at 100 °C. Finally, it was calcined at 500 °C in air atmosphere for 1 h to obtain CeMn metal with Ce-loaded surface. The molar ratio of Mn to metal M in the CeMn metal oxide with Ce-loaded surface obtained in this example was tested by XPS and ICP-OES, respectively.

[0074] 1.0 g of the prepared CeMn oxide with surface-loaded Ce and 1.0 g of the prepared HZSM-5 were ground and mixed, granulated, and loaded into a quartz reaction tube with an inner diameter of 6 mm. Before the reaction, the mixture was reduced with hydrogen at 400 °C for 3 hours. After the reduction was completed, a mixture of (n hydrogen:n carbon monoxide = 50:50) was introduced into the reaction tube and placed into a catalytic bed for reaction. The reaction temperature was 400 °C, the reaction system pressure was 5 MPa, and the gas hourly space velocity was 2000 h⁻¹. -1 The synthesis of aromatics from syngas was carried out under the specified conditions. The activity evaluation results are shown in Table 1.

[0075]

Example 8

[0076] Weigh 0.3 mol of manganese nitrate and 0.002 mol of cerium nitrate, dissolve them in 300 mL of distilled water, then dissolve 0.54 mol of sodium hydroxide in 500 mL of water. After co-precipitating the two aqueous solutions in parallel streams, age them at 80 °C for 2 h, filter them, dry them at 100 °C overnight, and calcine them at 500 °C in air atmosphere for 1 h to obtain CeMn oxide.

[0077] The obtained CeMn oxide, 0.008 mol of cerium nitrate, 20 ml of ethanol, and 2 g of urea were added to 100 ml of deionized water and stirred at room temperature for 2 h. The mixture was then transferred to a polytetrafluoroethylene liner and hydrothermally reacted at 120 °C for 5 h. After cooling to room temperature, the mixture was filtered, washed, and dried overnight at 100 °C. Finally, it was calcined at 500 °C in air atmosphere for 1 h to obtain CeMn metal with Ce-loaded surface. The molar ratio of Mn to metal M in the CeMn metal oxide with Ce-loaded surface obtained in this example was tested by XPS and ICP-OES, respectively.

[0078] 1.0 g of the prepared CeMn oxide with surface-loaded Ce and 1.0 g of the prepared HZSM-5 were ground and mixed, granulated, and loaded into a quartz reaction tube with an inner diameter of 6 mm. Before the reaction, the mixture was reduced with hydrogen at 400 °C for 3 hours. After the reduction was completed, a mixture of (n hydrogen:n carbon monoxide = 50:50) was introduced into the reaction tube and placed into a catalytic bed for reaction. The reaction temperature was 400 °C, the reaction system pressure was 5 MPa, and the gas hourly space velocity was 2000 h⁻¹. -1 The synthesis of aromatics from syngas was carried out under the specified conditions. The activity evaluation results are shown in Table 1.

[0079]

Example 9

[0080] Weigh 0.15 mol of manganese nitrate and 0.002 mol of zirconium nitrate, dissolve them in 150 mL of distilled water, then dissolve 0.34 mol of sodium hydroxide in 300 mL of water. Run the two aqueous solutions in parallel at 70 °C to co-precipitate, then age at 80 °C for 2 h, filter, wash, dry at 100 °C overnight, and calcine at 500 °C in air atmosphere for 1 h to obtain ZrMn oxide.

[0081] The obtained ZrMn oxide, 0.008 mol of zirconium nitrate, 20 ml of ethanol, and 2 g of urea were added to 100 ml of deionized water and stirred at room temperature for 2 h. The mixture was then transferred to a polytetrafluoroethylene liner and hydrothermally reacted at 120 °C for 5 h. After cooling to room temperature, the mixture was filtered, washed, and dried overnight at 100 °C. Finally, it was calcined at 500 °C in air atmosphere for 1 h to obtain ZrMn metal with Zr surface loading. The molar ratio of Mn to metal M in the ZrMn metal oxide with Zr surface loading obtained in this example was tested by XPS and ICP-OES, respectively.

[0082] 1.0 g of the prepared Zr-supported ZrMn oxide and 1.0 g of the prepared HZSM-5 were ground, mixed, granulated, and packed into a quartz reaction tube with an inner diameter of 6 mm. Before the reaction, the mixture was reduced with hydrogen at 400 °C for 3 hours. After the reduction was completed, a mixture of (n hydrogen:n carbon monoxide = 50:50) was introduced into the reaction tube and placed into a catalytic bed for reaction. The reaction temperature was 400 °C, the reaction system pressure was 5 MPa, and the gas hourly space velocity was 2000 h⁻¹. -1 The synthesis of aromatics from syngas was carried out under the specified conditions. The activity evaluation results are shown in Table 1.

[0083]

Comparative Example 1

[0084] Weigh 0.15 mol of manganese nitrate and 0.01 mol of cerium nitrate, dissolve them in 150 mL of distilled water, then dissolve 0.34 mol of sodium hydroxide in 300 mL of water. Run the two aqueous solutions in parallel at 70 °C to co-precipitate, then age at 80 °C for 2 h, filter, wash, dry at 100 °C overnight, and calcine at 500 °C in air atmosphere for 1 h to obtain CeMn oxide.

[0085] 1.0 g of prepared CeMn oxide and 1.0 g of prepared HZSM-5 were ground and mixed, granulated, and loaded into a quartz reaction tube with an inner diameter of 6 mm. Before the reaction, the mixture was reduced with hydrogen at 400 °C for 3 hours. After the reduction was completed, a mixture of (n hydrogen:n carbon monoxide = 50:50) was introduced into the reaction tube and placed into a catalytic bed for reaction. The reaction temperature was 400 °C, the reaction system pressure was 5 MPa, and the gas hourly space velocity was 2000 h⁻¹. -1 The synthesis of aromatics from syngas was carried out under the specified conditions. The activity evaluation results are shown in Table 1.

[0086] Table 1

[0087]

[0088] The specific embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A catalyst for the synthesis of aromatics from syngas, comprising a Mn-based metal oxide and a metal M supported on its surface, wherein the metal M is selected from Ce; In addition to Mn, the Mn-based metal oxide also includes metal N, wherein the metal N is selected from Ce; the Mn-based metal oxide is CeMn oxide; In Mn-based metal oxides and the metal M supported on their surfaces, the metal element distribution coefficient q ranges from 0 to 0.3; among which, q is the molar ratio of Mn to the sum of metallic M and N as measured by XPS, in elemental terms, / the molar ratio of Mn to the sum of metallic M and N as measured by ICP-OES, in elemental terms. In Mn-based metal oxides and the metal M supported on their surfaces, the molar ratio of Mn to the sum of metal M and metal N, in terms of elements, is 5 to 50.

2. The catalyst according to claim 1, characterized in that, In Mn-based metal oxides, the molar ratio of Mn to N, calculated by metal element, is 1 to 300.

3. The catalyst according to claim 2, characterized in that, In Mn-based metal oxides, the molar ratio of Mn to N, calculated by metal element, is 10 to 160.

4. The catalyst according to claim 3, characterized in that, In Mn-based metal oxides, the molar ratio of Mn to N, calculated by metal element, is 20 to 100.

5. The catalyst according to claim 1, characterized in that, In Mn-based metal oxides and the metal M supported on their surfaces, the molar ratio of Mn to the sum of metal M and metal N, in terms of elements, is 10~35.

6. The catalyst according to claim 5, characterized in that, In Mn-based metal oxides and the metal M supported on their surfaces, the molar ratio of Mn to the sum of metal M and metal N, in terms of elements, is 10~25.

7. The catalyst according to claim 1, characterized in that, The distribution coefficient q of metallic elements is 0 to 0.

2.

8. The catalyst according to claim 1, characterized in that, The catalyst further includes a molecular sieve; the molecular sieve is at least one of HZSM-5, HZSM-11, and HZSM-12 molecular sieves; and / or, the weight ratio of Mn-based metal oxides and the metal M supported on their surfaces, calculated as oxides, to the molecular sieve is 0.05 to 10.

9. The catalyst according to claim 8, characterized in that, The molecular sieve is HZSM-5 and / or HZSM-11; and / or, the weight ratio of Mn-based metal oxide and the metal M loaded on its surface (calculated as oxide) to the molecular sieve is 1~5.

10. A method for preparing the catalyst according to any one of claims 1-9, comprising: (1) Preparation of Mn-based metal oxides; (2) The Mn-based metal oxide from step (1) is mixed with the metal M precursor, ethanol, urea and water, and subjected to a hydrothermal reaction. Then it is dried and calcined to obtain the catalyst.

11. The preparation method according to claim 10, characterized in that, In step (2), the hydrothermal reaction temperature is 100~200℃ and the hydrothermal reaction time is 12~36h; and / or, the calcination temperature is 400~800℃ and the calcination time is 1~8h.

12. The preparation method according to claim 11, characterized in that, In step (2), the hydrothermal reaction temperature is 140~180°C; and / or, the calcination temperature is 450~650°C, and the calcination time is 1~4 h.

13. The preparation method according to claim 10, characterized in that, The preparation method further includes mixing the Mn-based metal oxide prepared in step (2) with a catalyst of metal M supported on its surface and a molecular sieve.

14. The application of the catalyst according to any one of claims 1-9 in the preparation of aromatics using carbon monoxide / hydrogen or a mixture of carbon monoxide / carbon dioxide / hydrogen as raw materials.

15. The application according to claim 14, wherein the preparation of aromatics is carried out in a fixed bed reaction at a reaction temperature of 350-450°C and / or a reaction pressure of 1-10 MPa and / or a space velocity of 800-10000 h⁻¹. -1 And / or the hydrogen-to-carbon ratio is 0.5-5.

Images