A catalyst for methanol synthesis from multi-component gas mixture and its preparation method

Abstract

A catalyst suitable for the production of methanol from a multi-component mixed gas and its preparation method are disclosed. The catalyst has a hydrotalcite-like structure, and in molar amounts, the ratio of Cu:Zn:Mn:promoter is 40-65:15-35:15-25:0.5-5. The promoter is one or more of Ca, Al, Mg, Sr, La, Ba, and Si. This catalyst exhibits highly efficient catalytic activity in the hydrogenation of a multi-component mixed gas to methanol.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, and in particular to a catalyst suitable for the production of methanol from a multi-component mixed gas and its preparation method. Background Technology

[0002] Carbon dioxide is not only a major greenhouse gas contributing to global warming, but also a cheap, clean, and abundant natural resource. To fully utilize this resource and promote the development of the chemical industry and a sustainable energy economy, biomass methanol technology utilizes renewable biomass resources to produce green methanol from syngas obtained through biomass gasification. It boasts advantages such as low carbon emissions throughout its lifecycle, relatively low production costs, and ease of obtaining EU green methanol certification, attracting widespread attention from the industry. However, syngas from biomass gasification often contains a large amount of CO2, with CO2 content reaching 30-40%. Traditional catalysts for syngas-to-methanol production are unsuitable for feedstock gases with high CO2 content. Furthermore, the excessively high CO composition in biomass gasification gas is also unsuitable for commercially available catalysts for the hydrogenation of pure CO2 to methanol. Therefore, it is necessary to develop a multi-component mixed gas catalyst with high CO2 and CO tolerance to meet the needs of biomass gasification for methanol production.

[0003] Currently, the main catalysts used for methanol production from syngas are Cu / ZnO / Al2O3 systems. However, due to the relatively stable chemical properties of CO2 molecules and the fact that CO2 hydrogenation to methanol produces water vapor as a byproduct, the high temperature and pressure conditions cause this water vapor to corrode the copper species in the catalyst, leading to rapid deactivation. Therefore, traditional syngas-to-methanol catalysts exhibit low catalytic activity and are prone to deactivation under feed gas conditions with high CO2 content. Generally, the CO2 content in the feed gas for syngas-to-methanol reactions does not exceed 5%. Furthermore, while mainstream copper-based catalysts for CO2 hydrogenation to methanol exhibit good catalytic performance and stability, their activation mechanisms for CO and CO2 differ. High CO content in the feed gas alters the chemical state of the catalyst surface, causing rapid deactivation. Therefore, developing a multi-component mixed gas catalyst with high CO2 and CO tolerance is one of the key issues in the development of biomass-to-methanol technology. This requires simultaneously improving the activation of copper-based catalysts for both CO and CO2 in the feed gas and enhancing their tolerance to both. Summary of the Invention

[0004] This invention provides a catalyst suitable for methanol production from a multi-component mixed gas and its preparation method. The catalyst exhibits high catalytic activity in the hydrogenation reaction of a multi-component mixed gas to methanol.

[0005] This invention provides a method for preparing a catalyst suitable for methanol production from multi-element mixed gases, the method comprising:

[0006] The system provides a first active metal mixed solution, a second active metal mixed solution, and a precipitant solution. The first active metal mixed solution contains soluble manganese salt and soluble zinc salt; the second active metal mixed solution contains soluble copper salt and soluble zinc salt; and the precipitant solution includes a sodium carbonate solution and a sodium hydroxide solution.

[0007] The first active metal mixed solution, the second active metal mixed solution, and the precipitant solution are mixed to carry out a precipitation reaction, and the precipitated product is dried and calcined.

[0008] The second active metal mixed solution and / or the precipitant solution contain an additive; the additive contains one or more of Ca, Al, Mg, Sr, La, Ba, and Si.

[0009] In molar amounts, Cu:Zn:Mn:additive is 40-65:15-35:15-25:0.5-5, and the additive is one or more of Ca, Al, Mg, Sr, La, Ba, and Si.

[0010] Furthermore, when the additive is one or more of Ca, Al, Mg, Sr, La, and Ba, the additive is added to the second active metal mixed solution; when the additive is Si, the additive is added to the precipitant solution.

[0011] Furthermore, in the first active metal mixed solution, the ratio of zinc salt in the first active metal mixed solution to the total zinc salt used is (0.5-1):1, in molar terms.

[0012] Furthermore, the concentration of the first active metal mixed solution is 0.5-2 mol / L, and the concentration of the second active metal mixed solution is 0.5-2 mol / L.

[0013] Furthermore, during the precipitation reaction, the method also includes:

[0014] The first active metal mixed solution is mixed with a portion of the precipitant solution;

[0015] After the first active metal mixed solution has precipitated completely, the second active metal mixed solution and a portion of the precipitant are simultaneously added to the precipitate obtained from the first active metal mixed solution and the precipitant solution.

[0016] After the second active metal mixed solution has precipitated completely, the resulting product is kept at a temperature to allow it to age.

[0017] The aged products are filtered, washed, dried, and calcined.

[0018] Furthermore, during the precipitation reaction, the reaction temperature is 10-70℃ and the pH of the reaction system is 7-10.

[0019] Furthermore, during the aging process, the aging temperature is 10-70℃ and the aging time is 6-24 hours.

[0020] Furthermore, the roasting temperature is 300-400℃, and the roasting time is 4-12h.

[0021] Furthermore, in the precipitant solution, the molar ratio of sodium carbonate to sodium hydroxide is 1-3:1.

[0022] This invention also provides a catalyst suitable for the production of methanol from a multi-element mixed gas. The catalyst has a hydrotalcite-like structure, and its molar ratio of Cu:Zn:Mn:additive is 40-65:15-35:15-25:0.5-5. The additive is one or more of Ca, Al, Mg, Sr, La, Ba, and Si.

[0023] In summary, this invention introduces Mn into the catalyst to replace the traditional copper-zinc-aluminum system, forming a novel copper-zinc-manganese catalyst system. The Mn element in this catalyst system has the characteristic of adjustable valence state, allowing for the application of Mn... 2+ To Mn 3+ Electron transfer promotes the formation of abundant oxygen vacancies on the catalyst surface. These oxygen vacancies can modulate the catalyst surface structure and the properties of active sites according to changes in the reaction atmosphere composition. Furthermore, copper-zinc-manganese catalyst systems are favorable for the formation of highly efficient Cu-ZnO and ZnO-MnO. x The active interface facilitates the non-dissociative adsorption of CO and CO2, enabling the simultaneous activation and conversion of CO and CO2. This allows the copper-zinc-manganese catalyst to achieve high catalytic activity and good stability in the CO2 / CO co-hydrogenation to methanol reaction. Furthermore, the sequential addition of multiple active metal mixed solutions with a precipitant, specifically sodium carbonate and sodium hydroxide, allows the copper, zinc, and manganese in the catalyst to form a hydrotalcite-like structure. The uniform atomic-scale distribution of metal cations in the hydrotalcite-like layer results in better copper species dispersion after reduction compared to ordinary catalysts. This leads to higher hydrogen activation capacity and exhibits higher hydrogenation activity compared to conventional copper-based catalysts. The stronger interaction between copper species and ZnO in the hydrotalcite-like structure helps suppress copper crystal formation and stabilize amorphous copper species, resulting in better thermal stability than traditional catalysts. This also helps inhibit and improve the migration and sintering of copper species, leading to better catalytic stability.

[0024] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0025] Figure 1 The figure shows a comparison of the long-term stability of catalyst 3, reference catalyst 1 to reference catalyst 4 over a period of 200 hours. Detailed Implementation

[0026] To further illustrate the technical means and effects adopted by the present invention in order to achieve the intended purpose, the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments.

[0027] This invention provides a catalyst suitable for methanol production from a multi-component mixed gas and its preparation method. The catalyst exhibits high catalytic activity in the hydrogenation reaction of a multi-component mixed gas to methanol.

[0028] The method for preparing a catalyst suitable for methanol production from a multi-element mixed gas provided by this invention includes the following steps:

[0029] A first active metal mixed solution is provided, which contains soluble manganese salt and soluble zinc salt.

[0030] In this embodiment, the concentration of the first active metal mixed solution can be 0.5-2 mol / L, and more specifically, it can be 0.6 mol / L, 0.8 mol / L, 1.0 mol / L, 1.3 mol / L, 1.7 mol / L, 1.9 mol / L, etc.

[0031] Preferably, the soluble manganese salt is manganese nitrate and the soluble zinc salt is zinc nitrate.

[0032] In other embodiments, it may also be a formate or acetate containing manganese or zinc.

[0033] A second active metal mixture solution is provided, which contains soluble copper salt, soluble zinc salt and soluble additives.

[0034] In this embodiment, the concentration of the second active metal mixed solution can be 0.5-2 mol / L, and more specifically, it can be 0.6 mol / L, 0.8 mol / L, 1.0 mol / L, 1.3 mol / L, 1.7 mol / L, 1.9 mol / L, etc.

[0035] In this embodiment, the additive may be a soluble salt containing one or more of Ca, Al, Mg, Sr, La, and Ba.

[0036] A precipitant solution is provided, which includes sodium carbonate and sodium hydroxide solutions.

[0037] In this embodiment, the concentration of the precipitant solution can be 0.5-2 mol / L, and more specifically, it can be 0.6 mol / L, 0.8 mol / L, 1.0 mol / L, 1.3 mol / L, 1.7 mol / L, 1.9 mol / L, etc.

[0038] The molar ratio of sodium carbonate to sodium hydroxide is 1-3:1.

[0039] It should be noted that in this embodiment, Si can also be present as an additive. When using an additive containing Si, it can be added to the precipitant in the form of sodium metasilicate.

[0040] Preferably, the soluble copper salt is copper nitrate and the soluble zinc salt is zinc nitrate.

[0041] In other embodiments, it may also be a copper or zinc-containing formate or acetate, etc.

[0042] In this embodiment, the molar ratio of Cu:Zn:Mn:additive is 40-65:15-35:15-25:0.5-5.

[0043] Both the first and second active metal mixed solutions contain a portion of soluble zinc salt. Specifically, in the first active metal mixed solution, the proportion of added zinc salt to the total zinc salt used is (0.5-1):1, by molar weight.

[0044] A first active metal mixed solution, a second active metal mixed solution, and a precipitant are mixed to induce a precipitation reaction. The precipitate is then dried and calcined to obtain a catalyst suitable for the production of methanol from a multi-component mixed gas.

[0045] More specifically, the method includes the following steps when carrying out the precipitation reaction:

[0046] A certain liquid level is established in the reactor, and the first active metal mixed solution is mixed with a portion of the precipitant under continuous stirring.

[0047] Preferably, when adding the first active metal mixed solution and the precipitant, the reaction temperature is 10-70℃ and the pH of the reaction system is 7-10.

[0048] In this step, the amount of precipitant added depends on the amount of the first active metal mixed solution used.

[0049] After the first active metal mixed solution has precipitated completely, the second active metal mixed solution and precipitant are added dropwise into the reaction vessel.

[0050] Preferably, when adding the second active metal mixed solution, the reaction temperature is 10-70℃ and the pH of the reaction system is 7-10.

[0051] After the second active metal mixed solution has precipitated completely, the addition of precipitant is stopped and the mixture is kept at a certain temperature to allow the resulting product to age and obtain the catalyst precursor slurry.

[0052] The catalyst precursor slurry was filtered and washed until it was neutral and free of sodium ions. It was then dried and calcined, and finally granulated and pressed into tablets to obtain the catalyst.

[0053] In this embodiment, the temperature is maintained at 10-70℃ and the aging time is 6-24h.

[0054] When drying the catalyst precursor slurry, the drying temperature is 100-120℃ and the drying time is 12h.

[0055] During roasting, the roasting temperature is 300-400℃ and the roasting time is 4-12 hours.

[0056] To facilitate demolding after tableting, the granulated catalyst can be overmixed with graphite during tableting.

[0057] A novel copper-zinc-manganese catalyst system is formed by introducing Mn into the catalyst instead of the traditional copper-zinc-aluminum system. The Mn element in this catalyst system has the characteristic of tunable valence state. 2+ To Mn 3+ Electron transfer promotes the formation of abundant oxygen vacancies on the catalyst surface. These oxygen vacancies can modulate the catalyst surface structure and the properties of active sites according to changes in the reaction atmosphere composition. Furthermore, copper-zinc-manganese catalyst systems are favorable for the formation of highly efficient Cu-ZnO and ZnO-MnO. xThe active interface facilitates the non-dissociative adsorption of CO and CO2, enabling the simultaneous activation and conversion of CO and CO2. This allows the copper-zinc-manganese catalyst to achieve high catalytic activity and good stability in the CO2 / CO co-hydrogenation to methanol reaction. Furthermore, the sequential addition of multiple active metal mixed solutions with a precipitant, specifically sodium carbonate and sodium hydroxide, allows the copper, zinc, and manganese in the catalyst to form a hydrotalcite-like structure. The uniform atomic-scale distribution of metal cations in the hydrotalcite-like layer results in better copper species dispersion after reduction compared to ordinary catalysts. This leads to higher hydrogen activation capacity and exhibits higher hydrogenation activity compared to conventional copper-based catalysts. The stronger interaction between copper species and ZnO in the hydrotalcite-like structure helps suppress copper crystal formation and stabilize amorphous copper species, resulting in better thermal stability than traditional catalysts. This also helps inhibit and improve the migration and sintering of copper species, leading to better catalytic stability.

[0058] The preparation method provided by the present invention will be further illustrated below with specific embodiments:

[0059] Example 1

[0060] 1) Dissolve 12.48 g manganese nitrate tetrahydrate and 11.84 g zinc nitrate hexahydrate in demineralized water to prepare a first active metal mixed solution with a concentration of 1 mol / L; dissolve 28.86 g copper nitrate trihydrate, 11.84 g zinc nitrate hexahydrate and 2.03 g magnesium nitrate hexahydrate in demineralized water to prepare a second active metal mixed solution with a concentration of 1 mol / L.

[0061] 21.46 g of sodium carbonate and 8.1 g of sodium hydroxide were dissolved in demineralized water (the molar ratio of sodium carbonate to sodium hydroxide was 1:1) to prepare a precipitant solution with a Na ion concentration of 1 mol / L.

[0062] 2) Establish a certain liquid level in the reactor and control the temperature at 70℃. Under continuous stirring, use a metering pump to simultaneously add the first active metal mixed solution and the precipitant solution to the reactor. Control the dropping rate of the precipitant to keep the pH of the system at 10, so as to form a precipitate.

[0063] 3) After the first active metal mixed solution has precipitated completely, the second active metal mixed solution and the precipitant solution are added dropwise to the reactor using a metering pump. The dropping rate of the precipitant is controlled to keep the pH of the system at 10, so as to form the catalyst precursor precipitate.

[0064] 4) After the second active metal mixed solution is added, stop adding the precipitant solution and continue aging at 70℃ for 6 h to obtain the catalyst precursor slurry. Then filter and wash the catalyst precursor slurry until it is neutral and free of sodium ions, and dry it at 120℃ for 12 h. Then transfer the sample to a calcination furnace and calcinate at 400℃ for 4 h. After granulation, it is mixed with graphite and pressed into tablets to obtain catalyst 1.

[0065] Example 2

[0066] 1) Dissolve 11.47 g manganese nitrate tetrahydrate and 9.06 g zinc nitrate hexahydrate in demineralized water to prepare a first active metal mixed solution with a concentration of 2 mol / L; dissolve 37.41 g copper nitrate trihydrate, 3.02 g zinc nitrate hexahydrate, 0.9 g calcium nitrate tetrahydrate and 1.89 g aluminum nitrate nonahydrate in demineralized water to prepare a second active metal mixed solution with a concentration of 1 mol / L;

[0067] 28.64 g of sodium carbonate, 7.2 g of sodium hydroxide and 1.42 g of sodium metasilicate nonahydrate were dissolved in demineralized water (the molar ratio of sodium carbonate to sodium hydroxide was 1.5:1) to prepare a precipitant solution with a Na ion concentration of 2 mol / L.

[0068] 2) Establish a certain liquid level in the reactor and control the temperature at 40℃. Under continuous stirring, use a metering pump to simultaneously add the first active metal mixed solution and the precipitant solution to the reactor. Control the dropping rate of the precipitant to make the pH of the system = 9, and form a precipitate.

[0069] 3) After the first active metal mixed solution has precipitated completely, the second active metal mixed solution and the precipitant solution are added dropwise to the reactor using a metering pump. The dropwise addition rate of the precipitant is controlled to keep the pH of the system at 9, so as to form the catalyst precursor precipitate.

[0070] 4) After the second active metal mixed solution is added, stop adding the precipitant solution and continue aging at 50 ℃ for 6 h to obtain the catalyst precursor slurry. Then filter and wash the catalyst precursor slurry until it is neutral and free of sodium ions, and dry it at 120 ℃ for 12 h. Then transfer the sample to a calcination furnace and calcinate it at 350 ℃ for 4 h. After granulation, it is mixed with graphite and pressed into tablets to obtain catalyst 2.

[0071] Example 3

[0072] 1) Dissolve 11.25 g of manganese nitrate tetrahydrate and 10.97 g of zinc nitrate hexahydrate in demineralized water to prepare a first active metal mixed solution with a concentration of 1.5 mol / L;

[0073] 32.79 g of copper nitrate trihydrate, 7.31 g of zinc nitrate hexahydrate and 1.63 g of strontium nitrate were dissolved in demineralized water to prepare a second active metal mixed solution with a concentration of 1.5 mol / L;

[0074] Dissolve 22.5 g sodium carbonate, 5.66 g sodium hydroxide and 2.37 g sodium metasilicate nonahydrate in demineralized water (molar ratio of sodium carbonate to sodium hydroxide is 1.5:1) to prepare a precipitant solution with a Na ion concentration of 1.5 mol / L.

[0075] 2) Establish a certain liquid level in the reactor and control the temperature at 50℃. Under continuous stirring, use a metering pump to simultaneously add the first active metal mixed solution and the precipitant solution to the reactor. Control the dropping rate of the precipitant to make the pH of the system = 9, so as to form a precipitate.

[0076] 3) After the first active metal mixed solution has precipitated completely, the second active metal mixed solution and the precipitant solution are added dropwise to the reactor using a metering pump. The dropwise addition rate of the precipitant is controlled to keep the pH of the system at 9, so as to form the catalyst precursor precipitate.

[0077] 4) After the second active metal mixed solution is added, stop adding the precipitant solution and continue aging at 50 ℃ for 6 h to obtain the catalyst precursor slurry. Then filter and wash the catalyst precursor slurry until it is neutral and free of sodium ions, and dry it at 120 ℃ for 12 h. Then transfer the sample to a calcination furnace and calcinate it at 350 ℃ for 4 h. After granulation, it is mixed with graphite and pressed into tablets to obtain catalyst 3.

[0078] Example 4

[0079] 1) Dissolve 14.38 g of manganese nitrate tetrahydrate and 20.75 g of zinc nitrate hexahydrate in demineralized water to prepare a first active metal mixed solution with a concentration of 0.75 mol / L;

[0080] 24.07 g of copper nitrate trihydrate and 5.17 g of zinc nitrate hexahydrate were dissolved in demineralized water to prepare a second active metal mixed solution with a concentration of 0.75 mol / L;

[0081] Dissolve 26.08 g sodium carbonate, 4.92 g sodium hydroxide and 1.9 g sodium metasilicate nonahydrate in demineralized water (the molar ratio of sodium carbonate to sodium hydroxide is 2:1) to prepare a precipitant solution with a Na ion concentration of 2 mol / L.

[0082] 2) Establish a certain liquid level in the reactor and control the temperature at 30℃. Under continuous stirring, use a metering pump to simultaneously add the first active metal mixed solution and the precipitant solution to the reactor. Control the dropping rate of the precipitant to make the pH of the system = 9, so as to form a precipitate.

[0083] 3) After the first active metal mixed solution has precipitated completely, the second active metal mixed solution and the precipitant solution are added dropwise to the reactor using a metering pump. The dropwise addition rate of the precipitant is controlled to keep the pH of the system at 7, so as to form the catalyst precursor precipitate.

[0084] 4) After the second active metal mixed solution is added, stop adding the precipitant solution and continue aging at 60 ℃ for 6 h to obtain the catalyst precursor slurry. Then filter and wash the catalyst precursor slurry until it is neutral and free of sodium ions, and dry it at 120 ℃ for 12 h. Then transfer the sample to a calcination furnace and calcinate it at 350 ℃ for 4 h. After granulation, it is mixed with graphite and pressed into tablets to obtain catalyst 4.

[0085] Example 5

[0086] 1) Dissolve 9.41 g of manganese nitrate tetrahydrate and 19.41 g of zinc nitrate hexahydrate in demineralized water to prepare a first active metal mixed solution with a concentration of 0.5 mol / L;

[0087] 32.02 g of copper nitrate trihydrate, 1.96 g of barium nitrate and 2.16 g of zinc nitrate hexahydrate were dissolved in demineralized water to prepare a second active metal mixed solution with a concentration of 0.5 mol / L;

[0088] Dissolve 31.79 g of sodium carbonate and 8.0 g of sodium hydroxide in demineralized water (the molar ratio of sodium carbonate to sodium hydroxide is 1.5:1) to prepare a precipitant solution with a Na ion concentration of 0.5 mol / L.

[0089] 2) Establish a certain liquid level in the reactor and control the temperature at 50℃. Under continuous stirring, use a metering pump to simultaneously add the first active metal mixed solution and the precipitant solution to the reactor. Control the dropping rate of the precipitant to make the pH of the system equal to 8, so as to form a precipitate.

[0090] 3) After the first active metal mixed solution has precipitated completely, the second active metal mixed solution and the precipitant solution are added dropwise to the reactor using a metering pump. The dropwise addition rate of the precipitant is controlled to keep the pH of the system at 8, so as to form the catalyst precursor precipitate.

[0091] 4) After the second active metal mixed solution is added, stop adding the precipitant solution and continue aging at 50 ℃ for 6 h to obtain the catalyst precursor slurry. Then filter and wash the catalyst precursor slurry until it is neutral and free of sodium ions, and dry it at 120 ℃ for 12 h. Then transfer the sample to a calcination furnace and calcinate it at 300 ℃ for 4 h. After granulation, it is mixed with graphite and pressed into tablets to obtain catalyst 5.

[0092] Example 6

[0093] 1) Dissolve 10.42 g of manganese nitrate tetrahydrate and 20.34 g of zinc nitrate hexahydrate in demineralized water to prepare a first active metal mixed solution with a concentration of 1 mol / L;

[0094] 28.32 g of copper nitrate trihydrate and 5.24 g of zirconium nitrate pentahydrate were dissolved in demineralized water to prepare a second active metal mixed solution with a concentration of 1 mol / L;

[0095] Dissolve 22.04 g sodium carbonate, 5.55 g sodium hydroxide and 1.9 g sodium metasilicate nonahydrate in demineralized water (molar ratio of sodium carbonate to sodium hydroxide is 1.5:1) to prepare a precipitant solution with a Na ion concentration of 1.5 mol / L.

[0096] 2) Establish a certain liquid level in the reactor and control the temperature at 20℃. Under continuous stirring, use a metering pump to simultaneously add the first active metal mixed solution and the precipitant solution to the reactor. Control the dropping rate of the precipitant to make the pH of the system equal to 8, so as to form a precipitate.

[0097] 3) After the first active metal mixed solution has precipitated completely, the second active metal mixed solution and the precipitant solution are added dropwise to the reactor using a metering pump. The dropwise addition rate of the precipitant is controlled to keep the pH of the system at 8, so as to form the catalyst precursor precipitate.

[0098] 4) After the second active metal mixed solution is added, stop adding the precipitant solution and continue aging at 70 ℃ for 6 h to obtain the catalyst precursor slurry. Then filter and wash the catalyst precursor slurry until it is neutral and free of sodium ions, and dry it at 120 ℃ for 12 h. Then transfer the sample to a calcination furnace and calcinate it at 300 ℃ for 4 h. After granulation, it is mixed with graphite and pressed into tablets to obtain catalyst 6.

[0099] Comparative Example 1, in which it has an oxide structure

[0100] 1) Dissolve 11.25 g of manganese nitrate tetrahydrate and 10.97 g of zinc nitrate hexahydrate in demineralized water to prepare a first active metal mixed solution with a concentration of 1.5 mol / L;

[0101] 32.79 g of copper nitrate trihydrate, 7.31 g of zinc nitrate hexahydrate and 1.63 g of strontium nitrate were dissolved in demineralized water to prepare a second active metal mixed solution with a concentration of 1.5 mol / L;

[0102] Dissolve 30 g of sodium carbonate and 2.37 g of sodium metasilicate nonahydrate in demineralized water to prepare a precipitant solution with a Na ion concentration of 1.5 mol / L.

[0103] 2) Establish a certain liquid level in the reactor and control the temperature at 50℃. Under continuous stirring, use a metering pump to simultaneously add the first active metal mixed solution and the precipitant solution to the reactor. Control the dropping rate of the precipitant to make the pH of the system = 9, so as to form a precipitate.

[0104] 3) After the first active metal mixed solution has precipitated completely, the second active metal mixed solution and the precipitant solution are added dropwise to the reactor using a metering pump. The dropwise addition rate of the precipitant is controlled to keep the pH of the system at 9, so as to form the catalyst precursor precipitate.

[0105] 4) After the second active metal mixed solution has precipitated completely, stop adding the precipitant solution and continue aging at 50 ℃ for 6 h to obtain the catalyst precursor slurry. Then filter and wash the catalyst precursor slurry until it is neutral and free of sodium ions, and dry it at 120 ℃ for 12 h. Then transfer the sample to a calcination furnace and calcinate it at 350 ℃ for 4 h. After granulation, it is mixed with graphite and pressed into tablets to obtain reference catalyst 1.

[0106] Comparative Example 2 also has a Cu / Zn / Al type hydrotalcite structure, but does not contain Mn.

[0107] 1) Dissolve 18.19 g of aluminum nitrate nonahydrate and 11.93 g of zinc nitrate hexahydrate in demineralized water to prepare a first active metal mixed solution with a concentration of 1.5 mol / L;

[0108] 35.67 g of copper nitrate trihydrate, 7.95 g of zinc nitrate hexahydrate and 1.77 g of strontium nitrate hexahydrate were dissolved in demineralized water to prepare a second active metal mixed solution with a concentration of 1.5 mol / L;

[0109] Dissolve 22.5 g sodium carbonate, 5.66 g sodium hydroxide and 2.37 g sodium metasilicate nonahydrate in demineralized water (molar ratio of sodium carbonate to sodium hydroxide is 1.5:1) to prepare a precipitant solution with a Na ion concentration of 1.5 mol / L.

[0110] 2) Establish a certain liquid level in the reactor and control the temperature at 50℃. Under continuous stirring, use a metering pump to simultaneously add the first active metal mixed solution and the precipitant solution to the reactor. Control the dropping rate of the precipitant to make the pH of the system = 9, so as to form a precipitate.

[0111] 3) After the first active metal mixed solution has precipitated completely, the second active metal mixed solution and the precipitant solution are added dropwise to the reactor using a metering pump. The dropwise addition rate of the precipitant is controlled to keep the pH of the system at 9, so as to form the catalyst precursor precipitate.

[0112] 4) After the second active metal mixed solution is added, stop adding the precipitant solution and continue aging at 50 ℃ for 6 h to obtain the catalyst precursor slurry. Then filter and wash the catalyst precursor slurry until it is neutral and free of sodium ions, and dry it at 120 ℃ for 12 h. Then transfer the sample to a calcination furnace and calcinate it at 350 ℃ for 4 h. After granulation, it is mixed with graphite and pressed into tablets to obtain reference catalyst 2.

[0113] Comparative Example 3: In Comparative Example 3, the addition of Ce, which also has adjustable valence state, results in a Cu / Zn / Ce-type hydrotalcite structure.

[0114] 1) Dissolve 16.34 g of cerium nitrate hexahydrate and 9.21 g of zinc nitrate hexahydrate in demineralized water to prepare a first active metal mixed solution with a concentration of 1.5 mol / L;

[0115] 27.54 g of copper nitrate trihydrate, 6.14 g of zinc nitrate hexahydrate and 1.65 g of strontium nitrate hexahydrate were dissolved in demineralized water to prepare a second active metal mixed solution with a concentration of 1.5 mol / L;

[0116] Dissolve 22.5 g sodium carbonate, 5.66 g sodium hydroxide and 2.37 g sodium metasilicate nonahydrate in demineralized water (molar ratio of sodium carbonate to sodium hydroxide is 1.5:1) to prepare a precipitant solution with a Na ion concentration of 1.5 mol / L.

[0117] 2) Establish a certain liquid level in the reactor and control the temperature at 50℃. Under continuous stirring, use a metering pump to simultaneously add the first active metal mixed solution and the precipitant solution to the reactor. Control the dropping rate of the precipitant to make the pH of the system = 9, so as to form a precipitate.

[0118] 3) After the first active metal mixed solution has precipitated completely, the second active metal mixed solution and the precipitant solution are added dropwise to the reactor using a metering pump. The dropwise addition rate of the precipitant is controlled to keep the pH of the system at 9, so as to form the catalyst precursor precipitate.

[0119] 4) After the second active metal mixed solution is added, stop adding the precipitant solution and continue aging at 50 ℃ for 6 h to obtain the catalyst precursor slurry. Then filter and wash the catalyst precursor slurry until it is neutral and free of sodium ions, and dry it at 120 ℃ for 12 h. Then transfer the sample to a calcination furnace and calcinate it at 350 ℃ for 4 h. After granulation, it is mixed with graphite and pressed into tablets to obtain reference catalyst 3.

[0120] Comparative Example 4: In Comparative Example 4, the addition of Fe element, which also has adjustable valence state, results in a Cu / Zn / Fe-type hydrotalcite structure.

[0121] 1) Dissolve 17.01 g of ferric nitrate nonahydrate and 10.31 g of zinc nitrate hexahydrate in demineralized water to prepare a first active metal mixed solution with a concentration of 1.5 mol / L;

[0122] 30.80 g of copper nitrate trihydrate, 6.87 g of zinc nitrate hexahydrate and 1.85 g of strontium nitrate hexahydrate were dissolved in demineralized water to prepare a second active metal mixed solution with a concentration of 1.5 mol / L;

[0123] Dissolve 22.5 g sodium carbonate, 5.66 g sodium hydroxide and 2.37 g sodium metasilicate nonahydrate in demineralized water (molar ratio of sodium carbonate to sodium hydroxide is 1.5:1) to prepare a precipitant solution with a Na ion concentration of 1.5 mol / L.

[0124] 2) Establish a certain liquid level in the reactor and control the temperature at 50℃. Under continuous stirring, use a metering pump to simultaneously add the first active metal mixed solution and the precipitant solution to the reactor. Control the dropping rate of the precipitant to make the pH of the system = 9, so as to form a precipitate.

[0125] 3) After the first active metal mixed solution has precipitated completely, the second active metal mixed solution and the precipitant solution are added dropwise to the reactor using a metering pump. The dropwise addition rate of the precipitant is controlled to keep the pH of the system at 9, so as to form the catalyst precursor precipitate.

[0126] 4) After the second active metal mixed solution is added dropwise, stop adding the precipitant solution and continue aging at 50 ℃ for 6 h to obtain the catalyst precursor slurry. Then filter and wash the catalyst precursor slurry until it is neutral and free of sodium ions, and dry it at 120 ℃ for 12 h. Then transfer the sample to a calcination furnace and calcinate it at 350 ℃ for 4 h. After granulation, it is mixed with graphite and pressed into tablets to obtain reference catalyst 4.

[0127] Table 1: Performance of multi-component mixed gas hydrogenation to methanol under different preparation processes

[0128] Reaction conditions: 230 ℃, GHSV = 10000 ml.gcat -1 . h -1 5MPa

[0129]

[0130] The experimental data above show that, compared to reference catalysts 1 to 4, the catalyst prepared by the method provided in this invention exhibits better carbon conversion rates for mixed gases with different components. This demonstrates that the catalyst possesses highly efficient catalytic activity in the hydrogenation of a multi-component mixed gas to methanol.

[0131] Further, please see Figure 1 In the long-term stability study of the catalyst over 200 hours (reaction conditions: 230 ℃, GHSV = 10000 ml gcat), -1 . h -1 The stability of reference catalyst 1 and reference catalyst 2 decreased significantly over time (5 MPa, H2 / CO2 / CO=73:16:11), while the stability of comparative catalyst 3 remained stable.

[0132] Further, see Figure 1 In the 200h stability study of the catalysts, the reference catalysts 3 and 4, which added elements with adjustable valence states, showed better stability than the reference catalysts 1 and 2, which did not add elements with adjustable valence states, but their stability was lower than that of the comparative example 3.

[0133] This invention also provides a catalyst suitable for the production of methanol from a multi-component mixed gas, which is prepared by the catalyst preparation method described above. The catalyst has a hydrotalcite-like structure, and its molar ratio of Cu:Zn:Mn:promoter is 40-65:15-35:15-25:0.5-5. The promoter is one or more of Ca, Al, Mg, Sr, La, Ba, and Si.

[0134] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing a catalyst suitable for methanol production from multi-component mixed gases, characterized in that: The method includes: The system provides a first active metal mixed solution, a second active metal mixed solution, and a precipitant solution. The first active metal mixed solution contains soluble manganese salt and soluble zinc salt; the second active metal mixed solution contains soluble copper salt and soluble zinc salt; and the precipitant solution includes a sodium carbonate solution and a sodium hydroxide solution. The first active metal mixed solution, the second active metal mixed solution, and the precipitant solution are mixed to carry out a precipitation reaction, and the precipitated product is dried and calcined. The second active metal mixed solution and / or the precipitant solution contain an additive; the additive contains one or more of Ca, Mg, Sr, Ba, and Si, and in molar amounts, Cu:Zn:Mn:additive is 40-65:15-35:15-25:0.5-5; The soluble manganese salt is manganese nitrate, and the manganese element in the catalyst system has the characteristic of adjustable valence state.

2. The method for preparing a catalyst suitable for methanol production from a multi-component mixed gas according to claim 1, characterized in that: When the additive is one or more of Ca, Mg, Sr, and Ba, the additive is added to the second active metal mixed solution; when the additive is Si, the additive is added to the precipitant solution.

3. The method for preparing a catalyst suitable for methanol production from a multi-component mixed gas according to claim 1, characterized in that: In the first active metal mixed solution, the ratio of zinc salt in the first active metal mixed solution to the total amount of zinc salt used is (0.5-1):1, in molar terms.

4. The method for preparing a catalyst suitable for methanol production from a multi-component mixed gas according to claim 1, characterized in that: The concentration of the first active metal mixed solution is 0.5-2 mol / L, and the concentration of the second active metal mixed solution is 0.5-2 mol / L.

5. The method for preparing a catalyst suitable for methanol production from a multi-component mixed gas according to claim 1, characterized in that: The method further includes the following steps during the precipitation reaction: The first active metal mixed solution is mixed with a portion of the precipitant solution; After the first active metal mixed solution has precipitated completely, the second active metal mixed solution and part of the precipitant are simultaneously added to the precipitate obtained from the first active metal mixed solution and the precipitant solution. After the second active metal mixed solution has precipitated completely, the resulting product is kept at a temperature to allow it to age. The aged products are filtered, washed, dried, and calcined.

6. The method for preparing a catalyst suitable for methanol production from a multi-component mixed gas according to claim 1 or 5, characterized in that: During the precipitation reaction, the reaction temperature is 10-70℃ and the pH of the reaction system is 7-10.

7. The method for preparing a catalyst suitable for methanol production from a multi-component mixed gas according to claim 5, characterized in that: During aging, the aging temperature is 10-70℃ and the aging time is 6-24h.

8. The method for preparing a catalyst suitable for methanol production from a multi-component mixed gas according to claim 1 or 5, characterized in that: The roasting temperature is 300-400℃, and the roasting time is 4-12 hours.

9. The method for preparing a catalyst suitable for methanol production from a multi-component mixed gas according to claim 1, characterized in that: In the precipitant solution, the molar ratio of sodium carbonate to sodium hydroxide is 1-3:

1.

10. A catalyst suitable for the production of methanol from a multi-element mixed gas, characterized in that: The catalyst for methanol production from a multi-element mixed gas has a hydrotalcite-like structure. In terms of molar weight, the ratio of Cu:Zn:Mn:promoter in the catalyst is 40-65:15-35:15-25:0.5-5, where thepromoter is one or more of Ca, Mg, Sr, Ba, and Si. During catalyst preparation, manganese is provided by a soluble manganese salt, specifically manganese nitrate. The manganese in the catalyst system has an adjustable valence state.

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