Copper-zinc-silicon catalyst and preparation method thereof

Abstract

The present application discloses a copper-zinc-silicon catalyst and its preparation method, which relate to the field of catalyst technology. The copper-zinc-silicon catalyst is used for the hydrogenation of carbon dioxide to produce methanol. The copper-zinc-silicon catalyst is composed of copper oxide, zinc oxide, and a layered silicate carrier. The mass of copper oxide in the copper-zinc-silicon catalyst is: 40-70%, the mass of zinc oxide is: 15-30%, and the mass of silicon dioxide is: 5-20%. The novel CuO / ZnO / SiO2 system catalyst of the present application, which uses a layered silicate with strong interaction between copper species and the carrier as a carrier, has a suitable Cu+ / Cu0 ratio, has higher methanol selectivity and space-time yield, and the layered silicate carrier of the copper-zinc-silicon catalyst has better hydrophobicity, which is conducive to the rapid diffusion and removal of water in the product and has better catalytic stability.

Description

Technical Field

[0001] The present application relates to the field of catalyst technology, and in particular to a copper-zinc-silicon catalyst and a preparation method thereof. Background Art

[0002] Global climate change poses a serious threat to the sustainable development of human society. The massive emission of greenhouse gases, including carbon dioxide, is one of the primary drivers of global climate change. The reaction of renewable energy-based green hydrogen (H2) with CO2 to produce methanol, a key platform compound, can yield high-value-added fuels and chemicals. This is technically feasible and economically viable, and represents a viable strategy for proactively addressing carbon dioxide emissions.

[0003] High-efficiency catalysts are the core of CO₂ hydrogenation to methanol technology. Currently, the most mature copper-based catalysts are those based on copper-zinc-aluminum systems. However, due to the high reverse water-gas shift (RWS) activity of copper-based catalysts, a large amount of CO is generated as a byproduct during the CO₂ hydrogenation reaction. Furthermore, the CO₂ hydrogenation process produces a large amount of water, which accelerates catalyst sintering and deactivation. Consequently, current copper-based catalysts exhibit low selectivity for methanol, the product of CO₂ hydrogenation. Summary of the Invention

[0004] The main purpose of this application is to provide a copper-zinc-silicon catalyst, aiming to solve the technical problem that the current copper-based catalyst has low selectivity for methanol, a product of carbon dioxide hydrogenation to methanol.

[0005] To achieve the above-mentioned objectives, in a first aspect, the present application provides a copper-zinc-silicon catalyst for use in the hydrogenation of carbon dioxide to produce methanol, characterized in that the copper-zinc-silicon catalyst is composed of copper oxide, zinc oxide and a layered silicate carrier, and the mass of copper oxide in the copper-zinc-silicon catalyst is: 40~70%; the mass of zinc oxide is: 15~30%; and the mass of silicon dioxide is: 5~20%.

[0006] According to the first aspect, the components of the copper-zinc-silicon catalyst further include an auxiliary agent, and the mass of the auxiliary agent is 0-10%.

[0007] According to the first aspect, or any implementation of the first aspect above, the auxiliary agent includes at least one of aluminum, zirconium, magnesium, and cerium.

[0008] According to the first aspect, or any implementation of the first aspect above, the molar ratio of copper element to the sum of copper and zinc elements in the layered silicate carrier is 0.3-1, and the molar ratio of the sum of copper and zinc elements to silicon element is 1.

[0009] In a second aspect, the present application provides a method for preparing a copper-zinc-silicon catalyst, which is applied to the copper-zinc-silicon catalyst described above, and the preparation method comprises:

[0010] reacting a copper-zinc mixed solution of a soluble copper salt and a soluble zinc salt with a silica sol solution to prepare a layered silicate carrier slurry;

[0011] A soluble copper salt and a soluble zinc salt are prepared into an active metal mixed solution, and a precipitant is prepared into a precipitant solution;

[0012] Performing fluid deposition on the active metal mixed solution and the precipitant solution to precipitate onto the layered silicate carrier slurry;

[0013] After the precipitation is completed, the precipitated layered silicate carrier slurry is aged, filtered, washed, dried and calcined to obtain the copper-zinc-silicon catalyst.

[0014] According to the second aspect, the step of reacting a copper-zinc mixed solution of a soluble copper salt and a soluble zinc salt with a silica sol solution to prepare a layered silicate carrier slurry comprises:

[0015] Establishing a certain level of desalted water in a reactor, adding soluble copper salt and soluble zinc salt to prepare an aqueous solution having a molar concentration of the sum of copper and zinc elements of 0.5 to 2 mol / L, thereby preparing a copper-zinc mixed solution of soluble copper salt and soluble zinc salt;

[0016] Adding concentrated aqueous ammonia to the copper-zinc mixed solution to form an ammonia complex solution with a pH of 10.5 to 11.5;

[0017] Slowly add the silica sol solution to the reactor, stir, and then heat to 90-95°C, maintain constant temperature and start stirring to evaporate excess ammonia;

[0018] After the pH value of the solution in the reactor drops to the range of 6.5-7.0, the ammonia distillation is terminated to obtain the layered silicate carrier slurry.

[0019] According to the second aspect, or any implementation of the second aspect above, the step of reacting a copper-zinc mixed solution of a soluble copper salt and a soluble zinc salt with a silica sol solution to prepare a layered silicate carrier slurry further includes:

[0020] Add the silica sol solution into the reactor and dilute it to 10wt% with deionized water. Control the water temperature at 20-40℃ and stir evenly.

[0021] Add urea to the reactor at a molar ratio of urea to the total amount of copper and zinc elements of 2-6, stir to fully dissolve, and then add a small amount of nitric acid to adjust the pH to within the range of 3-5;

[0022] adding a soluble copper salt and a soluble zinc salt to prepare an aqueous solution having a molar concentration of the total copper and zinc elements of 0.5 to 2 mol / L, thereby preparing a copper-zinc mixed solution of the soluble copper salt and the soluble zinc salt;

[0023] Open the cooling water of the reactor's condenser and heat the reactor to 90-95°C, maintain constant temperature and start stirring and reflux to slowly decompose urea;

[0024] The reaction is terminated after the pH value of the solution in the reactor rises to a range of 7.0 to 7.5 to obtain a layered silicate carrier slurry.

[0025] According to the second aspect, or any implementation of the second aspect above, the step of configuring the soluble copper salt and the soluble zinc salt into an active metal mixed solution, and configuring the precipitant into a precipitant solution, comprises:

[0026] Dissolving soluble copper salt, soluble zinc salt and auxiliary salt in desalted water to prepare an active metal mixed solution with an ion molar concentration of 0.5-2 mol / L;

[0027] Dissolve the precipitant in desalted water to prepare a 0.5~2 mol / L precipitant solution.

[0028] According to the second aspect, or any implementation of the second aspect above, the precipitant is at least one of sodium carbonate, NaHCO3, and NaOH.

[0029] According to the second aspect, or any implementation of the second aspect above, the step of aging, filtering, washing, drying, and calcining the precipitated layered silicate carrier slurry to obtain the copper-zinc-silicon catalyst comprises:

[0030] After the active metal mixed solution is added dropwise, the addition of the precipitant solution is stopped, and the temperature is maintained at 50-80° C. and stirred for 1-3 hours to obtain a catalyst precursor slurry;

[0031] The catalyst precursor slurry is filtered and washed until it is neutral and free of residual sodium ions, and then dried at 60-120° C. for 2-12 hours to obtain a catalyst sample;

[0032] The catalyst sample was transferred to a calcination furnace and calcined at 300-400°C for 4-12 hours, and then granulated, mixed with graphite and pressed into tablets to obtain a copper-zinc-silicon catalyst.

[0033] The present application proposes a copper-zinc-silicon catalyst for use in the hydrogenation of carbon dioxide to produce methanol. The copper-zinc-silicon catalyst is composed of copper oxide, zinc oxide, and a layered silicate carrier. The copper oxide mass of the copper-zinc-silicon catalyst is 40-70%, the zinc oxide mass is 15-30%, and the silicon dioxide mass is 5-20%. The present application proposes a novel CuO / ZnO / SiO2 system catalyst with a layered silicate carrier having a strong copper species-carrier interaction. The catalyst has a suitable CuO / ZnO / SiO2 system. + / Cu 0 ratio, has higher methanol selectivity and space-time yield, and the layered silicate carrier of the copper-zinc-silicon catalyst has better hydrophobicity, which is conducive to the rapid diffusion and removal of water in the product and has better catalytic stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic flow chart of an embodiment of a method for preparing a copper-zinc-silicon catalyst of the present application;

[0035] Figure 2 This is a schematic diagram of the long-term stability of the catalyst involved in this application.

[0036] The purpose of this application, its features and advantages will be further described in conjunction with the embodiments and with reference to the accompanying drawings. These drawings and textual descriptions are not intended to limit the scope of the present application in any way, but rather to illustrate the concepts of this application to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0037] It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application.

[0038] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0039] It should be understood that the experimental methods used in the following examples of this application are conventional methods unless otherwise specified. The materials, reagents, etc. used in the following examples of this application are all commercially available unless otherwise specified.

[0040] In the copper-based catalysts for carbon dioxide hydrogenation, the selectivity of methanol depends on the CO2 hydrogenation rate / intermediate product decomposition rate. Stabilizing the intermediate product formate and inhibiting its decomposition into CO can effectively reduce the selectivity of the byproduct CO and increase the yield of the target product methanol. It is understandable that Cu species with different valences play different roles in the CO2 hydrogenation reaction to methanol. 0 Species are mainly responsible for promoting H2 adsorption activation and hydrogen overflow, which is beneficial to improving the CO2 hydrogenation reaction rate; Cu + Species can stabilize intermediate products such as formate, inhibit their decomposition into CO, and promote further deep hydrogenation of intermediate products to produce methanol. + / Cu 0 The ratio of Cu has a significant effect on the catalytic reaction activity and the selectivity of the product methanol. Properly increasing the Cu + / Cu 0 The ratio is conducive to obtaining higher CO2 hydrogenation reaction activity and product methanol selectivity.

[0041] The present application provides a copper-zinc-silicon catalyst for use in the hydrogenation of carbon dioxide to produce methanol. The copper-zinc-silicon catalyst is composed of copper oxide, zinc oxide, and a layered silicate carrier. The mass of copper oxide in the copper-zinc-silicon catalyst is 40-70%, the mass of zinc oxide is 15-30%, and the mass of silicon dioxide is 5-20%. The components of the copper-zinc-silicon catalyst also include an auxiliary agent, the mass of which is 0-10%. The auxiliary agent includes at least one of aluminum, zirconium, magnesium, and cerium. The molar ratio of copper to the sum of copper and zinc elements in the layered silicate carrier is 0.3-1, and the molar ratio of the sum of copper and zinc elements to silicon is 1.

[0042] This application uses layered silicate material as a carrier, and precipitates copper, zinc, additives and other species on the surface of the layered silicate material carrier to form a new CuO / ZnO / SiO2 system copper-zinc-silicon catalyst. After the catalyst is reduced, the copper in the layered silicate carrier is mainly reduced to Cu + Species, the copper precipitated on the support surface is mainly reduced to Cu 0 By adjusting the ratio of the components in the copper-zinc-silicon catalyst, a suitable Cu + / Cu 0 The ratio of 2 to 4 is achieved, thereby improving the catalyst's CO2 hydrogenation activity and methanol selectivity. Furthermore, the layered silicate support has better hydrophobicity than conventional catalysts, facilitating the rapid diffusion and removal of water from the product. The copper-zinc-silicon catalyst also exhibits better catalytic stability.

[0043] Reference Figure 1 , Figure 1This is a flow chart of an embodiment of the method for preparing a copper-zinc-silicon catalyst of the present application. It should be noted that although a logical order is shown in the flow chart, in some cases, the steps shown or described may be performed in a different order than shown here.

[0044] An embodiment of the present invention provides a method for preparing a copper-zinc-silicon catalyst, which is applied to the copper-zinc-silicon catalyst described above. The preparation method comprises:

[0045] Step S100, reacting a copper-zinc mixed solution of a soluble copper salt and a soluble zinc salt with a silica sol solution to prepare a layered silicate carrier slurry;

[0046] Step S200, preparing a soluble copper salt and a soluble zinc salt into an active metal mixed solution, and preparing a precipitant into a precipitant solution;

[0047] Step S300, performing fluid deposition on the active metal mixed solution and the precipitant solution, and precipitating the mixed solution onto the layered silicate carrier slurry;

[0048] Step S400: After the precipitation is completed, the precipitated layered silicate carrier slurry is aged, filtered, washed, dried, and calcined to obtain a copper-zinc-silicon catalyst.

[0049] In this embodiment, a copper-zinc mixed solution obtained by mixing a soluble copper salt and a soluble zinc salt is first mixed with a silica sol solution using an ammonia distillation method or a urea uniform precipitation method to prepare a layered silicate carrier slurry. The molar ratio of copper to the total copper and zinc elements (i.e., copper plus zinc) in the copper-zinc mixed solution is 0.3-1. The molar ratio of the total copper and zinc elements in the copper-zinc mixed solution to the silicon element in the silica sol solution is 1. The remaining soluble copper salts and soluble zinc salts in the copper-zinc-silicon catalyst components, excluding the copper and zinc elements in the copper-zinc mixed solution, are then prepared into an active metal mixed solution, and a certain amount of precipitant is added to form a precipitant solution. The active metal mixed solution and precipitant solution are then subjected to fluid deposition, precipitating onto the layered silicate carrier slurry. After the active metal mixed solution is added dropwise, the addition of the precipitant solution is stopped, and precipitation is completed. The precipitated layered silicate carrier slurry is then aged, filtered, washed, dried, and calcined to obtain the copper-zinc-silicon catalyst.

[0050] The step of reacting a copper-zinc mixed solution of a soluble copper salt and a soluble zinc salt with a silica sol solution to prepare a layered silicate carrier slurry comprises:

[0051] Establishing a certain level of desalted water in a reactor, adding soluble copper salt and soluble zinc salt to prepare an aqueous solution having a molar concentration of the sum of copper and zinc elements of 0.5 to 2 mol / L, thereby preparing a copper-zinc mixed solution of soluble copper salt and soluble zinc salt;

[0052] Adding concentrated aqueous ammonia to the copper-zinc mixed solution to form an ammonia complex solution with a pH of 10.5 to 11.5;

[0053] Slowly add the silica sol solution to the reactor, stir, and then heat to 90-95°C, maintain constant temperature and start stirring to evaporate excess ammonia;

[0054] After the pH value of the solution in the reactor drops to the range of 6.5-7.0, the ammonia distillation is terminated to obtain the layered silicate carrier slurry.

[0055] Wherein, the step of reacting a copper-zinc mixed solution of a soluble copper salt and a soluble zinc salt with a silica sol solution to prepare a layered silicate carrier slurry further includes:

[0056] Add the silica sol solution into the reactor and dilute it to 10wt% with deionized water. Control the water temperature at 20-40℃ and stir evenly.

[0057] Add urea to the reactor at a molar ratio of urea to the total amount of copper and zinc elements of 2-6, stir to fully dissolve, and then add a small amount of nitric acid to adjust the pH to within the range of 3-5;

[0058] adding a soluble copper salt and a soluble zinc salt to prepare an aqueous solution having a molar concentration of the total copper and zinc elements of 0.5 to 2 mol / L, thereby preparing a copper-zinc mixed solution of the soluble copper salt and the soluble zinc salt;

[0059] Open the cooling water of the reactor's condenser and heat the reactor to 90-95°C, maintain constant temperature and start stirring and reflux to slowly decompose urea;

[0060] The reaction is terminated after the pH value of the solution in the reactor rises to a range of 7.0 to 7.5 to obtain a layered silicate carrier slurry.

[0061] The steps of configuring the soluble copper salt and the soluble zinc salt into an active metal mixed solution and configuring the precipitant into a precipitant solution include:

[0062] Dissolving soluble copper salt, soluble zinc salt and auxiliary salt in desalted water to prepare an active metal mixed solution with an ion molar concentration of 0.5-2 mol / L;

[0063] Dissolve the precipitant in desalted water to prepare a 0.5~2 mol / L precipitant solution.

[0064] Wherein, the precipitant is at least one of sodium carbonate, NaHCO3, and NaOH.

[0065] The step of aging, filtering, washing, drying and calcining the precipitated layered silicate carrier slurry to obtain the copper-zinc-silicon catalyst comprises:

[0066] After the active metal mixed solution is added dropwise, the addition of the precipitant solution is stopped, and the temperature is maintained at 50-80° C. and stirred for 1-3 hours to obtain a catalyst precursor slurry;

[0067] The catalyst precursor slurry is filtered and washed until it is neutral and free of residual sodium ions, and then dried at 60-120° C. for 2-12 hours to obtain a catalyst sample;

[0068] The catalyst sample was transferred to a calcination furnace and calcined at 300-400°C for 4-12 hours, and then granulated, mixed with graphite and pressed into tablets to obtain a copper-zinc-silicon catalyst.

[0069] In this embodiment, a copper-zinc mixed solution of a soluble copper salt and a soluble zinc salt is reacted with a silica sol solution to prepare a layered silicate carrier slurry. After reduction, the copper in the layered silicate carrier is mainly reduced to Cu + Species. The remaining soluble copper salt and soluble zinc salt are then configured as an active metal mixed solution, and the precipitant is configured as a precipitant solution. The active metal mixed solution and the precipitant solution are subjected to fluid deposition and precipitated onto the layered silicate carrier slurry. This embodiment uses a deposition precipitation method to precipitate the remaining copper, zinc, additives and other species onto the carrier surface of the layered silicate carrier slurry, and the copper precipitated on the carrier surface is mainly reduced to Cu 0 Species, thus by adjusting the component ratio of the copper silicon zinc catalyst, a suitable Cu + / Cu 0 After the precipitation is completed, the precipitated layered silicate carrier slurry is aged, filtered, washed, dried and calcined to obtain a copper-zinc-silicon catalyst. The copper-zinc-silicon catalyst thus prepared has a suitable Cu + / Cu 0 The ratio of the copper-zinc-silicon catalyst to the layered silicate catalyst is 2.3447 W / m, and the layered silicate carrier has better hydrophobicity than ordinary catalysts, which is conducive to the rapid diffusion and removal of water in the product. The copper-zinc-silicon catalyst also shows better catalytic stability.

[0070] Example 1

[0071] The components of the copper-zinc-silicon catalyst described in Example 1 are CuO: 51%, ZnO: 23%, Al2O3: 5%, MgO: 2%, and SiO2: 19%.

[0072] Step 1: Add 95 L of desalted water to a 250 L reactor, add 9.24 kg of copper nitrate trihydrate and 2.78 kg of zinc nitrate hexahydrate, stir and dissolve, and prepare an aqueous solution with a molar concentration of copper and zinc elements and (Cu + Zn) of 0.5 mol / L to prepare a copper-zinc mixed solution. Then, add concentrated ammonia water to the above copper-zinc mixed solution to form an ammonia complex solution with a pH value of 10.5-11.5; after confirming that the pH is qualified, slowly add 12.67 kg of 30% silica sol solution to the above reactor, stir for 30 minutes, and then begin to heat to 95°C, maintain constant temperature and start stirring to evaporate excess ammonia. After the pH value of the reactor drops to the range of 6.5-7.0, stop distilling ammonia to obtain a layered silicate carrier slurry;

[0073] Step 2: 27.15 kg of copper nitrate trihydrate, 7.55 kg of zinc nitrate hexahydrate, 5.7 kg of aluminum nitrate nonahydrate and 2.54 kg of magnesium nitrate hexahydrate were dissolved in 354 L of desalted water to prepare a 0.5 mol / L active metal mixed solution, and a certain amount of 0.5 mol / L sodium carbonate precipitant solution was also prepared; then the layered silicate carrier slurry obtained in step 1 was transferred to a 1000 L reactor, the temperature of the material was controlled at 50°C, and the active metal mixed solution and the precipitant solution were simultaneously added dropwise to the layered silicate carrier slurry reactor using a metering pump under continuous stirring conditions. The dropwise addition rate of the precipitant was controlled so that the pH value of the system was 9. After the active metal mixed solution was added dropwise, the addition of the precipitant solution was stopped, and the temperature was maintained at 50°C and stirred for aging for 3 hours to obtain a catalyst precursor slurry. The catalyst precursor slurry was then filtered and washed until it was neutral and free of residual sodium ions, and then dried at 120°C for 2 hours. The sample was then transferred to a calcination furnace and calcined at 300°C for 12 hours. After granulation, the sample was mixed with graphite and pressed into tablets to obtain copper-zinc-silicon catalyst 1.

[0074] Example 2

[0075] The components of the copper-zinc-silicon catalyst described in Example 2 are CuO: 40%, ZnO: 30%, Al2O3: 7%, CeO2: 3%, and SiO2: 20%.

[0076] Step 1: Add 13.33 kg of 30wt% silica sol solution to a 250 L reactor, add 37 L of desalted water to dilute, control the water temperature at 20~40℃ and stir evenly (10 min), then add 18 kg of urea to the reactor, the molar ratio of urea to copper and zinc elements (Cu+Zn) is 6, stir to fully dissolve, and then add a small amount of nitric acid to adjust to pH = 5; then add 12.16 kg of copper nitrate trihydrate to the reactor, stir and dissolve to form an aqueous solution with a concentration of 1 mol / L; then turn on the cooling water of the reactor condenser, heat the reactor to 90~95℃, maintain constant temperature and start stirring and reflux, as the urea slowly decomposes, the pH in the reactor begins to rise, and the reaction can be terminated when the pH rises to 7.0~7.5 to obtain a layered silicate carrier slurry.

[0077] Step 2: Dissolve 17.02 kg of copper nitrate trihydrate, 16.08 kg of zinc nitrate hexahydrate, 7.98 kg of aluminum nitrate nonahydrate, and 1.51 kg of cerium nitrate hexahydrate in 169 L of desalted water to prepare a 1 mol / L active metal mixed solution. + A mixed precipitant solution of sodium carbonate and sodium hydroxide with a concentration of 1 mol / L, wherein the molar ratio of sodium carbonate to sodium hydroxide is 4; then the layered silicate carrier slurry obtained in step 1 is transferred to a 1000 L reactor, the temperature of the material is controlled at 80°C, and the active metal mixed solution and the precipitant solution are simultaneously added dropwise to the layered silicate carrier slurry reactor using a metering pump under continuous stirring conditions, and the dropping rate of the precipitant is controlled to make the pH value of the system = 9. After the active metal mixed solution is added dropwise, the precipitant solution is stopped, and the temperature is maintained at 50°C and stirred for aging for 3 hours to obtain a catalyst precursor slurry. The catalyst precursor slurry is then filtered and washed until it is neutral and free of sodium ions, and then dried at 120°C for 2 hours. The sample is then transferred to a calcination furnace and calcined at 300°C for 12 hours. After granulation and mixing with graphite, the copper-zinc-silicon catalyst 2 is obtained.

[0078] Example 3

[0079] The components of the copper-zinc-silicon catalyst described in Example 3 are CuO: 70%, ZnO: 15%, ZrO2: 3%, CeO2: 1%, and SiO2: 10%.

[0080] Step 1: Add 17 L of desalted water to a 100 L reactor, add 2.43 kg of copper nitrate trihydrate and 4.39 kg of zinc nitrate hexahydrate, stir and dissolve, and prepare an aqueous solution with a molar concentration of copper and zinc elements and (Cu + Zn) of 1.5 mol / L as a copper-zinc mixed solution. Then add concentrated ammonia water to the above copper-zinc mixed solution to form an ammonia complex solution with a pH value of 10.5-11.5; after confirming that the pH is qualified, slowly add 6.67 kg of 30% silica sol solution to the above reactor, stir for 30 minutes, and then begin to heat to 95°C, maintain constant temperature and start stirring to evaporate excess ammonia. After the total pH of the reactor drops to the range of 6.5-7.0, stop distilling ammonia to obtain a layered silicate carrier slurry;

[0081] Step 2: Dissolve 39.51 kg copper nitrate trihydrate, 7.31 kg zinc nitrate hexahydrate, 2.09 kg zirconium nitrate pentahydrate, 0.50 kg cerium nitrate hexahydrate and 1.27 kg magnesium nitrate hexahydrate in 133 L desalted water is prepared into a 1.5 mol / L active metal mixed solution, and a certain amount of 1.5 mol / L sodium carbonate precipitant solution is also prepared; then the layered silicate carrier slurry obtained in step 1 is transferred to a 1000 L reactor, the temperature of the material is controlled at 80°C, and the active metal mixed solution and the precipitant solution are simultaneously added dropwise to the layered silicate carrier slurry reactor using a metering pump under continuous stirring conditions, and the dropping rate of the precipitant is controlled to make the pH value of the system = 7. After the active metal mixed solution is added dropwise, the precipitant solution is stopped, and the temperature is maintained at 50°C and stirred for aging for 3 hours to obtain a catalyst precursor slurry. The catalyst precursor slurry is then filtered and washed until it is neutral and free of sodium ions, and then dried at 120°C for 2 hours. The sample is then transferred to a calcination furnace and calcined at 300°C for 12 hours. After granulation and mixing with graphite, the copper-zinc-silicon catalyst 3 is obtained.

[0082] Example 4

[0083] The components of the copper-zinc-silicon catalyst described in Example 4 are CuO: 49.5%, ZnO: 17.5%, Al2O3: 7%, ZrO2: 8%, and SiO2: 18%.

[0084] Step 1: Add 12 kg of 30wt% silica sol to a 50 L reactor, add 9 L of desalted water to dilute, control the water temperature at 20~40℃ and stir evenly (10 min), then add 5.35 kg of urea to the reactor, the molar ratio of urea to copper, zinc and (Cu+Zn) is 2, stir to fully dissolve, and then add a small amount of nitric acid to adjust to pH = 5; then add 3.28 kg of copper nitrate trihydrate and 9.21 kg of zinc nitrate hexahydrate to the reactor, stir and dissolve to prepare an aqueous solution with a molar concentration of copper, zinc and (Cu+Zn) ions of 2 mol / L; then turn on the cooling water of the reactor condenser, heat the reactor to 90~95℃, maintain constant temperature and start stirring and reflux, as the urea slowly decomposes, the pH in the reactor begins to rise, and the reaction can be terminated when the pH rises to the range of 7.0~7.5 to obtain a layered silicate carrier slurry.

[0085] Step 2: 26.44 kg of copper nitrate trihydrate, 4.02 kg of zinc nitrate hexahydrate, 7.98 kg of aluminum nitrate nonahydrate and 5.58 kg of zirconium nitrate pentahydrate were dissolved in 177 L of desalted water to prepare a 1 mol / L active metal mixed solution, and a certain amount of 1 mol / L sodium bicarbonate precipitant solution was also prepared; then the layered silicate carrier slurry obtained in step 1 was transferred to a 1000 L reactor, the temperature of the material was controlled at 60 ° C, and the active metal mixed solution and the precipitant solution were added dropwise to the layered silicate carrier slurry reactor simultaneously with continuous stirring using a metering pump, and the precipitant addition rate was controlled to make the pH of the system = 7. After the addition of the active metal mixed solution is completed, stop adding the precipitant solution, maintain the temperature at 60°C and continue stirring and aging for 1 hour to obtain a catalyst precursor slurry, then filter and wash the catalyst precursor slurry until it is neutral and free of sodium ions, dry it at 60°C for 12 hours, then transfer the sample to a calcination furnace and calcine it at 400°C for 4 hours, then granulate it, mix it with graphite and press it into tablets to obtain copper-zinc-silicon catalyst 4.

[0086] Example 5

[0087] The components of the copper-zinc-silicon catalyst described in Example 5 are CuO: 64%, ZnO: 21%, Al2O3: 10%, and SiO2: 5%.

[0088] Step 1: Add 25 L of desalted water to a 100 L reactor, add 1.52 kg of copper nitrate trihydrate and 1.83 kg of zinc nitrate hexahydrate, stir and dissolve, and prepare an aqueous solution with a molar concentration of copper and zinc elements and (Cu + Zn) of 0.5 mol / L. Then add concentrated ammonia water to the above solution to form an ammonia complex solution with a pH value of 10.5-11.5; after confirming that the pH is qualified, slowly add 3.33 kg of 30% silica sol solution to the above reactor, stir for 30 minutes, and then begin to heat to 95°C, maintain constant temperature and start stirring to evaporate excess ammonia. After the total pH of the reactor drops to the range of 6.5-7.0, stop the ammonia evaporation to obtain a layered silicate carrier slurry;

[0089] Step 2: Dissolve 37.08 kg copper nitrate trihydrate, 13.89 kg zinc nitrate hexahydrate, and 11.4 kg aluminum nitrate nonahydrate in 130 L desalted water is prepared into a 2 mol / L active metal mixed solution, and a certain amount of 2 mol / L sodium carbonate precipitant solution is also prepared; then the layered silicate carrier slurry obtained in step 1 is transferred to a 1000 L reactor, the temperature of the material is controlled at 70°C, and the active metal mixed solution and the precipitant solution are simultaneously added dropwise to the layered silicate carrier slurry reactor using a metering pump under continuous stirring conditions, and the dropping rate of the precipitant is controlled to make the pH value of the system = 8. After the active metal mixed solution is added dropwise, the precipitant solution is stopped, and the temperature is maintained at 70°C and stirred for aging for 3 hours to obtain a catalyst precursor slurry. The catalyst precursor slurry is then filtered and washed until it is neutral and free of sodium ions, and then dried at 120°C for 2 hours. The sample is then transferred to a calcination furnace and calcined at 300°C for 12 hours. After granulation and mixing with graphite, the copper-zinc-silicon catalyst 5 is obtained.

[0090] Example 6

[0091] The components of the copper-zinc-silicon catalyst described in Example 6 are CuO: 59%, ZnO: 19%, MgO: 2%, and SiO2: 20%.

[0092] Step 1: Add 13.33 kg of 30wt% silica sol to a 100 L reactor, add 37 L of desalted water to dilute it, control the water temperature at 20~40℃ and stir evenly (10 min), then add 12 kg of urea to the reactor, the molar ratio of urea to copper, zinc and (Cu+Zn) is 4, stir to fully dissolve, and then add a small amount of nitric acid to adjust the pH to 2; then add 9.12 kg of copper nitrate trihydrate and 3.65 kg of zinc nitrate hexahydrate to the reactor, stir and dissolve to prepare an aqueous solution with a molar concentration of copper, zinc and (Cu+Zn) ions of 1 mol / L; then turn on the cooling water of the reactor condenser, heat the reactor to 90~95℃, maintain constant temperature and start stirring and reflux. As the urea slowly decomposes, the pH in the reactor begins to rise. When the pH value rises to the range of 7.0~7.5, the reaction can be terminated to obtain a layered silicate carrier slurry.

[0093] Step 2: Dissolve 27.76 kg of copper nitrate trihydrate, 9.02 kg of zinc nitrate hexahydrate, and 2.54 kg of magnesium nitrate hexahydrate in 155 L of desalted water to prepare a 1 mol / L active metal mixed solution. At the same time, a certain amount of 1 mol / L sodium carbonate precipitant solution was also prepared. Then, the layered silicate carrier slurry obtained in step 1 was transferred to 1000 L's reactor, the temperature of the material is controlled at 60°C, and the active metal mixed solution and the precipitant solution are simultaneously added dropwise to the layered silicate carrier slurry reactor using a metering pump under continuous stirring conditions. The dropping rate of the precipitant is controlled to make the pH value of the system = 7. After the active metal mixed solution is added dropwise, the addition of the precipitant solution is stopped, and the temperature is maintained at 60°C and stirred for aging for 1 hour to obtain a catalyst precursor slurry. The catalyst precursor slurry is then filtered and washed until it is neutral and free of sodium ion residues, and then dried at 60°C for 12 hours. The sample is then transferred to a calcination furnace and calcined at 400°C for 4 hours. After granulation and mixing with graphite, it is pressed into tablets to obtain copper-zinc-silicon catalyst 6.

[0094] Comparative Example 1

[0095] 31.0 kg of copper nitrate trihydrate, 16.81 kg of zinc nitrate hexahydrate, 5.70 kg of aluminum nitrate nonahydrate and 2.54 kg of magnesium nitrate hexahydrate were dissolved in 224 L of desalted water to prepare a 1 mol / L active metal mixed solution. A certain amount of 1 mol / L sodium carbonate precipitant solution was also prepared. Then, 100 L of desalted water and 12.67 kg of 30% silica sol solution were added to a 1000 L reactor and stirred for 30 min. Then, the temperature of the material was controlled at 50 ° C. Under continuous stirring, the active metal mixed solution and the precipitant solution were added dropwise to the carrier slurry reactor using a metering pump. The precipitant addition rate was controlled to make the pH of the system = 9. After the addition of the active metal mixed solution is completed, stop adding the precipitant solution, maintain the temperature at 50°C and continue stirring and aging for 3 hours to obtain a catalyst precursor slurry, then filter and wash the catalyst precursor slurry until it is neutral and free of sodium ions, dry it at 120°C for 2 hours, then transfer the sample to a calcination furnace and calcine it at 300°C for 12 hours, then granulate it, mix it with graphite and press it into tablets to obtain a reference catalyst.

[0096] Experimental results

[0097] The performance of the catalysts prepared under different preparation process conditions for the above different embodiments and comparative examples for the hydrogenation of carbon dioxide to methanol is as follows: Figure 1 shown.

[0098] Experimental reaction conditions: 220°C, GHSV (Gas hourly space velocity) = 10000ml.gcat ~1 .h ~1 , 5MPa, H2:CO2:N2=23.5:70.5:6.

[0099] Table 1 Performance of catalysts for CO2 hydrogenation to methanol under different preparation conditions

[0100]

[0101] It can be seen from the above table that the methanol selectivity of the copper-zinc-silicon catalyst in each example of the present application is significantly higher than that of the reference catalyst in Comparative Example 1 which does not use layered silicate as a carrier.

[0102] In addition, refer to Figure 2 , Figure 2 This is a schematic diagram of the long-term stability of the catalyst involved in this application. Figure 2 The long-term stability of CuZnSi catalyst 1 and the reference catalyst are shown in Figure 2. Figure 2It can be seen that the copper-zinc-silicon catalyst 1 of this embodiment does not show a significant downward trend in the space-time yield of methanol over time, while the reference catalyst shows a very significant downward trend in the space-time yield of methanol over time, and the gap between the reference catalyst and the copper-zinc-silicon catalyst 1 is getting bigger and bigger.

[0103] Therefore, the copper-zinc-silicon catalyst of the present application has higher methanol selectivity and space-time yield and also exhibits better catalytic stability.

[0104] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity / operation / object from another entity / operation / object, and do not necessarily require or imply any actual relationship or order between these entities / operations / objects; the terms "include", "comprise", or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or system that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or system. In the absence of further limitations, an element defined by the phrase "includes a ..." does not exclude the presence of other identical elements in the process, method, article, or system that includes the element.

[0105] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0106] The above are only preferred embodiments of the present application and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A copper-zinc-silicon catalyst for producing methanol by hydrogenation of carbon dioxide, characterized in that: The copper-zinc-silicon catalyst is composed of copper oxide, zinc oxide, and a layered silicate carrier. The mass of copper oxide in the copper-zinc-silicon catalyst is 40-70%, the mass of zinc oxide is 15-30%, and the mass of silicon dioxide is 5-20%. The molar ratio of copper element to the sum of copper and zinc elements in the layered silicate carrier is 0.3-1, and the molar ratio of the sum of copper and zinc elements to silicon element is 1. The layered silicate carrier is obtained by reacting a copper-zinc mixed solution of a soluble copper salt and a soluble zinc salt with a silica sol solution.

2. The copper-zinc-silicon catalyst according to claim 1, wherein The components of the copper-zinc-silicon catalyst also include an auxiliary agent, and the mass of the auxiliary agent is 0-10%.

3. The copper-zinc-silicon catalyst according to claim 2, characterized in that The auxiliary agent includes at least one of aluminum, zirconium, magnesium and cerium.

4. A method for preparing a copper-zinc-silicon catalyst, applied to the copper-zinc-silicon catalyst according to any one of claims 1 to 3, characterized in that: The preparation method comprises: reacting a copper-zinc mixed solution of a soluble copper salt and a soluble zinc salt with a silica sol solution to prepare a layered silicate carrier slurry; A soluble copper salt and a soluble zinc salt are configured to form an active metal mixed solution, and a precipitant is configured to form a precipitant solution; performing fluid deposition on the active metal mixed solution and the precipitant solution to precipitate onto the layered silicate carrier slurry; After the precipitation is completed, the precipitated layered silicate carrier slurry is aged, filtered, washed, dried and calcined to obtain the copper-zinc-silicon catalyst.

5. The preparation method according to claim 4, wherein The step of reacting a copper-zinc mixed solution of a soluble copper salt and a soluble zinc salt with a silica sol solution to prepare a layered silicate carrier slurry comprises: Establishing a certain level of desalted water in a reactor, adding soluble copper salt and soluble zinc salt to prepare an aqueous solution having a molar concentration of the sum of copper and zinc elements of 0.5 to 2 mol / L, thereby preparing a copper-zinc mixed solution of soluble copper salt and soluble zinc salt; Adding concentrated aqueous ammonia to the copper-zinc mixed solution to form an ammonia complex solution with a pH of 10.5 to 11.5; Slowly add the silica sol solution to the reactor, stir, and then heat to 90-95°C, maintain constant temperature and start stirring to evaporate excess ammonia; After the pH value of the solution in the reactor drops to the range of 6.5-7.0, the ammonia distillation is terminated to obtain the layered silicate carrier slurry.

6. The preparation method according to claim 4, wherein The step of reacting a copper-zinc mixed solution of a soluble copper salt and a soluble zinc salt with a silica sol solution to prepare a layered silicate carrier slurry further includes: Add the silica sol solution into the reactor and dilute it to 10wt% with deionized water. Control the water temperature at 20-40℃ and stir evenly. Add urea to the reactor at a molar ratio of urea to the total amount of copper and zinc elements of 2-6, stir to fully dissolve, and then add a small amount of nitric acid to adjust the pH to within the range of 3-5; adding a soluble copper salt and a soluble zinc salt to prepare an aqueous solution having a molar concentration of the total copper and zinc elements of 0.5 to 2 mol / L, thereby preparing a copper-zinc mixed solution of the soluble copper salt and the soluble zinc salt; Open the cooling water of the reactor's condenser and heat the reactor to 90-95°C, maintain constant temperature and start stirring and reflux to slowly decompose urea; The reaction is terminated after the pH value of the solution in the reactor rises to a range of 7.0 to 7.5 to obtain a layered silicate carrier slurry.

7. The preparation method according to claim 4, wherein The steps of configuring the soluble copper salt and the soluble zinc salt into an active metal mixed solution and configuring the precipitant into a precipitant solution include: Dissolving soluble copper salt, soluble zinc salt and auxiliary salt in desalted water to prepare an active metal mixed solution with an ion molar concentration of 0.5-2 mol / L; Dissolve the precipitant in desalted water to prepare a 0.5~2 mol / L precipitant solution.

8. The preparation method according to claim 7, wherein The precipitant is at least one of sodium carbonate, NaHCO3, and NaOH.

9. The preparation method according to claim 5, wherein The step of aging, filtering, washing, drying and calcining the precipitated layered silicate carrier slurry to obtain the copper-zinc-silicon catalyst comprises: After the active metal mixed solution is added dropwise, the addition of the precipitant solution is stopped, and the temperature is maintained at 50-80° C. and stirred for 1-3 hours to obtain a catalyst precursor slurry; The catalyst precursor slurry is filtered and washed until it is neutral and free of residual sodium ions, and then dried at 60-120° C. for 2-12 hours to obtain a catalyst sample; The catalyst sample was transferred to a calcination furnace and calcined at 300-400°C for 4-12 hours, and then granulated, mixed with graphite and pressed into tablets to obtain a copper-zinc-silicon catalyst.

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