Methanol catalyst forming method, methanol catalyst and application

Abstract

The invention discloses a methanol catalyst forming method, a methanol catalyst and application, and relates to the technical field of catalyst preparation. The forming method specifically comprises the following steps: preparing catalyst raw powder; roasting part of the catalyst raw powder; mixing the catalyst raw powder, the roasted catalyst raw powder and a release agent; pouring the mixed material into a granulator, granulating, and screening by using a mesh screen; and pouring the sieved catalyst particles into a tablet machine, and carrying out tablet forming, so as to obtain the formed catalyst. By adding a small amount of unroasted catalyst raw powder as the pore-forming agent, the pore diameter can be more uniformly expanded, the diffusion of reactants and products is improved, and the effect of the pore-forming agent is achieved, so that the hydrogenation activity of the catalyst can be improved, the use of additives can be reduced, and the preparation cost of the catalyst can be reduced.

Description

Technical Field

[0001] The present invention relates to the field of catalyst preparation, and in particular to a methanol catalyst forming method, a methanol catalyst and applications. Background Art

[0002] Solid catalysts, when used in industrial applications, require specific shapes and sizes to fit into catalytic reactors. Solid powders are typically formed through processes such as tableting, extrusion, spherical molding, spray molding, and oil column molding to create catalysts of specific shapes and sizes. The molding process often requires the addition of auxiliary materials such as binders and pore-forming agents. The catalyst's molding method and formulation are closely linked to its activity and stability, making them particularly important in catalyst preparation.

[0003] Methanol catalysts are typically produced using a tableting process. During this process, the catalyst's pore structure deforms or even collapses, resulting in a decrease in the catalyst's specific surface area and pore volume, and consequently, a reduction in the catalyst's hydrogenation performance. Conventional methods increase the catalyst's specific surface area and pore volume by adding pore-forming agents, and the catalyst requires a secondary calcination. However, prolonged calcination enlarges the copper active species particles, reducing the catalyst's hydrogenation activity. Summary of the Invention

[0004] In order to solve the above problems, the present invention provides a methanol catalyst molding method, a methanol catalyst and its application. By adding a small amount of uncalcined catalyst raw powder as a pore-forming agent, the pore size can be more evenly expanded, the diffusion of reactants and products can be improved, and the effect of the pore-forming agent can be achieved, thereby improving the hydrogenation activity of the catalyst, reducing the use of additives, and lowering the cost of catalyst preparation.

[0005] The present invention provides a methanol catalyst molding method, comprising the following steps: preparing catalyst raw powder; calcining part of the catalyst raw powder to form a calcined catalyst; mixing the catalyst raw powder, the calcined catalyst raw powder, and a release agent; pouring the mixed material into a granulator for granulation and screening with a mesh screen; pouring the screened catalyst particles into a tabletting machine for tableting and molding to obtain a molded catalyst.

[0006] In one embodiment of the present invention, the catalyst raw powder is prepared by a co-precipitation method, specifically comprising: weighing zinc nitrate hexahydrate and aluminum nitrate nonahydrate, adding them to deionized water, stirring and dissolving, and recording as solution A; weighing copper nitrate trihydrate and zirconium nitrate and dissolving them in deionized water, recording as solution B; weighing anhydrous sodium carbonate, adding deionized water, stirring and dissolving to form a precipitant solution, recording as solution C; simultaneously adding solution A and solution C dropwise to a container containing deionized water, controlling the pH value of the suspension in the container, and after the addition of solution A is completed, adding solution B and solution C dropwise to the suspension, and maintaining the pH value of the suspension; aging the suspension after the addition is completed; washing and drying the aged slurry for later use, and the dried sample is the catalyst raw powder.

[0007] In one embodiment of the present invention, the mesh size of the sieve is 20-60 meshes.

[0008] In one embodiment of the present invention, the catalyst raw powder needs to be subjected to ignition loss control during the roasting process, and the ignition loss is controlled at 2%-12%. In the mixed material, the addition amount of the catalyst raw powder is 2%-10%.

[0009] In one embodiment of the present invention, the sizes of the shaped catalyst include 3*3mm, 4*4mm, 4*5mm, 5*5mm, 6*5mm, and 6*6mm.

[0010] In one embodiment of the present invention, the mass proportion of copper in the catalyst raw powder is 50-70%, the mass proportion of zinc oxide is 20-30%, and the mass proportion of aluminum oxide is 10-20%.

[0011] In one embodiment of the present invention, the release agent includes one or more of graphite, talc and carbon black, and the mass proportion of the release agent in the mixed material is 1%-6%.

[0012] In one embodiment of the present invention, the calcination temperature is 300-500° C., and the calcination time is 2-5 hours.

[0013] The present invention also provides a methanol catalyst, which is prepared according to the above-mentioned methanol catalyst forming method.

[0014] The present invention also provides a methanol catalyst prepared according to the above-mentioned methanol catalyst forming method or the use of the above-mentioned methanol catalyst, which is used in the reaction of preparing methanol by hydrogenating carbon dioxide.

[0015] Compared with the existing technology, the present invention has the following beneficial technical effects: The present invention provides a methanol catalyst forming method, a methanol catalyst and applications. During the catalyst forming process, no additional binder or pore-forming agent is required. Instead, the particle size of the active copper species can be minimized by controlling the ignition loss index of the catalyst itself and adding uncalcined catalyst powder during catalyst preparation and synthesis. A lower calcination temperature and a shorter calcination time are used, thereby improving the catalytic hydrogenation activity. In addition, the gas generated during the decomposition of the uncalcined catalyst powder can expand the pore structure, promote the diffusion of reactants and products, better improve the hydrogenation activity and stability of the catalyst, and reduce the catalyst cost. DETAILED DESCRIPTION

[0016] The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0017] The present invention provides a methanol catalyst forming method, comprising the following steps: The method comprises preparing catalyst raw powder; calcining a portion of the catalyst raw powder; mixing the catalyst raw powder, the calcined catalyst, and a release agent; pouring the mixed material into a dry granulator for granulation and screening with a mesh screen; and pouring the screened catalyst particles into the feed port of a tabletting machine for tableting. The molding method provided by the present invention does not require the addition of additional binders and pore-forming agents during the catalyst molding process. Instead, uncalcined catalyst raw powder is added during catalyst preparation and synthesis, and the catalyst raw powder decomposes itself to increase the pore size and pore volume of the catalyst, thereby better improving the hydrogenation activity and stability of the catalyst and reducing the catalyst cost.

[0018] On the one hand, since the undecomposed catalyst powder acts as a pore-forming agent during the decomposition process, it can expand the pore size more evenly, improve the diffusion of reactants and products, and thus improve the hydrogenation activity of the catalyst; in addition, the expansion of the catalyst pore size is conducive to the diffusion of product water vapor, which can inhibit the oxidation and sintering effects of water vapor on the catalyst.

[0019] On the other hand, during the calcination process, the catalyst raw powder needs to be tested for loss on ignition, and the temperature needs to be controlled and the calcination time needs to be reduced. The control of loss on ignition can improve the dispersion of copper species, reduce the size of copper particles, and eliminate the need for secondary calcination of the catalyst, thereby further improving the hydrogenation activity and reducing the preparation cost of the catalyst. Optimization of the calcination temperature and time can also improve the dispersion of the copper species in the catalyst. The uniform dispersion of copper particles is conducive to inhibiting Ostwald ripening, thereby further improving the stability of the catalyst.

[0020] In one embodiment of the present invention, the catalyst powder is prepared by a coprecipitation method, which specifically includes: Weigh zinc nitrate hexahydrate and aluminum nitrate nonahydrate, add them to deionized water, stir and dissolve, and record it as solution A; weigh copper nitrate trihydrate and zirconium nitrate and dissolve them in deionized water, record it as solution B; weigh anhydrous sodium carbonate, add it to deionized water, stir and dissolve to form a precipitant solution, record it as solution C; add solution A and solution C dropwise to a container containing deionized water at the same time, control the pH value of the suspension in the container, after the addition of solution A is completed, add solution B and solution C dropwise to the suspension, and maintain the pH value of the suspension; after the addition is completed, age the suspension; wash and dry the aged slurry for later use, and the dried sample is the catalyst raw powder.

[0021] In one embodiment of the present invention, the coprecipitation method is as follows: Weigh 8.29g zinc nitrate hexahydrate and 5.82g aluminum nitrate nonahydrate, add 90mL deionized water, stir and dissolve in a 200mL beaker, recorded as solution A; weigh 18.04g copper nitrate trihydrate and 0.51g zirconium nitrate and dissolve in 153mL deionized water, recorded as solution B; weigh 41.6g anhydrous sodium carbonate, add 400ml deionized water, stir and dissolve to form a 1mol / L precipitant solution, recorded as solution C; solutions A and C are added dropwise to a three-necked flask containing 100ml deionized water at the same time, and the pH value of the suspension in the three-necked flask is maintained at 7. After the addition of solution A is completed, solution B and solution C are added dropwise to the suspension, and the pH value of the suspension is maintained at 7; after the addition is completed, the suspension is maintained at 60°C for aging for 3h; the aged slurry is washed and dried for use, and the dried sample is the catalyst powder.

[0022] In one embodiment of the present invention, the mesh size of the sieve is 20-60 meshes.

[0023] In one embodiment of the present invention, the ignition loss of the catalyst raw powder is controlled at 2%-12%, for example, 2%, 4%, 5%, 10%, 12%, and the addition amount of the catalyst raw powder is 2%-10%, for example, 2%, 4%, 6%, 10%.

[0024] In one embodiment of the present invention, the sizes of the shaped catalyst include 3*3mm, 4*4mm, 4*5mm, 5*5mm, 6*5mm, and 6*6mm.

[0025] In one embodiment of the present invention, the mass proportion of copper in the catalyst raw powder is 50-70%, for example, 50%, 60%, 70%, the mass proportion of zinc oxide is 20-30%, for example, 20%, 25%, 30%, and the mass proportion of aluminum oxide is 10-20%, for example, 10%, 15%, 20%.

[0026] In one embodiment of the present invention, the release agent includes one or more of graphite, talc and carbon black, and the mass proportion of the release agent is 1%-6%, for example, 1%, 3%, 5%, 6%.

[0027] In one embodiment of the present invention, the calcination temperature is 300-500° C., for example, 300° C., 400° C., 500° C., and the calcination time is 2-5 hours, for example, 2 hours, 3 hours, 4 hours, 5 hours.

[0028] The present invention also provides a methanol catalyst, which is prepared according to the above-mentioned methanol catalyst forming method.

[0029] The present invention also provides a methanol catalyst prepared according to the above-mentioned methanol catalyst forming method or the use of the above-mentioned methanol catalyst for the reaction of preparing methanol by hydrogenation of carbon dioxide.

[0030] The present invention will be further described below with reference to the embodiments.

[0031] Example 1 The uncalcined catalyst powder was calcined in a muffle furnace at 300°C for 3 hours. The resulting catalyst was labeled Catalyst 1. A portion of Catalyst 1 was subjected to a loss-on-ignition test. 100g of Catalyst 1, 3g of uncalcined catalyst powder, and 2g of graphite were mixed in a mixer. The mixed material was poured into a dry granulator for granulation and screened with a 20-60 mesh sieve. The screened catalyst particles were poured into the feed port of a tabletting machine for tableting and labeled as Catalyst 1.

[0032] Example 2 The uncalcined catalyst powder was calcined in a muffle furnace at 400°C for 4 hours. The resulting catalyst was labeled Catalyst 2. A portion of Catalyst 2 was subjected to a loss-on-ignition test. 100g of Catalyst 2, 5g of uncalcined catalyst powder, and 2g of talc were mixed in a mixer. The mixed material was poured into a dry granulator for granulation and screened with a 20-60 mesh sieve. The screened catalyst granules were poured into the feed port of a tabletting machine for tableting and labeled as Catalyst 2.

[0033] Example 3 The uncalcined catalyst powder was calcined in a muffle furnace at 350°C for 3 hours. The resulting catalyst was labeled Catalyst 3. A portion of Catalyst 3 was subjected to a loss-on-ignition test. 100g of Catalyst 3, 2g of uncalcined catalyst powder, and 1g of graphite were mixed in a mixer. The mixed material was poured into a dry granulator for granulation and screened with a 20-60 mesh sieve. The screened catalyst granules were poured into the feed port of a tabletting machine for tableting and labeled as Catalyst 3.

[0034] Example 4 The uncalcined catalyst powder was calcined in a muffle furnace at 500°C for 3 hours. The resulting catalyst was labeled Catalyst 4. A portion of Catalyst 4 was subjected to a loss on ignition test. 100g of Catalyst 4, 8g of uncalcined catalyst powder, and 5g of carbon black were mixed in a mixer. The mixed material was poured into a dry granulator for granulation and screened with a 20-60 mesh sieve. The screened catalyst granules were poured into the feed port of a tabletting machine for tableting and labeled as Catalyst 4.

[0035] Example 5 The uncalcined catalyst powder was calcined in a muffle furnace at 450°C for 5 hours. The resulting catalyst was labeled Catalyst 5. A portion of Catalyst 5 was subjected to a loss-on-ignition test. 100g of Catalyst 5, 6g of uncalcined catalyst powder, and 4g of graphite were mixed in a mixer. The mixed material was poured into a dry granulator for granulation and screened with a 20-60 mesh sieve. The screened catalyst granules were poured into the feed port of a tableting machine for tableting and labeled as Catalyst 5.

[0036] Example 6 The uncalcined catalyst powder was calcined in a muffle furnace at 350°C for 4 hours. The resulting catalyst was labeled Catalyst 6. A portion of Catalyst 6 was subjected to a loss-on-ignition test. 100g of Catalyst 6, 5g of uncalcined catalyst powder, and 3g of graphite were mixed in a mixer. The mixed material was poured into a dry granulator for granulation and screened with a 20-60 mesh sieve. The screened catalyst granules were poured into the feed port of a tabletting machine for tableting and labeled as Catalyst 6.

[0037] Comparative Example 1 The uncalcined catalyst powder was calcined in a muffle furnace at 500°C for 4 hours. The resulting catalyst was labeled Catalyst 7. A portion of Catalyst 7 was subjected to a loss on ignition test. 100g of Catalyst 7 was mixed with 4g of graphite in a mixer. The mixed material was poured into a dry granulator for granulation and screened with a 20-60 mesh sieve. The screened catalyst particles were poured into the feed port of a tabletting machine for tableting and labeled as Catalyst 7.

[0038] Loss on Ignition test method: Take 10g of the calcined catalyst powder and place it in a 500℃ muffle furnace for the first calcination for 30 minutes. After the muffle furnace temperature drops to room temperature, remove the sample and cool it in a desiccator. Place the cooled sample on an analytical balance and weigh the catalyst mass as m1. Then, place the sample in a 500℃ muffle furnace for a second calcination for 30 minutes and weigh the cooled sample mass as m2. Repeat this process until m1 = mn (n times). The catalyst loss on ignition w = (10-mn) / 10.

[0039] The catalysts in the above examples and comparative examples were used in the carbon dioxide hydrogenation to methanol reaction, and the catalyst performance was tested under the following conditions: reaction temperature of 250°C, reaction pressure of 5 MPa, reaction space velocity of 10000 mL∙h -1 ∙g cat -1 , the flow ratio of H2 and CO2 is 3:1, and the test results are shown in Table 1.

[0040] Table 1 Test results of catalyst performance in Examples 1-6 and Comparative Example 1

[0041] As can be seen from Table 1, by comparing Examples 1-6 with Comparative Example 1, the catalysts in Examples 1-6 were prepared by controlling the loss on ignition index of the catalyst itself and adding uncalcined catalyst powder during the molding process. The catalyst in Comparative Example 1 was only subjected to a loss on ignition test during the molding process, and no uncalcined catalyst powder was added. The methanol space-time yields in Examples 1-6 were all higher than that in Comparative Example 1, the deactivation rates were all lower than those in Comparative Example 1, and the molding strengths were all higher than those in Comparative Example 1. It can be seen that during the catalyst molding process, controlling the loss on ignition index of the catalyst itself and adding uncalcined catalyst powder can increase the pore size and pore volume of the catalyst through the decomposition of the catalyst itself, thereby better improving the hydrogenation activity and stability of the catalyst.

[0042] From the above description, it can be seen that the methanol catalyst forming method, methanol catalyst and application provided by the present invention do not require the addition of additional binders and pore-forming agents during the catalyst forming process. Only by controlling the ignition loss index of the catalyst itself and adding uncalcined catalyst powder during catalyst preparation and synthesis, the pore size and pore volume of the catalyst can be increased through the decomposition of the catalyst itself. By using a lower calcination temperature and a shorter calcination time, the particle size of the active copper species can be minimized, thereby improving the catalytic hydrogenation activity. In addition, the gas generated during the decomposition of the uncalcined catalyst powder can expand the pore structure, promote the diffusion of reactants and products, better improve the hydrogenation activity and stability of the catalyst, and reduce the catalyst cost.

[0043] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical content disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A methanol catalyst forming method, characterized in that: The steps include: preparing catalyst raw powder; calcining a portion of the catalyst raw powder; Mixing the catalyst raw powder, the calcined catalyst raw powder, and the release agent; The mixed material is poured into a granulator for granulation and screened with a mesh sieve; The screened catalyst particles are poured into a tabletting machine for tableting and forming to obtain a formed catalyst.

2. The methanol catalyst forming method according to claim 1, characterized in that: The catalyst raw powder is prepared by a co-precipitation method, comprising the following steps: Weigh zinc nitrate hexahydrate and aluminum nitrate nonahydrate, add them into deionized water, stir and dissolve, and record it as solution A; Weigh copper nitrate trihydrate and zirconium nitrate and dissolve them in deionized water, which is called solution B. Weigh anhydrous sodium carbonate, add deionized water, and stir to dissolve to form a precipitant solution, which is recorded as solution C; Add solution A and solution C simultaneously dropwise into a container containing deionized water, control the pH value of the suspension in the container, and after the addition of solution A is completed, add solution B and solution C dropwise into the suspension, while maintaining the pH value of the suspension; After the addition is completed, the suspension is aged; The aged slurry is washed and dried for later use, and the dried sample is the catalyst raw powder.

3. The methanol catalyst forming method according to claim 1, characterized in that: The mesh number of the sieve is 20-60 meshes.

4. The methanol catalyst forming method according to claim 1, characterized in that: The catalyst raw powder needs to be controlled for loss on ignition during the roasting process, and the loss on ignition is controlled at 2%-12%. The amount of the catalyst raw powder added to the mixed material is 2%-10%.

5. The methanol catalyst forming method according to claim 1, characterized in that: The sizes of the shaped catalyst include 3*3mm, 4*4mm, 4*5mm, 5*5mm, 6*5mm, and 6*6mm.

6. The methanol catalyst forming method according to claim 2, characterized in that: The mass proportion of copper in the catalyst raw powder is 50-70%, the mass proportion of zinc oxide is 20-30%, and the mass proportion of aluminum oxide is 10-20%.

7. The methanol catalyst forming method according to claim 1, characterized in that: The release agent includes one or more of graphite, talc and carbon black, and the mass proportion of the release agent in the mixed material is 1%-6%.

8. The methanol catalyst forming method according to claim 1, characterized in that: The calcination temperature is 300-500° C., and the calcination time is 2-5 hours.

9. A methanol catalyst, characterized in that: Prepared by the methanol catalyst molding method according to any one of claims 1 to 8.

10. A use of a methanol catalyst prepared by the methanol catalyst forming method according to any one of claims 1 to 8 or the methanol catalyst according to claim 9, characterized in that: Used in the reaction of producing methanol by hydrogenation of carbon dioxide.

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