Method for producing molded catalyst for hydrogen reduction of carbon dioxide

Abstract

To provide a technology to mold a functional material without impairing a function thereof.SOLUTION: A method for producing a molded body of a functional material of the present disclosure includes dispersing a functional material in a water-alcohol mixture to yield a dispersion, impregnating the dispersion into a porous molding base material to yield an impregnated body, and drying the impregnated body.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a method for producing a functional material molded body, a functional material molded body, and a reactor. [Background technology]

[0002] As the use of renewable energy is expected to expand, technology to generate energy carriers that can be stored and transported using renewable energy is being actively studied. For example, it is being considered to use renewable energy to electrolyze water to generate hydrogen, which can then be used as a thermal energy source or fuel for fuel cells. It is also being considered to convert hydrogen into methane or ammonia for use. In particular, methane is the main component of natural gas, and has the advantage of being able to use existing infrastructure, so it is expected to be used as an energy carrier.

[0003] The Sabatier reaction is known as a method for converting hydrogen into methane. This Sabatier reaction is a method in which hydrogen and carbon dioxide are catalytically reacted to produce methane and water. The Sabatier reaction is a reaction in which the reduction rate of carbon dioxide by hydrogen reaches nearly 100% at a temperature of 350°C, making it possible to reduce carbon dioxide to hydrogen with high efficiency. In addition, the Sabatier reaction is an autonomous reaction that generates heat, and it is possible to continue the reaction without the need for an external supply of heat energy, etc.

[0004] As a catalyst for the Sabatier reaction, Patent Document 1 discloses a catalyst for reducing carbon dioxide with hydrogen, in which catalytic metal nanoparticles and metal oxide particles are dispersed and supported on a powdered support. There is a need to establish a method for secondary molding of such powdered catalysts.

[0005] Known methods for forming a larger structure by molding a powder of a functional material such as a catalyst include compressing the functional material, mixing it with an adhesive such as a binder and granulating it, and adhering the functional material to a structure that has previously been coated with an adhesive.

[0006] Patent Document 2 discloses a method for producing a carrier-supported solid catalyst for producing aldehydes, in which a catalyst component is supported on a carrier made of a through-type porous material. In the method of Patent Document 2, a molded body is obtained by mixing the catalyst with water, impregnating the porous body, and drying and calcining the mixture (see Example 1 of Patent Document 2).

[0007] Patent Document 3 discloses a method for supporting a catalyst powder containing a composite metal oxide containing molybdenum as an essential component on an inert carrier by a rolling granulation method. In the method of Patent Document 3, a binder is used (see Example 1 of Patent Document 3). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2019-048249 A [Patent Document 2] JP 2017-047377 A [Patent Document 3] International Publication No. 2013 / 161703 Summary of the Invention [Problem to be solved by the invention]

[0009] However, due to the nature of its function, the Sabatier catalyst described in Patent Document 1 deteriorates in performance when overheated by calcination, making it difficult to apply a molding method that involves a calcination step as in Patent Document 2. In addition, molding using a binder as in Patent Document 3 covers the surface of functional materials such as catalysts, which can reduce the functionality of the functional materials.

[0010] Therefore, the present disclosure provides a technique for forming a functional material without impairing the function of the functional material. [Means for solving the problem]

[0011] In order to solve the above problems, the manufacturing method of the functional material molded body of the present disclosure includes dispersing a functional material in a water-alcohol mixed liquid to obtain a dispersion, impregnating a porous molded base material with the dispersion to obtain an impregnated body, and drying the impregnated body.

[0012] Further features related to the present disclosure will become apparent from the description of the present specification and the accompanying drawings. Also, the aspects of the present disclosure are achieved and realized by the elements and combinations of various elements and the following detailed description and the appended claims. The description of the present specification is merely exemplary and is not intended to limit the scope or application of the present disclosure in any way. Effect of the Invention

[0013] According to the technology of the present disclosure, it is possible to mold a functional material without impairing the function of the functional material. Problems, configurations, and effects other than those described above will become apparent from the description of the following embodiments. [Brief description of the drawings]

[0014] [Figure 1] 1 is a flowchart illustrating a method for producing a functional material molded body according to an embodiment of the present disclosure. [Diagram 2] 2 is a schematic diagram of a porous molded base material and a functional material molded body before being impregnated with a functional material dispersion liquid. FIG. [Diagram 3] 1 is a schematic cross-sectional view showing a configuration of a part of a reactor having a functional material molded body. [Figure 4] 1 is an enlarged photograph of an alumina plate. [Diagram 5] 1 is a photograph of an alumina plate and a powder catalyst molding. [Figure 6] 2 is an enlarged photograph of a powder catalyst molding according to Example 1. [Figure 7] 1 is a photograph of a reactor in which 15 powder catalyst molded bodies are packed into the reactor. [Figure 8] 2 is a graph showing the catalytic performance of powder catalyst molded bodies according to Example 1 and Comparative Example 1. [Figure 9]1 is a photograph of a reactor having a flat plate structure according to Example 3. [Figure 10] 4 is a graph showing the catalytic performance of the powder catalyst molded bodies according to Examples 1 and 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] [Method of manufacturing functional material molded body] FIG. 1 is a flowchart showing a method for producing a functional material molded product according to an embodiment of the present disclosure.

[0016] <Step S11> The manufacturer prepares the functional material for molding. The functional material is in the form of a powder or particles. Examples of the functional material include catalysts and adsorbents. Examples of the catalytic material include metals and metal oxides that exhibit catalytic activity. Examples of the adsorbent material include silica gel, activated carbon, zeolite, resins, minerals, etc.

[0017] The catalyst may be in the form of particles, or may be a powder catalyst in which catalyst particles are supported on carrier particles. Furthermore, in addition to the catalyst particles, particles of other substances may be supported on the carrier particles in order to maintain the function of the catalyst. Patent Document 1 describes a powder catalyst in which catalytic metal nanoparticles and metal oxide particles that suppress the grain growth of the catalytic metal nanoparticles are dispersed and supported on a carrier as a catalyst for reducing carbon dioxide with hydrogen (Sabatier catalyst).

[0018] The catalytic metal nanoparticles of the powder catalyst for reducing carbon dioxide with hydrogen are, for example, nanoparticles containing at least one metal selected from the group consisting of Fe, Co, Ni, Cu, Ru, Pd, Ag, Ir and Pt. The catalytic metal nanoparticles may contain metal oxides to the extent that the catalytic function is not impaired.

[0019] The metal oxide particles of the powder catalyst for reducing carbon dioxide with hydrogen are formed from a metal oxide that is not easily changed by heating in the presence of hydrogen and has high resistance to reduction. The metal oxide includes, for example, at least one metal oxide selected from the group consisting of titanium dioxide and zirconium dioxide. The metal oxide may contain a catalytic metal to the extent that the resistance to reduction is not impaired. These metal oxides may be used alone or in combination.

[0020] Examples of the carrier for the powder catalyst for reducing carbon dioxide with hydrogen include silicon dioxide, magnesium oxide, titanium dioxide, zirconium dioxide, niobium pentoxide, zeolite, and calcium phosphate. These may be used alone or in combination of two or more. The shape of the carrier may be spherical, polyhedral, amorphous, flaky, or scaly. The average particle size of the carrier is not particularly limited, but may be, for example, 0.01 to 30 μm or 0.02 to 2.0 μm.

[0021] The powder catalyst can be produced by performing sputtering while rolling a support using a target containing the above-mentioned metal and metal oxide. This allows nanoparticles containing a metal and nanoparticles containing a metal oxide to be dispersed and supported on the surface of the support. For example, a polygonal barrel sputtering device can be used as a device for performing sputtering while rolling a support.

[0022] <Step S12> The manufacturer prepares a porous molding base material. The shape of the porous molding base material is not particularly limited, and can be, for example, a plate-like, disk-like, rectangular, cuboidal, spherical, hemispherical, pyramidal, conical, cylindrical, or a combination thereof. The shape of the porous molding base material can be selected according to the shape of the functional material after molding. In particular, when molding a Sabatier catalyst, the thermal stability can be improved by making the porous molding base material plate-like and thinning the reaction area.

[0023] Examples of the material of the porous molding base material include porous ceramics, porous metals, etc. By using a material having affinity with the functional material as the porous molding base material, the functional material can be easily fixed.

[0024] Examples of ceramics that can be used as raw materials for porous ceramics include, but are not limited to, oxides such as alumina, zirconia, and barium titanate; hydroxides such as hydroxyapatite; carbides such as silicon carbide; nitrides such as silicon nitride; halides such as fluorite; phosphates; and carbonates.

[0025] As the metal to be used as the raw material of the porous metal, a metal element or an alloy can be used, and examples thereof include titanium, copper, and SUS.

[0026] The pore size of the porous base material may be equal to or larger than the particle size of the functional material, which allows the functional material to penetrate into and be retained in the pores of the porous base material.

[0027] By adjusting the porosity of the porous molding base material, the amount of the functional material held in the porous molding base material per unit volume can be adjusted, and the reactivity can be controlled. The porosity of the porous molding base material is not limited, and can be, for example, 10 to 90%, 20 to 80%, or 30 to 70%.

[0028] The specific surface area of ​​the porous base material is, for example, 0.5 to 10 m 2 / g or 1.0~5.0m 2 / g.

[0029] <Step S13> The manufacturer adds the functional material to a water-alcohol mixture, disperses it, and obtains a dispersion (including a slurry). The mixing ratio (volume ratio) of water and alcohol can be, for example, 5:95 to 95:5, 10:90 to 90:10, 20:80 to 80:20, or 30:70 to 70:30.

[0030] Examples of alcohol include, but are not limited to, methanol, ethanol, n-propanol, isopropanol, n-butanol, ethylene glycol, propylene glycol, butanediol, etc. In particular, by using an alcohol that forms an azeotropic water-alcohol mixture, the water-alcohol mixture evaporates without changing its composition in the drying step described below, and the functional material can be stably retained in the porous molded base material.

[0031] The mixing ratio (weight ratio) of the water-alcohol mixed solution to the functional material can be, for example, 20:80 to 80:20, 30:70 to 70:30, or 40:60 to 60:40. Although it depends on the type of functional material and the concentration of the water-alcohol mixed solution, a ratio of 70:30 to 80:20 is particularly excellent in workability during impregnation.

[0032] Any additive may be added to the water-alcohol mixture as long as it does not impair the function of the functional material.

[0033] <Step S14> The manufacturer impregnates the porous base material with the dispersion liquid to obtain an impregnated body. The dispersion liquid penetrates into the pores of the porous base material by capillary action, so that the dispersion liquid can reach the inside of the porous base material. There is no particular limitation on the impregnation method, and examples of the method include a method of dropping the dispersion liquid onto the porous base material and a method of immersing the porous base material in a container filled with the dispersion liquid.

[0034] The impregnation amount of the dispersion is, for example, 50 to 300 mg / cm 3 , 100-250mg / cm 3 or 150-200mg / cm 3 It can be said that:

[0035] The dispersion may be uniformly impregnated into the entire porous base material, or may be unevenly impregnated. That is, the amount of functional material held in the porous base material may have a gradient. For example, the amount of functional material may change from one end of the porous base material to the other end, or the amount of functional material may change concentrically.

[0036] <Step S15> The manufacturer obtains a functional material molded body by drying the porous molded base material impregnated with the dispersion liquid and removing the water-alcohol mixture. The drying may be performed by natural drying or by using a dryer. The drying temperature may be any temperature that does not impair the function of the functional material, and may be, for example, room temperature to 300°C. For example, since the Sabatier catalyst used in the examples described later shows high catalytic activity at 220°C, the drying temperature may be 220°C or lower to prevent performance deterioration due to heating at a higher temperature. If the function of the functional material is not impaired even when heated at a high temperature, it may be dried at a temperature equal to or higher than the usage temperature of the functional material.

[0037] According to the manufacturing method of the functional material molded body of this embodiment, the functional material is held in the pores of the porous molded base material. When the entire porous molded base material is impregnated with the dispersion liquid, the functional material is held evenly in the pores, and a high holding amount can be achieved. This is effective in improving the reactivity of the reaction using the functional material molded body. The holding amount of the functional material in the functional material molded body is, for example, 50 to 300 mg / cm, depending on the weight of the functional material and the porosity of the porous molded base material. 3 , 80-250mg / cm 3 or 100-230mg / cm 3 It can be said that:

[0038] Steps S14 and S15 may be repeated multiple times. The obtained functional material molded body may be calcined to the extent that the function of the functional material is not impaired. The calcination temperature can be set according to the type of functional material. However, when the functional material is a Sabatier catalyst, the Sabatier catalyst is active even at temperatures below 220°C, so that the catalytic performance can be maintained by not calcining.

[0039] Fig. 2 is a schematic diagram of a porous molded base material 10 and a functional material molded body 20 before impregnation with a functional material dispersion liquid. As shown on the left side of Fig. 2, the porous molded base material 10 is, for example, plate-shaped. As shown on the right side of Fig. 2, the obtained functional material molded body 20 is molded into substantially the same shape as the porous molded base material 10. The functional material molded body 20 may be processed into other shapes, for example, by cutting.

[0040] <Summary> As described above, the method for producing a functional material molded body according to this embodiment includes dispersing a functional material in a water-alcohol mixed liquid to obtain a dispersion, impregnating a porous molded base material with the dispersion to obtain an impregnated body, and drying the impregnated body. In this way, since the functional material can be molded without using a binder, the binder does not cover the functional material. Therefore, since the functional material can be molded while maintaining the surface area of ​​the functional material, it is possible to prevent the deterioration of the function of the functional material. In addition, by making the water-alcohol mixed liquid an azeotropic mixture, the mixed liquid evaporates at a temperature lower than the boiling point of water, so the drying temperature can be lowered. Therefore, the thermal load on the functional material can be reduced, so that the deterioration of the function due to heat can be prevented. Furthermore, since the functional material can be molded without performing firing, it is possible to prevent irreversible deterioration of the functional material due to overheating.

[0041] [Reactor] 3 is a schematic cross-sectional view showing a configuration of a part of a reactor 100 having a functional material molded body 20. As shown in FIG. 3, the reactor 100 includes the functional material molded body 20, a reaction tank 101, and a porous material 102.

[0042] The reaction vessel 101 is open at both ends, and the functional material molded body 20 is filled inside. The number of the functional material molded body 20 filled in the reaction vessel 101 may be only one or may be multiple. One of the openings of the reaction vessel 101 is connected to a raw material supply pipe (not shown), and raw material (gas or liquid) for the reaction is supplied. The other opening is connected to an exhaust pipe (not shown), and the reaction product (gas or liquid) is discharged. The shape of the reaction vessel 101 is not particularly limited, and may be, for example, a cylindrical shape, an elliptical cylindrical shape, or a polygonal cylindrical shape. The material of the reaction vessel 101 is not particularly limited as long as it is not reactive to the raw material supplied and the reaction product discharged, and is resistant to the reaction temperature. The material of the reaction vessel 101 may be, for example, plastic, metal, ceramics, glass, etc.

[0043] The porous material 102 does not allow the functional material molded body 20 to pass therethrough, but allows gases and liquids such as carbon dioxide, hydrogen, methane, and water (water vapor) to pass therethrough. As the porous material 102, for example, a metal fiber filter, a ceramic filter, a glass filter, a metal foam, or glass wool can be used.

[0044] The reactor 100 may have a heater for adjusting the reaction temperature. The reactor 100 may also have a thermometer for measuring the temperature inside the reaction vessel 101.

[0045] When the functional material is a catalyst, the reactor 100 can be used as a catalytic reaction device. In particular, when the functional material is a Sabatier catalyst, the reactor 100 can be used as a hydrogen reduction device for carbon dioxide. In this case, carbon dioxide and hydrogen are supplied to the reaction vessel 101 as raw material gases, and methane and water are discharged as reaction products.

[0046] When the functional material is an adsorbent, the reactor 100 can be used as an adsorption reactor. EXAMPLES

[0047] An embodiment of the technology of the present disclosure will be described below.

[0048] Experimental Example 1: Production of powder catalyst compacts [Example 1] <Production of powder catalyst> As a functional material, a powder catalyst (Sabatier catalyst) for hydrogen reduction of carbon dioxide was prepared by the following procedure.

[0049] The target holder of the polygonal barrel sputtering device was fitted with a Ru target as a metal target and a ZrO target as a metal oxide target. 2 The target was placed on the target holder. The Ru target and ZrO 2 The area ratio of the sputtering surfaces of the targets was 1:0.5. The target holder was set to separate the Ru target from the ZrO 2 The target was tilted so that the sputtering surface faced downward.

[0050] In the octagonal barrel of the polygonal barrel sputtering device, 3.0 g of TiO 2 Powder (anatase type) was added. TiO 2 The powder used had an average particle size of 100 nm.

[0051] Next, the inside of the octagonal barrel was pumped with a rotary pump and an oil diffusion pump to obtain 8.0×10 -4 The pressure in the octagonal barrel was reduced to 0.8 Pa or less. Then, Ar gas was introduced into the octagonal barrel by the argon gas introduction mechanism, and the pressure in the octagonal barrel was set to 0.8 Pa. Then, the rotation mechanism was operated to swing the octagonal barrel at an angle of 75° and at 4.3 rpm, and the TiO 2 While stirring the powder, a 100 W high-frequency wave was applied to the high-frequency application mechanism (RF oscillator) for 12 hours to form Ru-ZrO 2 Supported TiO 2 Granules (Ru-ZrO 2 / TiO 2 ) was obtained. 2 Supported TiO 2 The granules were designated as "powder catalysts." The powder catalysts were titanium dioxide (TiO 2Ruthenium (Ru) and zirconium oxide (ZrO 2 ) was dispersed and supported, and the color was black.

[0052] The amount of Ru supported on the powder catalyst was confirmed by X-ray fluorescence analysis and found to be 23.3 wt%. 2 The amount of Ru was estimated to be about 3.5 wt%. The particle size of the Ru particles supported on the powder catalyst was 0.4 to 3.0 nm, and the average particle size was 1.3 nm (n = 142).

[0053] <Preparation of powder catalyst slurry> A water-IPA mixture was obtained by mixing 25% water and 75% isopropanol (IPA) by volume. The water-IPA mixture and the powder catalyst were mixed in a mixing ratio (weight ratio) of 10:1 to disperse the powder catalyst and obtain a slurry.

[0054] <Preparation of ceramic porous bodies> A ceramic porous body was used as the porous molding base material. 2 O 3 The dimensions of the alumina plates were 1.9 cm in length × 1.2 cm in width × 0.2 cm in thickness, with a porosity of 30 to 60% and a specific surface area of ​​1 to 3 m. 2 / g. Figure 4 is an enlarged photograph of the alumina plate. As shown in Figure 4, the porous alumina plate is white in color, and it can be seen that it has fine pores.

[0055] <Production of Molded Product> A portion of the powder catalyst slurry was dropped onto an alumina plate, impregnated by capillary action, and dried in an oven (constant temperature drying furnace) at a temperature of 100°C or less (30 to 50°C) for 30 to 60 minutes. This process was repeated several times to obtain a powder catalyst molded body. Fifteen alumina plates were similarly impregnated with the slurry and dried to obtain 15 powder catalyst molded bodies. The amount of the powder catalyst slurry impregnated into the alumina plate was 150 to 200 mg / cm. 3The amount of powder catalyst held by the obtained powder catalyst molded body was 42 to 51 mg.

[0056] Figure 5 is a photograph of the alumina plate and powder catalyst molding. As shown in Figure 5, the alumina plate (left side) before impregnation with the slurry was white, and the powder catalyst molding (right side) obtained by impregnating with the slurry and drying was gray. Furthermore, the shape of the powder catalyst molding was almost unchanged from that of the alumina plate, demonstrating that the powder catalyst could be molded into the shape of a porous molding base material. Figure 6 is an enlarged photograph of the powder catalyst molding. As shown in Figure 6, it can be seen that the black powder catalyst is fixed and held in the fine pores of the alumina plate.

[0057] [Comparative Example 1] <Production of Molded Product> 0.7 g of the powder catalyst prepared in the same manner as in Example 1 was mixed and dispersed in 2 g of glass wool (molding base material), thereby obtaining a powder catalyst molding according to Comparative Example 1.

[0058] [Evaluation of moldability] The moldability of the powder catalyst moldings according to Example 1 and Comparative Example 1 was evaluated as follows.

[0059] <Easy to work with when fixed to base material> Example 1: The work was carried out without any problems during the impregnation of the slurry. Comparative Example 1: During dispersion in the glass wool, the powder catalyst was detached, and the workability was inferior to that of Example 1.

[0060] <Fixed state of powder catalyst in molded body> Example 1: The powder catalyst was fixed to the entire surface of the alumina plate, and no detachment or powdering of the powder catalyst was observed. Comparative Example 1: The powder catalyst was partially detached.

[0061] <Summary> As described above, the powder catalyst could be easily fixed and molded on an alumina plate by the manufacturing method of powder catalyst molded body according to Example 1. This method does not use a binder, and the powder catalyst is not covered with a binder, so it can be said that the catalytic function of the powder catalyst is maintained.

[0062] [Evaluation of catalyst performance] The powder catalyst molded bodies according to Example 1 and Comparative Example 1 were used to carry out a hydrogen reduction reaction of carbon dioxide, and the catalytic performance was evaluated as follows.

[0063] <Filling of powder catalyst compacts into the reactor> Fifteen sheets of the powder catalyst molded body according to Example 1 were stacked together to form a columnar catalyst layer measuring 1.9 cm x 1.2 cm x 2.8 cm, and packed into the reaction vessel of the reactor. The volume of the internal space of the reaction vessel was 6 cm2 in cross-sectional area. 2 × Height 3.2cm = 19.2cm 3 The amount of powder catalyst held in the columnar catalyst layer was 0.67 g. Any slight gaps between the inner dimensions of the reaction vessel and the columnar catalyst layer were filled with a filler mainly composed of alumina. Figure 7 is a photograph of the reactor filled with 15 powder catalyst compacts. As shown in Figure 7, the powder catalyst compacts are each perpendicular to the gas flow direction in the reaction vessel and are layered along the gas flow direction.

[0064] Thermocouples were placed at three points on the packed columnar catalyst bed. The reactor was placed on a heater, and the upper opening of the reactor was connected to a gas supply pipe equipped with a mass flow meter (MFC), and the lower opening was connected to an exhaust pipe.

[0065] The powder catalyst molded body according to Comparative Example 1 was packed into the reaction vessel of the reactor. The volume of the internal space of the reaction vessel was 19.2 cm 3 Since the amount of powder catalyst held by the glass wool was 0.7 g, the amount of powder catalyst held by the glass wool was 0.036 g / cm 3 The rest of the reactor was prepared in the same manner as in Example 1 above.

[0066] <Carbon dioxide reduction reaction with hydrogen> For each of Example 1 and Comparative Example 1, 2 10mL / min and H 2 While flowing the mixed gas at 40 mL / min into the reactor, the heater was driven to heat the powder catalyst compact to a predetermined temperature. The temperature of the powder catalyst compact was measured with a thermocouple, and when the value of each thermocouple became almost constant, the gas that had passed through the powder catalyst compact was sampled.

[0067] After sampling, change the heater temperature setting and add CO to the reaction tank in the same manner as above. 2 / H 2 A mixed gas was supplied, and the gas after passing through the powder catalyst molded body was sampled. The heater temperatures in Example 1 were set to 160° C., 180° C., 200° C., and 220° C. The heater temperatures in Comparative Example 1 were set to 160° C., 180° C., 200° C., 220° C., and 240° C.

[0068] The sampled gas is analyzed by gas chromatography, and the CH 4 (Product) and CO 2 The reaction conversion was calculated from the peak of (unreacted raw material). When comparing the results with those of other conditions in a graph, the conversion obtained was expressed as a function of the maximum catalyst temperature measured.

[0069] <Result> 8 is a graph showing the catalytic performance of the powder catalyst molded bodies according to Example 1 and Comparative Example 1. The horizontal axis shows the measurement temperature, and the vertical axis shows CH 4 The measurement temperatures in Example 1 were 163°C, 183°C, 203°C, and 222°C. The measurement temperatures in Comparative Example 1 were 155°C, 174°C, 190°C, 210°C, and 234°C. As shown in FIG. 8, the CH 4 The yield of CH in Comparative Example 1 was 40.4% when the reaction temperature was 163°C, and the yield increased as the reaction temperature was increased, reaching 72.3% at 183°C, 94.5% at 202°C, and 99.4% at 222°C. 4The yield was 31.3% at 155°C, and increased as the reaction temperature was raised, reaching 90.5% at 210°C and 97.2% at 234°C. The approximation curves of Example 1 and Comparative Example 1 shown in Fig. 8 are similar. Therefore, it is found that the catalytic performance of the powder catalyst molding according to Example 1 is equivalent to that of Comparative Example 1 at each reaction temperature, and the powder catalyst molding according to the method of Example 1 maintains its catalytic function.

[0070] [Example 2] A powder catalyst molded body in which a powder catalyst was supported on an alumina plate was produced in the same manner as in Example 1. The amount of powder catalyst supported by the powder catalyst molded body obtained in Example 2 was 70 mg. Thus, the dimensions of the powder catalyst molded body were 1.9 cm x 1.2 cm x 0.2 cm = 0.456 cm. 3 70 mg of powder catalyst could be supported on the alumina plate. That is, 153.5 mg / cm 3 We were able to achieve a retention amount of .

[0071] Experimental example 2: Changing the shape of the catalyst layer [Example 3] A reactor having a flat plate structure was fabricated by arranging 3 pieces vertically and 4 pieces horizontally (total of 12 pieces) of the powder catalyst molded bodies according to Example 1 on a flat surface. FIG. 9 is a photograph of the reactor having a flat plate structure according to Example 3.

[0072] In the same manner as in Example 1, the reactor according to Example 3 was used to produce CO 2 / H 2 A mixed gas was supplied, and the gas after passing through the catalyst layer was sampled.

[0073] 10 is a graph showing the catalytic performance of the powder catalyst molded bodies according to Examples 1 and 3. As shown in FIG. 10, Example 3 has a higher CH 4 Although the yield of the catalyst powder is slightly lower than that of the catalyst powder in Example 1, the yield is almost the same as that of the catalyst powder in Example 3. Therefore, it was found that the catalytic performance was maintained whether the powder catalyst molded bodies were stacked (Example 1) or arranged on a flat surface (Example 3).

[0074] Experimental Example 3: Changing the concentration of water-alcohol mixture [Example 4] A powder catalyst molded body according to Example 4 was produced in the same manner as in Example 1, except that the mixing ratio of the water-IPA mixture was 50% water:50% IPA by volume.

[0075] [Example 5] A powder catalyst molded body according to Example 5 was produced in the same manner as in Example 4, except that the mixing ratio of the water-IPA mixture was 80% water:20% IPA.

[0076] [Example 6] A powder catalyst molded body according to Example 6 was produced in the same manner as in Example 4, except that the mixing ratio of the water-IPA mixture was 20% water:80% IPA.

[0077] [Comparative Example 2] A powder catalyst molding according to Comparative Example 2 was produced in the same manner as in Example 4, except that the mixing ratio of the water-IPA mixture was 100% water:0% IPA.

[0078] [Comparative Example 3] A powder catalyst molding according to Comparative Example 3 was produced in the same manner as in Example 4, except that the mixing ratio of the water-IPA mixture was 0% water:100% IPA.

[0079] [Evaluation of moldability] The moldability of the powder catalyst molded bodies according to Examples 4 to 6 and Comparative Examples 2 and 3 was evaluated as follows.

[0080] <Workability during slurry impregnation into base material> Example 4: The work was carried out without any problems during the impregnation of the slurry. Example 5: The work was carried out without any problems during the impregnation of the slurry. Example 6: Although the work could be performed without any problem during the impregnation of the slurry, the workability was slightly inferior to Examples 4 and 5. Comparative Example 2: Almost no slurry (water dispersion of powder catalyst) adhered to the alumina plate. Comparative Example 3: The slurry (IPA dispersion of powder catalyst) dried too quickly to be worked with.

[0081] <Fixed state of powder catalyst in molded body> Example 4: The powder catalyst was fixed to the entire surface of the alumina plate, and no detachment or powdering of the powder catalyst was observed. Example 5: The powder catalyst was fixed to the entire surface of the alumina plate, and no detachment or powdering of the powder catalyst was observed. Example 6: The powder catalyst was fixed to the entire surface of the alumina plate, and no detachment or powdering of the powder catalyst was observed. Comparative Example 2: The amount of immobilized powder catalyst was small. Comparative Example 3: The amount of immobilized powder catalyst was small.

[0082] <Fixed state of powder catalyst after reaction> Using the powder catalyst molded bodies of Examples 4 to 6, carbon dioxide was reduced with hydrogen in the same manner as in Example 1. Thereafter, the immobilization state of the powder catalyst was confirmed. Example 4: The powder catalyst was fixed to the entire surface of the alumina plate, and no detachment or powdering of the powder catalyst was observed. Example 5: The powder catalyst was fixed to the entire surface of the alumina plate, and no detachment or powdering of the powder catalyst was observed. Example 6: The powder catalyst was fixed to the entire surface of the alumina plate, and no detachment or powdering of the powder catalyst was observed.

[0083] Experimental Example 4: Use of binder and metal molding base material [Comparative Example 4] <Production of powder catalyst compact> A SUS porous body (MF-55, manufactured by Nagamine Manufacturing Co., Ltd.) was prepared as a porous molding base material. The material of the SUS porous body was SUS316L, the cell density was 55 PPI, the average pore diameter was 0.20 mm, and the average porosity was 86%.

[0084] The powder catalyst produced in Experimental Example 1 was mixed with an alumina-based adhesive as a binder to obtain a slurry. The slurry was applied to a porous SUS and dried at 120°C or less for 30 minutes to obtain a powder catalyst molding according to Comparative Example 4.

[0085] [Comparative Example 5] A powder catalyst molding according to Comparative Example 5 was obtained in the same manner as in Comparative Example 4, except that a titanium porous body (material: Ti) was used as the porous molding base material.

[0086] [Comparative Example 6] A powder catalyst molding according to Comparative Example 6 was obtained in the same manner as in Comparative Example 4, except that a copper porous body (material: Cu) was used as the porous molding base material.

[0087] [Evaluation of catalyst performance] In the same manner as in Example 1, a hydrogen reduction reaction of carbon dioxide was carried out using the powder catalyst molded bodies according to Comparative Examples 4 to 6, and the catalytic performance was evaluated. As a result, in all of Comparative Examples 4 to 6, 4 It was found that the yield of was low and almost no reaction occurred. This is thought to be because the binder covered the powder catalyst, reducing the exposed area of ​​the powder catalyst.

[0088] Experimental Example 5: Calcination of powder catalyst compact <Firing conditions> Each of the powder catalyst molded bodies of Examples 1 to 6 and Comparative Examples 2 to 6 was fired under the following four firing conditions, and four powder catalyst molded bodies each of Examples 1 to 6 and Comparative Examples 2 to 6 were produced and fired under the respective conditions. Condition 1...30℃, 8h Condition 2: 80℃, 1h Condition 3: 120℃, 30 minutes Condition 4: 150℃, 10 minutes

[0089] <Fixed state of powder catalyst after calcination> The powder catalyst molded body after calcination was fixed, and a load was applied with an air gun, and the fixed state of the powder catalyst was confirmed. In all of Examples 1 to 6, after calcination under conditions 1 to 4, the powder catalyst was fixed without temperature dependency. This shows that the fixed state of the powder catalyst does not change even when the powder catalyst molded body is calcined, and there is no problem even if calcination is performed. In addition, since the calcination was performed at a temperature lower than the use temperature of the Sabatier catalyst (about 220°C), it can be said that the catalytic performance is also maintained.

[0090] Experimental Example 6: Another method for forming powder catalysts [Comparative Example 7] TiO as a support for powder catalysts 2 The particles and water were mixed at a ratio of 1:10 to obtain a slurry, which was then molded into pellets (size: 5 mm) and dried at 80°C for 30 minutes.

[0091] A water-IPA mixture (volume ratio: water 25%:IPA 75%) and Ru-supported TiO 2 The powder catalyst prepared from the catalyst was mixed at a mixing ratio (weight ratio) of 10:1 to disperse the powder catalyst, and a slurry was obtained. The slurry was applied to the surface of the pellets, and dried at 80°C for 30 minutes. In this way, the powder catalyst pellets according to Comparative Example 7 were prepared.

[0092] [Comparative Example 8] TiO as a support for powder catalysts 2 Particles and Ru-supported TiO prepared in the same manner as in Experimental Example 1. 2 The powder catalyst prepared from the catalyst was mixed at a ratio of 25:75 to obtain a mixed powder. A water-IPA mixture (volume ratio of 25% water:75% IPA) and the above mixed powder were mixed at a mixing ratio (weight ratio) of 10:1 to obtain a slurry. The slurry was formed into pellets (size: 5 mm) and dried at 80°C. In this way, the powder catalyst pellets according to Comparative Example 8 were produced.

[0093] [Comparative Example 9] TiO 2 Powder catalyst pellets according to Comparative Example 9 were produced in the same manner as in Comparative Example 8, except that the mixing ratio of the particles and the powder catalyst was 75:25.

[0094] [Evaluation of moldability] When the pellets of the powder catalyst according to Comparative Example 7 were visually inspected, the powder catalyst was detached from the pellet surface after drying, making handling difficult. When the pellets of the powder catalyst according to Comparative Examples 8 and 9 were visually inspected, the pellets were crumbled after drying. Thus, the method of forming pellets and drying them as in Comparative Examples 7 to 9 does not provide excellent moldability of the powder catalyst, and causes clogging when filling a reactor with such molded bodies of the powder catalyst. [Explanation of symbols]

[0095] 10…Porous molding base material 20…Functional material molded body 100…Reactor 101...Reaction tank 102...Porous material

Claims

1. A method of dispersing only a catalyst for hydrogen reduction of carbon dioxide in a water-alcohol mixed liquid to obtain a dispersion; impregnating a porous ceramic body with the dispersion to obtain an impregnated body; and drying the impregnated body to obtain a catalyst shaped body for reducing carbon dioxide with hydrogen.

2. The catalyst for reducing carbon dioxide with hydrogen is 2. The method for producing a catalyst molded body for reducing carbon dioxide with hydrogen according to claim 1, wherein the catalyst has a structure in which catalytic metal nanoparticles and a metal oxide for suppressing grain growth of the catalytic metal nanoparticles are dispersed and supported on a support.

3. 2. The method for producing a catalyst molded body for reducing carbon dioxide with hydrogen according to claim 1, wherein the porosity of the porous ceramic is 10 to 90%.

4. The specific surface area of ​​the porous ceramic is 0.5 to 10 m ２ The method for producing a catalyst molded body for reducing carbon dioxide with hydrogen according to claim 1, wherein the molecular weight of the catalyst molded body is 1000 or more.

5. 2. The method for producing a catalyst molded body for reducing carbon dioxide with hydrogen according to claim 1, wherein a mixing ratio of the water-alcohol mixture and the catalyst for reducing carbon dioxide with hydrogen in the dispersion is 20:80 to 80:20 by weight.

6. 2. The method for producing a catalyst molded body for reducing carbon dioxide with hydrogen according to claim 1, wherein a mixing ratio of water to alcohol in the water-alcohol mixed liquid is 5:95 to 95:5 by volume.

7. 2. The method for producing a catalyst molded body for reducing carbon dioxide with hydrogen according to claim 1, wherein the porous ceramic has a shape of a plate, a disk, a rectangular parallelepiped, a cube, a sphere, a hemisphere, a pyramid, a cone, a cylinder, or a combination thereof.

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