Method for producing catalyst support and method for producing fibrous carbon nanostructures

Abstract

The present invention relates to a method for producing a catalyst support used to produce a fibrous carbon nanostructure. This production method comprises: a stirring step for stirring a particulate support by rotating a substantially cylindrical rotary drum about the center axis thereof; a spraying step for spraying a catalyst solution onto the particulate support in the rotary drum; and a drying step for drying the catalyst solution attached to the particulate support by introducing a dry gas from the outside of the rotary drum into the rotary drum. In addition, in this production method, at least a portion of a time period in which the stirring step is performed overlaps with at least a portion of a time period in which the spraying step is performed.

Description

[Technical Field]

[0001] This invention relates to a method for producing a catalyst support and a method for producing fibrous carbon nanostructures. [Background technology]

[0002] Fibrous carbon nanostructures, such as carbon nanotubes (hereinafter sometimes referred to as "CNTs"; see, for example, Non-Patent Document 1), are being applied to a wide range of uses because they possess excellent mechanical strength, sliding properties, flexibility, semiconducting and metallic conductivity, thermal conductivity, and high chemical stability. Therefore, in recent years, methods for efficiently and inexpensively manufacturing fibrous carbon nanostructures with such excellent properties have been investigated.

[0003] Here, methods for manufacturing carbon nanotubes have been reported, including arc discharge, laser evaporation, and chemical vapor deposition (CVD). Among these, the CVD method is a manufacturing method that has been extensively studied as a suitable method for the large-scale, continuous, and high-purity synthesis of single-walled carbon nanotubes with the above-mentioned properties (see, for example, Non-Patent Document 2).

[0004] For example, Patent Document 1 discloses a technique for synthesizing carbon nanotubes on a support substrate by flowing a raw material gas consisting of acetylene, carbon dioxide, and an inert gas at a predetermined partial pressure over the surface of a support substrate on which a catalyst containing Fe or the like is supported.

[0005] Furthermore, Patent Document 2 discloses a fluidized bed reaction method in which a catalyst layer is formed on the surface of a particulate carrier within a fluidized bed or kiln-type support tank, and the carbon nanofiber growth reaction is carried out using the particulate carrier with the catalyst layer formed on its surface. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] International Publication No. 2012 / 057229 [Patent Document 2] Japanese Patent Publication No. 2004-238261 [Non-patent literature]

[0007] [Non-Patent Document 1] S.Iijima, Nature 354, 56 (1991). [Non-Patent Document 2] Riichiro Saito and Hisanori Shinohara (eds.), "Fundamentals and Applications of Carbon Nanotubes," pp. 33-34, Baifukan, 2004. [Overview of the project] [Problems that the invention aims to solve]

[0008] Here, methods for producing a catalyst support, which is formed by forming a catalyst layer on the surface of a particulate carrier, include a dry method in which a catalyst raw material gas is blown onto the surface of the particulate carrier, and a wet method in which a catalyst solution is applied to the surface of the particulate carrier. However, the wet method is considered superior to the dry method in that it can form the catalyst layer more uniformly. However, conventional methods for producing catalyst supports have the problem that, as the size of the particulate support decreases, it becomes difficult to form a uniform catalyst layer, and carbon nanotubes cannot always be produced efficiently. Furthermore, among the wet methods, there is an immersion method in which particulate carriers are immersed in a catalyst solution. However, in this immersion method, liquid crosslinking can occur between the particulate carriers, causing them to stick together, and making it impossible to uniformly form a catalyst layer on the surface of the particulate carriers. Therefore, there is a need for a method for producing a catalyst support that can uniformly form a catalyst layer on the surface of a particulate support. [Means for solving the problem]

[0009] The inventors conducted thorough research to achieve the above objective. The inventors have discovered that by rotating a rotating drum containing particulate carriers to agitate and fluidize the particulate carriers, spraying a catalyst solution onto the fluidized particulate carriers while simultaneously introducing a drying gas into the rotating drum, and drying the catalyst solution adhering to the surface of the particulate carriers to form a catalyst coating, it is possible to suppress adhesion of the particulate carriers to the inner wall surface of the rotating drum and adhesion of the particulate carriers to each other, thereby uniformly forming a catalyst layer on the surface of the particulate carriers, and thus completed the present invention.

[0010] In other words, the present invention aims to advantageously solve the above problems, and the method for manufacturing a catalyst support of the present invention is a method for manufacturing a catalyst support used in manufacturing fibrous carbon nanostructures, comprising: a stirring step of stirring the particulate support by rotating a substantially cylindrical rotating drum containing particulate support inside around a central axis that makes an angle of 0° or more and less than 90° with respect to the horizontal direction; a spraying step of spraying a catalyst solution onto the particulate support inside the rotating drum; and a drying step of introducing a drying gas into the rotating drum from outside the rotating drum and bringing the drying gas into contact with the particulate support to which the catalyst solution was sprayed in the spraying step, thereby drying the catalyst solution, wherein at least a portion of the duration of the stirring step and at least a portion of the duration of the spraying step overlap. In this way, by rotating a rotating drum containing particulate carriers around a central axis that makes a predetermined angle with respect to the horizontal, the particulate carriers are agitated, a catalyst solution is sprayed onto the agitated particulate carriers, and the particulate carriers to which the catalyst solution has been sprayed are dried by introducing a drying gas into the rotating drum, thereby obtaining a catalyst support in which a catalyst layer is uniformly formed on the surface of the particulate carriers. According to this invention, by mechanically rotating a rotating drum, the particulate carrier can be made to flow up and down in the direction of gravity (vertical direction). For example, since it is not necessary to suspend the particulate carrier as in the conventional fluidized bed method, the particulate carrier can be used as the target material of this invention even when the particle size is large. Furthermore, in this invention, since the stirring step involving the rotation of the rotary drum and the drying step involving the inflow of drying gas into the rotary drum are implemented as independent steps, various conditions in each step can be adjusted separately. Therefore, it is possible to form the catalyst layer under more suitable conditions, and thus the catalyst layer can be formed more uniformly. Note that a catalyst layer may or may not be formed on the surface of the particulate carrier. That is, the obtained catalyst support may have a plurality of catalyst layers or may have only one catalyst layer. Also, in this specification, the term "substantially cylindrical" means not only a shape including at least a part of a cylindrical shape with a circular cross-section, but also a shape including at least a part of a polygonal prism shape, and further a shape including at least a part of a frustum of a cone shape or a frustum of a polygonal pyramid shape.

[0011] Here, in the method for producing the catalyst support of the present invention, it is preferable that the angle formed by the spraying direction of the catalyst solution and the inflow direction of the drying gas in the rotary drum is 0° or more and 45° or less. If the angle formed by the spraying direction of the catalyst solution and the inflow direction of the drying gas in the rotary drum is 0° or more and 45° or less, the catalyst solution can be efficiently sprayed onto the particulate carrier, and the particulate carrier onto which the catalyst solution has been sprayed can be efficiently dried.

[0012] Also, in the method for producing the catalyst support of the present invention, it is preferable that at least a part of the implementation period of the stirring step, at least a part of the implementation period of the spraying step, and at least a part of the implementation period of the drying step overlap with each other. By doing so, the throughput can be improved, and a catalyst support with a catalyst layer uniformly formed on the surface of the particulate carrier can be efficiently obtained.

[0013] Here, in the method for manufacturing the catalyst carrier of the present invention, in the drying step, it is preferable that the drying gas flows in while being temperature-adjusted to 0°C or higher and 200°C or lower. In the drying step, if the drying gas flows in while being temperature-adjusted to 0°C or higher and 200°C or lower, the particulate carrier sprayed with the catalyst solution can be efficiently dried, and a catalyst carrier with a more uniform catalyst layer formed on the surface of the particulate carrier can be obtained. In the drying step, when the drying gas flows in while being temperature-adjusted to 0°C or higher and 200°C or lower, the particulate carrier is in a state of being temperature-adjusted and fluidized. Therefore, even when the surface tension of the sprayed catalyst solution is high, the catalyst solution can be quickly dried, suppressing repelling, and a catalyst carrier with a more uniform catalyst layer formed on the surface of the particulate carrier can be obtained.

[0014] Here, in the method for manufacturing the catalyst carrier of the present invention, the axis may form an angle of 0° or more and 20° or less with respect to the horizontal direction. If the central axis forms an angle of 0° or more and 20° or less with respect to the horizontal direction, the particulate carrier in the rotating drum can be efficiently fluidized up and down in the gravitational direction (vertical direction).

[0015] Also, in the method for manufacturing the catalyst carrier of the present invention, in the drying step, in the peripheral wall portion which is the outer peripheral portion of the rotating drum, an inlet for flowing the drying gas from outside the rotating drum into the rotating drum and an outlet for discharging the drying gas from inside the rotating drum to outside the rotating drum are preferably formed. In the drying step, if an inlet and an outlet are formed in the peripheral wall portion of the rotating drum, the particulate carrier sprayed with the catalyst solution can be efficiently dried.

[0016] Also, in the method for manufacturing the catalyst carrier of the present invention, it is preferable that the inlet and the outlet are formed at positions facing each other with respect to the central axis. If the inlet and the outlet are formed at positions facing each other via the central axis, the particulate carrier sprayed with the catalyst solution can be dried more efficiently.

[0017] In the method for producing the catalyst support of the present invention, the central axis may be at an angle of more than 20° but less than 90° with respect to the horizontal direction. If the central axis is at an angle of more than 20° but less than 90° with respect to the horizontal direction, the particulate support housed inside the rotating drum can be efficiently stirred, and the spray area of ​​the catalyst solution and the contact area of ​​the dry gas can be increased.

[0018] Furthermore, in the method for manufacturing a catalyst support of the present invention, it is preferable that in the drying step, an inlet is formed on the front side of the rotating drum in the direction of the central axis to allow the drying gas to flow into the peripheral wall portion, and an outlet is formed on the rear side of the rotating drum in the direction of the central axis to allow the drying gas to be discharged from the peripheral wall portion of the rotating drum. If an inlet is formed at the front end of the rotating drum and an outlet is formed at the rear end of the rotating drum in the drying step, the particulate support to which the catalyst solution has been sprayed can be dried efficiently.

[0019] In the method for producing a catalyst support of the present invention, it is preferable that the inlet and / or outlet are formed in a mesh shape, and that the mesh-shaped outlet is structured to allow the drying gas to pass through but not the particulate support. If the inlet and / or outlet are formed in a mesh shape, and such a mesh-shaped outlet allows the drying gas to pass through but not the particulate support, the particulate support to which the catalyst solution has been sprayed can be dried more efficiently.

[0020] Furthermore, in the method for producing the catalyst support of the present invention, the particulate support has a particle density (apparent density) of 2.0 g / cm³. 3 Preferably, the particle density (apparent density) of the particulate carrier is 2.0 g / cm³. 3 If the above conditions are met, aggregation between particulate carriers by the catalyst solution can be suppressed, the fluidity of the particulate carriers can be improved, and the catalyst layer can be formed more uniformly on the surface of the particulate carriers. In this specification, "apparent density" refers to density based on the volume including the volume of closed pores inside the particulate carrier. Apparent density can be measured using a pycnometer.

[0021] Furthermore, in the method for producing the catalyst support of the present invention, it is preferable that the particulate support is composed of a metal oxide. If the particulate support is composed of a metal oxide, the heat resistance can be improved.

[0022] In the method for producing the catalyst support of the present invention, the metal oxide may be zirconium dioxide, aluminum oxide, or zircon. Using zirconium dioxide (zirconia), aluminum oxide, or zircon as the metal oxide can further improve heat resistance. In particular, oxides containing zirconium dioxide (zirconia) have high surface smoothness, which allows for the formation of a more uniform catalyst layer.

[0023] Furthermore, in the method for producing a catalyst support of the present invention, the catalyst solution may contain at least one metal from Ni, Fe, Co, and Mo. If the catalyst solution contains at least one metal from Ni, Fe, Co, and Mo, a catalyst support suitable for producing fibrous carbon nanostructures can be produced.

[0024] Furthermore, in the method for producing a catalyst support of the present invention, the particulate carrier may have a base layer and / or a catalyst layer on its surface. The catalyst layer may be a used catalyst layer, and in the present invention, used particulate carriers can also be reused. Furthermore, the method for producing the catalyst support of the present invention may further include a calcination step of calcining the particulate support at a temperature of 50°C to 900°C.

[0025] Furthermore, this invention aims to advantageously solve the above-mentioned problems, and the method for producing fibrous carbon nanostructures of the present invention is characterized by including a step of supplying a raw material gas to a catalyst support obtained by the method for producing catalyst support of the present invention to synthesize fibrous carbon nanostructures on the catalyst layer. In this way, by supplying a raw material gas to a catalyst support obtained by the method for producing catalyst support of the present invention to synthesize fibrous carbon nanostructures on the catalyst layer, fibrous carbon nanostructures such as carbon nanotubes can be synthesized with high efficiency and have excellent mass-productivity. [Effects of the Invention]

[0026] According to the present invention, it is possible to provide a method for producing a catalyst support that enables the uniform formation of a catalyst layer on the surface of a particulate support. Furthermore, according to the present invention, fibrous carbon nanostructures such as carbon nanotubes can be synthesized with high efficiency, and a method for producing fibrous carbon nanostructures with excellent mass productivity can be provided. [Brief explanation of the drawing]

[0027] [Figure 1A] This is a schematic cross-sectional view showing the schematic configuration of an example of a rotary drum type fluidizing apparatus used in the first embodiment of the method for manufacturing a catalyst support of the present invention. [Figure 1B] Figure 1A is a cross-sectional view along the central axis showing the schematic configuration of the rotating drum in the rotary drum type fluidization apparatus. [Figure 2] This figure (part 1) illustrates the case in which a catalyst support is manufactured using a rotary drum type fluidizer used in the first embodiment of the method for manufacturing a catalyst support of the present invention. [Figure 3] This is a diagram illustrating the case in which a catalyst support is manufactured using a rotary drum type fluidizing apparatus used in the first embodiment of the method for manufacturing a catalyst support of the present invention (part 2). [Figure 4] This is a diagram (part 3) illustrating the case in which a catalyst support is manufactured using a rotary drum type fluidizing apparatus used in the first embodiment of the method for manufacturing a catalyst support of the present invention. [Figure 5] This figure (part 4) illustrates the case in which a catalyst support is manufactured using a rotary drum type fluidizing apparatus used in the first embodiment of the method for manufacturing a catalyst support of the present invention. [Figure 6A] This is a schematic cross-sectional view showing the schematic configuration of an example of a rotary drum type fluidizing apparatus used in the second embodiment of the method for manufacturing a catalyst support of the present invention. [Figure 6B] Figure 6A is a perspective view showing the schematic configuration of the rotating drum in the rotary drum type fluidizing apparatus. [Figure 6C] Figure 6A is a schematic cross-sectional view showing a schematic configuration of a modified example of the rotating drum in the rotary drum type fluidizing apparatus shown. [Modes for carrying out the invention]

[0028] (Method for manufacturing catalyst support) The method for producing the catalyst support of the present invention will be described in detail below. Herein, the method for producing a catalyst support of the present invention can be used when producing a catalyst support used in the production of fibrous carbon nanostructures. Furthermore, the method for producing a fibrous carbon nanostructure of the present invention can be suitably used when producing a fibrous carbon nanostructure using a catalyst support obtained by the method for producing a catalyst support of the present invention. The method for producing a catalyst support of the present invention can be carried out, for example, by a rotary drum type fluidizing apparatus described later. Here, specific examples of rotary drum type fluidization apparatuses include, for example, the rotary drum type fluidization apparatus shown in Figure 1A (a rotary drum type fluidization apparatus used in the first embodiment of the method for manufacturing a catalyst support of the present invention), and the rotary drum type fluidization apparatus shown in Figure 6A (a rotary drum type fluidization apparatus used in the second embodiment of the method for manufacturing a catalyst support of the present invention).

[0029] <First Embodiment> First, a first embodiment of the method for producing the catalyst support of the present invention will be described. Figure 1A is a schematic cross-sectional view perpendicular to the central axis direction, showing the schematic configuration of an example of a rotary drum type fluidizing apparatus used in the first embodiment of the catalyst support manufacturing method of the present invention, and Figure 1B is a cross-sectional view in the direction of the central axis direction, showing the schematic configuration of the rotary drum in the rotary drum type fluidizing apparatus shown in Figure 1A. As shown in Figures 1A and 1B, the rotary drum type fluidizer 100 comprises a housing 30, a rotary drum 20 housed inside the housing 30 so as to be rotatable around a central axis X in a substantially horizontal direction, a rotary drive mechanism 23g for rotating the rotary drum 20 around the central axis X, a spray device 40 as a spraying unit for spraying a catalyst solution C onto particulate carriers A housed inside the rotary drum 20, and a drying gas supply device (not shown) for supplying drying gas G to the housing 30. Here, in this specification, "substantially horizontal direction" means that the smaller angle between the horizontal direction and the central axis X is 0° or more and 20° or less. In this embodiment, the left side of the rotary drum 20 in Figure 1B (the side with the front end opening 23d) is the front side, and the right side of the rotary drive mechanism 23g in Figure 1B is the rear side.

[0030] The housing 30 has an air inlet 30a for supplying drying gas G into the housing 30 and an exhaust port 30b for exhausting the drying gas G supplied into the housing 30 from the inside of the housing 30. Furthermore, a gap 30c is provided between the housing 30 and the rotating drum 20, and the partition plate 24, which will be described later, is configured to be movable within this gap 30c. Here, the air inlet 30a and the exhaust port 30b are located opposite each other with respect to the central axis X of the rotating drum 20.

[0031] Furthermore, as shown in Figure 1A, the drying gas G inside the rotating drum 20 is configured to flow along the inflow direction H. Here, when the spraying direction of the catalyst solution C is the arrangement direction I of the spray device 40, the arrangement direction I forms an angle θ of 0° to 45° with respect to the inflow direction H of the drying gas G inside the rotating drum 20.

[0032] The rotating drum 20 comprises a drum body 23 and a plurality of partition plates 24. As shown in Figure 1B, the drum body 23 comprises a cylindrical drum portion 23i and a tapered portion 23c provided on the rear side of the drum portion 23i and formed to decrease in diameter toward the rear. The drum portion 23i comprises a cylindrical peripheral wall portion 23a having a polygonal cross-section (in this embodiment, a dodecagonal cross-section), a ring-shaped front end ring portion 23e provided on the front side of the peripheral wall portion 23a, and a rear end ring portion 23h provided on the rear side of the peripheral wall portion 23a and having the same shape as the front end ring portion 23e.

[0033] A circular front end opening 23d is formed in the front end ring portion 23e, and through this front end opening 23d, it is possible to supply particulate carrier A into the rotating drum 20 and discharge particulate carrier A or the manufactured catalyst support from the rotating drum 20.

[0034] The tapered section 23c is formed with a hollow interior and communicates with the internal space of the drum section 23i, and is designed to accommodate the particulate carrier A introduced through the front end opening 23d. A rotary drive mechanism 23g, which rotates the rotating drum 20, is connected to the rear side of the tapered section 23c via a connecting section 23f.

[0035] The peripheral wall portion 23a has a ventilation section that connects the internal space of the rotating drum 20 with the gap portion 30c, which is the outside of the rotating drum 20. This ventilation section can be formed in the shape of a mesh, for example, with multiple holes of a size that prevents the particulate carrier from passing through but allows the drying gas to pass through.

[0036] Multiple partition plates 24 are arranged at predetermined intervals along the outer circumference of the peripheral wall portion 23a, between the front end ring portion 23e and the rear end ring portion 23h. Each partition plate 24 has approximately the same dimensions as the dimension in the direction of the central axis X of the peripheral wall portion 23a and is arranged on the outer circumference of the peripheral wall portion 23a in a direction parallel to the central axis X of the rotating drum 20. The partition plates 24 are erected radially from each vertex of the polygon (12-sided in Figure 1A) of the peripheral wall portion 23a toward the outer circumference. The partition plates 24 slide along the inner circumferential surface 30d of the housing 30 when the rotating drum 20 rotates.

[0037] Multiple communication spaces are formed on the outer circumference of the peripheral wall portion 23a, each partitioned by a front end ring portion 23e and a plurality of partition plates 24 provided at the vertices of the polygon. Each communication space is open on the outward side (the side facing the peripheral wall portion 23a). Therefore, multiple communication spaces are formed on the outer circumference of the peripheral wall portion 23a, corresponding to the number of sides of the polygon. In this embodiment, since the cross-sectional shape of the peripheral wall portion 23a is a dodecagon, 12 of the aforementioned communication spaces are formed. The opening of each communication space is formed to a size similar to the air intake port 30a formed in the housing 30. Dry gas G supplied from the air intake port 30a is supplied to each communication space, and the partition plates 24 prevent it from flowing out into the gap portion 30c, thus ensuring that it is reliably supplied into the rotating drum 20. Furthermore, since the openings of each communication space are formed to be approximately the same size as the exhaust ports 30b formed in the housing 30, the drying gas G inside the rotating drum 20 can be reliably discharged to the outside of the housing 30 through the exhaust ports 30b via each communication space.

[0038] Furthermore, in the drying process described later, the ventilation section in the peripheral wall 23a located opposite the air intake port 30a functions as an inlet 23ab for introducing drying gas G into the rotating drum 20, and the ventilation section located opposite the exhaust port 30b functions as an outlet 23ac for discharging drying gas from the rotating drum 20. In other words, in one example, the mesh-like ventilation section in the peripheral wall 23a forms an inlet 23ab when it moves to a position corresponding to the air intake port 30a as the rotating drum 20 rotates during the drying process, and forms an outlet 23ac when it moves to a position corresponding to the exhaust port 30b. The inlet 23ab is located above the spray device 40 in the direction of gravity (vertical direction) relative to the surface S of the layer of particulate carrier A (particulate carrier layer) when the rotating drum 20 is rotating, and the outlet 23ac is located below the spray device 40 in the direction of gravity (vertical direction) relative to the surface S of the layer of particulate carrier A (particulate carrier layer) when the rotating drum 20 is rotating. Here, it is preferable that the length of the perpendicular from the inlet 23ab to the surface S of the layer made of particulate carrier A (particulate carrier layer) during the rotation of the rotating drum 20, La (not shown), and the length of the perpendicular from the outlet 23ac to the surface S of the layer made of particulate carrier A (particulate carrier layer) during the rotation of the rotating drum 20, Lb (not shown), satisfy the relationship La > Lb, for example, as shown in Figure 1A.

[0039] The operation of the rotary drum type fluidizer 100 will be described below. First, particulate carrier A is introduced into the rotating drum 20 through a front end opening 23d provided at the front end 23b of the rotating drum 20. Next, the rotating drum 20 into which the particulate carrier A has been introduced rotates around the central axis X by the operation of the rotation drive mechanism 23g. As the rotating drum 20 rotates, the particulate carrier A contained within the rotating drum 20 is swept upward in the direction of gravity (vertical direction), and then flows downward in the direction of gravity (vertical direction) due to the gravitational action of its own weight. Thus, the particulate carrier A can be efficiently moved up and down in the direction of gravity (vertical direction), and consequently, the particulate carrier A can be efficiently agitated.

[0040] Next, catalyst solution C is sprayed from the spray device 40 onto the particulate carrier A flowing in the rotating drum 20, and drying gas G is passed through the air inlet 30a, the inlet 23ab, the particulate carrier A housed inside the rotating drum 20, the outlet 23ac, and the exhaust port 30b in that order, thereby drying the surface of the particulate carrier A to which the catalyst solution C has adhered, and obtaining a particulate carrier A with a catalyst coating film formed thereon. Furthermore, the drying gas G supplied from the drying gas supply device to the housing 30 and reaching the air inlet 30a collides with the partition plate 24a (Figure 1A), which moves in approximately the opposite direction to the inflow direction of the drying gas G due to the rotation of the rotating drum 20. As a result, the drying gas G is prevented from passing through the gap 30c of the housing 30 without flowing into the interior of the rotating drum 20, and almost the entire amount of drying gas G supplied to the air inlet 30a can flow into the interior of the rotating drum 20. Furthermore, the opening area of ​​the exhaust port 30b is designed to be smaller than the surface area S of the layer formed by the particulate carrier A inside the rotating drum 20. This effectively prevents the dry gas G from passing through the gap 30c without coming into contact with the particulate carrier A. In this way, almost the entire amount of dry gas G supplied to the air intake port 30a can pass through the air intake port 30a, the inlet 23ab, the particulate carrier A housed inside the rotating drum 20, the outlet 23ac, and the exhaust port 30b in that order.

[0041] In the rotary drum type fluidizer 100 used in the first embodiment of the catalyst support manufacturing method of the present invention, the rotational speed of the rotary drum 20 varies depending on the diameter of the apparatus, but is preferably 1 rpm or more, more preferably 3 rpm or more, particularly preferably 5 rpm or more, preferably 100 rpm or less, more preferably 50 rpm or less, and particularly preferably 30 rpm or less. If the rotation speed of the rotating drum 20 is 1 rpm or more, a sufficient stirring effect can be obtained, and if it is 100 rpm or less, the particulate carrier A can be prevented from remaining in close contact with the inner wall surface of the peripheral wall portion 23a of the rotating drum 20 due to centrifugal force.

[0042] In the rotary drum type fluidizer 100 used in the first embodiment of the catalyst support manufacturing method of the present invention, as shown in Figure 1A, it is preferable that both the inflow direction H of the drying gas G within the rotary drum 20 and the arrangement direction I of the spray device 40, which serves as the spraying direction for the catalyst solution C, are substantially perpendicular to the surface S of the layer of particulate carrier A (particulate carrier layer) contained within the rotary drum 20 during rotation. In this way, if both the inflow direction H and the arrangement direction I are substantially perpendicular to the surface S of the layer of particulate carrier A (particulate carrier layer) contained within the rotary drum 20 during rotation, the catalyst solution C can be efficiently sprayed onto the particulate carrier A, and the particulate carrier A to which the catalyst solution C has been sprayed can be efficiently dried.

[0043] In the rotary drum type fluidizer 100 used in the first embodiment of the catalyst support manufacturing method of the present invention, if the spray device 40, which serves as the spraying unit, is equipped with a constant flow rate pump, the catalyst solution C can be delivered quantitatively, and consequently, the flow rate can be easily controlled. Furthermore, if the spray device 40, which serves as the spraying unit, is equipped with an automatic spray gun, a fine and uniform mist can be sprayed, and consequently, a coating with a low aggregate formation rate, uniform particle size, and fineness can be achieved. The spray device 40, which serves as the spraying unit, is not particularly limited and may, for example, be a two-fluid nozzle or may have a mist generator such as an ultrasonic atomizer. The spray device 40, which serves as the spraying unit, is preferably positioned approximately perpendicular (90 degrees ± 30 degrees) to the surface S of the layer made of particulate carrier A (particulate carrier layer) during rotation, and it is preferable that the distance from the surface S of the layer made of particulate carrier A (particulate carrier layer) during rotation is 30 mm or more and 1000 mm or less.

[0044] The catalyst support produced by the first embodiment of the method for producing the catalyst support of the present invention will be described below. <<Catalyst support>> The catalyst support produced by the method for producing a catalyst support of the present invention comprises a particulate carrier and a catalyst layer formed on the outermost surface of the particulate carrier. That is, the catalyst support is produced by the method for producing a catalyst support of the present invention and only needs to have a catalyst formed on its outermost surface; for example, it may have only one catalyst layer or it may have multiple catalyst layers. Here, the catalyst support acts as an intermediary, promoter, and optimizer of the synthesis and growth of fibrous carbon nanostructures within the reaction field. The catalyst support is not particularly limited in its nature, but plays a role in taking up carbon raw materials from the supplied raw material gas on its surface and synthesizing fibrous carbon nanostructures such as carbon nanotubes. More specifically, for example, if the catalyst has a fine particulate shape, each catalyst particle continuously generates carbon while forming a tubular structure or other structure with a diameter corresponding to the size of the catalyst particle, thereby synthesizing and growing fibrous carbon nanostructures. The catalyst support is usually used after reducing the catalyst by contact with a high-temperature reducing gas (e.g., hydrogen gas, ammonia, water vapor, and mixtures thereof).

[0045] [Particulate carrier] The particulate carrier has a particle shape made of any material and forms a matrix structure on which a catalyst is attached, fixed, film-formed, or formed on the surface of the carrier to support it. In this way, if a particulate carrier is used, the catalyst support body manufactured using the particulate carrier will also be particulate. The term "particulate" means that the material is roughly shaped like a particle, and it is preferable that the aspect ratio is 10 or less. When the aspect ratio of the particulate carrier is 10 or less, the catalyst solution described later can be sprayed uniformly. In this invention, the "aspect ratio of the particulate carrier" can be determined by measuring the short and long axes of 100 randomly selected particulate carriers using a transmission electron microscope. Furthermore, the structure of the particulate carrier may consist of the particulate carrier alone, or it may be a particulate carrier with an underlayment, wherein an arbitrary underlayment is provided on the surface of the particulate carrier to properly support the catalyst. The underlayment can be made of any material, and for example, one or more layers can be formed on the surface of the particulate carrier. From the viewpoint of properly supporting the catalyst on the particulate carrier and effectively utilizing the catalyst carrier, it is preferable that the particulate carrier is a particulate carrier with an underlayment. The composition of the underlayer is not particularly limited and can be appropriately selected depending on the type of particulate carrier and the type of catalyst described later. The underlayer can be formed from, for example, ceramic materials such as alumina, titania, titanium nitride, and silicon oxide. The thickness of the underlayer can also be appropriately adjusted depending on the desired amount of catalyst supported. The underlayer can be formed on the surface of the particulate carrier, for example, by using a solution for forming the ceramic material instead of the catalyst solution and carrying out the spraying, drying, and firing processes described later. Furthermore, the particulate carrier may have a catalyst layer on its surface. The catalyst layer may be a used one, in which case the used particulate carrier can be reused in the present invention.

[0046] The particle density (apparent density) of the particulate carrier is 2.0 g / cm³. 3 Preferably, it should be 3.5 g / cm³ or more. 3 It is more preferable that the value be greater than or equal to 9.0 g / cm³. 3 Preferably, it is 6.0 g / cm³. 3 The following is more preferable: When the particle density (apparent density) of the particulate carrier is within the above range, aggregation between particulate carriers by the catalyst solution can be suppressed, the fluidity of the particulate carrier can be improved, and the catalyst layer can be formed more uniformly on the surface of the particulate carrier.

[0047] The material of the particulate carrier is not particularly limited, but it is preferably a metal oxide, more preferably a metal oxide containing at least one element selected from the group consisting of magnesium (Mg), aluminum (Al), silicon (Si), zirconium (Zr), and molybdenum (Mo), and even more preferably a metal oxide such as zirconium dioxide (zirconia), aluminum oxide, or zircon. The heat resistance can be improved by making the particulate carrier a metal oxide. Furthermore, the heat resistance can be further improved by using zirconium dioxide (zirconia), aluminum oxide, or zircon as the metal oxide.

[0048] The particle size (diameter) of the particulate carrier is not particularly limited, but it is preferably 50 μm or more and 10 mm or less. If the diameter of the particulate carrier is 50 μm or more, the separation of the particulate carrier and CNTs after CNT synthesis can be easily performed, and if it is 10 mm or less, the total surface area of ​​the particles in the same volume is increased, which can increase the production efficiency of CNTs. Note that the "particle size (diameter)" of the particulate carrier refers to the volume-average particle size D50. The volume-average particle size D50 represents the particle size at which the cumulative volume calculated from the smallest diameter side in the particle size distribution (volume-based) measured for the particulate carrier by laser diffraction method becomes 50%. Furthermore, in the method for manufacturing catalyst carriers of the present invention, since it is not necessary to suspend the particulate carrier as in the conventional fluidized bed method, for example, particulate carriers with larger particle sizes can be used. This makes it possible to increase the mesh opening in the ventilation section provided to prevent the catalyst carrier from falling off the rotating drum, thereby reducing the pressure loss in the ventilation section.

[0049] The porosity of the particulate carrier is preferably 10% or less. A porosity of 10% or less allows for the formation of a more uniform catalyst layer.

[0050] 〔catalyst〕 The catalyst is supported on the surface of the particulate carrier described above. The catalyst may also be directly supported on the surface of the particulate carrier as a catalyst layer to form a catalyst support, or it may be indirectly supported on the surface of the particulate carrier via the base layer or the like to form a catalyst support (for example, from the inside out: particulate carrier / base layer / catalyst layer). Furthermore, for example, the base layer and / or catalyst layer may be provided in any number of layers. The catalyst is typically located on the outermost surface of the catalyst support and promotes the synthesis of fibrous carbon nanostructures.

[0051] The following describes each step of the first embodiment of the method for producing the catalyst support of the present invention. A first embodiment of the method for manufacturing a catalyst support of the present invention includes the steps of: stirring the particulate support A by rotating a substantially cylindrical rotating drum 20 containing the particulate support A around a central axis X (stirring step); spraying a catalyst solution C onto the particulate support A in the rotating drum (spraying step); and introducing a drying gas G into the rotating drum 20 from outside the rotating drum 20 and bringing the drying gas G into contact with the particulate support A to which the catalyst solution C was sprayed in the spraying step to dry the catalyst solution C (drying step). Optionally, the method may further include a step of calcining the particulate support A at a temperature of 50°C to 900°C after the drying step (calcination step). In this embodiment, at least a portion of the duration of the stirring step and at least a portion of the duration of the spraying step overlap.

[0052] <<Stirring process>> In the stirring process, a rotating drum 20 containing particulate carrier A is rotated around a central axis X. In this way, by rotating the rotating drum 20 around the central axis X, the particulate carrier A contained inside the rotating drum 20 is swept upward in the direction of gravity (vertical direction) as the rotating drum 20 rotates, and then flows downward in the direction of gravity (vertical direction) due to the gravitational effect of its own weight, so that the particulate carrier A can be efficiently stirred.

[0053] Furthermore, there are no particular restrictions on the temperature during stirring, and it can be appropriately selected depending on the type of particulate carrier A, the composition of the catalyst solution C described later, etc.

[0054] <<Spraying process>> In the spraying process, the catalyst solution is sprayed onto the particulate carrier inside the rotating drum. As described above, in this embodiment, at least a portion of the duration of the stirring process and at least a portion of the duration of the spraying process overlap, so the spraying process includes a period during which the catalyst solution C is sprayed onto the stirred particulate carrier A. This allows for the uniform formation of a coating film of catalyst solution C on the surface of the particulate carrier A. There are no particular restrictions on the method of spraying the catalyst solution C onto the particulate carrier A. For example, spraying from a spray device 40 (spraying means) such as a spray gun or spray nozzle is preferred. There are no particular restrictions on the conditions for spraying the catalyst solution C onto the particulate support A; known conditions can be used, and the spray volume, the size of the mist particles, and the spraying time can be appropriately selected. When using a spray gun or the like for the spraying, the spray air pressure is preferably, for example, 0.1 MPa to 0.5 MPa. When spraying two or more catalyst solutions C, the mixture of the two or more catalyst solutions C may be sprayed from a single spray device 40 (spraying means), or it may be sprayed using separate spray devices 40 (spraying means), but it is preferable to spray using separate spray devices 40 (spraying means).

[0055] [Catalyst solution] The catalyst solution C preferably contains at least one metal, such as nickel (Ni), iron (Fe), cobalt (Co), and molybdenum (Mo). By containing at least one metal, the catalyst solution can function as a catalyst for CNT synthesis. Specific examples of catalyst components contained in the catalyst solution include, for example, iron acetate, ferrocene, iron acetylacetonate, and cobalt acetate. Various organic solvents such as alcohols, glycols, ketones, ethers, esters, and hydrocarbons can be used as the solvent in catalyst solution C, but the use of alcohols is preferred. These organic solvents may be used individually or in mixtures of two or more. Methanol, ethanol, and isopropyl alcohol are preferred as alcohols in terms of handling and storage stability. Catalyst solution C may also contain water. Catalyst solution C may contain both the solvent and water, or only one of them. In addition, it is preferable that the catalyst components in catalyst solution C are soluble in water and / or a solvent. There are no particular restrictions on the solid content concentration of catalyst solution C, but it is preferably 20% by mass or less, and more preferably 10% by mass or less. A solid content concentration of 20% by mass or less in catalyst solution C ensures a stable coating film and a catalyst support with a uniformly formed catalyst layer on the surface of the particulate carrier. This allows for highly efficient synthesis of fibrous carbon nanostructures such as carbon nanotubes, resulting in excellent mass productivity. Furthermore, catalyst solution C may also contain components of the aforementioned underlayer.

[0056] <<Drying process>> In the drying process, a uniform catalyst coating can be formed on the surface of the particulate carrier A by drying the particulate carrier A to which the catalyst solution C has been sprayed. Specifically, as described above, drying gas G is introduced into the rotating drum 20 from outside the drum 20, and the drying gas G is brought into contact with the particulate carrier A to which the catalyst solution C has been sprayed in the spraying process, thereby drying the catalyst solution C adhering to the surface of the particulate carrier A and forming a catalyst coating. The particulate carrier A to which the catalyst coating has been formed can be used as a catalyst carrier as is, but depending on the composition of the catalyst solution C, a firing process described later may be performed on the particulate carrier A to which the catalyst coating has been formed after the drying process if necessary. Here, the catalyst coating forms a catalyst layer.

[0057] The drying gas G used in the drying process is not particularly limited and may include, for example, compressed air or nitrogen. In this specification, "drying gas" means a gas used to dry a particulate carrier on which a catalyst solution has been sprayed. Therefore, the "drying gas" itself may have any attributes. For example, the dew point of the "drying gas" is not particularly limited. Furthermore, there are no particular restrictions on the temperature of the drying gas G, but it is preferably 0°C or higher, more preferably 20°C or higher, even more preferably 25°C or higher, preferably 200°C or lower, and more preferably 100°C or lower. When the drying gas G is introduced in the drying process while its temperature is adjusted to 0°C to 200°C or lower, the particulate carrier A is heated and fluidized. As a result, even if the surface tension of the sprayed catalyst solution C is high, the catalyst solution C is quickly dried to suppress repulsion, and a more uniform catalyst coating is formed on the surface of the particulate carrier A. There are no particular restrictions on the amount of dry gas supplied, but it is preferably 50 L / min or more, more preferably 100 L / min or more, and preferably 10,000 L / min or less. If the drying gas supply rate is 50 L / min or more, a sufficient drying effect can be obtained. If it is 10,000 L / min or less, the scattering of particulate carrier A by the drying gas G can be suppressed, and the spray droplets can be prevented from drying before they adhere to the particulate carrier A.

[0058] There are no particular restrictions on the atmospheric concentration (solvent concentration) inside the rotating drum 20 during the drying process, but it is preferably 2% by volume or less, and more preferably 1% by volume or less. By keeping the atmospheric concentration (solvent concentration) inside the rotating drum 20 below the above upper limit, drying can be stabilized.

[0059] <<Firing Process>> In the firing process, the particulate carrier A that has undergone the drying process may be fired at a temperature of 50°C to 900°C.

[0060] Furthermore, the calcination may be performed using a muffle furnace, fluidized bed, or rotary kiln after removing the particulate carrier A, on which a catalyst coating has been formed on its surface, from the rotating drum 20, or it may be performed inside the rotating drum 20 without removing it. It is preferable to perform the calcination in an oxygen atmosphere. The calcination temperature is preferably 300°C or higher. The calcination time is preferably 5 minutes to 60 minutes, and more preferably 5 minutes to 40 minutes. For example, a coating containing aluminum needs to be calcined at 300°C or higher. Also, for example, a coating containing an iron catalyst needs to be calcined at 80°C or higher.

[0061] The thickness of the catalyst layer is typically in the range of 0.1 nm to 100 nm. Preferably, the thickness of the catalyst layer containing the components of the underlayer is 10 nm to 100 nm, and preferably the thickness of the catalyst layer not containing the components of the underlayer is 0.1 nm to 10 nm.

[0062] Furthermore, in the first embodiment of the method for producing a catalyst support of the present invention, it is preferable that at least a portion of the duration of the stirring step, at least a portion of the duration of the spraying step, and at least a portion of the duration of the drying step overlap. This improves throughput and allows for efficient production of a catalyst support in which a catalyst layer is uniformly formed on the surface of the particulate carrier. The start timing of each step is not particularly limited; the stirring step may be started first, followed by the spraying step and the drying step simultaneously or sequentially; all three steps may be started simultaneously; or the spraying step may be started first, followed by the stirring step and the drying step simultaneously or sequentially. Similarly, the end timing of each step is not particularly limited; for example, the spraying step may be finished before the other steps, followed by the stirring step and the drying step simultaneously or sequentially; or all steps may be finished simultaneously.

[0063] Furthermore, in the first embodiment of the method for manufacturing a catalyst support of the present invention, droplets of catalyst solution C sprayed from the spray device 40 (spraying means) adhere to the particulate carrier A, which is the target of spraying, before drying (the solvent in the droplets evaporates). Subsequently, the adhered catalyst solution C dries (the solvent in the adhered catalyst solution C evaporates), forming a coating film, thereby enabling the uniform formation of a catalyst layer on the surface of the particulate carrier A. The drying rate of the catalyst solution C can be adjusted, for example, by adjusting (i) the volatility of the solvent in the catalyst solution C, (ii) the size of the droplets, (iii) the spraying speed of the catalyst solution C, (iv) the amount of drying gas G supplied, and (v) the temperature of the drying gas G.

[0064] The following is a specific example of the procedure for manufacturing a catalyst support using the first embodiment of the method for manufacturing a catalyst support of the present invention. However, the procedure is not limited to the following specific example, and calcination may not be performed, and a single-layer structure may be used. Figure 2 illustrates the process of manufacturing a catalyst support having a three-layer structure consisting of a particulate carrier, a base layer (aluminum oxide layer), and an iron catalyst layer, using a rotary drum type fluidizing apparatus used in the first embodiment of the catalyst support manufacturing method of the present invention. First, a particulate carrier 1 is prepared (Figure 2(a)). Next, the prepared particulate carrier 1 (particulate carrier A) is introduced into the rotating drum 20 through the front opening 23d and stirred (stirring step). An aluminum-containing solution is sprayed using a spray device 40 to form a base layer (spraying step), and then dried using drying gas G that flows into the rotating drum 20 through the air inlet 30a and inlet 23ab (drying step) to form an aluminum-containing coating 2, thereby producing a coated particulate carrier 3 with a coating 2 on its surface (Figure 2(b)). Next, the coated particulate carrier 3 with a coating 2 on its surface is fired (firing step) to produce a coated particulate carrier 5 with a base layer 4 made of aluminum oxide (Al2O3) formed on the surface of the particulate carrier 1 (Figure 2(c)). Next, the particulate carrier 5 with a base layer is introduced into the rotating drum 20 through the front opening 23d and stirred (stirring step), and an iron-containing solution as catalyst solution C is sprayed using a spray device 40 (spraying step). The particulate carrier 7 is then dried using a drying gas G that flows into the rotating drum 20 through the air inlet 30a and the inlet 23ab (drying step) to obtain a catalyst carrier consisting of particulate carrier 7 on which a coating film 6 containing an iron catalyst is formed on the surface (Figure 2(d)).

[0065] Figure 3 illustrates the process of manufacturing a catalyst support having a particulate carrier / underlayer (aluminum oxide layer) / iron oxide layer (3-layer structure) using a rotary drum type fluidizing apparatus used in the first embodiment of the catalyst support manufacturing method of the present invention. First, a particulate carrier 1 is prepared (Figure 3(a)). Next, the prepared particulate carrier 1 (particulate carrier A) is introduced into the rotating drum 20 through the front opening 23d and stirred (stirring step). An aluminum-containing solution is sprayed using a spray device 40 to form a base layer (spraying step), and then dried using drying gas G that flows into the rotating drum 20 through the air inlet 30a and inlet 23ab (drying step) to form an aluminum-containing coating 2, thereby producing a coated particulate carrier 3 with a coating 2 on its surface (Figure 3(b)). Next, the coated particulate carrier 3 with a coating 2 on its surface is fired (firing step) to produce a coated particulate carrier 5 with a base layer 4 made of an aluminum oxide layer formed on the surface of the particulate carrier 1 (Figure 3(c)). Next, the particulate carrier 5 with a base layer is introduced into the rotating drum 20 through the front opening 23d and stirred (stirring step), while an iron-containing solution as catalyst solution C is sprayed using a spray device 40 (spraying step), and then dried using drying gas G that flows into the inside of the rotating drum 20 through the air inlet 30a and inlet 23ab (drying step) to obtain a particulate carrier 7 with a catalyst coating 6 containing an iron catalyst on its surface (Figure 3(d)). Finally, the particulate carrier 7 with the catalyst coating 7 is calcined (calcination step) to obtain a catalyst carrier 11 with an iron oxide layer 10 (catalyst layer) formed on the surface of the particulate carrier 5 with a base layer (Figure 3(e)).

[0066] Figure 4 illustrates the process of manufacturing a catalyst support having a two-layer structure consisting of a particulate carrier and a catalyst layer made of aluminum oxide and iron oxide, using a rotary drum type fluidizing apparatus used in the first embodiment of the catalyst support manufacturing method of the present invention. First, a particulate carrier 1 is prepared (Figure 4(a)). Next, the prepared particulate carrier 1 (particulate carrier A) is introduced into the rotating drum 20 through the front opening 23d and stirred (stirring step), while a catalyst solution C containing aluminum and iron is sprayed using a spray device 40 (spraying step). Then, it is dried using a drying gas G that flows into the inside of the rotating drum 20 through the air inlet 30a and inlet 23ab (drying step) to form a coating film 12 containing aluminum and iron catalyst, thereby producing a coated particulate carrier 13 (Figure 4(b)). Next, the coated particulate carrier 13 is fired (firing step) to obtain a catalyst carrier 15 in which a catalyst layer 14 containing aluminum oxide and iron oxide is formed on the surface of the particulate carrier 1 (Figure 4(c)).

[0067] Figure 5 illustrates the process of manufacturing a catalyst support having a three-layer structure consisting of a particulate carrier, a catalyst layer made of aluminum oxide and iron oxide, and an iron oxide layer, using a rotary drum type fluidizing apparatus used in the first embodiment of the catalyst support manufacturing method of the present invention. First, a particulate carrier 1 is prepared (Figure 5(a)). Next, the prepared particulate carrier 1 (particulate carrier A) is introduced into the rotating drum 20 through the front opening 23d and stirred (stirring step), while a catalyst solution C containing aluminum and iron is sprayed using a spray device 40 (spraying step). Then, it is dried using a drying gas G that flows into the inside of the rotating drum 20 through the air inlet 30a and inlet 23ab (drying step) to form a coating film 12 containing aluminum and iron catalyst, thereby producing a coated particulate carrier 13 (Figure 5(b)). Next, the coated particulate carrier 13 is fired (firing step) to obtain a particulate carrier 15 in which a catalyst layer 14 containing aluminum oxide and iron oxide is formed on the surface of the particulate carrier 1 (Figure 5(c)). Next, the particulate carrier 15 on which the catalyst layer 14 is formed is introduced into the rotating drum 20 through the front opening 23d and stirred (stirring step), while an iron-containing solution as catalyst solution C is sprayed using a spray device 40 (spraying step), and then dried using drying gas G that flows into the inside of the rotating drum 20 through the air inlet 30a and inlet 23ab (drying step) to form a coating film 16 containing iron catalyst, thereby producing a catalyst-coated particulate carrier 17 (Figure 5(d)). Finally, the catalyst-coated particulate carrier 17 is fired (firing step) to produce a catalyst support 19 on which an iron oxide layer 18 is formed as a catalyst layer on the surface of the particulate carrier 1 on which the catalyst layer 14 is formed (Figure 5(e)).

[0068] In this first embodiment, the central axis X is configured to be in a substantially horizontal direction. However, the system is not limited to this configuration. As will be explained in the second embodiment described later, the central axis Y corresponding to the central axis X may be configured to be inclined from the horizontal direction, and the angle of inclination is not particularly limited. Furthermore, the configuration is such that the drying gas G is supplied into and discharged from the peripheral wall portion 23a corresponding to the outer circumference of the rotating drum 20, but the supply position and discharge position of the drying gas G are not particularly limited.

[0069] <Second Embodiment> Next, a second embodiment of the method for manufacturing the catalyst support of the present invention will be described. Here, the same parts as in the first embodiment of the method for manufacturing the catalyst support of the present invention described above will be omitted from the explanation, and the rotating drum type fluidizer, which is a different part, will be described. Figure 6A is a schematic cross-sectional view along the central axis Y showing the schematic configuration of an example of a rotary drum type fluidizing apparatus used in the second embodiment of the catalyst support manufacturing method of the present invention; Figure 6B is a perspective view showing the schematic configuration of the rotary drum in the rotary drum type fluidizing apparatus shown in Figure 6A; and Figure 6C is a schematic cross-sectional view along the central axis Y showing the schematic configuration of a modified example of the rotary drum in the rotary drum type fluidizing apparatus shown in Figure 6A. The second embodiment differs from the first embodiment mainly in the angle of the rotation axis of the rotating drum. The rotating drum type fluidizer 200 comprises a housing 80, a rotating drum 50 housed inside the housing 80 so as to be rotatable around a central axis Y in a predetermined direction, a rotation drive mechanism 60 that rotates the rotating drum 50 around the central axis Y, a spray device 70 as a spraying unit that sprays a catalyst solution C onto particulate carrier A housed inside the rotating drum 50, and a drying gas supply device (not shown) that supplies drying gas G to the housing 80. Here, in this embodiment, "predetermined direction" means a direction that forms an angle greater than 20° and less than 90° with respect to the horizontal direction, preferably a direction that forms an angle greater than 20° and 70° or less with respect to the horizontal direction, and more preferably a direction that forms an angle of 30° or more and 45° or less with respect to the horizontal direction. The rotating drum 50 rotates around a central axis Y (a line passing through the center of the front end 51 (not shown) and the center P of the rear end 52) which forms a predetermined angle with respect to the horizontal direction. In this way, because the rotating drum 50 rotates around a central axis Y which forms a predetermined angle with respect to the horizontal direction, the particulate carrier A contained inside the rotating drum 50 can be efficiently agitated, and the spray area of ​​the catalyst solution C and the contact area of ​​the drying gas G can be increased. Furthermore, the rotating drum 50 can increase the packing density of the particulate carrier A. The rotating drum 50 has a peripheral wall portion 53 of a predetermined shape (see Figures 6A and 6B), a front end portion 51 provided on the front side in the direction of the central axis Y, and a rear end portion 52 provided on the rear side in the direction of the central axis Y. The front side in the direction of the central axis Y is the side located upstream in the spray direction from the intersection point obtained when the spray direction is crossed with respect to the central axis Y. The rear side in the direction of the central axis Y is the side opposite to the front side. More specifically, in the illustrated embodiment, the side with the front end opening 51a, which is provided for supplying particulate carrier A to the rotating drum 50 and for discharging particulate carrier A or catalyst carrier from the rotating drum 50, is referred to as the front side, and the side opposite the front side, which is the shaft side where the rotation drive mechanism 60 is provided, is referred to as the rear side.

[0070] The housing 80 is provided with an air inlet 80a for supplying drying gas G into the housing 80 and an exhaust port 80b for exhausting the drying gas G supplied into the housing 80 from the inside of the housing 80. Furthermore, the housing 80 is provided with a gap 80c on the outer circumference of the rotating drum 50 that connects the air inlet 80a and the exhaust port 80b. The front end portion 51, which is continuous with the front end of the peripheral wall portion 53, and the rear end portion 52, which is continuous with the rear end of the peripheral wall portion 53, are each provided with ventilation portions that connect the inside and outside of the rotating drum 50. At the front end portion 51, the front end opening 51a functions as a ventilation portion (an inlet for allowing the drying gas G to flow into the inside of the rotating drum 50), and at the rear end portion 52, the mesh opening 52a, which is formed in a mesh-like manner with multiple holes, functions as a ventilation portion (an outlet for discharging the drying gas G from the inside of the rotating drum 50).

[0071] The operation of the rotary drum type fluidizer 200 will be described below. First, particulate carrier A is introduced into the rotating drum 50 through a front end opening 51a provided at the front end 51 of the rotating drum 50. Next, the rotating drum 50 into which the particulate carrier A has been introduced rotates around a central axis Y in a predetermined direction by the operation of the rotation drive mechanism 60. As the rotating drum 50 rotates, the particulate carrier A contained within the rotating drum 50 is swept upward in the direction of gravity (vertical direction), and then flows downward in the direction of gravity (vertical direction) due to the gravitational action of its own weight. Thus, the particulate carrier A can be efficiently moved up and down in the direction of gravity (vertical direction), and consequently, the particulate carrier A can be efficiently agitated. Furthermore, by using the rotating drum 50, the spray area of ​​the catalyst solution C by the spray device 70 and the contact area of ​​the drying gas G (the surface area S of the layer made of particulate carrier A in Figure 6A) can be increased, and the packing density of the particulate carrier A can be increased.

[0072] Next, as described above, while rotating the rotating drum 50, the catalyst solution C is sprayed onto the particulate carrier A from the spray device 70, which acts as the spraying unit. This allows the catalyst solution C to adhere uniformly to the surface of the particulate carrier A. Furthermore, the drying gas G is passed through the air inlet 80a, the front end opening 51a, the particulate carrier A housed inside the rotating drum 50, the mesh opening 52a, and the exhaust port 80b in that order. As a result, the surface of the particulate carrier A to which the catalyst solution C is attached is dried, and a particulate carrier A with a catalyst coating film is obtained.

[0073] <Variation> In the rotary drum type fluidizer 100, 200 used in the method for manufacturing the catalyst carrier of the present invention, baffles may be provided on the inner wall surfaces of the peripheral wall portions 23a, 53 of the rotary drums 20, 50. When baffles are installed on the inner wall surfaces of the peripheral wall portions 23a, 53 of the rotary drums 20, 50, it is preferable to install them in a spiral shape toward the central axis direction of the rotary drums 20, 50, and it is also preferable that they are not in the vicinity of the spray devices 40, 70 which serve as spraying sections. By providing baffles on the inner wall surfaces of the peripheral wall portions 23a, 53 of the rotary drums 20, 50, the particulate carrier A can be moved to the rear side (axis side) of the rotary drums 20, 50, preventing leakage of the particulate carrier A from the front end openings 23d, 51a provided at the front end portions 23b, 51, and a sufficient stirring effect can be obtained.

[0074] The shape of the rotating drums 20 and 50 in the rotary drum type fluidizers 100 and 200 used in the method for producing catalyst carriers of the present invention is not particularly limited. For example, they may be polygonal (polygonal prism) or cylindrical (cylindrical), but a polygonal (polygonal prism) shape is preferred. The polygonal (polygonal prism) shape of the rotating drums 20 and 50 allows for efficient stirring of particulate carriers, and in particular, provides high stirring performance for particles with a low angle of repose. Furthermore, polygonal (polygonal prism) and cylindrical (cylinder) shapes include those with protrusions on the sides (see, for example, Figures 6A-C) and those with recesses (constrictions). Here, having protrusions is preferable in terms of increasing the capacity of the rotating drum.

[0075] The mesh opening size (maximum length of one hole) formed in the peripheral wall portion 23a and mesh opening 52a of the rotating drums 20 and 50 used in the method for manufacturing the catalyst support of the present invention is not particularly limited, but it is preferably 80% or less of the average particle diameter of the particulate carrier A, more preferably 70% or less, and preferably 20% or more. By setting the mesh opening size to 80% or less of the average particle diameter of the particulate carrier A, it is possible to suppress the particulate carrier A from falling off the rotating drums 20 and 50. On the other hand, by setting the mesh opening size to 20% or more of the average particle diameter of the particulate carrier A, it is possible to reduce the pressure loss in the peripheral wall portion 23a and mesh opening 52a, and the particulate carrier A to which the catalyst solution C has been sprayed can be dried more efficiently.

[0076] In the rotary drum type fluidizer 100 used in the first embodiment of the catalyst carrier manufacturing method of the present invention, a ventilation section is formed on substantially the entire surface of the peripheral wall 23a to connect the inside and outside of the rotary drum 20. However, multiple ventilation sections may be provided on a part of the peripheral wall 23a, in which case it is preferable that the ventilation sections are positioned to face each other via a central axis X. Here, it is preferable that the number of ventilation sections be even. When multiple ventilation sections are provided on a part of the peripheral wall 23a, the dry gas G passes through the following in order when the ventilation sections face the air intake port 30a and / or exhaust port 30b: air intake port 30a, ventilation section (inlet port 23ab), particulate carrier A housed inside the rotary drum 20, ventilation section (outlet port 23ac), and exhaust port 30b. Here, similar to the case where the ventilation section is provided across the entire surface of the peripheral wall 23a, if multiple ventilation sections are provided on a part of the peripheral wall 23a, it is preferable that multiple partition plates 24 are arranged at predetermined intervals in the circumferential direction around the outer circumference of the peripheral wall 23a of the rotating drum 20, and that the opening area of ​​the exhaust port 30b is designed to be smaller than the surface area S of the layer formed by the particulate carrier A inside the rotating drum 20. This prevents the drying gas G from passing through the gap 30c without contacting the particulate carrier A, and allows almost the entire amount of drying gas G supplied to the air intake port 30a to pass through in the following order: air intake port 30a, ventilation section (inlet 23ab), particulate carrier A housed inside the rotating drum 20, ventilation section (outlet 23ac), and exhaust port 30b.

[0077] In the rotary drum type fluidizer 200 used in the second embodiment of the catalyst support manufacturing method of the present invention, the front end opening 51a of the rotary drum 50 is an open system with nothing provided, but it is not limited to this, and the entire front end opening 51a or a part of it may be formed in a mesh shape. If the entire front end opening 51a is formed in a mesh shape, it is preferable that the mesh is installed in a detachable state, for example, so that the particulate carrier A can be supplied into the rotary drum 50 and the particulate carrier A or the manufactured catalyst support can be discharged from the rotary drum 50 through the front end opening 51a.

[0078] In the rotary drum type fluidizer 200 used in the second embodiment of the catalyst support manufacturing method of the present invention, the rotary drum 50 has mesh openings 52a over its entire rear end 52, but is not limited to this, and mesh openings 52a may be provided only on a part of the rear end 52.

[0079] In the rotary drum type fluidizer 200 used in the second embodiment of the catalyst support manufacturing method of the present invention, the rotary drum 50 has a front end opening 51a and a mesh opening 52a, respectively, which are provided on the entire front end 51 and rear end 52 of the rotary drum 50. However, it is not limited to this, and may be provided on a part of the front end 51 and / or rear end 52. In this case, if the front end opening 51a and mesh opening 52a are provided at multiple locations on a part of the front end 51 and rear end 52, respectively, it is preferable that the front end opening 51a and mesh opening 52a are positioned opposite each other via the central axis Y, and it is preferable that the front end opening 51a is located above the particulate carrier A in the direction of gravity (vertical direction), while it is preferable that the mesh opening 52a is located below the particulate carrier A in the direction of gravity (vertical direction).

[0080] In the rotary drum type fluidizer 200 used in the second embodiment of the catalyst support manufacturing method of the present invention, the rotary drum 50 has mesh openings 52a formed along a direction substantially perpendicular to the central axis Y of the rotary drum 50. However, it is not limited to this, and for example, as shown in Figure 6C, the mesh openings 52a may be formed along a direction that makes a predetermined angle with the direction perpendicular to the central axis Y of the rotary drum 50.

[0081] In the rotary drum type fluidizer 200 used in the second embodiment of the catalyst carrier manufacturing method of the present invention, a plurality of partition plates (not shown) may be arranged at predetermined intervals in the circumferential direction around the outer circumference of the peripheral wall portion 53. If a plurality of partition plates (not shown) are arranged at predetermined intervals in the circumferential direction around the outer circumference of the peripheral wall portion 53, the passage of the dry gas G through the gap portion 80c can be suppressed, and substantially the entire amount of the dry gas G supplied to the air inlet 80a can be passed through in the order of the air inlet 80a, the front end opening 51a, the particulate carrier A housed inside the rotary drum 50, the mesh opening 52a, and the exhaust port 80b.

[0082] (Method for manufacturing fibrous carbon nanostructures) The present invention relates to a method for producing fibrous carbon nanostructures. The present invention relates to a method for producing fibrous carbon nanostructures, which includes a step (synthesis step) of supplying a raw material gas to a catalyst support obtained by the method for producing a catalyst support of the present invention to synthesize fibrous carbon nanostructures on the catalyst layer.

[0083] <Fibrous carbon nanostructures> The fibrous carbon nanostructures are not particularly limited, and examples include fibrous carbon nanostructures with an aspect ratio greater than 10. Specifically, examples of fibrous carbon nanostructures include CNTs and vapor-grown carbon fibers. In this invention, the "aspect ratio of the fibrous carbon nanostructure" can be determined by measuring the diameter (outer diameter) and length of 100 randomly selected fibrous carbon nanostructures using a transmission electron microscope. The following describes the case in which the fibrous carbon nanostructure obtained by the manufacturing method of the present invention includes CNTs, but the present invention is not limited thereto.

[0084] <<Carbon nanotubes>> CNTs are materials that have a structure in which graphene sheets are rolled into a tube and have a one-dimensional structure with a very large aspect ratio (see Non-Patent Document 1). Here, the fibrous carbon nanostructure containing CNTs may consist only of CNTs, or it may be a mixture of CNTs and fibrous carbon nanostructures other than CNTs.

[0085] Furthermore, the CNTs are not particularly limited and can be single-walled carbon nanotubes and / or multi-walled carbon nanotubes. However, from the viewpoint of improving various properties such as mechanical strength, electrical properties, and thermal conductivity, the CNTs are preferably composed of 10 layers or less, more preferably of 5 layers or less, and even more preferably single-walled carbon nanotubes. The single-walled carbon nanotubes / multi-walled carbon nanotubes can be appropriately adjusted by changing various reaction conditions, such as catalyst size, catalyst composition, reaction time, and raw material gas supply flow rate.

[0086] [Properties] Furthermore, the average diameter of the fibrous carbon nanostructures containing CNTs can be set to a desired value depending on the application. For example, if the particle size of the metal nanoparticles used as a catalyst, which are typically produced by the reduction of the catalyst layer described above, is between 1 nm and 2 nm, the average diameter of the CNTs can be adjusted to around 1 nm. If the particle size of the metal nanoparticles is around 30 nm, the average diameter of the CNTs can be adjusted to between 20 nm and 30 nm. Generally, the finer the average diameter of the CNTs, the better the various properties. The "average diameter" of fibrous carbon nanostructures, including CNTs, can be determined, for example, by measuring the diameter (outer diameter) of 100 randomly selected fibrous carbon nanostructures using a transmission electron microscope.

[0087] Furthermore, while the average length of the fibrous carbon nanostructure containing CNTs can be set to a desired value depending on the application, it is preferable that the average length during synthesis be 1 μm or more, and more preferably 50 μm or more. This is because if the average length of the fibrous carbon nanostructure containing CNTs during synthesis is 1 μm or more, the resulting fibrous carbon nanostructure can exhibit various properties such as mechanical strength, electrical properties, and thermal conductivity more effectively. Also, the longer the length of the fibrous carbon nanostructure containing CNTs during synthesis, the more susceptible it is to damage such as fracture or breakage; therefore, it is preferable that the average length of the fibrous carbon nanostructure containing CNTs during synthesis be 5000 μm or less. Furthermore, the "average length" of the fibrous carbon nanostructures containing CNTs can be adjusted as appropriate, for example, by changing the synthesis reaction time.

[0088] <Synthesis process> In the method for producing fibrous carbon nanostructures of the present invention, a raw material gas is supplied to a catalyst support obtained in the method for producing catalyst supporters of the present invention to synthesize fibrous carbon nanostructures on the catalyst layer. For example, by supplying a raw material gas to the outermost catalyst layer of a catalyst supporter obtained in the method for producing catalyst supporters of the present invention to generate fibrous carbon nanostructures on the catalyst layer, and growing the generated fibrous carbon nanostructures by chemical vapor deposition, fibrous carbon nanostructures such as carbon nanotubes can be synthesized and grown with high efficiency, and are excellent in terms of mass productivity. Note that the catalyst supporter is usually subjected to a reduction treatment before being used in the method for producing fibrous carbon nanostructures. In the synthesis process, at least one of the catalyst layer and the raw material gas is usually heated, but from the viewpoint of growing fibrous carbon nanostructures at a uniform density, it is preferable to heat at least the raw material gas. The heating temperature is preferably between 400°C and 1100°C. In the synthesis process, the raw material gas, and optionally an inert gas, a reducing gas, and / or a catalyst activator are introduced into a fibrous carbon nanostructure growth furnace containing the catalyst support.

[0089] Furthermore, from the viewpoint of improving the manufacturing efficiency of fibrous carbon nanostructures, it is preferable to supply the reducing gas and raw material gas to the catalyst in the catalyst layer by a gas shower.

[0090] - Raw material gas - As the raw material gas, a gaseous substance containing a carbon source at the temperature at which fibrous carbon nanostructures grow is used. Among these, hydrocarbons such as methane, ethane, ethylene, propane, butane, pentane, hexane, heptane, propylene, and acetylene are preferred. In addition, lower alcohols such as methanol and ethanol, and low-carbon oxygen compounds such as acetone and carbon monoxide may also be used. Mixtures of these can also be used.

[0091] -Inert gas- The raw material gas may be diluted with an inert gas. The inert gas should be inert at the temperature at which the fibrous carbon nanostructures grow and should not react with the growing fibrous carbon nanostructures, and preferably one that does not reduce the activity of the catalyst. Examples include noble gases such as helium, argon, neon, and krypton; nitrogen; hydrogen; and mixtures thereof.

[0092] -Reducing gas- Examples of reducing gases that can be used include hydrogen gas, ammonia, water vapor, and mixtures thereof. Alternatively, the reducing gas may be a mixture of hydrogen gas with an inert gas such as helium gas, argon gas, or nitrogen gas.

[0093] -Catalyst- Activating Substance- In the synthesis process of the fibrous carbon nanostructure, a catalyst activating substance may be added. By adding the catalyst activating substance, the production efficiency and purity of the fibrous carbon nanostructure can be further improved. The catalyst activating substance used here is generally a substance containing oxygen, and it is preferably a substance that does not cause significant damage to the fibrous carbon nanostructure at the temperature at which the fibrous carbon nanostructure grows. For example, oxygen-containing compounds with a low carbon number such as water, oxygen, ozone, acid gas, nitrogen oxide, carbon monoxide, and carbon dioxide; alcohols such as ethanol and methanol; ethers such as tetrahydrofuran; ketones such as acetone; aldehydes; esters; and mixtures thereof are effective. Among these, water, oxygen, carbon dioxide, carbon monoxide, and ethers are preferred, and water is particularly preferred.

[0094] The volume concentration of the catalyst activating substance is not particularly limited, but a trace amount is preferred. For example, in the case of water, in the introduced gas into the furnace, it is usually 10 ppm or more and 10,000 ppm or less, preferably 50 ppm or more and 1,000 ppm or less.

[0095] -Other conditions- The pressure and treatment time in the reaction furnace in the synthesis process may be appropriately set in consideration of other conditions. For example, the pressure is 1×10 2 Pa or more and 1×10 7 Pa or less, and the treatment time can be about 1 minute or more and 60 minutes or less.

Examples

[0096] Examples of the present invention will be described below, but the present invention is not limited to these examples in any way.

[0097] (Example 1) <Manufacture of catalyst support> A catalyst support was manufactured in the same manner as the embodiment of FIG. 3. Zirconia (zirconium dioxide) beads (ZrO 2、750g of zirconia beads (volume average particle size D50: 300μm) were placed into the rotating drum 20 of the rotating drum type fluidizer 100 shown in the first embodiment. While stirring the zirconia beads (particulate carrier A) (rotation speed of the rotating drum 20: 20 rpm, rotating around the central axis X with the horizontal direction as the central axis X), an aluminum-containing solution was sprayed using a spray gun (spray device 40) to form a base layer (spray volume 3g / min, spray time 940 seconds, spray air pressure 10MPa). While spraying, compressed air (0.5MPa) as a drying gas G was supplied into the rotating drum 20 at a rate of 300L / min and discharged from the rotating drum 20 to dry the material, forming a coating film of aluminum-containing solution on the zirconia beads. Next, a firing treatment was performed at 480°C for 45 minutes to obtain a particulate carrier with a base layer, on which an aluminum oxide layer as the base layer was formed. Furthermore, the angle between the direction I of the spray gun (spray device 40) used to spray the aluminum-containing solution and the direction H of the inflow of the drying gas G within the rotating drum 20 was 0°. Furthermore, while stirring the obtained particulate carrier with a base layer (rotating drum 20 at a rotation speed of 20 rpm, rotating around the central axis X with the horizontal line as the central axis X), the iron catalyst solution (catalyst solution C) was sprayed using a spray gun (spray device 40) (spray volume 2 g / min, spray time 480 seconds, spray air pressure 5 MPa). While spraying, compressed air (0.5 MPa) as a drying gas G was supplied into the rotating drum 20 at a rate of 300 L / min and discharged from the rotating drum 20 to dry the carrier, forming a coating film of iron catalyst solution (catalyst solution C) on the particulate carrier with a base layer. Next, a firing treatment was performed at 220°C for 20 minutes to obtain a catalyst support in which an iron oxide layer as a catalyst layer was further formed.

[0098] <Synthesis of carbon nanotubes> To the catalyst support obtained as described above, a raw material gas containing ethylene gas (C2H4) was supplied into the reaction tube at atmospheric pressure, a temperature of 850°C, and a total flow rate of 1500 sccm for 10 minutes. By supplying the raw material gas in this manner, carbon nanotubes were synthesized on the catalyst support using a fluidized bed method. Then, using the catalyst support on which the carbon nanotubes were synthesized, the production yield of the carbon nanotubes was calculated according to the method described below. As a result, the production yield of the carbon nanotubes was 4.4%. <<Carbon nanotube production yield Y>> The weight G of the carbon raw material contained in the ethylene supplied to the reaction site c-source (g) The total supply flow rate of the raw material gas F (sccm), and the ethylene concentration C C2H4 Using (volume %), reaction time t (minutes), molar volume V = 22400 (cc / mol) of the gas at standard conditions, and molar mass M ≈ 12 (g / mol), the following equation (I): G c-source (g) = F×(C C2H4 / 100)×t×(1 / V)×(M×2)···(I) It was calculated according to the following. Next, the yield G of carbon nanotubes synthesized on the catalyst carried by the catalyst support. CNT (g) was weighed using an electronic balance. CNT This was determined by subtracting the mass of the catalyst support from the total mass of the catalyst support on which the carbon nanotubes were synthesized. Then, equation (II) below: Carbon nanotube production yield Y(%) = (G CNT / G c-source ) × 100···(II) The calculation was performed according to the formula. A higher value for the manufacturing yield Y indicates a higher efficiency in carbon nanotube production.

[0099] (Example 2) In Example 1, carbon nanotube synthesis and calculation of the carbon nanotube production yield were performed in the same manner as in Example 1, except that the catalyst support was manufactured as described below. As a result, the carbon nanotube production yield was 4.1%. <Manufacturing of catalyst support structures> Zirconia (zirconium dioxide) beads as a metal oxide (ZrO 2、3000g of zirconia beads (volume-average particle size D50: 300μm) were placed into the rotating drum 50 of the rotating drum type fluidizer 200 shown in the second embodiment. While stirring the zirconia beads (particulate carrier A) (rotation speed of the rotating drum 50: 15 rpm, rotating around the central axis Y with a line making a 30° angle with the horizontal direction as the central axis Y), the aluminum solution was sprayed using a spray gun (spray device 70) (spray volume 5g / min, spray time 2250 seconds, spray air pressure 10MPa). Then, while spraying, compressed air (0.5MPa) as a drying gas G was supplied into the rotating drum 50 at a rate of 500L / min and discharged from the rotating drum 50 to dry the material, forming a coating film of aluminum-containing solution on the zirconia beads. Next, a firing treatment was performed at 480°C for 45 minutes to obtain a particulate carrier with a base layer of aluminum oxide formed as the base layer. Furthermore, the angle between the direction I of the spray gun (spray device 70) used to spray the aluminum-containing solution and the direction H of the inflow of the drying gas G within the rotating drum 50 was 0°. Furthermore, while stirring the obtained particulate carrier with a base layer (rotating drum 50 at a rotation speed of 15 rpm, rotating around the central axis Y with a line making a 45° angle with the horizontal), the iron catalyst solution (catalyst solution C) was sprayed using a spray gun (spray device 70) (spray volume 4 g / min, spraying time 960 seconds, spray air pressure 10 MPa). While spraying, compressed air (0.5 MPa) as a drying gas G was supplied into the rotating drum 50 at a rate of 600 L / min and discharged from the rotating drum 50 to dry the carrier, forming a coating film of iron catalyst solution (catalyst solution C) on the particulate carrier with a base layer. Next, a firing treatment was performed at 220°C for 20 minutes to obtain a catalyst support in which an iron oxide layer as a catalyst layer was further formed.

[0100] (Comparative Example 1) In Example 1, carbon nanotube synthesis and calculation of the carbon nanotube production yield were carried out in the same manner as in Example 1, except that the catalyst support was manufactured as described below. As a result, the carbon nanotube production yield was 2%. <Manufacturing of catalyst support structures> Zirconia (zirconium dioxide) beads as a metal oxide (ZrO 2、 150g of volume-average particle size D50 (320μm) was immersed in an aluminum-containing solution (immersion time 20 seconds), and dried by supplying air (temperature 45°C) (50L / min for 1000 seconds) to form a coating film of aluminum-containing solution on the zirconia beads. Next, a firing treatment was performed at 480°C for 30 minutes to obtain a particulate carrier with a base layer of aluminum oxide formed as the base layer. Furthermore, the obtained particulate carrier with a base layer was immersed in an iron catalyst solution (immersion time 20 seconds) and dried by supplying air (temperature 45°C) (50 L / min for 1000 seconds) to form a coating film of iron catalyst solution on the particulate carrier with a base layer. Next, a firing treatment was performed at 220°C for 20 minutes to obtain a catalyst support in which an iron oxide layer as a catalyst layer was further formed.

[0101] In Examples 1 and 2, the production efficiency of carbon nanotubes is higher compared to Comparative Example 1. This indicates that in Examples 1 and 2, the catalyst layer can be formed more uniformly on the surface of the particulate support compared to Comparative Example 1. [Industrial applicability]

[0102] According to the present invention, it is possible to provide a method for producing a catalyst support that enables the uniform formation of a catalyst layer on the surface of a particulate support. Furthermore, according to the present invention, fibrous carbon nanostructures such as carbon nanotubes can be synthesized with high efficiency, and a method for producing fibrous carbon nanostructures with excellent mass productivity can be provided. [Explanation of symbols]

[0103] 1. Particulate carrier 2. Coating film 3. Particulate carrier with coating 4 Base layer 5. Particulate carrier with underlayer 6. Coating 7. Particulate carrier with catalyst coating 10 Iron oxide layer 11 Catalyst support 12. Coating film 13. Particulate carrier with coating 14 Catalyst layer 15. Particulate carrier with catalyst coating 16. Coating film 17. Particulate carrier with catalyst coating 18 Iron oxide layer 19 Catalyst support 20 RPM drum 23 Drum body 23a Peripheral wall part 23ab inlet 23ac outlet 23b Front end 23c tapered section 23d Front end opening 23e Front end ring section 23f Connecting part 23g Rotary drive mechanism 23h Rear end ring section 23i Drum Section 24 partition plates 30 cabinets 30a Air supply port 30b Exhaust port 30cm gap 30d inner surface 40 Spray device 50 RPM drum 51 Front end 51a Front end opening 52 Rear end 52a Mesh opening 53 Peripheral wall section 60 Rotational drive mechanism 70 Spray device 80 cabinets 80a Air supply port 80b Exhaust port 80c gap 100 Rotating Drum Type Fluidized System 200 Rotary Drum Type Fluidized System A particulate carrier C catalyst solution G Dry gas H Inflow direction I. Configuration Direction P Center S surface X-axis Y-axis θ angle

Claims

1. A method for producing a catalyst support used in the production of fibrous carbon nanostructures, A stirring step is performed by rotating a substantially cylindrical rotating drum containing particulate carriers around a central axis that forms an angle of 0° to less than 90° with respect to the horizontal direction, thereby stirring the particulate carriers. A spraying step in which a catalyst solution is sprayed onto the particulate carrier in the rotating drum, The process includes a drying step in which a drying gas is introduced into the rotating drum from outside the rotating drum, and the drying gas is brought into contact with the particulate carrier on which the catalyst solution has been sprayed in the spraying step, thereby drying the catalyst solution. At least a portion of the duration of the stirring process and at least a portion of the duration of the spraying process overlap, and furthermore, The catalyst solution contains at least one metal among nickel, iron, cobalt, and molybdenum as a catalyst component. (a) When the central axis is at an angle of 0° to 20° with respect to the horizontal, the central axis and the inflow direction of the drying gas flowing radially from a specific position on the outer circumference of the rotating drum toward the central axis do not coincide, and the spraying direction of the catalyst solution and the inflow direction of the drying gas inside the rotating drum do not coincide, and the angle is 45° or less, or (b) When the central axis is at an angle greater than 20° and less than 90° with respect to the horizontal, the drying gas flows in from a specific position on the upper side of the rotating drum toward a specific position on the opposite side with respect to the central axis, and furthermore, the central axis and the direction of the inflow of the drying gas intersect obliquely within the rotating drum. A method for producing a catalyst support.

2. The method for producing a catalyst support according to claim 1, wherein the angle between the spraying direction of the catalyst solution and the inflow direction of the drying gas in the rotating drum is 45° or less.

3. A method for producing a catalyst support according to claim 1 or 2, wherein at least a portion of the duration of the stirring step, at least a portion of the duration of the spraying step, and at least a portion of the duration of the drying step overlap.

4. A method for producing a catalyst support according to any one of claims 1 to 3, wherein in the drying step, the drying gas is introduced while its temperature is adjusted to be between 0°C and 200°C.

5. If (a) is satisfied and (b) is not satisfied, In the drying process, A method for manufacturing a catalyst support according to any one of claims 1 to 4, wherein the peripheral wall portion, which is the outer circumference of the rotating drum, is formed with an inlet for introducing the drying gas into the rotating drum from outside the rotating drum and an outlet for discharging the drying gas from inside the rotating drum to outside the rotating drum.

6. The method for manufacturing a catalyst support according to claim 5, wherein the inlet and outlet are formed at positions opposite to each other with respect to the central axis.

7. If the above (b) is satisfied and the above (a) is not satisfied, In the drying process, An inlet is formed on the front side of the rotating drum in the direction of its central axis, allowing the drying gas to flow into the peripheral wall portion, which is the outer circumference of the rotating drum. A method for manufacturing a catalyst support according to any one of claims 1, 3, or 4, wherein an outlet for discharging the drying gas from inside the rotating drum is formed on the rear side of the rotating drum in the direction of the central axis.

8. The inlet and / or outlet are formed in a mesh-like manner. The method for producing a catalyst support according to any one of claims 5, 6, and 7, wherein the discharge port formed in a mesh shape is structured to allow the dry gas to pass through but not the particulate carrier.

9. The particulate carrier has a particle density (apparent density) of 2.0 g / cm³. ３ The method for producing a catalyst support according to any one of claims 1 to 8.

10. The method for producing a catalyst support according to any one of claims 1 to 9, wherein the particulate support is composed of a metal oxide.

11. The method for producing a catalyst support according to claim 10, wherein the metal oxide is zirconium dioxide, aluminum oxide, or zircon.

12. The method for producing a catalyst support according to any one of claims 1 to 11, wherein the particulate carrier has a base layer and / or a catalyst layer on its surface.

13. A method for producing a catalyst support according to any one of claims 1 to 12, further comprising a firing step of firing the particulate support at a temperature of 50°C or higher and 900°C or lower.

14. A method for producing a fibrous carbon nanostructure, comprising the step of supplying a raw material gas to a catalyst support obtained by a method for producing a catalyst support according to any one of claims 1 to 13, to synthesize a fibrous carbon nanostructure on the catalyst layer of the catalyst support.

Images