JP4064758B2 - Method and apparatus for producing carbon nanofiber - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for producing carbon nanofibers by a fluidized bed system.
[0002]
[Prior art]
The carbon nanotube is a tubular carbon polyhedron having a structure in which a graphite (graphite) sheet is closed in a cylindrical shape. The carbon nanotube includes a multi-layer nanotube having a multilayer structure in which a graphite sheet is closed in a cylindrical shape, and a single-wall nanotube having a single-layer structure in which a graphite sheet is closed in a cylindrical shape.
[0003]
One multi-walled nanotube was discovered by Iijima in 1991. That is, it was discovered that multi-walled nanotubes exist in the carbon mass deposited on the cathode of the arc discharge method. Since then, research on multi-walled nanotubes has been actively conducted, and in recent years, it has become possible to synthesize a large number of multi-walled nanotubes.
[0004]
In contrast, single-walled nanotubes have an inner diameter of approximately 0.4 to 100 nanometers (nm), and their synthesis was simultaneously reported in 1993 by a group of Iijima and IBM. The electronic state of single-walled nanotubes has been predicted theoretically, and it is thought that the electronic properties change from metallic properties to semiconducting properties depending on how the spiral is wound. Therefore, such single-walled nanotubes are considered promising as future electronic materials.
[0005]
Other applications of single-walled nanotubes include nanoelectronic materials, field electron emitters, highly directional radiation sources, soft X-ray sources, one-dimensional conducting materials, high thermal conducting materials, hydrogen storage materials, and the like. Further, it is considered that the use of single-walled nanotubes is further expanded by functionalization of the surface, metal coating, and inclusion of foreign substances.
[0006]
Conventionally, the single-walled nanotubes described above are manufactured by mixing a metal such as iron, cobalt, nickel, or lanthanum into a carbon rod of an anode and performing arc discharge. However, in this production method, in addition to single-walled nanotubes, multi-walled nanotubes, graphite, and amorphous carbon are mixed in the product, and not only the yield is low, but also the diameter and length of single-walled nanotubes vary. In addition, it was difficult to produce single-walled nanotubes with relatively uniform yarn diameter and yarn length in high yield.
[0007]
In addition to the arc method described above, a vapor phase pyrolysis method, a laser sublimation method, a condensed phase electrolysis method, and the like have been proposed as methods for producing carbon nanotubes.
[0008]
By the way, all these manufacturing methods are laboratory-level manufacturing methods, and there is a problem that the yield of carbon materials is particularly low.
[0009]
In addition, with the above-described method, it has been difficult to perform stable mass production because it cannot be continuously manufactured.
[0010]
On the other hand, nano-unit carbon materials (so-called carbon nanofibers) have recently been desired for their usefulness in various fields, and it is desired that they can be industrially manufactured in large quantities.
[0011]
Then, the manufacturing method by the fluidized bed reaction means using a fluidized material is proposed as a method of mass-producing carbon nanofiber.
[0012]
[Problems to be solved by the invention]
However, when carbon nanofibers are produced using fluidized bed reaction means, the gas and scattered particles scattered from the fluidized bed reaction means adhere to the recovery line together with unreacted raw materials, etc. There is a problem of low recovery efficiency.
[0013]
This invention makes it a subject to provide the manufacturing method and apparatus of carbon nanofiber with high collection | recovery efficiency of carbon nanofiber in view of said situation.
[0014]
[Means for Solving the Problems]
First invention for solving the above problems is to provide a fluidizing gas and the carbon source and the catalyst metal component into the fluidized bed reaction unit, a carbon nanofiber of a method for producing carbon nanofibers over using a fluidized material While producing the carbon nanofibers while circulating the fluidized material, the fluidized material and the carbon nanofibers are supplied from the upper part of the fluidized bed reaction means and a plurality of outlets provided in the longitudinal direction of the fluidized bed reaction means. After recovering and separating, the fluidized material is recycled to the fluidized bed reaction means .
[0016]
The second invention is the first invention, the carbon nanofibers, characterized supplies the circulating fluidized material and catalytic metal component from the lower fluidized bed reaction unit, to supply at the carbon raw material downstream of it It is in the manufacturing method.
[0017]
According to a third aspect of the present invention, there is provided a fluidized bed reaction section filled with a fluidized material therein, a raw material supply means for supplying a carbon raw material into the fluidized bed reaction section, and a catalyst supply means for supplying a catalytic metal into the fluidized bed reaction section. , A fluidized gas supply means for supplying a fluidized gas that is introduced into the fluidized bed reaction section and causes the fluidized material inside to flow, a heating means for heating the fluidized bed reaction section, and a carbon nano-particle generated from the fluidized bed reaction section. A recovery line for recovering the fiber and the fluidized material, a plurality of extraction means provided in the longitudinal direction of the fluidized bed reaction section, and the carbon nanofibers recovered from the recovery line and the extraction means and the fluidized material were separated from each other. after, there flow material in the production apparatus of the carbon nanofibers, characterized by comprising a circulation line which Ru is recycled to the fluidized bed reaction unit.
[0018]
A fourth invention is the carbon nanofiber production apparatus according to the third invention, wherein a separation means for separating the fluidized material circulating in the circulation line and the carbon nanofiber is interposed.
[0020]
A fifth invention is characterized in that, in the third invention, the catalytic metal and the flowing gas supplied to the fluidized bed reaction section are supplied from the bottom side of the furnace, and the carbon raw material is supplied further downstream than that. It is in the manufacturing apparatus of carbon nanofiber.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the method for producing carbon nanofibers according to the present invention will be described below, but the present invention is not limited to these embodiments.
[0022]
[First Embodiment]
FIG. 1 shows an example of an apparatus for producing carbon nanofibers.
As shown in FIG. 1, the carbon nanofiber manufacturing apparatus includes a fluidized bed reaction unit 12 filled with a fluidized material 11 therein, a raw material supply unit 14 for supplying a carbon raw material 13 into the fluidized bed reaction unit 12, A catalyst supply means 16 for supplying the catalyst metal 15 into the fluidized bed reaction section 12; a fluidized gas supply means 19 for supplying a fluidized gas 18 introduced into the fluidized bed reaction section 12 and flowing the fluidized material 11 inside; The heating means 20 for heating the fluidized bed reaction unit 12, the recovery line 23 for recovering the carbon nanofibers 22 and the fluidized material 11 generated from the fluidized bed reaction unit 12, and the fluidized material 11 recovered by the recovery line 23 Separation means 24 for separating the carbon nanofibers 22, and a recirculation line 31 provided with a circulation means 25 for recirculating the separated fluidized material 11 into the fluidized bed reaction section 12. It is intended to.
[0023]
By recirculating the fluidized material into the fluidized bed reaction section 12 by the recirculation line 31, there is no adhesion of unreacted products or the like in the recovery line 23, and the carbon nano-particles adhered to the unreacted products. The fiber can be peeled and collected, and the collection efficiency of the carbon nanofiber is improved.
As the circulation means 25, for example, a known circulation means such as an ejector can be used.
[0024]
The fluidized bed reaction mode of the fluidized bed reaction section 12 includes a bubble type fluidized bed type and a jet type fluidized bed type, and any of them may be used in the present invention.
[0025]
The carbon raw material 13 supplied from the carbon material supply means 14 may be any carbon-containing compound, for example, CO, CO ₂ , alkanes such as methane, ethane, propane and hexane, Examples include unsaturated organic compounds such as ethylene, propylene and acetylene, aromatic compounds such as benzene and toluene, polymer materials such as polyethylene and polypropylene, and petroleum and coal (including coal conversion gas). The invention is not limited to these examples.
In addition to C and H, an organic compound containing an S component or a Cl component may be used.
[0026]
The carbon raw material 13 is supplied in a gas state into the fluidized bed reaction section 12, and a uniform reaction is performed by stirring with the fluidized material 11, thereby growing carbon nanofibers. At this time, an inert gas is separately introduced into the fluidized bed reaction section 17 by the gas supply means 19 as a fluidized gas so as to satisfy a predetermined fluidization condition.
[0027]
Examples of the catalyst metal 15 include transition metals typified by iron (Fe), cobalt (Co), and nickel (Ni), or alloys made of these metals.
Examples of the alloy include a Co—Mo based catalytic metal component, but the present invention is not limited thereto.
[0028]
Then, using the catalytic metal 15, carbon fiber is synthesized by contacting a carbon raw material such as benzene at a temperature range of 400 ° C. to 1200 ° C. with a catalyst in a mixed gas having a hydrogen partial pressure of 0% to 90% for a certain period of time. is doing.
[0029]
Although the particle size of the fluidizing material 11 is not particularly limited, for example, a material in the range of 0.02 to 20 mm can be used.
Examples of the fluidizing material include known silica particles, alumina, silica, aluminosilicate, oxide particles such as zeolite, and the like, but the present invention is not limited thereto.
[0030]
As the separation means 24 other than the cyclone, known separation means such as a bag filter, a ceramic filter, and a sieve can be used.
[0031]
The carbon nanofibers 22 separated by the separation means 24 are recovered as a product 28 by the purification means 27.
As the purification means 27 , a known filtration means such as a bag filter can be used.
[0032]
Then, the carbon raw material 10, the catalyst metal 15, and the fluidizing material 11 are respectively supplied into the fluidized bed reaction unit 12, and the fluidizing material gas 19 is supplied to cause the fluidizing material 11 to flow, and a predetermined pressure and temperature are set. As a result, the carbon nanofibers 22 can be efficiently collected by performing a uniform reaction in the fluidized bed.
[0033]
[Second Embodiment]
FIG. 2 shows a schematic view of an apparatus for producing carbon nanofibers.
As shown in FIG. 2, in the carbon nanofiber manufacturing apparatus shown in FIG. 1, a plurality of extraction ports 33 that are means for extracting the carbon nanofibers and the fluidized material 11 from the fluidized bed reaction unit 12 are provided in the furnace vertical direction, Different carbon nanofibers are collected by the separation means 24B and 24C.
[0034]
Thereby, carbon nanofibers having different properties can be extracted depending on the difference in flow time of the fluidized bed reaction unit 12.
[0035]
[Third Embodiment]
FIG. 3 shows a schematic view of an apparatus for producing carbon nanofibers.
As shown in FIG. 3, in the carbon nanofiber manufacturing apparatus shown in FIG. 1, the catalyst metal 15 and the fluid gas 18 to be supplied to the fluidized bed reaction part are supplied from the bottom side of the furnace, and the carbon raw material 13 is supplied. By supplying it further downstream, more stable catalyst performance can be exhibited.
[0036]
For example, in the case of a bimetal (Co / Mo) catalyst as the catalyst metal, when the Co component and the Mo component are respectively supplied into the furnace in a liquid state and used as the bimetal metal, the catalyst is sufficient. After generating as a bimetal, the reaction efficiency is improved by making it react with a carbon raw material.
[0037]
【The invention's effect】
As described above, according to the present invention, by recirculating the fluidized material into the fluidized bed reaction part, adhesion of unreacted products and the like in the recovery line from the fluidized bed reaction part is eliminated. The carbon nanofibers adhering to the reaction product can be peeled and recovered, and the recovery efficiency of the carbon nanofibers is improved.
[Brief description of the drawings]
FIG. 1 is a diagram showing an outline of a carbon nanofiber manufacturing apparatus according to a first embodiment.
FIG. 2 is a diagram showing an outline of a carbon nanofiber production apparatus according to a second embodiment.
FIG. 3 is a diagram showing an outline of a carbon nanofiber production apparatus according to a third embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Fluidizer 12 Fluidized bed reaction part 13 Carbon raw material 14 Raw material supply means 15 Catalyst metal 16 Catalyst supply means 18 Fluid gas 19 Fluid gas supply means 20 Heating means 22 Carbon nanofiber 23 Recovery line 24 Separation means 31 Circulation line 33 Extraction port

Claims (5)

Supplying a fluidizing gas with the carbon raw material and the catalytic metal component in the fluidized bed reaction unit, a carbon nanofiber of a method for producing carbon nanofibers over using a fluidized material,
While producing the carbon nanofiber while circulating the fluid material ,
After recovering and separating the fluidized material and the carbon nanofibers from the fluidized bed reaction means and a plurality of outlets provided in the longitudinal direction of the fluidized bed reaction means, the fluidized material is separated from the fluidized bed reaction means. A method for producing carbon nanofibers, wherein the carbon nanofibers are recycled . Oite to claim 1,
A method for producing carbon nanofibers, wherein the circulating fluid material and the catalytic metal component are supplied from the lower part of the fluidized bed reaction means, and the carbon raw material is supplied downstream thereof. A fluidized bed reaction section filled with a fluidizing material;
A raw material supply means for supplying a carbon raw material into the fluidized bed reaction section;
Catalyst supply means for supplying a catalyst metal into the fluidized bed reaction section;
Fluidized gas supply means for introducing a fluidized gas that is introduced into the fluidized bed reaction section and fluidizes the fluidized material inside;
Heating means for heating the fluidized bed reaction section;
A collection line for collecting the carbon nanofibers and fluidized material generated from the fluidized bed reaction section;
A plurality of extraction means provided in the longitudinal direction of the fluidized bed reaction section;
After the recovery line and the withdrawal of carbon nanofibers collected by we mean a flow material is separated respectively, and wherein <br/> that the flow member has and a circulation line which Ru is recycled to the fluidized bed reaction unit Carbon nanofiber manufacturing equipment. In claim 3 ,
An apparatus for producing carbon nanofibers, comprising a separating means for separating the fluidized material circulating in the circulation line and the carbon nanofibers. In claim 3 ,
An apparatus for producing carbon nanofibers, wherein the catalyst metal and the fluid gas supplied to the fluidized bed reaction part are supplied from the bottom side of the furnace, and the carbon raw material is supplied downstream thereof.

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