JP5066828B2 - Method for producing carbon material - Google Patents

Description

  The present invention relates to a method for producing a carbon material capable of producing a carbon material efficiently and with high purity.

  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.

  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 (Non-Patent Document 1). 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.

  In contrast, single-walled nanotubes have an inner diameter of approximately 0.4 to 10 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.

  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.

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 (Patent Document 1).
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.

  In addition to the arc discharge method described above, a gas nanotube pyrolysis method, a laser sublimation method, a condensed phase electrolysis method, and the like have been proposed as methods for producing carbon nanotubes (Patent Documents 2 to 4).

S, Iijima, Nature, 354, 56 (1991) Japanese Patent Laid-Open No. 06-280116 Japanese Patent No. 3100962 JP-T-2001-520615 JP 2001-139317 A

  However, any of the production methods disclosed in these documents is a laboratory or small-scale production method, and there is a problem that the yield of the carbon material is low and the purity is particularly low.

Here, the mechanism by which impurity carbon, which is an example of a carbon material with poor purity, grows will be described with reference to FIG.
As shown in FIG. 20, an active metal 2 that is a catalyst is supported on a carrier 1 that is a base material, and a carbon source (for example, methane CH ₄ ) that is a carbon raw material is supplied to the surface of such an active metal 2. Then, carbon is dissolved from methane adhering to the active metal surface and re-deposited, whereby the nanocarbon material 3 grows. The carbon of the carbon source gradually dissolves to reprecipitate the nanocarbon material, but impurities 4 such as amorphous carbon and graphite carbon also grow simultaneously on the surface of the active metal 3.
By covering the surface of the active metal 2 with the impurities 4, the penetration of carbon (C source) from the carbon source is inhibited, and as a result, the growth of the nanocarbon material 3 is stopped.

  In recent years, various uses of carbon materials have been expanded, and for this reason, the advent of an apparatus that can produce carbon materials with good purity while being able to be produced efficiently in large quantities is desired.

  In view of the above circumstances, an object of the present invention is to provide a manufacturing method and apparatus capable of continuously mass-producing and manufacturing a carbon material having high purity.

The first invention of the present invention for solving the above-described problem is a method for producing a carbon material using a carbon raw material by a reactor, and decomposes impurity carbon generated during the growth of the carbon material. The carbon material production method is characterized in that the carbon material is produced while controlling the concentration of water to be discharged from the reactor at 770 ppm or more and 10,000 ppm or less .

A second invention is the carbon material production method according to the first invention, wherein the carbon material is produced while controlling the concentration of the moisture at the reactor inlet to be 12000 ppm or less.

A third invention is the method for producing a carbon material according to the first or second invention, wherein the carbon material is nanocarbon.

A fourth invention is the method for producing a carbon material according to the third invention, wherein the nanocarbon is a single-walled or multi-walled carbon nanotube, a fishbone type or a platelet type carbon fiber.

According to the present invention, the activity of the catalyst can be promoted and the life of the catalyst can be extended by controlling the outlet concentration of the water reactor for decomposing impurity carbon to be 770 ppm or more.
As a result, the carbon material can be efficiently manufactured, and large-scale mass production can be realized.

  Further, when the carbon material is a carbon nanotube, as a result of promoting the catalytic reaction, the density is very high, and the length of the carbon nanotube can be dramatically increased.

  Further, as a result of the absence of impurity carbon, only a pure carbon material is obtained, and a high-purity carbon material can be obtained from the carbon material product even if additional operations such as catalyst removal and impurity removal are performed.

  Hereinafter, the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by this embodiment and an Example. In addition, constituent elements in the following embodiments and examples include those that can be easily assumed by those skilled in the art or those that are substantially the same.

[First Embodiment]
A carbon material manufacturing apparatus for manufacturing a carbon material according to a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic view showing a carbon material manufacturing apparatus according to the first embodiment.
As shown in FIG. 1, a carbon material manufacturing apparatus 10A according to the present embodiment includes a fluid source 21 composed of a carbon source 14 such as methane, a carrier having an active component such as iron, and the fluid catalyst 21. A fluidized gas 22 to be fluidized in the fluidized bed reactor 23 is supplied to the fluidized bed reactor 23 supplied through the material supply line 20 and the material supply line 20 to adjust the moisture concentration. An adjustment device 25 and an outlet-side moisture meter 27 that measures the moisture concentration on the outlet side are provided in the discharge line 26 of the carbon material product 24 on the outlet side of the fluidized bed reactor 23. Instead of the fluid catalyst 21, a fluid may be supplied separately by supplying a catalyst. Further, the material supply lines 20 may be separate from each other.

  In the present embodiment, the material supply line 20 to which the carbon source 14, the flow catalyst 21, and the flow gas 22 are supplied is provided with a moisture concentration adjusting device 25 that adjusts the moisture concentration, and measurement using the outlet-side moisture meter 27. Therefore, the concentration of moisture that decomposes the impurity carbon is adjusted so as to obtain a predetermined concentration.

  In the present invention, the moisture content is adjusted by the outlet-side moisture meter 27 on the outlet side of the fluidized bed reactor 23, and the moisture concentration adjusting device 25 is used with a control device (not shown) so that the moisture concentration becomes 770 ppm or more. The water content is adjusted to control the reaction so that the impurity carbon is not generated.

  Further, the upper limit of the water concentration on the outlet side of the reactor is preferably about 32000 ppm, preferably about 10000 ppm. Especially preferably, it is suitable to set it as the range of 770-6800 ppm.

  As a result of adjusting the concentration of the impurity carbon decomposition product by the moisture concentration adjusting device 25, the impurity carbon decomposition product having a predetermined concentration decomposes the impurity carbon such as amorphous carbon and graphite carbon covering the catalyst surface in the fluidized bed reactor 23. It can be removed and the catalytic activity can be maintained, and a good fluidization reaction is promoted. As a result, the carbon material product 24 with high purity can be grown.

Here, as a moisture measuring device used for the outlet side moisture meter 27, for example, moisture: dew point meter, telescopic hygrometer, plate-type hygrometer, earthman hygrometer, specular cooling dew point meter, electric hygrometer (resistance type, Capacitance type), but the present invention is not limited to these.
By this moisture measurement, the moisture on the outlet side can be set to a predetermined amount of moisture, and the carbon material can be produced with high efficiency and high purity.

  In addition, a moisture meter may be provided in the moisture concentration adjusting device 25 to measure the moisture concentration on the inlet side. In this case, it is preferable that the concentration of water at the reactor inlet is 12000 ppm or less, more preferably 6000 ppm or less.

Moreover, when manufacturing the fluid catalyst 21, the upper limit of the sum total of the water content which the fluid catalyst 21 contains and the water content added separately is set to 12000 ppm.
Note that the amount of moisture may be adjusted so that it does not become 770 ppm or less, which is the lower limit value of the moisture concentration on the outlet side.

  Here, the carbon material in the present invention is a carbon material of a nano unit and a micro unit, and the supplied carbon source acts on the catalyst, and is reprecipitated and appears, for example, in a fiber shape, a tube shape, a cup shape, etc. It refers to carbon having various shapes. Here, the nano-unit carbon material is referred to as nanocarbon.

  Examples of the nanocarbon include, for example, single-walled carbon nanotubes (SWNTs), other nanotubes such as multi-walled carbon nanotubes (MWNTs), fishbone-type or platelet-type carbon fibers, and the like. In the production, the carbon material can be drastically grown by applying the impurity carbon decomposition product.

  An outline of the decomposition mechanism for decomposing the impurity carbon is shown in FIG. 2 by taking as an example the production of a carbon nanotube which is one of the carbon materials. Note that this decomposition mechanism is an estimation example, and the present invention is not limited to this.

  As shown in FIG. 2, the presence of moisture in the vicinity of the catalyst 11 supported on the carrier 12 inhibits the decomposition or growth of the impurity carbon 17 that grows on the surface of the catalyst 11, and as a result, the carbon dissolves. The obstruction factor is removed. Therefore, as a result of the impurity carbon 17 being decomposed and removed, the growth of the carbon nanotubes 16 is not inhibited and the growth is promoted.

  As described above, when moisture in a suitable range is present, the water acts as a protective agent so that the impurity carbon 17 covering the catalyst is decomposed and the catalyst surface is not covered with the impurity carbon 17 such as amorphous carbon. Will be fulfilled.

  In the moisture concentration adjusting device 25, examples of the humidity control method for applying moisture include the following methods, but the present invention is not limited to this.

  Examples of the humidity control method for applying moisture include a method of supplying water to a gas line with a pump. Other examples include, for example, a method of bubbling gas into water, a method of mixing a predetermined amount of particles containing a predetermined amount of water of crystallization into a catalyst, a method of simultaneously charging the reactor, for example, magnesium hydroxide inert to the reactor Various methods such as a method of adding a hydrate or the like can be mentioned.

[Second Embodiment]
Next, an example of production in a fluidized bed reactor when water is applied as the impurity carbon decomposition product will be described with reference to FIG.
FIG. 3 is a schematic view of a carbon material production apparatus 10B using a fluidized bed reactor that performs moisture adjustment and decomposes and removes impurity carbon according to the second embodiment. In addition, about the same member as the fluidized bed reactor of FIG. 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted.
As shown in FIG. 3, in the carbon material manufacturing apparatus 10 </ b> B according to the present embodiment, the fluidized catalyst 21 is heat-treated in a pretreatment apparatus 31 provided in the material supply line 20. Here, the heat treatment condition in the pretreatment apparatus 31 is to perform either a dehumidification treatment of about 200 to 300 ° C. or a heat treatment of 300 ° C. or higher, preferably 800 ° C.

  The dehumidifying treatment at about 200 to 300 ° C. is for removing water contained in the fluidized catalyst 21. On the other hand, the heat treatment at 300 ° C. or higher makes the active sites smaller by refining the sites of the catalyst supported on the carrier. By performing this pretreatment, a finer nano-unit carbon material can be obtained.

  The fluid catalyst 21 pretreated by the pretreatment device 31 has its moisture concentration measured by the first moisture meter 33-1.

  In addition, the carbon source 14 and the flowing gas 22 are dehumidified by the dehumidifying device 32, and the moisture concentration is measured by the second moisture system 33-2. As a result, the fluid catalyst 21, fluid gas 22 and carbon source 14 are all dehumidified. Therefore, by supplying a predetermined amount of water 34 to the material supply line 20, the moisture is adjusted before entering the fluidized bed reactor 23.

After the addition of moisture, the third moisture meter 33-3 is monitored on the inlet side of the fluidized bed reactor 23 in order to confirm whether the addition is within the specified range.
Further, in order to confirm whether or not moisture is maintained at a predetermined concentration in the fluidized bed reactor 23, an outlet side moisture meter 27 is installed on the outlet side of the fluidized bed reactor 23.

  After supplying a predetermined amount of water 34 in this way, the third moisture meter 33-3 and the outlet moisture meter 27 are installed on the inlet side and the outlet side of the fluidized bed reactor 23. For example, the inlet is 10000 ppm, The outlet can be continuously monitored to reach 800 ppm, and when the reference value of the moisture concentration on the outlet side is exceeded, the carbon content is constantly decomposed in the fluidized bed reactor 23 by appropriately adjusting the amount. A good carbon material having a high purity and a long length is produced so that the water 34 as a product falls within a specified range.

Here, examples of the method for removing moisture include a cooling dehumidification method, a compression dehumidification method, a solid adsorption dehumidification method, a liquid absorption dehumidification method (cassava method), and a membrane separation method. It is not limited to these.
As the cooling and dehumidifying method, for example, air is cooled to a dew point or lower to remove condensed water. It can be applied when the dew point is 8 to 10 ° C or higher.
As the compression dehumidification method, wet air is compressed and cooled to separate moisture.
Moreover, as said solid adsorption type dehumidification method, water | moisture content is adsorbed | sucked to a solid moisture absorbent by capillary action.
In addition, as the liquid absorption dehumidification method (cassava method), air is absorbed during spraying of the lithium chloride aqueous solution to absorb moisture.
As the membrane separation method, separation is performed using a moisture-impermeable membrane.

  When carbon materials are manufactured by applying such various water removal methods, the gas introduced into the reactor and the water in the catalyst are controlled so that the impurity carbon is efficiently decomposed and removed. ing.

  Alternatively, a water supply device that supplies a predetermined amount of water after the water is almost completely removed may be used.

  Further, the water supply portion may be heated, or water may be supplied to the gas preheating portion. Further, after humidity adjustment, heating may be performed by a separately provided heating means.

  Further, after dehumidification, for example, a molecular species containing oxygen gas or oxygen atom can be used as a substance other than the water to be introduced, which can be used as a substitute for water.

[Third Embodiment]
Next, an example of production in another fluidized bed reactor in the case of applying water as the impurity carbon decomposition product will be described with reference to FIG.
FIG. 4 is a schematic view of a carbon material production apparatus 10C using a fluidized bed reactor that performs moisture adjustment according to the third embodiment to decompose and remove impurity carbon. In addition, the same code | symbol is attached | subjected about the same member as the fluidized bed reactor of FIG.1 and FIG.3, and the description is abbreviate | omitted.
As shown in FIG. 4, the carbon material manufacturing apparatus 10 </ b> C according to the present embodiment converts moisture contained in the fluid catalyst 21 into fluid gas 22 instead of the pretreatment device 31 in the manufacturing apparatus shown in FIG. 3 described above. A water exchange device 35 is installed.

The moisture exchange device 35 converts the moisture contained in the fluid catalyst 21 into the fluid gas 22 and turns the fluid gas into the moisture rich fluid gas 36.
The moisture-rich fluid gas 36 is measured for its moisture content by an inlet-side moisture meter 33 installed on the inlet side of the fluidized bed reactor 23, and the moisture exchange rate in the moisture exchange device 35 is adjusted so as to obtain a predetermined moisture content. It is adjusted.

  In the present embodiment, an outlet-side moisture meter 27 is also installed on the outlet side of the fluidized bed reactor 23 so that the moisture content is monitored on the inlet side and the outlet side of the fluidized bed reactor 23. Therefore, for example, it is possible to continuously monitor the inlet at 10000 ppm and the outlet at 770 ppm. And, for example, when the reference value is exceeded, the water content is adjusted appropriately so that the water content, which is the impurity carbon decomposition product, is always within the specified range in the fluidized bed reactor 23. A good carbon material having a high length and a long length is produced.

[Fourth Embodiment]
In the present embodiment, a carbon material production system including a fluidized bed reactor and a recovery device will be described with reference to FIG.
FIG. 5 is a schematic view of a specific example of an apparatus for producing carbon nanofibers according to the fourth embodiment.
As shown in FIG. 5, a carbon material product (coarse particles) 24-in which a carbon material is produced and adhered to the carbon material production apparatus 50 and the coarse granular fluid catalyst 21 staying in the fluidized bed among the carbon materials. 2 is recovered from the manufacturing apparatus, and the carbon material product (fine particles) 24-1 generated and attached to the fine fluid catalyst 21 accompanied with the exhaust gas 57 is separated from the exhaust gas 57 and the recovery apparatus 52, And a carbon material refining device 55 for separating the fluid catalyst 21 from the recovered carbon material.

  Specifically, the carbon material production system includes a fluidized bed reaction unit 23-1 filled with a fluidized catalyst 21 that is a fluidized material, and a raw material that supplies the carbon source 14 into the fluidized bed reaction unit 23-1. The supply device 41, the fluidized catalyst supply device 42 for supplying the fluidized catalyst 21 into the fluidized bed reaction unit 23-1, and the fluidized catalyst 21 that is the fluidized material in the fluidized bed reaction unit 23-1 scatter and flow down. A free board part 23-2 having a space, a fluidized gas supply device 43 for supplying a fluidized gas 22 introduced into the fluidized bed reaction part 23-1 and fluidizing the fluid catalyst 21 inside, and a fluidized bed reaction part 23- A first recovery line 51-1 for recovering the carbon material product (fine particles) 24-1 scattered together with the exhaust gas 57 from the free board portion 23-2, and a first recovery line Collect at line 51-1. The separation / recovery device 52 for separating and recovering the exhaust gas 57 from the fluidized catalyst 21 and the carbon material product (fine particles) 24-1 and the fluidized catalyst 21 and the carbon material product (coarse particles) from the fluidized bed reaction unit 23-1. ) The second recovery line 51-2 for extracting 24-2, the extracted fluid catalyst 21 and the carbon material product (coarse particles) 24-2, and the carbon material product (fine particles) from the separation / recovery device 52) 24-1 is recovered, and the carbon material product (fine particles) 24-1 and the catalyst adhering to the carbon material product (coarse particles) 24-2 recovered by the recovery device 53 are removed. The carbon material refining device 55, which is a pure carbon material 56, the exhaust gas treatment device 58 for treating the exhaust gas 57 separated by the separation / recovery device 52, and the outlet side provided in the first recovery line 51-1. of Those comprising an outlet-side water meter 27 for measuring a quantity.

  In this embodiment, an impurity carbon decomposition product concentration control device 15 that controls the amount of impurity carbon decomposition products that decompose the impurity carbon in the carbon source 14, the flowing gas 22, and the flow catalyst 21 is provided in the material supply line 20. Thus, the amount of impurity carbon decomposition products is adjusted on the upstream side of the fluidized bed reaction section 23-1. In the present embodiment, the manufacturing apparatus according to the second embodiment is applied as the carbon material manufacturing apparatus 50, but the present invention is not limited to this.

The fluidized bed reaction mode of the fluidized bed reaction section 23-1 includes a bubble fluidized bed type and a jet fluidized bed type, and any of them may be used in the present invention.
In this embodiment, the fluidized bed reactor 23 is comprised from the fluidized bed reaction part 23-1, the free board part 23-2, and the heating part 23-3. Moreover, the free board part 23-2 has a larger flow-path cross-sectional area than the fluidized bed reaction part 23-1.

The carbon source 14 supplied from the raw material supply device 41 may be any carbon-containing compound, such as CO, CO ₂ , alkanes such as methane, ethane, propane and hexane, ethylene, and the like. , Unsaturated organic compounds such as propylene and acetylene, aromatic compounds such as benzene and toluene, organic compounds having an oxygen-containing functional group such as alcohols, ethers and carboxylic acids, polymer materials such as polyethylene and polypropylene, or petroleum And coal (including coal conversion gas) and the like, but the present invention is not limited to these. In order to control the oxygen concentration, two or more oxygen-containing carbon sources CO, CO ₂ , alcohols, ethers, carboxylic acids and the like and carbon sources not containing oxygen can be supplied in combination.

  The carbon source 14 is supplied in a gas state into the fluidized bed reaction section 23-1, and a uniform reaction is performed by stirring with the fluidized catalyst 21 that is a fluidized material, thereby growing the carbon material. At this time, an inert gas is separately introduced into the fluidized bed reaction section 23-1 as the fluidized gas 22 by the fluidized gas supply device 43 so as to satisfy the predetermined fluidization conditions.

  Further, the catalyst may be supplied into the reaction means in a solid or gas state. In this case, a catalyst supply means may be provided separately.

  The carbon material is brought into contact with the catalyst for a certain period of time in a coexisting environment of impurity carbon decomposition products in a temperature range of 300 ° C. to 1300 ° C., more preferably in a temperature range of 400 ° C. to 1200 ° C. Synthesizing.

  In addition to the cyclone, the separation / collection device 52 may be a known separation means such as a bag filter, a ceramic filter, or a sieve.

Further, the carbon material product 24 separated by the separation / recovery device 52 is converted into a nano-unit carbon material (for example, carbon nanotube, carbon nanofiber, etc.) pure product 56 by a carbon material purification device 55 for separating the attached catalyst. To be collected as.
In the present embodiment, the proportion of moisture that decomposes the impurity carbon is adjusted by the outlet-side moisture meter 27, so that the activity of the catalyst can be promoted in the reactor, and the life of the catalyst can be extended. Materials can be manufactured efficiently, and as a result, large-scale mass production can be realized.

  In the present invention, the size of the carbon material is not limited to that of a nano unit, and can be applied in the production of all carbon materials.

  Further, the production can also be applied to known carbon material reaction methods such as a gas bed reaction method, a fixed bed reaction method, a moving bed reaction method, and a fluidized bed reaction method.

Next, although one Example which manufactured the carbon material by adjusting an outlet side moisture concentration is shown below, the present invention is not limited to this.
In this example, as the carbon material reactor, for example, a fixed bed reactor in which a catalyst is arranged on a substrate was used. As the carbon raw material, methane (CH ₄ ) was used, and as the catalyst, an Fe—Mo based catalyst using MgO as a carrier was used. Then, at a reaction temperature of the reactor of, for example, 750 ° C., the moisture concentration on the outlet side is adjusted to a moisture content of 770 ppm, 1500 ppm, 1800 ppm, 5200 ppm, 6800 ppm to produce carbon nanotubes. It decomposed and promoted the growth of single-walled carbon nanotubes.

  The TEM photographs at that time are shown in FIGS. 6 to 10, and the corresponding TG / DTG curves are shown in FIG. 13 (water concentration: 1500 ppm), FIG. 14 (water concentration: 1800 ppm), and FIG. 15 (water concentration: 6800 ppm). .

  Here, for example, thermogravimetric analysis (TG) was used as a means for burning the carbon nanotubes and measuring the thermogravimetry thereof. The thermogravimetric analysis (TG) shows the relationship between the temperature (° C.) and the thermogravimetric analysis (%) when the carbon nanotubes are burned 100%, and the combustion curve is also called a TG curve. The differentiated TG curve is called a DTG curve, which shows the relationship between temperature and differential thermogravimetric analysis (μg / sec).

  For comparison, the case where the outlet water concentration was 230 ppm and 10400 ppm was shown. The TEM photographs at that time are shown in FIGS. 11 to 12, and the TG / DTG curve is shown in FIG. 16 (230 ppm). Carbon nanotubes could not be formed when the outlet water concentration was 230 ppm. In addition, when the outlet water concentration was 10400 ppm, the amount of carbon nanotubes produced was very small.

  Thus, single-walled carbon nanotubes having a length of about 2.5 mm could be grown for 10 minutes at a predetermined outlet moisture concentration (for example, 770 to 6800 ppm).

  As a result of promoting the catalytic reaction with water, the single-walled carbon nanotube forest is very dense and drastically grown in length (single-walled carbon nanofibers grow as densely as a forest Such a state). In addition, the catalyst could be easily removed from the product, and the purity of the carbon nanotubes after removal of the catalyst was 99.98% or more.

[Test example]
Next, the inlet side moisture concentration, the moisture concentration during the reaction, and the outlet side moisture concentration were measured, and the relationship between the moisture concentration and the amount of produced carbon was tested.

In this example, as the carbon material reactor, for example, a fixed bed reactor in which a catalyst is arranged on a substrate was used. As the carbon raw material, methane (CH ₄ ) was used, and as the catalyst, an Fe—Mo based catalyst using MgO as a carrier was used. When the reaction temperature of the reactor is, for example, 750 ° C. and the moisture concentration on the inlet side is 20% CH ₄ , the reactor is adjusted to 570 ppm, 3000 ppm, 4400 ppm, 3200 ppm, 4050 ppm, 4700 ppm, 4900 ppm, 5000 ppm, 6000 ppm, 7000 ppm, 12000 ppm. In the case of 80% CH ₄ , carbon nanotubes were prepared by adjusting to 3000 ppm, 6000 ppm, 12000 ppm, and 16000 ppm.
The results are shown in FIGS.

In the figure, white square marks indicate the case of CH ₄ 20%, and black square marks indicate the case of CH ₄ 80%.
FIG. 17-1 shows the relationship between the inlet water concentration [ppm] and the produced carbon (C) / catalyst [%], and FIG. 17-2 shows the inlet S (steam) / C (carbon) and the produced carbon (C). / The relationship with the catalyst [%] is shown.
FIG. 18-1 shows the relationship between the maximum outlet moisture concentration [ppm] during the reaction and the produced carbon (C) / catalyst [%], and FIG. 18-2 shows the maximum outlet S (steam) / C during the reaction. The relationship between (carbon) and produced carbon (C) / catalyst [%] is shown.
FIG. 19-1 shows the relationship between the final outlet moisture concentration [ppm] and the produced carbon (C) / catalyst [%], and FIG. 19-2 shows the final outlet S (steam) / C (carbon). And carbon (C) / catalyst [%].

  From the results of the test, the carbon generation was good when the inlet water concentration was 12000 ppm or less. At this time, the maximum water concentration during the reaction was about 32000 ppm. Further, when the outlet water concentration at the end of the reaction was about 7300 ppm or less, the production of carbon was good.

  As described above, the method for producing a carbon material according to the present invention promotes the activity of the catalyst and extends the life of the catalyst by controlling the ratio of the impurity carbon decomposition product that decomposes the impurity carbon in the reactor. Carbon material can be efficiently manufactured, and mass production of a large-scale carbon material can be realized.

It is the schematic of the manufacturing apparatus of the carbon material which concerns on 1st Embodiment. It is the schematic of the mechanism of decomposition | disassembly which decomposes | disassembles impurity carbon. It is the schematic of the manufacturing apparatus of the carbon material which concerns on 2nd Embodiment. It is the schematic of the manufacturing apparatus of the carbon material which concerns on 3rd Embodiment. It is the schematic of the specific example of the apparatus which manufactures the carbon nanofiber which concerns on 4th Embodiment. It is a transmission electron microscope (TEM) photograph of the product of the present invention (exit water concentration 770 ppm). It is a transmission electron microscope (TEM) photograph of the product of the present invention (exit water concentration 1500 ppm). It is a transmission electron microscope (TEM) photograph of the product of the present invention (exit water concentration 1800 ppm). It is a transmission electron microscope (TEM) photograph of the product of the present invention (exit water concentration 5200 ppm). It is a transmission electron microscope (TEM) photograph of the product of the present invention (exit water concentration 6800 ppm). It is a transmission electron microscope (TEM) photograph of a comparative product (exit water concentration 230 ppm). It is a transmission electron microscope (TEM) photograph of a comparative product (exit water concentration 10400 ppm). It is a TG / DTG curve diagram of the product of the present invention (exit water concentration 1500 ppm). It is a TG / DTG curve diagram of the product of the present invention (exit water concentration 1800 ppm). It is a TG / DTG curve diagram of the product of the present invention (exit water concentration 6800 ppm). It is a TG / DTG curve diagram of a comparative product (exit water concentration 230 ppm). It is a relationship diagram of inlet water concentration [ppm] and produced carbon (C) / catalyst [%]. FIG. 4 is a relationship diagram of inlet S (steam) / C (carbon) and produced carbon (C) / catalyst [%]. It is a relationship diagram of maximum outlet water concentration [ppm] in the middle of reaction and produced carbon (C) / catalyst [%]. It is a relationship diagram of the largest exit S (steam) / C (carbon) in the middle of reaction, and produced | generated carbon (C) / catalyst [%]. FIG. 4 is a relationship diagram between the final outlet moisture concentration [ppm] and the produced carbon (C) / catalyst [%]. FIG. 4 is a relationship diagram of the final reaction outlet S (steam) / C (carbon) and produced carbon (C) / catalyst [%]. It is a schematic diagram of the impurity generation in the production | generation of a carbon material.

Explanation of symbols

14 Carbon source (C source)
DESCRIPTION OF SYMBOLS 21 Fluid catalyst 22 Fluid gas 23 Fluidized bed reactor 24 Carbon material product 25 Moisture concentration adjusting device 27 Outlet side moisture meter

Claims (4)

In the method for producing a carbon material in which a carbon material is produced by a reactor using a carbon raw material,
A method for producing a carbon material, comprising producing a carbon material while controlling a concentration at a reactor outlet of moisture that decomposes impurity carbon generated during the growth of the carbon material to be 770 ppm or more and 10,000 ppm or less . Oite to claim 1,
A method for producing a carbon material, comprising producing a carbon material while controlling the concentration of moisture at a reactor inlet to be 12000 ppm or less. In claim 1 or 2 ,
The method for producing a carbon material, wherein the carbon material is nanocarbon. In claim 3 ,
The method for producing a carbon material, wherein the nanocarbon is a single-walled or multi-walled carbon nanotube, a fishbone-type or platelet-type carbon fiber.

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