WO2003066521A1

WO2003066521A1 - Method and apparatus for producing fine carbon material

Info

Publication number: WO2003066521A1
Application number: PCT/JP2002/001016
Authority: WO
Inventors: Kunio Nishimura; Hiromichi Maeno; Makoto Kato
Original assignee: Carbon Nanotech Research Institute Inc.
Priority date: 2002-02-07
Filing date: 2002-02-07
Publication date: 2003-08-14
Also published as: AU2002233631A1

Abstract

An apparatus for producing carbon nanotube which comprises a reacting furnace (10) which is vertically installed for forming a fine carbon material by the chemical vapor deposition method, a carrier supplying device (14) which is connected to the reacting furnace at its upper end portion for introducing carrier particles having a catalyst carried thereon into the reacting furnace, a reacting gas supplying device (17) for supplying a reacting gas containing a hydrocarbon into the reacting furnace, a carrier recovery device (21) which is connected to the reacting furnace at its lower end portion for discharging the carrier particles after the reaction out of the reacting furnace, and a reacted gas recovery device (27) which is connected to the reacting furnace at its upper end portion for discharging the gas having been reacted in the reacting furnace out of the furnace; and a method for producing a carbon nanotube using the apparatus. The apparatus can be used for producing a carbon nanotube having a fine fiber diameter and a sharp distribution of the diameter on a large scale with stability.

Description

TECHNICAL FIELD The present invention relates to various secondary batteries, such as Li-ion batteries, and fuel cells, which have excellent electron-emitting ability, hydrogen-absorbing ability, conductivity, and thermal conductivity. , FED, superconducting device, semiconductor, manufacturing method of fine carbon material used for conductive composite material and the like, and in particular, catalyst carrier using organic material such as hydrocarbon or carbon as raw material and carrying transition metal Technology for continuously producing fine carbon materials by chemical pyrolysis (CCVD), which synthesizes carbon fibers by reaction in a non-oxidizing atmosphere using

Background art

Among the fine carbon materials, the most noticeable are carbon nanotubes. Carbon nanotubes are a type of vapor-grown carbon fiber (VGCF) that has been studied for a long time, and have various names depending on the thickness of the fiber. Although the range and name of the fiber diameter are not uniquely defined, generally, a fiber diameter of 1 Atm or more is vapor-phase carbon fiber (VGCF), and a fiber diameter of 2 Onm or less is carbon fiber. Nanotubes (CNT) and those with a fiber diameter larger than 20 nm, which is between them, and smaller than 1 im are called carbon nanofibers (CNF).

Further, fine carbon materials having various shapes, such as a rifon shape and a coil shape, instead of the tube shape as described above, are known. The crystal structure of these fine carbon materials takes a variety of forms, including carbon-based basin planes (SWNTs), each of which has a cylindrical shape with a single layer rounded, and multiple layers of base plane Are laminated and have a concentric laminated structure (or an annual ring-shaped structure). Among them are nanohorns having a horn-like crystal structure in which the crystal plane is intermediate between the two, that is, the crystal plane spreads at a certain angle with respect to its central axis.

Examples of the fine carbon material having a shape other than the tube shape include a rifon-like fine carbon material having a structure in which basal planes are stacked so as to be orthogonal to a fiber direction, and a coil-like fine carbon material having an amorphous structure which does not exhibit crystallinity. Power such as carbon materials. Regardless of their shape, these fine carbon materials are produced by a CVD method that carbonizes a carbon source such as hide-hole carbon in the gas phase and at the same time crystallizes it in a fibrous form. Which type of material is to be produced can be selected by selecting the reaction system, for example, by appropriately setting the production conditions such as the type of carbon raw material, the type and combination of catalyst, the reaction atmosphere, and the reaction temperature. it can. The starting point of the research in this field was the study of vapor grown carbon fiber in the 1970s. The early development of VGCF centered on the fixed-bed method (CCVD method) in which the fiber diameter was large and the catalyst was placed on a substrate or supported on a carrier to react. However, in the early fixed-bed method for producing VGCF with relatively large fiber diameter, the growth rate of the fiber was low and the reaction yield power was low. Was.

However, in the 1980s, a CVD method was developed in which the catalyst was made to flow and react, and the yield power was significantly improved. It was actively researched again by companies such as Showa Denko, Nikkiso and Hyperion, and was commercialized in the mid 1990's with a fiber diameter of about 50 nm. However, even when this method is used to produce carbon nanotubes having a smaller fiber strength, the yield is reduced and the production is more difficult. At present, methods for producing carbon nanotubes with a fine fiber diameter of 20 nm or less include chemical pyrolysis (CVD), chemical pyrolysis using a catalyst-supporting carrier (CCVD), arc method, and laser method. It has been reported.

In particular, carbon nanotubes were relatively easily formed by the arc method in 1991. Since the report was published (Nature, 354, 56-58 (1991)), there has been an increasing movement to develop finer carbon fibers.

The method for producing single-walled carbon nanotubes and multi-walled carbon nanotubes with a fiber diameter of 50 nm0 or less, especially 20 nm0 or less, is produced by evaporating carbon at extremely high temperatures using the arc method and laser method. And a CCVD method using a fixed layer carrying a catalyst. However, the arc method and the laser method are not production methods suitable for mass production, and cannot be said to be production methods that can withstand industrialization.

On the other hand, the CCVD method using a fixed layer supporting a catalyst is basically the same method as the fixed layer method studied in the early stage of the development of VGCF, and it is necessary to manufacture fine carbon nanotubes. However, they differ in that fine pores such as zeolite are used for the catalyst carrier. In other words, the use of zeolite has succeeded in producing fine catalyst particles, and has made it possible to produce extremely fine carbon nanotubes.

However, at this stage, only a trial production capacity by the batch method, in which the operation of the production equipment is stopped every predetermined amount, is performed, and no industrial mass production report has yet been made.

(Problems of arc method and laser method)

The arc method and the laser method are not suitable as industrial production methods, because they not only complicate the structure of the apparatus, but also have poor productivity and difficulty in continuity. In addition, these methods are not only low in yield because non-fibrous carbon materials such as amorphous carbon are easily produced, but also produce the carbon nanotubes and the non-fibrous carbon materials. Separation is also difficult. Therefore, it is considered difficult to produce high-purity carbon nanotubes suitable for industrial products using the arc method.

(Problems of the CVD method)

The conventional CVD method, which does not use a catalyst carrier, uses a material with a fine fiber diameter that is considered to be the most suitable production method for mass production of carbon nanotubes. The quality of production is high, and the dispersion of the fiber diameter is large, which tends to be uneven. Further, there is a problem that the yield power decreases as the fiber diameter becomes smaller. Therefore, it is considered that it is difficult to stably produce a large amount of thin carbon nanotubes having a fiber diameter of 20 nm or less only by the conventional CVD method. DISCLOSURE OF THE INVENTION The present invention has been made in order to solve the above problems, and provides a production method capable of stably mass-producing carbon nanotubes having a small fiber diameter and a sharp distribution. It is one of the purposes.

Another object of the present invention is to provide a manufacturing apparatus capable of stably mass-producing carbon nanotubes having the above characteristics.

(C C V D method)

As mentioned above, the arc method, the laser method, and the CVD method have a difficult task to mass-produce carbon nanotubes with a small fiber diameter. Accordingly, the present inventors force ^s fiber diameter 5 0 nm or less, particularly thin fine force extremely fiber diameter of less than the fiber diameter 2 0 nm - was conducted various studies about the industrial process capable of mass production of carbon nanotubes However, it was concluded that a new CCVD method using a catalyst-supported carrier was preferable. That is, as a means for controlling the particle size of the transition metal catalyst supported on the carrier, a method using a carrier having fine pores is used.

Therefore, the reaction apparatus and the manufacturing process differ greatly depending on what kind and shape of the carrier for supporting the catalyst and in what method are used. For example, means for introducing the carrier into the reaction zone, means for moving the carrier in the reaction furnace, means for recovering the product, and the like, depending on the type of carrier selected from a molded body, a pellet, and a powder. In addition, the configuration of the separation means for separating the carbon nanotubes from the carrier and the configuration of the means for purifying the carbon nanotubes are greatly different. The present inventor has developed a method using a molded body or a method using a pellet-shaped carrier as a method for producing carbon nanotubes using the above-mentioned CCVD method. However, it has become clear that the following problems to be solved also exist in these methods using a molded article or a pellet-shaped carrier.

First, advanced technology is required to produce a molded carrier with strength and properties that can withstand industrial use. In other words, a complicated process is required to produce a molded body having excellent properties, which naturally increases the cost of the carrier. Also, when recycling the molded body to suppress the cost increase of the carrier, it is quite difficult to regenerate the porous carrier while maintaining the characteristics without destroying it. Second, regardless of whether a molded or pellet-shaped carrier is used, a part of the carrier undergoes a force during the movement or regeneration, and its characteristics gradually deteriorate, and the carrier is added to the product. Of fine powder is mixed.

Third, it is difficult to reliably remove and recover the carbon nanotubes generated on the surface of the support, and the process for separation is complicated.

Fourth, the efficiency of catalyst utilization is poor because the catalyst that has entered the inside of the carrier is not used effectively.

In particular, in the method using a molded or pellet-shaped carrier, the production equipment became complicated and the catalyst inside the carrier could not be effectively used. As a manufacturing method that can solve the above-mentioned problems of the CCVD method, development of a manufacturing method using fine zeolite powder as a carrier has been started. While working on the development of this production method, they learned that the following points are important for producing fine carbon materials with a small fiber diameter using a powdery catalyst carrier.

First, in order to effectively utilize the surface of the catalyst, a catalyst in which the catalyst is supported on a fine powder carrier is used as much as possible.

Second, the residence time of the catalyst in the reactor is made short and fixed to prevent the CVD reaction from proceeding further on the surface of the fine carbon material formed on the catalyst surface. Third, the catalyst-carrying carrier is supplied stably (the supply amount and the supply speed are kept constant), and the carrier is uniformly dispersed in the reactor.

Fourth, raise the temperature of the catalyst to the CVD reaction temperature as quickly as possible.

Fifth, stabilize the CVD reaction in the reactor.

Among these, suppressing the reaction on the surface of the generated fine carbon material is particularly important in producing a carbon material having a fine fiber diameter without increasing the fiber thickness. For this purpose, it is preferable to make the reaction time between the catalyst and the reaction gas (that is, the residence time in the reaction furnace) as short as possible.

As a result of intensive studies based on the above findings, in order to efficiently and stably produce a fine carbon material, a catalyst is supported on fine powder carrier particles, and the carrier particles are allowed to flow in a reaction furnace, The inventors have concluded that the power for generating a fine carbon material on the surface of the carrier particles is good, and have completed the present invention. The present invention solves the problems of the arc method, the laser method, and the ordinary CCVD method as described above, and can continuously produce a fine carbon material having excellent characteristics. It is intended to provide a production method and a production apparatus of the invention. In the method for producing a fine carbon material according to the present invention, a carrier particle carrying a contact butterfly containing at least one or more transition metals is introduced into a reaction gas containing a hydrocarbon, and the carrier particles are contained in the reaction gas. The method is characterized in that a fine carbon material is generated on the surface of the carrier particles while flowing the particles in one direction as a whole.

Such a production method is a production method in which a catalyst is supported on powder or fine particulate carrier particles, and the carrier particles are allowed to flow in a reaction gas to grow a fine carbon material on the surface of the carrier particles. In other words, by setting the shape of the carrier supporting the catalyst to be powder or fine particles, the surface area of the carrier can be increased and the CVD reaction can be efficiently performed on the surface. Further, since the carrier particles are caused to flow in the reaction gas, the residence time of the carrier particles in the reaction gas can be easily shortened and made constant. For example, in the case of producing a fibrous fine carbon material, the distribution of the fiber diameter of the carbon fibers can be made more uniform. In the present invention, " The term "total flow in one direction" means not the behavior of individual carrier particles in the reaction gas but the macroscopic behavior of the carrier particles flowing in the reaction gas. Next, the method for producing a fine carbon material according to the present invention comprises: introducing a carrier particle carrying a contact butterfly containing at least one or more transition metals into a reaction gas containing hide-portion carbon; Forming a fine carbon material containing fine carbon fibers having a diameter of 50 nm 0 or less and an aspect ratio of 10 or more on the surface of the carrier particles while flowing the carrier particles in one direction. And

According to this configuration, it is possible to provide a method for easily and stably producing a fibrous fine carbon material having excellent characteristics with a small fiber diameter and a large fiber length. Next, the method for producing a fine carbon material according to the present invention comprises: introducing a carrier particle carrying a contact butterfly containing at least one or more transition metals into a reaction gas containing hide-portion carbon; While the carrier particles are allowed to flow in one direction as a whole, the single-walled carbon nanotubes and the single-walled carbon nanotubes Z or the single-walled carbon nanotubes having a carbon planar force cylindrical shape composed of carbon atoms are laminated on the surface of the carrier particles. The method is characterized in that a fine carbon material including the multilayered carton nanotube is produced.

According to such a configuration, it is possible to provide a method for easily and stably producing single-walled and Z- or multi-walled carbon nanotubes. Next, in the method for producing a fine carbon material according to the present invention, a reaction gas for producing a fine carbon material therein by a thermochemical decomposition method is provided with a reaction gas containing a hydrocarbon and one or more transition metals. And introducing the reaction gas and the carrier particles in a direction facing each other (alternating current) to fluidize the catalyst and generate a fine carbon material on the surface of the carrier particles. Features.

According to such a configuration, the CVD reaction can proceed while keeping the concentration of the reaction gas in contact with the carrier particles and the flow rate of the reaction gas with respect to the carrier particles almost constant, so that the CVD reaction is formed on the carrier particles. Variations in the shape and dimensions of the fine carbon material can be reduced, and a fine carbon material with desired characteristics can be stably manufactured. You. Next, in the method for producing a fine carbon material according to the present invention, the reaction furnace is arranged in a vertical position, the carrier particles are introduced into the reaction furnace from an upper end of the reaction furnace, and the reaction gas is reacted with the reaction gas. The method is characterized in that it is introduced into the reaction furnace from the lower end of the furnace and the two are contact-reacted with each other by an alternating current to produce a fine carbon material on the surface of the carrier particles in the reaction furnace. In this production method, a reaction furnace arranged in a vertical position is used, a reaction gas is introduced from a lower end of the reaction furnace, and carrier particles are introduced from an upper end of the reaction furnace. This is a method for forming a fine carbon material. In this manufacturing method, the carrier particles introduced from the upper end of the reactor naturally fall toward the lower part of the reactor, pass through the reaction gas flowing from the lower part of the reactor toward the upper part of the reactor, and are supplied to the CVD reaction. Is done. Therefore, not only can the time for which the carrier particles stay in the gas be kept substantially constant, but also the falling speed of the carrier particles can be adjusted by changing the gas amount. In addition, the characteristics of the fine carbon material formed on the carrier particles can be controlled, and the variation can be suppressed. Next, in the method for producing a fine carbon material according to the present invention, the carrier particles are continuously introduced into the reaction furnace, and the surface of the carrier particles is introduced into the reaction furnace in which the reaction gas is continuously introduced. The method is characterized in that a fine carbon material is generated, and the carrier particles generated by the fine carbon material are continuously taken out of the reaction furnace.

According to such a manufacturing method, since the fine carbon material can be manufactured by continuously operating the reaction furnace, the fine carbon material can be efficiently manufactured. In particular, when the reactor is arranged vertically, the control of the reaction time (retention time of the carrier particles in the reactor) is easy, and the carrier particle force after the reaction is lower. Therefore, the supply and recovery of carrier particles are extremely easy, and a stable and efficient production of fine carbon material is possible. Next, in the method for producing a fine carbon material according to the present invention, at least a part of the post-reaction gas after being subjected to the reaction in the reactor is recycled by a recycling process provided outside the reactor. It is characterized in that it is put into the reactor again by a step and reused.

According to such a manufacturing method, since the gas after the reaction is recycled and reused, not only can the amount of the reaction gas used be reduced, but also the unreacted gas is recycled to the reaction furnace and becomes the raw material again. Thus, the manufacturing cost can be reduced. In particular, hydrogen gas and argon gas used as carrier gas tend to be used in large quantities in the production of fine carbon materials, even though they are relatively expensive, so recycling this carrier gas reduces costs. It is extremely effective. Next, the method for producing a fine carbon material according to the present invention is characterized in that the temperature of the reaction gas containing the hide-portion carbon is 500 ° C. or more and 130 ° C. or less. By setting the reaction gas temperature within the above range, a fine carbon material having uniform quality can be efficiently produced. If the reaction gas temperature is lower than 500 ° C., the reaction rate is low, and the production rate of the fine carbon material is low, which is not practical. On the other hand, when the temperature exceeds 130 ° C., the carbonization rate and the fiberization rate do not match, so that no fiber is produced. Further, a more preferable range of the reaction gas temperature is not less than 600 ° C. and not more than 125 ° C. Next, the method for producing a fine carbon material according to the present invention is characterized in that the carrier particles supporting the catalyst have an average particle size of 50 O jum or less.

By setting the average particle size of the carrier particles in the above range, a fine carbon material containing a large amount of fine carbon fibers having a fiber diameter of 50 mm or less can be produced. Next, the method for producing a fine carbon material according to the present invention is characterized in that the carrier particles supporting the catalyst have an average particle size of 10 μμπι or less.

By setting the average particle size of the carrier particles in the above range, a fine carbon material containing a large amount of fine carbon fibers having a fiber diameter of 50 mm or less can be produced in the same manner as described above. Next, the method for producing a fine carbon material according to the present invention is characterized in that the linear velocity of the reaction gas containing the hydrocarbon is in a range of 0.0 lm / sec or more and lmZ sec. By setting the linear velocity of the reaction gas within the above range, the residence time of the carrier particles can be easily adjusted, so that the reaction can be performed within a predetermined range of the residence time. Next, the apparatus for manufacturing a fine carbon material according to the present invention is connected to a reactor which is disposed in a vertical position to generate the fine carbon material by a thermochemical decomposition method therein, and an upper end of the reactor. A carrier particle supply unit for introducing a carrier particle carrying a catalyst into the reaction furnace; and a reaction connected to a lower end of the reaction furnace for supplying a reaction gas containing hydrocarbon into the reaction furnace. A gas supply unit, a carrier particle recovery unit connected to a lower end of the reaction furnace, and a carrier particle recovery unit for leading the carrier particles after the reaction out of the reaction furnace; and a reaction unit connected to an upper end of the reaction furnace. A reaction gas recovery unit for drawing out a post-reaction gas after being subjected to a reaction in the furnace to the outside of the reaction furnace; and a manufacturing apparatus having the above configuration. Stable and continuous fine carbon material with characteristics It can be produced efficiently. Next, the apparatus for producing a fine carbon material according to the present invention is characterized in that it is provided with a recycling means for re-introducing the post-reaction gas recovered in the reaction gas recovery section into the reaction furnace.

According to the manufacturing apparatus having such a configuration, the amount of the raw material and the carrier gas used for the manufacturing can be reduced, and the unreacted portion of the reaction gas can be recycled again as the raw material, so that the manufacturing cost can be reduced. . BRIEF DESCRIPTION OF THE FIGURES

FIG. I is a configuration diagram showing an example of the apparatus for producing a fine carbon material according to the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention is not limited to the following embodiments, with reference to the drawings. [Fine carbon material manufacturing equipment]

FIG. 1 is a configuration diagram showing an example of a configuration of a fine carbon material manufacturing apparatus according to the present invention.

The manufacturing apparatus shown in this figure comprises a tubular reactor 10 arranged in a vertical position, a heating device 11 arranged around the outer periphery of the reactor 10, and a reactor 10 at the upper end of the reactor 10. The carrier supply device (carrier particle supply unit) 14 connected to the provided carrier introduction port 10a and the reaction gas connected to the reaction gas introduction port 10c provided on the side of the lower end of the reactor 10 Supply device (reaction gas supply unit) 17, carrier recovery device (carrier particle recovery unit) 21 connected to carrier outlet 10 d provided at lower end of reactor 10, and reactor 10 A post-reaction gas recovery device (post-reaction gas recovery unit) 27 is connected to the reaction gas outlet 10b provided at the upper end. The reactor 10 has a cylindrical shape made of a heat-resistant material such as various types of ceramics and quartz, and is heated by a heating device 11 surrounding the outer periphery thereof, so that a thermochemical decomposition reaction proceeds therein. Further, FIG. 1 shows a cylindrical reactor 10, and the shape of the force reactor 10 is not limited to a cylindrical shape. The carrier supply device 14 includes a carrier supply source 1 for supplying carrier particles carrying a catalyst, a storage tank 13 for temporarily storing the carrier connected to the carrier supply source 12, and a storage tank 13. And a feeder 15 for supplying a certain amount of carrier particles from the storage tank 13 to the reactor 10 .The feeder 15 is connected to the carrier inlet 10 a at the upper end of the reactor 10. It is connected. According to the carrier supply device 14 having the above configuration, a certain amount of carrier particles can be continuously supplied to the reaction furnace 10. The feeder 15 can be used without any problem as long as it can transfer the powder at a constant speed, and various feeder powers such as an electromagnetic feeder, a screw feeder, and a table feeder can be applied.

The carrier supply device 14 shown in FIG. 1 is an example of a device configuration capable of supplying a certain amount of carrier particles. For example, a carrier is provided between the feeder 15 and the reaction furnace 10a. A configuration in which a heating means for preheating particles is provided may be employed. If performed, the catalyst supported on the carrier particles can be activated before being charged into the reaction furnace 10, and the reaction efficiency of the CVD reaction can be increased. The heating means for preheating heats the carrier particles until the carrier particles reach the reaction region (region where the carrier particle force s is generated when the fine carbon material is generated on the surface of the carrier particles) in the reactor 10. Any configuration is possible as long as it can be applied without any problem.For example, it may be provided at the upper end of the reaction furnace 10, or even if the storage tank 13 or the feeder 15 is directly heated by heating means. Good. As shown in FIG. 1, the reaction gas supply device 17 includes a source gas supply source 16 for supplying a source gas such as hydrocarbon and carbon monoxide, and a source gas supply source for adjusting the flow rate of the source gas. A mass flow controller (MFC) 16a connected to a supply source 16 and a carrier gas supply source 18 for supplying a carrier gas such as hydrogen gas or argon gas for diluting the source gas to a predetermined concentration. And an MFC 18a connected to a carrier gas supply source 18a for adjusting the flow rate of the carrier gas, and a gas pipe connected to the MFC 16a and 18a. It is connected to a reaction gas inlet 10 c provided at the lower end side surface of the reactor 10 through 19. As described above, the reaction gas supply device 17 of the present embodiment prepares a reaction gas by previously mixing the raw material gas and the carrier gas at a predetermined mixing ratio, and supplies the reaction gas to the reaction furnace 10. It has become. Further, it is also possible to adopt a configuration in which the raw material gas and the carrier gas are directly introduced into the reactor 10 respectively.

Further, in addition to the above basic configuration, a vaporizer for vaporizing the raw material to generate a raw material gas may be provided, for example, when the raw material is liquid at normal temperature. The carrier recovery device 21 is provided with a carrier recovery tank 20. The carrier recovery tank 20 has an inlet side 20 a force and a carrier outlet port 1 provided at the lower end of the reactor 10. 0 d is connected to a bag filter 25 described later, and the outlet side 2 O b is connected to a carbon material separation system 22 for separating the carrier and the fine carbon material grown on the surface thereof. . The post-reaction gas recovery device 27 is a device that collects and discharges post-reaction gas from the reaction furnace 10 after being subjected to the CVD reaction in the reaction furnace 10. Inside the cooling device 24 for cooling the gas, the bag filter 25 for separating the fine carbon material and the carrier, etc., which flowed in with the gas after the reaction from the gas after the reaction, and the gas recovery device 27 after the reaction And a blower 26 for adjusting the gas pressure.

The cooling device 24 reduces the load on the bag filter 25 and the blower 26 by cooling the high-temperature reaction gas. As the cooling device, it is preferable to use a cooling device capable of cooling the gas after the reaction by the heat resistance temperature of the bag filter 25 or the blower 26 to 130 ° C. or less. However, depending on the type of the raw material gas, liquefaction force s is generated by cooling, so that the temperature of the post-reaction gas is preferably equal to or higher than the temperature of the reaction gas supplied from the reaction gas supply device 17.

The pug filter 25 is connected to the cooling device 24 through a post-reaction gas inlet 25a, and converts the post-reaction gas introduced into the inside from the inlet 25a into a gas component (raw material). It has the function of separating solid components (such as carriers, fine carbon materials, and by-products of the CVD reaction) from components contained in gas and carrier gas. The separated gas component is exhausted from a gas component outlet 25 b provided at the upper part of the bag filter 25, and the solid component is discharged from the solid component outlet 2 provided at the lower portion of the bag filter 25. 5c is to be discharged.

The blower 26 is connected to the gas component outlet 25 b of the pug filter 25, and the pressure on the outlet side is higher than the pressure on the inlet side. That is, the post-reaction gas force s ′ flows from the reactor 10 power to the blower 26 through the cooling device 24 and the bag filter 25. This prevents the gas after the reaction from flowing back to the reaction furnace 10. The outlet side of the blower 26 is branched in two directions in the piping path, one of which is connected to the exhaust gas treatment system 28, and the other is connected to the reaction gas supply device 17 and the reactor It merges with the pipe 19 connecting the 10 and 10. With this configuration, in the manufacturing apparatus of the present embodiment, part of the post-reaction gas collected from the reaction furnace 10 is treated as exhaust gas, and the remainder is mixed with the reaction gas and recycled. In other words, in the manufacturing apparatus of the present embodiment, the post-reaction gas Recovering device 27 Forces The structure also functions as a means for recycling post-reaction gas.

Further, the carrier particles and the fine carbon material discharged from the solid component outlet 25 c of the bag filter 25 are sent to the carrier recovery tank 20, and passed through the carrier outlet 10 d of the reactor 10. It is sent to the carbon material separation system 22 together with the recovered carrier particles and fine carbon material. In the apparatus for manufacturing a fine carbon material according to the present embodiment, the atmosphere in the reaction zone (the inside of the reaction furnace 10 and a portion connected thereto) is not only a reducing atmosphere such as hydrogen, but also a hydride as a raw material. Because of the presence of carbon, the contact between the atmosphere of the reaction system and the outside air when the carrier particles are charged or recovered may cause an explosion or fire, and the fine carbon material generated on the surface of the carrier particles There is a high possibility that a polymer of hydrocarbon is attached to the surface, and when exposed to outside air at a high temperature, there is a risk that the fine carbon material will burn together with this polymer. Therefore, the following safety measures are taken in the manufacturing apparatus according to the present invention.

First, in order to prevent the outside air from coming into contact with the atmosphere of the reaction system, nitrogen gas or inert gas is supplied as necessary to maintain the pressure inside the system higher than that of the outside air. Prevent air contamination.

Second, the carrier supply device 14 and the carrier recovery device 21 directly connected to the reactor 10 are also provided with an inert gas supply source (not shown) and a cooling means (not shown). Since the catalyst supported on the carrier particles recovered in the carrier recovery device 21 is in a fine and highly active state, the atmosphere is replaced with an inert gas, and cooling is performed. The reactivity of the surface of the material is reduced, and the carrier particles are taken out after the material does not burn. The apparatus for producing a fine carbon material according to the present invention having the above-described configuration heats the carrier particles supporting the catalyst supplied from the carrier supply device 14 and the reaction gas supplied from the reaction gas supply device 17. The materials are mixed in a reaction furnace 10 heated to a predetermined temperature by the device 11, and a fine carbon material is generated by a CVD reaction on the surface of the carrier particles. this The carrier particles containing the fine carbon material generated by the CVD reaction in the reaction furnace 10 are collected in the carrier recovery unit 21, and the post-reaction gas after the reaction is subjected to the post-reaction gas recovery unit 27. Is to be collected.

Then, the post-reaction gas collected in the post-reaction gas recovery device 27 is separated into a solid component and a gas component by a bag filter 25, and the solid component is recovered in the carrier recovery device 21 and the carbon material is recovered. It is sent to the separation system 22. In addition, a part of the gas component separated by the bag filter 25 is mixed with the reaction gas supplied from the reaction gas supply device 17, re-input to the reaction furnace 10, and recycled. . Gas components of the non-recycled post-reaction gas are appropriately treated in an exhaust gas treatment system 28 and then discharged as exhaust gas. By recycling such post-reaction gas, it is possible to reduce the amount of reaction gas (particularly carrier gas) used, and to reduce the scale of the carrier gas system and the production cost. At the same time, the amount of gas discharged as exhaust gas is also reduced, thus reducing the cost of exhaust gas treatment. As described above, according to the apparatus for manufacturing a fine carbon material of the present embodiment, the carrier particles that continuously support the catalyst and the fine carbon material are placed in a reactor for producing the fine carbon material by the CVD reaction. The reaction gas containing the raw material is continuously supplied, and the carrier particles and the post-reaction gas used in the CVD reaction and the generated fine carbon material can be continuously recovered from the reaction furnace 10. As a result, continuous operation for a long time is possible. In addition, the reactor is disposed at a vertical position of 10 s, and the carrier particles move from the upper part to the lower part of the reactor 10, and the reaction gas moves from the lower part to the upper part of the reactor 10. Therefore, even when the time (reaction time) for force contact between the carrier particles and the reaction gas is shortened, the control can be easily performed, and the variation in the reaction time for each carrier particle can be reduced. This makes it possible to easily and stably produce carbon nanotubes of stable and uniform quality even when producing extremely fine force-bon nanotubes with a fiber diameter of 20 nm or less. In the manufacturing apparatus according to the present invention, the fine carbon material is Any type of production system can be used, including the type and combination of catalysts, catalyst concentration on carrier particles, selection of raw materials, gas flow rate, reaction gas concentration, reaction temperature, furnace gas composition, etc. The production can be appropriately changed depending on the type of the fine carbon material to be produced (fiber diameter ゃ length, etc.).

[Method for producing carbon nanotubes]

Next, a method for producing carbon nanotubes using the production apparatus according to the present invention will be described below. In the present embodiment, a case where an inert gas or a reducing gas is used as a carrier gas will be described using a manufacturing apparatus having the configuration shown in FIG. As the inert gas, helium, argon, neon, xenon, krypton, radon, nitrogen and the like can be used. When a reducing gas is used as a carrier gas, hydrogen and methane can be used.

(Preparation of reaction system)

In order to produce carbon nanotubes by the production apparatus of the present embodiment having the configuration shown in FIG. 1, first, a reaction system is prepared. For example, the reactor 10 and a portion connected to the reactor 10 are replaced with a non-oxidizing atmosphere by flowing argon gas, for example. Next, the heating device 11 on the outer periphery of the reaction furnace 10 is operated, and the inside of the reaction furnace 10 is heated to a predetermined temperature within a range of 500 to 130 ° C., and the temperature is increased. To maintain. Then, a carrier gas is introduced into the system from the reaction gas supply device 17. When using a reducing gas such as hydrogen gas or methane gas, flow an inert carrier gas for a certain period of time, and then check the oxygen concentration in the reactor 1. If it is confirmed that the oxygen concentration is below the explosion limit, preferably 1% or less, the reducing gas can be supplied. When the preparation of the reaction system is completed by the above operations, the supply of the catalyst carrier can be started. In the production method of the present invention, examples of the catalyst supported on the surface of the carrier particles include iron, cobalt, nickel, yttrium, titanium, vanadium, manganese, chromium, copper, niobium, molybdenum, palladium, tungsten, and platinum. Transition metal Con, and these compounds can be used. These may be used alone or in combination of two or more.

The form of the compound of the catalyst may be a simple metal, an organic compound, an inorganic compound, or a combination thereof. For example, examples of the organic compound include Hua-Sen, Nickel-Sen, Cobalt-Sen and other metal complexes, or iron acetate, cobalt acetate, and nickel acetate. In addition, the inorganic compound may be in any form such as an oxide, a hydroxide, a nitrate, a sulfate, a chloride, and a carbonyl compound of the transition metal.

Further, as the carrier particles for supporting the catalyst, there can be used general carrier particles such as alumina, silica gel, zeolite, magnesia, activated carbon, etc. As far as possible, the pore force is small, and Pore shape is good. The shape of the carrier particles applied to the present invention is a powder. The carrier particles supplied from the carrier supply source 12 for use in the present reaction are preliminarily loaded with a catalyst and subjected to a predetermined pretreatment. For example, an ethanol solution of the catalyst is prepared, and the carrier particles are immersed in this solution, and then a predetermined amount of the catalyst is adsorbed on the surface while rotating. The carrier particles can be obtained by heating to about 140 ° C. to evaporate ethanol. It is preferable that the carrier particles carrying the catalyst be heated to about 700 ° C. to be activated before being charged into the reaction furnace 10.

The average particle diameter of the carrier particles is preferably 500 μm or less, more preferably 100 im or less. By using such carrier particles whose average particle size is controlled, it becomes easier to control the fiber diameter / aspect ratio (ratio of fiber diameter to fiber length) of the formed fine carbon material, and to obtain uniform quality fine particles. The production capacity of carbon materials becomes easier.

(Supply of carrier)

Next, the carrier particles are supplied to the reaction furnace 10. In order to supply the carrier particles to the reaction furnace 10, first, the carrier particles are put into the storage tank 13 from the carrier supply source 12 of the carrier supply device 14, and a predetermined amount is stored in advance. At this time, the carrier particles may be activated by heating. In addition, the atmosphere in the portion connected to the reactor 10 is inert gas ^ And keep it in an inert atmosphere. Next, after confirming that the preparation of the reaction system has been completed, the carrier particles are introduced from the storage tank 13 to the reaction furnace 10 at a constant supply speed by the feeder 15. In the manufacturing apparatus of the present invention, the supply speed of the carrier particles can be easily and accurately controlled by the transport speed of the feeder 15.

(Chemical pyrolysis reaction)

At the same time as or before the supply of the carrier particles into the reaction furnace 10 is started, the supply of the reaction gas from the reaction gas supply device 17 is started. That is, the source gas is supplied from the source gas supply source 16 while controlling the flow rate by the MFC 16a, and the carrier gas is supplied from the carrier gas supply source 18 while controlling the flow rate by the MFC 18a to supply the gas. The reaction gas is mixed in the reactor 9 to generate a reaction gas, and the reaction gas is introduced from the reaction gas inlet 1 Oc on the side of the lower end of the reactor 10 through the gas pipe 19. As the raw material gas, general hydrocarbon or carbon monoxide can be used, and even if it is liquid at normal temperature, it can be used after being vaporized by vaporizing means. Specific examples include, but are not limited to, benzene, toluene, methane, ethane, alcohol, butane, pentane, hexane, ethylene, cyclohexane, and acetylene. Further, a heating means can be provided in the gas pipe 19 to preheat the reaction gas introduced into the reaction furnace 10. In this case, it is preferable to heat the solution to 200 ° C. or more and introduce it into the reaction furnace 10.

Then, the carrier particles introduced from the upper part of the reaction furnace 10 are introduced into the reaction furnace 10 in a state where the reaction gas flows at a predetermined flow rate from the lower part to the upper part of the reaction furnace 10. While falling toward the bottom of 0, a fine carbon material is grown on the surface of the carrier particles by a chemical pyrolysis reaction.

(Removal of catalyst carrier)

The carrier particles formed on the surface of the fine carbon material by the CVD reaction while falling in the reactor 10 reach the bottom of the reactor 10. (At that time, some of them were separated from the carrier.) Then, the carrier was recovered from the carrier outlet 10 d at the bottom of the reactor 10 into the carrier recovery tank 20 of the carrier recovery unit 21. You. Carrier recovery tank The carrier particles taken out into the carrier particles and the fine carbon material separated from the carrier particles are temporarily stored in the carrier recovery tank 20 and, after being cooled, unreacted hydrocarbons adhered to the surface by an inert gas. After the reaction and reaction by-products are replaced, they are taken out of the carrier recovery tank 20. The carrier particles taken out of the carrier recovery tank 20 are sent to a carbon material separation system 28 for separating and collecting the fine carbon material on the surface, where the fine carbon material on the surface is separated and collected. In order to separate the carbon material from the carrier particles in the carbon material separation system 28, for example, when the carrier particles are zeolite, only the fine carbon material can be easily removed by dissolving the zeolite by means of an aluminum alloy. Can be put out.

By the above operation, the production apparatus according to the present invention can continuously and stably produce a fine carbon material.

[Example 3

Hereinafter, the ability to clarify the effects of the present invention with reference to the examples. The following examples do not limit the present invention.

In this example, the carbon nanotubes were formed on the surface of the powdery carrier particles using the carbon nanotube manufacturing apparatus shown in FIG. '' As the reactor 10, a cylindrical tube made of SiC having an inner diameter of 22 O mm 0 and a length of 210 O mm L was used.The heating device 11 had a length of 120 O O mm L. A tube having a heating portion with an inner diameter of 26 O mm0 was arranged so as to surround the outer periphery of the reactor 10.

Y-type zeolite with an average particle size of 2 m was used as the carrier particles, and cobalt and vanadium were used as the transition metals of the catalyst to be adsorbed on the surface of the carrier particles. To support the catalyst on the carrier particles, a 2.5% ethanol solution of cobalt acetate and vanadium acetate is prepared, the carrier is immersed in the solution, and a predetermined amount is adsorbed while rotating the carrier. Was. Then, the support was heated to 140 ° C. to dry, and heated to 700 ° C. to activate the catalyst.

Then, the reaction furnace 10 was heated to 7110 ° C. by the heating device 11, and this temperature was maintained. Acetylene was used as the source gas to be introduced into the reactor 10, and its flow rate was Was set to 3 LZmin. Argon was used as the carrier gas, and the flow rate was 22 LZ min.

The powdery carrier particles supporting the catalyst were continuously charged into a production apparatus in which the reaction system was maintained under the above production conditions, and carbon nanotubes were grown on the carrier particles. The fiber diameter of the carbon nanotubes produced in this example was extremely thin, 2 to 5 nm, and the fiber diameter had little variation. The total production amount of carbon nanotubes and carrier particles in this production was 1 38 g per hour. When zeolite was dissolved from the collected carrier particles with alkali to separate carbon nanotubes alone, the amount of carbon nanotubes produced per hour was 70 g / h. The yield of this generated amount with respect to the carbon amount of the input raw material gas was 36%, which was higher than the yield of carbon nanotubes by the conventional batch method.

Further, by using the above-described production apparatus and production method of the present invention and adjusting the combination of the conditions of the reaction system (type of raw material, concentration of hydrocarbon, type of catalyst, type of carrier, etc.), the fiber diameter is 20 nm. It was confirmed that the above-mentioned multi-carbon nanotubes and carbon nanofibers can be manufactured.

Industrial applicability

According to the present invention, a technology capable of continuously producing fine carbon materials such as fine carbon nanotubes has been developed. This method is not only capable of continuous power, but also has excellent operational stability, and is suitable for mass production of fine carbon materials. In addition, it is a technology that can control the residence time of the catalyst in the furnace and enables a short reaction time, and is suitable for producing carbon nanotubes with uniform thickness and excellent linearity. In particular, it is a method suitable for producing fine fibrous carbon materials with a fiber diameter of 50 nm or less, especially 20 nm or less.In the examples, the fiber diameter is extremely thin, 2 to 5 nm, and by-products It has been confirmed that good carbon nanotubes can be obtained with less power.

Further, in the production method according to the present invention, fine carrier particles are used as carrier particles for supporting the catalyst, so that not only the existing carrier can be used as it is, but also the Since it can be used, the surface of the support can be used reliably, and the reaction proceeds with high efficiency. The catalyst utilization efficiency is high, and the reaction rate and carbon yield are good. As described above, the method for producing a fine carbon material according to the present invention is capable of being continuous, and has a high yield, so that carbon nanotubes of high quality and with little variation can be obtained at low cost, It is a suitable manufacturing method. In addition, when the production method of the present invention is compared with a method using a molded article or a pellet, the present invention is characterized by a force s' that makes it possible to extremely increase the use efficiency of the catalyst. Next, the manufacturing apparatus for a fine carbon material according to the present invention is a useful manufacturing apparatus to which the manufacturing method according to the present invention is applied, and is capable of inexpensively obtaining carbon nanotubes of high quality and less variation thereof. This is a manufacturing device suitable for industrialization. It should be noted that the present invention can be implemented in various other forms without departing from its main features. The above embodiments are merely examples and should not be construed as limiting. The scope of the present invention is defined by the appended claims, and is not restricted by the specification text. Also, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

Claims

The scope of the claims

1. Into a reaction gas containing a hydrocarbon, carrier particles carrying a winged butterfly containing at least one or more transition metals are introduced, and the carrier particles are caused to flow in a certain direction as a whole in the reaction gas. And producing a fine carbon material on the surface of the carrier particles.

2. Introducing carrier particles carrying at least one or more transition metals into a reaction gas containing a hydrocarbon, and allowing the carrier particles to flow in one direction in the reaction gas, 2. The method for producing a fine carbon material according to claim 1, wherein a fine carbon material having a diameter of 50 nm0 or less and a fine carbon fiber having an aspect ratio of 10 or more is produced on the surface.

3. Introduce carrier particles carrying a winged butterfly containing at least one transition metal into a reaction gas containing a hydrocarbon, and allow the carrier particles to flow in one direction as a whole in the reaction gas. While producing a fine carbon material including single-walled carbon nanotubes having a cylindrical carbon plane formed of carbon atoms on the surface of the carrier particles and / or multi-walled carbon nanotubes on which the single-walled carbon nanotubes are stacked. 3. The method for producing a fine carbon material according to claim 2, wherein

4. Introducing a reaction gas containing hydrocarbon and carrier particles carrying a catalyst containing one or more transition metals into a reactor for generating a fine carbon material by thermochemical decomposition inside,

The reaction gas and the carrier particles in a direction facing each other.

The method for producing a fine carbon material according to any one of claims 1 to 3, wherein the method further comprises flowing the catalyst to fluidize the catalyst to generate a fine carbon material on the surface of the carrier particles.

5. Placing the reactor in a vertical position, introducing the carrier particles into the reactor from the upper end of the reactor, and introducing the reaction gas from the lower end of the reactor into the reactor. The contact reaction between the two is carried out by alternating current,

5. The method for producing a fine carbon material according to claim 4, wherein a fine carbon material is generated on the surface of the carrier particles in the reaction furnace.

6. continuously introducing the carrier particles into the reaction furnace, generating a fine carbon material on the surface of the carrier particles in the reaction furnace in which the reaction gas is continuously introduced; 6. The method for producing a fine carbon material according to claim 4, wherein the carrier particles produced by the material are continuously taken out.

7. At least a part of the post-reaction gas after being subjected to the reaction in the reaction furnace is supplied to the reaction furnace again by a recycle means provided outside the reaction furnace and reused. The method for producing a fine carbon material according to any one of claims 4 to 6, wherein:

8. The fine coal according to any one of claims 1 to 7, wherein the temperature of the reaction gas containing the hide port carbon is 500 ° C. or more and 130 ° C. or less. Manufacturing method of raw materials.

9. The method for producing a fine carbon material according to claim 1, wherein the carrier particles supporting the catalyst have an average particle diameter of 500 μπι or less.

10. The method for producing a fine carbon material according to claim 9, wherein the carrier particles supporting the catalyst have an average particle diameter of 100 m or less.

11. The fine particle according to any one of claims 1 to 10, wherein the linear velocity of the reaction gas containing the carbon at the hide port is in the range of 0.1 Olm / sec or more to 1 mZsec. Manufacturing method of carbon material.

1 2. A reactor placed vertically to generate fine carbon material by thermochemical decomposition inside,

A carrier particle supply unit connected to an upper end of the reaction furnace, for introducing carrier particles supporting a catalyst into the reaction furnace;

A reaction gas supply unit connected to a lower end of the reaction furnace, for supplying a reaction gas containing hydrocarbon into the reaction furnace;

A carrier particle recovery unit connected to a lower end of the reaction furnace, for leading the carrier particles after the reaction out of the reaction furnace;

A post-reaction gas recovery unit that is connected to an upper end of the reaction furnace and guides post-reaction gas after the reaction in the reaction furnace to outside the reaction furnace;

An apparatus for producing a fine carbon material, comprising:

13. The apparatus for producing a fine carbon material according to claim 12, further comprising a recycle unit for re-introducing the post-reaction gas collected in the reaction gas recovery unit into the reaction furnace. .