JP2012166991A - Raw material gas diffusion suppression-type apparatus for producing carbon nanostructure - Google Patents

Abstract

[PROBLEMS] To suppress the diffusion of a raw material gas in the continuous synthesis process of carbon nanostructures and maintain the initial concentration of the raw material gas at a high concentration, and to suppress the diffusion of the raw material gas capable of mass-producing high-quality carbon nanostructures. It is providing a type carbon nanostructure manufacturing apparatus.
SOLUTION: A conveyor belt 19 having a catalyst layer 31 formed on the surface thereof is carried into a reaction furnace 1 to sequentially transport a temperature rising region 3 and a reaction region 2, and the catalyst layer that has passed through the temperature rising region 3 is transferred to the reaction region 2. And the CNTs are grown on the catalyst layer by the raw material gas. The diffusion suppressors 6 and 7 reduce the cross section in the furnace, leaving a gap 8 through which the transport belt 19 can pass, partition the boundary region between the temperature raising region 3 and the reaction region 2, and supply the raw material gas supplied to the reaction region 2 Is suppressed to the temperature rising region 3 side.
[Selection] Figure 1

Description

  The present invention relates to a carbon nanostructure manufacturing apparatus for manufacturing carbon nanostructures such as carbon nanotubes and carbon nanocoils, and in particular, high quality carbon nanostructures by suppressing diffusion of a raw material gas in a reaction region. The present invention relates to a raw material gas diffusion suppression type carbon nanostructure manufacturing apparatus.

  The carbon nanostructure of the present invention is a nano-sized material composed of carbon atoms. For example, carbon nanotubes (CNT), beaded CNTs in which beads are formed on carbon nanotubes, brush-like CNTs in which many CNTs are erected CNTs are twisted carbon nano twists, coiled carbon nano coils (CNC), carbon nano horns, and the like. Hereinafter, these many carbon materials are collectively referred to as carbon nanostructures.

  As a method for producing these carbon nanostructures, a thermal CVD method, which is a type of chemical vapor deposition method (CVD method, chemical vapor deposition) in which a source gas such as hydrocarbon is decomposed to grow a target material, That is, a catalytic chemical vapor deposition method (CCVD, Catalyst Chemical Vapor Deposition) in which a target substance is grown using a catalyst is known.

  When mass-producing carbon nanostructures based on catalytic chemical vapor deposition, the reaction area for continuous growth of carbon nanostructures using a catalyst substrate is expanded to make the carbon nanostructure production equipment large. It is necessary to make it.

Emperor Suekin, Takeshi Nagasaka, Toshinori Nosaka, Yoshiaki Nakayama, Applied Physics 13, Volume 73 (2004), No. 5, pp. 615-619 M.M. Ymaguchi, L .; Pan, S.M. Akita, and Y.A. Nakayama. Effect of Residual Accessylene Gas on Growth of Vertically Aligned Carbon Nanotubes. Japan Journal of Applied Physics, Vol. 47, no. 4, pp. 1937-1940, 2008.

Non-Patent Document 1 discloses a study of a formation mechanism related to the synthesis of brush-like CNTs. The formation mechanism based on this consideration is as follows. When the temperature of the raw material gas acetylene gas C ₂ H ₂ is raised to around 700 ° C. before being supplied to the reaction furnace, the Fe catalyst film is granulated. As an initial stage of CVD synthesis, carbon atoms are absorbed from the C ₂ H ₂ molecules into the particulate catalyst, a part of it diffuses inside the catalyst, and the other migrates on the catalyst surface. When a graphene layer with a curvature on the catalyst surface (hereinafter referred to as a cap) is formed, it is considered that CNTs grow at a stretch. Therefore, efficient cap formation is necessary to produce high-quality brush-like CNTs. Becomes important. In particular, Non-Patent Document 1 suggests that the cap can be formed efficiently if the concentration of the raw material gas in the initial reaction is increased.
Non-Patent Document 2 discloses that in order to synthesize higher-quality highly-oriented CNTs, it is necessary to reduce the concentration of acetylene C ₂ H ₂ gas serving as a carbon source to a low concentration of 10 ppm or less before the reaction. Has been.

In order to carry out continuous synthesis of CNTs by increasing the initial concentration of the raw material gas, the temperature of the catalyst substrate is raised in the temperature rising region, then transferred to the reaction region, and the raw material gas is supplied to the surface. A manufacturing process that sequentially performs a synthesis process by gas supply is effective. However, when such a manufacturing process is attempted, the inside of the reactor is open, so that the source gas flows out and diffuses out of the reaction region, and the catalyst substrate is exposed to a high concentration of C ₂ H ₂ during the temperature rising process. In addition, since the initial concentration of the raw material gas is lowered, the CNT growth becomes insufficient, resulting in a problem that high quality CNTs cannot be produced.

In view of the above problems, an object of the present invention is to prevent diffusion of a raw material gas in a continuous synthesis process of carbon nanostructures and to prevent the catalyst base from being exposed to a high concentration of C ₂ H ₂ during a temperature rising process. An object of the present invention is to provide a raw material gas diffusion suppression type carbon nanostructure manufacturing apparatus capable of maintaining an initial gas concentration at a high concentration and capable of mass-producing high-quality carbon nanostructures.

As a result of intensive studies to solve the above problems, the present inventors have grown a carbon nanostructure by raising the temperature of the catalyst substrate to the synthesis temperature and supplying the raw material gas to the heated catalyst substrate. We succeeded in continuously synthesizing high-quality carbon nanostructures by providing a diffusion suppression region that suppresses the diffusion of the source gas between the growth regions (reaction regions).
In the first aspect of the present invention, a reaction furnace provided with a reaction region and a temperature raising region, a raw material gas supply means for supplying a raw material gas provided in the reaction region, and a carrier gas for supplying the temperature rising region A carrier gas supply means, a heating means for heating the reaction region to the growth temperature of the carbon nanostructure, a temperature raising means for raising the temperature raising region, and a catalyst substrate carried into the reaction furnace, A catalyst substrate transport means for sequentially transporting the temperature rising region and the reaction region, transferring the catalyst substrate that has passed through the temperature rising region to the reaction region, and carbon nanostructures on the catalyst substrate by the source gas A carbon nanostructure manufacturing apparatus for growing a gas, wherein a cross section in the furnace is reduced leaving a gap through which the catalyst substrate can pass, and a boundary region between the temperature rising region and the reaction region is partitioned and supplied to the reaction region Was Serial raw material gas, the a raw material gas diffusion suppressing type carbon nanostructure manufacturing apparatus with suppressing diffusion suppressing body diffusion into the heated region side.

  According to a second aspect of the present invention, in the first aspect, the diffusion suppressor is a single partition plate having a predetermined thickness that sharply reduces the concentration distribution of the source gas at a partition end in contact with the reaction region. Or it is the raw material gas diffusion suppression type | mold carbon nanostructure manufacturing apparatus which consists of several partition plates which have predetermined | prescribed total thickness.

  According to a third aspect of the present invention, in the second aspect, the equation of motion of a model fluid as a laminar flow continuum that diffuses from the reaction region to the temperature rising region via the diffusion suppressor, the continuity equation, and the raw material Set gas mass fraction transport equations, apply the characteristic values of the source gas to the velocity and pressure of the model fluid derived from these equations, and at least the reaction region and the diffusion suppressor In the raw material gas diffusion suppression type carbon nanostructure manufacturing apparatus, the concentration distribution of the raw material gas is determined, and the predetermined thickness or the predetermined total thickness and the reduced partial cross-sectional shape of the diffusion suppression body are determined according to the determined concentration distribution. is there.

According to a fourth aspect of the present invention, in the second aspect, the density of the model fluid is represented by ρ, the viscosity coefficient is μ, and the velocity is u (u is u = (u _x , u _y , u _z ). The vector component is omitted in the following description.), The pressure of the model fluid is p, the generation term for the flow velocity u (the generated amount per unit time / unit volume) is _Su , and the mass fraction of the source gas is m. _{i represents} the diffusion flux of the source gas as J _i (J _i is a vector represented by J _i = (J _ix , J _iy , J _iz ), and the component display is omitted hereinafter). Then, the equation of motion is ρ (u · grad) u = div (μgradu) −gradu + S _u (F1)
And
The continuous equation is
div (ρu) = 0 (F2)
And
The mass fraction transport formula of the source gas is
div (ρum _i ) = − divJ _i (F3)
And
It is a raw material gas diffusion suppression type carbon nanostructure manufacturing apparatus that obtains the concentration distribution by applying the characteristic value of the raw material gas to the pressure p and the velocity u.

  According to a fifth aspect of the present invention, in the second, third, or fourth aspect, the concentration distribution of the source gas is indicated by a molar fraction of the source gas with respect to the carrier gas, and at least the source material at the partition end It is a raw material gas diffusion suppression type carbon nanostructure manufacturing apparatus in which the molar fraction of gas is 100 ppm or less.

  A sixth aspect of the present invention is the raw material gas diffusion suppression type carbon nanostructure manufacturing apparatus according to any one of the second to fifth aspects, wherein the predetermined thickness or the predetermined total thickness is 15 mm or more. is there.

  A seventh aspect of the present invention is the raw material gas diffusion suppression type carbon nanostructure manufacturing apparatus according to any one of the first to sixth aspects, wherein the catalyst substrate transport means is an endless belt running in the reaction furnace. is there.

  An eighth aspect of the present invention is the raw material gas diffusion suppression type carbon nanostructure manufacturing apparatus according to the seventh aspect, wherein the endless belt is formed of a SUS material.

  According to a ninth aspect of the present invention, in any one of the first to sixth aspects, the belt body travels in the reaction furnace while winding one end side of the belt body wound around the winding roller around the winding roller. The catalyst substrate transport means is configured by a roll-to-roll device, and a catalyst layer is formed on the surface side of the belt body to form the catalyst substrate, and the belt body is spaced from the temperature rising region to the gap. A raw material gas diffusion suppression type in which the carbon nanostructure is grown on the catalyst layer by passing it to the reaction region, the grown carbon nanostructure is recovered, and the belt body is wound around the winding roller This is a carbon nanostructure manufacturing apparatus.

  A tenth aspect of the present invention is the raw material gas diffusion suppression type carbon nanostructure manufacturing apparatus according to the ninth aspect, wherein the belt body is formed of a SUS material.

  According to an eleventh aspect of the present invention, in any one of the first to tenth aspects, the catalyst substrate transport means includes a plurality of supply ports in the width direction of the catalyst substrate for supplying the source gas to the reaction region. A raw material comprising a raw material gas supply pipe provided with an outflow passage for flowing out the raw material gas supplied to the reaction region to the back side of the catalyst base, and an exhaust means for exhausting the raw material gas flowing out of the outflow passage It is a gas diffusion suppression type carbon nanostructure manufacturing apparatus.

  According to a twelfth aspect of the present invention, in any one of the first to eleventh aspects, a raw material gas diffusion suppression type carbon nanostructure, wherein the carbon nanostructure is a brush-like carbon nanotube grown on the catalyst substrate. It is a manufacturing device.

  According to the first aspect of the present invention, the catalyst base is carried into the reaction furnace by the catalyst base transporting means, the temperature rising region and the reaction region are sequentially transported, and the catalyst that has passed through the temperature rising region. The substrate is transferred to the reaction region and carbon nanostructures are grown on the catalyst substrate by the source gas, and the diffusion suppressor reduces the cross section in the furnace leaving a gap through which the catalyst substrate can pass. Partitioning the boundary region between the temperature rising region and the reaction region, and suppressing diffusion of the source gas supplied to the reaction region to the temperature rising region side, the carbon nanostructure in the continuous synthesis process The diffusion of the raw material gas is prevented, the catalyst base is not exposed to the high concentration raw material gas in the temperature rising region, and the initial concentration of the raw material gas can be maintained at a high concentration in the reaction region. car It is possible to perform mass production of N'nano structure. The gap has a size that allows at least the catalyst substrate to pass therethrough, and can be formed by a narrow gap that suppresses diffusion of the source gas into the temperature rising region as much as possible.

  The carbon nanostructure manufacturing apparatus according to the present invention can be used for manufacturing carbon nanostructures such as CNTs, CNTs with beads, brush-like CNTs, carbon nanotwists, CNCs, and carbon nanohorns.

The source gas is not limited to acetylene, and for example, alkanes such as methane, ethane, propane, and butane, alkenes such as ethylene, and hydrocarbon gases such as alkynes other than acetylene can be used.
As the carrier gas, a rare gas such as He or Ar can be used.
The catalyst used for the growth of the carbon nanostructure of the present invention includes Fe, FeInSn and FeInCo Fe-In-Sn catalysts, and Fe-Mg-Sn catalysts FeMgSn and FeMgCo in which In is replaced with inexpensive Mg. Furthermore, Fe—SnCo and FeMgSnCo which are Fe—Mg—Sn—Co based catalysts to which Co is added can be used.

  According to the second aspect of the present invention, the diffusion suppressor is a single partition plate having a predetermined thickness that sharply drops the concentration distribution of the source gas at a partition end in contact with the reaction region, or a predetermined partition plate. Since it comprises a plurality of partition plates having a total thickness, when the catalyst base passes through the diffusion suppressing body, the concentration of the source gas rises sharply from the vicinity of the partition end, and the initial concentration of the source gas is increased. The carbon nanostructure can be smoothly grown while maintaining the concentration, and a high-quality carbon nanostructure can be produced.

  According to the third aspect of the present invention, the equation of motion of a model fluid as a laminar flow continuum that diffuses from the reaction region to the temperature rising region via the diffusion suppressor, the continuity equation, and the mass of the source gas By setting the fractional transport equation and applying the characteristic value of the source gas to the velocity and pressure of the model fluid derived from these equations, at least the reaction region and the diffusion suppressor The concentration distribution is obtained, and the predetermined thickness or the predetermined total thickness and the reduced partial cross-sectional shape of the diffusion suppressing body are determined in accordance with the obtained concentration distribution. Therefore, the diffusion mode of the model fluid is determined from the obtained concentration distribution. By grasping and determining the predetermined thickness or the predetermined total thickness capable of maintaining the initial concentration of the source gas at a high concentration and the reduced partial cross-sectional shape of the diffusion suppressing body, high-quality carbon Roh structure it is possible to realize a material gas diffusion suppression type carbon nanostructure manufacturing apparatus which enables production.

  According to the fourth aspect of the present invention, from the equation of motion of (F1), the equation of continuity of (F2) and the mass fraction transport equation of (F3), the pressure of the source gas is increased at the pressure p and the velocity u. Since the concentration distribution is obtained by applying a characteristic value, the diffusion mode of the model fluid is grasped from the concentration distribution obtained based on the equation of motion, the continuous equation and the mass fraction transport equation, Carbon capable of determining the predetermined thickness or the predetermined total thickness capable of maintaining the initial concentration of the raw material gas at a high concentration and the reduced partial cross-sectional shape of the diffusion suppressing body, and capable of producing a high-quality carbon nanostructure A nanostructure manufacturing apparatus can be realized.

  For example, the amount of leakage due to the diffusion of the raw material gas into the temperature rising region is about 1000 ppm, and even if the decrease in the raw material gas concentration in the reaction region is negligible, the catalyst substrate is high in the temperature rising region. If exposed to the concentration of the source gas, good quality carbon nanostructures cannot be grown in the reaction region. That is, according to the fifth aspect of the present invention, the source gas at the time of heating in the temperature rising region is set by the diffusion suppressor so that the molar fraction of the source gas at least at the partition end is 100 ppm or less. Can be maintained in a non-contact state, so that the synthesis of the reaction region and the temperature increase in the temperature rising region can be performed separately, and a high-quality carbon nanostructure can be smoothly produced without causing growth failure in the reaction region. You can grow things. In particular, a carbon nanostructure of better quality can be grown preferably by setting the molar fraction of the source gas to 10 ppm or less.

  According to the sixth aspect of the present invention, the diffusion suppressor having the predetermined thickness or the predetermined total thickness of 15 mm or more suppresses diffusion of the source gas to the temperature rising region side. Therefore, it is possible to prevent the raw material gas from diffusing in the continuous synthesis process of the carbon nanostructure, maintain the initial concentration of the raw material gas at a high concentration, and perform mass production of the high-quality carbon nanostructure.

  In the seventh aspect of the present invention, the catalyst substrate transport means comprises an endless belt that travels in the reaction furnace. Therefore, the catalyst substrate transport means is placed on the catalyst substrate on the endless belt, and the temperature raising region and the reaction region are separated from each other. It can convey sequentially and can perform the continuous synthesis | combination of a high quality carbon nanostructure.

  According to the eighth aspect of the present invention, since the endless belt is formed of a SUS material, the carbon nanostructure by continuous synthesis in which high-temperature treatment is performed using a SUS material excellent in heat resistance, rust prevention property, and strength. Contributes to high quality and mass production.

  According to a ninth aspect of the present invention, the catalyst substrate transport means is configured by the roll-to-roll device, a catalyst layer is formed on the surface side of the belt body to form the catalyst substrate, and the belt body is The carbon nanostructure is grown on the catalyst layer by passing through the gap from the temperature region to the reaction region, the grown carbon nanostructure is collected, and the belt body is wound around the winding roller. Therefore, the belt body itself can be used as a catalyst carrier, and the belt body can be reused by collecting the grown carbon nanostructure, and the quality, mass production and low production of the carbon nanostructure can be reduced. Cost reduction can be realized.

  According to the tenth aspect of the present invention, since the belt body is formed of a SUS material, a high temperature treatment is performed using a SUS material excellent in heat resistance, rust prevention and strength as a catalyst carrier. Contributes to high quality and mass production of carbon nanostructures by continuous synthesis.

  According to an eleventh aspect of the present invention, the catalyst substrate transport means comprises a source gas supply pipe provided with a plurality of supply ports for supplying the source gas to the reaction region in the width direction of the catalyst substrate, and the reaction Since the outflow passage through which the raw material gas supplied to the region flows out to the back side of the catalyst base and the exhaust means for exhausting the raw material gas outflowed from the outflow passage are provided, the raw material gas supply pipe allows the catalyst base to be exhausted. The source gas is uniformly supplied in the width direction of the gas, and the source gas flowing out from the outflow passage can be exhausted by the exhaust means, and the source gas is quantitatively supplied to the entire catalyst surface of the catalyst base. To achieve mass production of high-quality carbon nanostructures and improved yield by homogeneous growth.

  The raw material gas diffusion-suppressing carbon nanostructure manufacturing apparatus according to the present invention prevents the raw material gas from diffusing in the continuous synthesis process and maintains the initial concentration of the raw material gas at a high concentration, High quality can be achieved. In particular, according to the twelfth aspect of the present invention, mass production of highly oriented brush-like carbon nanotubes sufficiently grown on the catalyst substrate can be realized.

It is a schematic sectional drawing which shows the schematic sectional structure of the raw material gas diffusion suppression type | mold CNT manufacturing apparatus which concerns on embodiment of this invention. It is an external appearance perspective view which shows the diffusion suppression body which concerns on this invention. It is the longitudinal cross-sectional view and the partial cross-sectional view of the reaction furnace 1 of the said embodiment. It is a schematic sectional drawing of the source gas diffusion suppression type | mold CNT manufacturing apparatus which concerns on another embodiment of this invention. It is the longitudinal cross-sectional view which shows the modification of a reaction furnace, and a partial cross-sectional view. It is a figure which shows typically the CNT growth process principal part of the reaction furnace 1, the heating temperature distribution figure in each area | region Z1-Z3, and the ideal acetylene density | concentration distribution figure in the CNT synthetic | combination area | region Z1 and the diffusion suppression area | region Z2. It is a schematic longitudinal cross-sectional view which shows the CNT reaction process part of an analysis model. C ₂ H ₂ concentration distribution diagram based on analysis of thermal fluid model, schematic longitudinal sectional view of the reactor 1 schematically showing the gas flow along the longitudinal direction of the reactor 1, and gas flow below the slider 32 schematically It is a schematic cross-sectional view of the reaction furnace 1 shown in FIG. It is a schematic sectional drawing of the partition plate arrangement | positioning model of the diffusion suppression body (partition plate) which varied the number or shape of the partition plate. FIG. 10 is a C ₂ H ₂ concentration distribution diagram calculated based on the partition plate arrangement conditions of (9A) to (9E) of FIG. It is a perspective view of the partition plate installation example of (9A) and (9B) of FIG. It is a perspective view of the partition plate installation example of (9C) and (9E) of FIG. It is a schematic perspective view of the partition plate arrangement | positioning model which varied He introduction form. It is a schematic sectional drawing of the partition plate arrangement | positioning model which varied He introduction form. It is a schematic block diagram of the CNT synthetic | combination process control part 200 of the said embodiment. 5 is a flowchart illustrating a processing procedure of a CNT synthesis process performed by a CNT synthesis process control unit 200. FIG. 6 is a C ₂ H ₂ concentration distribution diagram calculated in a simulation in which the introduction portion of He is changed into three types: (1) diffusion suppression region, (2) temperature rising region, and (3) catalyst substrate loading end. . He gas and Ar gas is C ₂ H ₂ concentration distribution diagram of each when used in the carrier gas. FIG. 5 is a SEM tomographic image of CNT synthesized using Ar gas carrier gas by the CNT manufacturing apparatus of FIG. 4. SEM tomographic image of CNT synthesized using Ar gas as carrier gas and C ₂ H ₂ as source gas, and SEM tomography of CNT synthesized using He gas as carrier gas and C ₂ H ₂ as source gas It is a photograph. It is the top view which shows arrangement | positioning of the raw material gas supply pipe | tube 307 used for the raw material gas spraying experiment, a side view, a front view, and the SEM tomographic photograph and imaging position photograph of CNT synthesized by this raw material gas spraying experiment. It is the SEM tomographic photograph and imaging position photograph of CNT synthesized by another source gas spraying experiment. The heating temperature changes and C ₂ H ₂ gas supply period height shows the diagram showing the relationship between (reaction time t2), the CNT height reaction time t2 variable to obtained various performed CNT synthesis - reaction time It is a graph of. It is a graph which shows the change before and behind the diffusion suppression area | region of the material diffusion coefficient with respect to three types of furnace pressure, and a thermal diffusion coefficient.

  Hereinafter, a raw material gas diffusion suppression type CNT manufacturing apparatus according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic cross-sectional structure of a raw material gas diffusion suppression type CNT manufacturing apparatus according to an embodiment of the present invention.
The raw material gas diffusion suppression type CNT manufacturing apparatus of the present embodiment is provided in a circular quartz reaction furnace 1 in which a reaction region 2 and a temperature raising region 3 for CNT growth are arranged in the furnace, and on the outer periphery of the reaction furnace 1. And a heating device 9 for heating the reaction region 2 and the temperature raising region 3. In the reaction furnace 1, a conveyor belt 19 having a catalyst layer formed on the surface side is disposed along the longitudinal direction of the core. The conveyor belt 19 can travel along a quartz plate slider 32 disposed along the longitudinal direction of the core. The reaction region 2 is a partition region partitioned by a partition 4 on the carry-out side for carrying out the CNTs 50 grown on the belt surface and the diffusion suppressing bodies 6 and 7. The temperature raising region 3 is a partitioned region partitioned by a partition wall 5 on the carry-in side for transporting a belt surface for growing CNTs and diffusion suppressing bodies 6 and 7. The heating device 9 is an infrared lamp. In the reaction furnace 1, a source gas supply pipe 11 that supplies a source gas (acetylene C ₂ H ₂ gas) to the reaction region 2 and a carrier gas supply pipe that supplies a carrier gas (helium He gas) to the temperature rising region 3. 10 is piped along the longitudinal direction of the core. The width in the furnace is 1000 mm, and the total lengths of the reaction region 2 and the temperature raising region 3 are 8000 mm and 1000 mm, respectively. The thickness of the diffusion suppressing bodies 6 and 7 is 100 mm. The traveling speed of the conveyor belt 19 is 1000 mm / min.

The diffusion inhibitors 6 and 7 are half-moon shaped partition plates that separate between the reaction region 2 and the temperature raising region 3, and are located on the front side and the back side of the conveyor belt 19, respectively.
(2A) in FIG. 2 shows the front-side diffusion suppressing body 6. On the upper side of the diffusion suppressing body 6, through holes 6 a and 6 b through which the carrier gas supply pipe 10 and the source gas supply pipe 11 are inserted are formed in the vertical direction. Thermocouple quartz pipes 53 for disposing thermocouples for measuring the in-furnace temperatures of the reaction region 2 and the temperature raising region 3 on both sides of the diffusion suppressing body 6 (see (3A) in FIG. 3). Through-holes 6c and 6d through which are inserted are formed. In FIG. 1, the thermocouple piping is omitted.

FIG. 3 shows a longitudinal section (3A) and a transverse section (3B) of the reactor 1. (3A) in FIG. 3 shows a longitudinal section in the reaction region 2, and (3B) in FIG. 3 shows a section taken along the line AA in (3A).
The diffusion suppressing bodies 6 and 7 are arranged to face each other via spacers 48 at both ends with a gap 8 in which the transport belt 19 and the slider 32 can be loosely inserted, and are attached in close contact with the inner wall of the furnace. The diffusion suppressing bodies 6 and 7 and the spacer 48 are made of quartz.

  The conveyor belt 19 is made of SUS material and is suspended between the winding roller 20 and the winding roller 22. The winding roller 20 and the winding roller 22 are respectively disposed on the inlet side and the outlet side of the reaction furnace 1. The inlet side of the reaction furnace 1 is covered with a cover body 17 and has a sealed structure in which the gas in the furnace does not leak. The outlet side of the reaction furnace 1 is covered with a cover body 16 that constitutes a CNT recovery processing unit. A lower exhaust pump 25 for exhausting the charged gas in the reaction region 2 from below the conveyor belt 19 is disposed inside the reaction furnace 1, and a main exhaust pump 24 for exhausting the furnace gas from the opening 23 of the cover body 16 is disposed. It is installed. Exhaust gas from the lower exhaust pump 25 and the main exhaust pump 24 is discharged to the outside through the opening 23. The total exhaust capacity of the main exhaust pump 24 and the lower exhaust pump 25 can be set to 250 to 3000 L / min.

  The conveyor belt 19 is used as a catalyst carrier. On the SUSU surface 18 of the conveyor belt 19, as shown in the enlarged portion 33 of the belt cross section of FIG. 1, a heat-resistant resin layer 29 such as polyimide and an Al layer 30 deposited on the heat-resistant resin layer 29 are used as a buffer layer. In addition, a multilayer structure in which an Fe catalyst layer 31 is formed on the Al layer 30 is formed. The CNTs 50 are CVD synthesized on the catalyst layer 31 introduced into the reaction region 2.

  The conveyor belt 19 constitutes a roll-to-roll apparatus that is pulled out from the winding roller 20 and travels in the reaction furnace 1 while winding one end of the conveyor belt 19 around the winding roller 22. The catalyst layer 31 formed on the belt surface side is used as the catalyst base of the present invention, and the transport belt 19 is transferred from the temperature rising region 3 through the gap 8 to the reaction region 2 to grow CNTs 50 in the catalyst layer 31. After the grown CNT 50 is collected, the processed conveyor belt 21 is wound around the winding roller 22.

  The conveyor belt 19 used as the catalyst carrier is made of SUS, and the SUS material is excellent in heat resistance, rust prevention and strength, and is suitable for high quality and mass production by continuous CNT synthesis involving high temperature treatment.

  The carrier gas supply pipe 10 has a carrier gas introduction port 14 for introducing He gas from a He cylinder (not shown) installed outside the cover body 17, and the carrier gas introduction port 14 is installed on the outer wall of the cover body 17. . In the carrier gas supply pipe 10, four supply ports 12 for supplying the carrier gas toward the temperature rising region 3 are formed around the partition wall 5.

The source gas supply pipe 11 has a source gas introduction port 15 for introducing acetylene gas from an acetylene C ₂ H ₂ gas cylinder (not shown) installed outside the cover body 17, and the source gas introduction port 15 is formed on the outer wall of the cover body 17. is set up. In the raw material gas supply pipe 11, five supply ports 13 for supplying the raw material gas toward the reaction region 2 are formed in the reaction region 2. In this embodiment, C ₂ H ₂ having a lower thermal decomposition temperature than the C ₂ H ₄ gas is used as the carbon source.
When the CNT yield was measured in advance by a small preliminary experimental apparatus having the same structure as that of the CNT production apparatus in FIG. 1 and the reaction region 2, the temperature raising region 3, and the diffusion inhibitors 6 and 7 having an overall length of 100 mm, C _{When 2} H ₂ gas was 90 sccm and He gas was 210 sccm, the amount of supplied carbon was 128 mg / min, and the total amount of supplied carbon became 772 mg by supplying for 8 minutes, resulting in a mass of 9.3 mg of synthetic CNT. The CNT yield from this preliminary experiment is 1.2%.
In the present embodiment, the traveling speed of the conveyor belt 19 is 1000 mm / min, and the total length of the reaction region 2, the temperature raising region 3, and the diffusion inhibitors 6 and 7 is 9100 mm, so the necessary carbon amount is 3075 mg / min. The amount of supplied carbon necessary to obtain the same yield as in the preliminary experiment is 256250 mg / min. For this, C ₂ H ₂ gas is supplied to the reaction region 2 at a rate of 239 L / min (0 ° C., 1 atm conversion) through the source gas supply pipe 11. Further, He gas is supplied into the furnace at 558 L / min (0 ° C., 1 atm conversion) through the carrier gas supply pipe 10.

  As shown in (3B) of FIG. 3, the slider 32 is formed with a narrow portion 49 that is notched along the longitudinal direction in the reaction region 2. A broken line 52 in (3B) indicates a formation width region of the catalyst layer 31. Since the space between the slider 32 and the reactor wall of the reactor 32 is widened by the narrow portion 49 and a gas outflow passage through which the gas in the furnace escapes to the lower side on the back side of the conveyor belt 19 is formed, the supply port 13 of the source gas supply pipe 11 is used. The supplied source gas is subjected to the exhaust action of the lower exhaust pump 25 and can easily flow through the gas outflow path to the conveying belt 19, that is, the back side of the catalyst layer 31 without staying. By facilitating the flow of the raw material gas through the narrow portion 49, the raw material gas can be quantitatively supplied onto the catalyst layer 31, so that the CNTs can be grown uniformly on the entire surface of the catalyst layer 31.

  In the opening 23 of the cover body 16, an extendable arm 27 of the CNT collecting actuator device 28 is disposed so as to be able to enter and exit. A CNT scooping member 26 is attached to the tip of the telescopic arm 27. The CNTs 50 grown in the reaction region 2 vertically above the forest are scooped up by moving the CNT scooping member 26 along the catalyst layer 31 and moved outward from the opening 23 by the retracting movement of the telescopic arm 27. Removed and collected. Therefore, the conveyor belt 19 is pulled out from the winding roller 20 and travels in the reaction furnace 1 while winding one end of the conveyor belt 19 around the winding roller 22, and the temperature rising region 3 and the reaction region 2 are sequentially transferred to grow CNTs. By performing and collecting, mass production by continuous synthesis of CNTs can be performed. In particular, the present embodiment has a configuration in which CNTs are grown on the belt surface using a roll-to-roll device using the conveyor belt 19 itself as a catalyst carrier to perform continuous synthesis. Thus, the conveyor belt 19 can be wound around the take-up roller 22 and a catalyst layer can be formed again on the wound conveyor belt 19 so that it can be reused. Thus, the manufacturing cost of CNT can be reduced.

  According to the CNT manufacturing apparatus having the above-described configuration, the catalyst belt 31 is carried into the reaction furnace 1 by the transport belt 19 formed on the surface, and the temperature rising region 3 and the reaction region 2 are sequentially transported through the temperature rising region 3. The catalyst layer is transferred to the reaction region 2 to grow CNTs on the catalyst layer with the raw material gas, and the diffusion suppressors 6 and 7 reduce the cross section in the furnace leaving a gap 8 through which the transport belt 19 can pass. The boundary region between the temperature rising region 3 and the reaction region 2 is partitioned, and the diffusion of the raw material gas supplied to the reaction region 2 to the temperature rising region 3 side is suppressed. After being heated without being exposed to the gas, it is transferred to the reaction region 2. Accordingly, diffusion of the raw material gas can be prevented in the continuous synthesis process of CNTs, and the initial concentration of the raw material gas can be maintained at a high concentration, and mass production of highly oriented CNT can be performed.

  Instead of the roll-to-roll apparatus, individually provided catalyst substrates are sequentially transferred from the temperature raising region 3 through the gap 8 to the reaction region 2, and the CNTs formed on each catalyst substrate are collected, thereby collecting the CNTs. Mass production by continuous synthesis may be performed.

FIG. 4 shows a schematic cross-sectional structure of a raw material gas diffusion suppression type CNT manufacturing apparatus according to another embodiment of the present invention, in which individual catalyst substrates are transported to perform continuous CNT synthesis. In FIG. 4, the same members as those in FIG.
In the case of FIG. 4, instead of the roll-to-roll apparatus, a catalyst substrate transport means including an endless belt 34 that transports a catalyst substrate 39 as a catalyst substrate is used. The endless belt 34 is disposed along the longitudinal direction of the core of the reaction furnace 1 and is suspended between a driving roller 35 that is rotated by a driving shaft 36 and a driven roller 37 that is rotated by a rotating shaft 38.

The catalyst substrate 39 is made of a 6 inch square silicon substrate. In the catalyst substrate 39, a heat-resistant resin layer such as polyimide was formed on a silicon substrate, and an Al layer buffer layer deposited on the heat-resistant resin layer was formed, and an Fe catalyst layer was further formed on the Al layer. It has a multilayer structure. In addition to silicon, alumina Al ₂ O ₃ , silicon oxide SiO ₂ , silicon nitride Si ₃ N ₄ or the like can be used as the catalyst forming substrate material. The catalyst substrate 39 is carried in from a substrate introduction port (not shown) provided in the cover body 17 and is placed and set on the endless belt 34 at a predetermined interval. By rotating the endless belt 34 toward the reaction region 2 side, the catalyst substrates 39 and 40 on the endless belt 34 are sequentially sent out to the temperature raising region 3 and the reaction region 2. In the reaction region 2, the CNT 42 is grown on the catalyst layer of the catalyst substrate 41 by supplying the raw material gas, and is transported to the recovery side of the cover body 16. The traveling speed of the endless belt 34 is 1000 mm / min, and about 3400 catalyst substrates 39 can be processed per hour.

  In the opening 23 of the cover body 16, a telescopic arm 46 of a substrate recovery actuator device 47 for recovering the catalyst substrate 43 on which the CNTs 51 are grown together with the substrate is detachable. A robot hand device 45 capable of gripping a substrate is attached to the tip of the telescopic arm 46. The catalyst substrate 43 on which the CNTs 51 grown in a vertically upward direction in the reaction region 2 are formed is sandwiched between the claw members 44 of the robot hand device 45 and opened by moving the telescopic arm 46 backward from the endless belt 34. It can be taken out from the mouth 23. The extracted catalyst substrate 43 is transferred to a collection tray (not shown) and collected together with the substrate. Also in the case of FIG. 4, continuous synthesis can be performed by introducing individual catalyst substrates 39, sequentially transferring the temperature raising region 3 and the reaction region 2, and repeating the temperature raising treatment and the CNT growth treatment.

  The endless belt 34 is made of SUS like the conveyor belt 19 and the SUS material is excellent in heat resistance, rust prevention and strength, and is suitable for high quality and mass production by continuous CNT synthesis involving high temperature treatment.

  Although the circular reaction furnace 1 is used in the embodiment of FIGS. 1 and 4, the space below the conveyor belt 19 or the endless belt 34 can be reduced by using a square reactor.

FIG. 5 shows a modification of the reactor, and FIGS. 5A and 5B respectively show a vertical cross section and a partial cross section of the square reactor of the modification. (5B) shows a cross section taken along line BB of (5B).
The reactor shown in FIG. 5 includes a furnace material 100 having a U-shaped cross section and an upper plate 101 that closes an opening of the furnace material 100, and forms a rectangular frame cross-sectional shape as a whole. The furnace material 100 and the upper plate 101 are made of quartz. FIG. 5 shows an installation example in which the conveyor belt 19 and the slider 32 in the embodiment of FIG. 1 are introduced into the furnace.

  Since the square reactor constituted by the furnace material 100 and the upper plate 101 has a rectangular frame cross section, the diffusion suppressing body 102 that separates the reaction region and the remaining heat region can be constituted by a rectangular quartz plate.

(2B) of FIG. 2 shows the diffusion suppressing body 102.
A through hole 105 a through which the carrier gas supply pipe 105 is inserted is formed in the upper center of the diffusion suppressing body 102. In the rectangular reactor shown in FIG. 5, a straight pipe is not used as the source gas supply pipe, but a bent pipe is used. That is, as shown in (5B), the source gas supply pipe 106 is provided with five branch pipes 107 bent in an L shape in the width direction of the conveyor belt 19 in the reaction region. A plurality of source gas supply ports 108 are formed in the branch pipe 107. A through hole 106 a through which the source gas supply pipe 106 is inserted is formed in the upper side portion of the diffusion suppressing body 102. Furthermore, through holes 109 through which thermocouple pipes (not shown) for disposing thermocouples for measuring the in-furnace temperature of the reaction region are inserted are formed on both sides of the diffusion suppressing body 102. ing.

  The diffusion suppressing body 102 is disposed in a rectangular furnace with a gap 110 above the conveyor belt 19 and the slider 32 via the spacers 103 on both ends, and is attached in close contact with the inner wall of the furnace. The gap 110 corresponds to the gap 8 in FIG.

According to the square reactor having the above-described configuration, the conveyance belt 19 and the slider 32 can be disposed close to the bottom of the furnace material 100, so that it is not necessary to install the lower diffusion suppressing body in FIG. The volume of the lower space 104 of the conveyor belt 19 can be greatly reduced by covering most of the cross section with one diffusion suppressing body 102. Therefore, as the lower space 104 is reduced, the supply amount of the source gas supplied to the reaction region by the source gas supply pipe 106 can be reduced, which contributes to the reduction of the CNT manufacturing cost.
In the case of FIG. 5, since the source gas is supplied toward the surface of the catalyst layer 31 through the branch pipe 107 communicating with the source gas supply pipe 106, the source gas is uniformly supplied in the width direction of the catalyst layer 31. Can do. In addition, the raw gas is exhausted and circulated through the lower space 104 without stagnation by suction of the lower exhaust pump 25 through the gas outlet passage by the narrow portion 49 described above, and the raw material gas is uniformly supplied to the entire width of the catalyst layer 31. Therefore, CNT can be grown uniformly on the entire surface of the catalyst layer 31.

The diffusion suppressing bodies 6 and 7 used in the CNT manufacturing apparatus of FIG. 1 will be described in detail.
In order to synthesize higher-quality highly aligned CNTs, the concentration of acetylene C ₂ H ₂ gas (raw material gas) serving as a carbon source in the temperature rising region 3 is a low concentration of 10 ppm or less, and the gaps formed by the diffusion inhibitors 6 and 7. The acetylene gas concentration needs to rise sharply in the diffusion suppression region formed by 8 (see Non-Patent Document 2).

(6A) of FIG. 6 schematically shows a main part of the CNT growth processing of the reactor 1.
The conveyor belt 19 with the catalyst layer 31 formed on the surface moves along the conveyance direction indicated by the arrow x, and sequentially passes through the temperature raising region Z3, the diffusion suppression region Z2, and the CNT synthesis region Z1, and the CNT 50 is grown and wound. It will be taken. The CNT synthesis region Z1, the diffusion suppression region Z2, and the temperature increase region Z3 correspond to the reaction region 2, the temperature increase region 3, and the pair of diffusion suppression bodies 6 and 7, respectively.

FIG. 15 is a schematic block diagram of the CNT synthesis processing control unit 200 of this embodiment.
The CNT composition processing control unit 200 is configured by a microprocessor including a CPU 201, and a ROM 202 storing a CNT composition processing program and a RAM 203 including various data work areas are connected to the CPU 201.

  The CPU 201 is connected to a key input device 206, a start switch (SW) 207, and a thermocouple 208, which are used for inputting various data as external input means. Further, the sensor output of the optical sensor 209 for detecting a reaction processing start position mark and a reaction end position mark formed on the conveyance belt 19 described later can be input. By the key input operation of the key input device 206, the input value of the set temperature of the heating temperature curve, the driving time of the conveyor belt 19, and the like can be set and input. The optical sensor 209 is installed in the vicinity of the labor of the temperature raising region 3 and at a position where the reaction processing start position mark and the reaction end position mark of the moving conveyor belt 19 can be detected. Connected to the CPU 201 as external output means are a conveyor belt driving device 204 that rotationally drives the driven roller 37 of the conveyor belt 19, a heating controller 205 of the heating device 9, and an electromagnetic valve 210 of the source gas supply path. The solenoid valve 210 includes a source gas supply control solenoid valve provided in a supply path between the source gas inlet 15 of the source gas supply pipe 11 and the acetylene gas cylinder, the carrier gas inlet 14 of the carrier gas supply pipe 10, and the aforementioned It is a source gas supply control solenoid valve provided in a supply path between the He gas cylinder.

(6B) of FIG. 6 shows the heating temperature distribution by the heating device 9 in each of the regions Z1 to Z3. The internal pressure in the reactor 1 during CNT synthesis is 10 Torr.
FIG. 16 is a flowchart showing a processing procedure of CNT synthesis processing by the CNT synthesis processing control unit 200.

The processing procedure of the CNT synthesis process by the CNT synthesis process control unit 200 will be described with reference to FIG.
Prior to the start of the synthesis process, the electromagnetic valve 210 is opened in the reaction furnace 1 to start supplying the carrier gas and circulate in advance. When the activation SW 207 is turned on, the CNT composition processing program is activated (step S1). With this activation, the electromagnetic valve 210 is opened to start supplying the raw material gas, and heating control of the reaction furnace 1 of the heating device 9 by the heating controller 205 is started (step S2). Further, the driving of the conveyor belt driving device 204 is started and the driving of the conveyor belt 19 is turned on (step S3).

  The reaction processing start position mark is detected by driving the transport belt 19 (step S4). The reaction processing start position mark is formed on the front end side of the formation of the catalyst layer 31 of the transport belt 19 and is detected by the optical sensor 209. Timer detection is started by this sensor detection, and after detection of the reaction processing start position mark, belt conveyance is performed for a certain period of time (conveying time t1 from the temperature rising region 3 to the reaction region 2) (steps S5 and S6). This conveyance time t1 is 1 minute.

  As the transfer time t1 elapses, the unreacted catalyst layer 31 is transferred to the CNT synthesis region Z1 through the temperature increase region Z3. By passing through the temperature raising region Z3, for example, the temperature is raised from 25 ° C. (apparatus ambient temperature) to the CNT synthesis temperature of 730 ° C. The temperature-heated catalyst layer 31 quickly passes through the diffusion suppression region Z2 and is carried into the CNT synthesis region Z1, and the belt drive is stopped during the reaction time t2. The synthesis time from the stop of the belt drive, that is, the reaction time t2 is 8 minutes (step S7). The temperatures of the diffusion suppression region Z2 and the CNT synthesis region Z1 are maintained at the CNT synthesis temperature of 730 ° C., and a CNT synthesis process for growing CNTs 50 on the catalyst layer 31 is performed in the CNT synthesis region Z1. The CNTs 50 are sequentially scooped and collected by the CNT scooping member 26.

The synthesis for one time is completed after the reaction time t2. When the above temperature rise and synthesis are completed once, the conveyor belt 19 is driven again and the next synthesis process is started (step S9). Until the synthesis of all the catalyst layers 31 on the conveyor belt 19 is completed, the above temperature rise and synthesis can be repeated to perform continuous synthesis. The reaction end position mark formed on the peripheral edge of the catalyst layer 31 is detected by driving the transport belt 19 (step S9). By detecting the reaction end position mark by the optical sensor 209, the electromagnetic valve 210 is closed to stop the supply of the raw material gas and the carrier gas, and the belt drive and heating control are stopped to complete the CNT synthesis process (step S10). ).
The reaction time t2 was set based on data measured in advance under CVD conditions at a pressure of 10 Torr by forming an Fe catalyst layer on a Si substrate by a wet method.
(23A) of FIG. 23 shows an example of the relationship between the heating temperature change used for the measurement and the C ₂ H ₂ gas supply period (reaction time t2). FIG. 23B is a graph showing the CNT height obtained by variously performing CNT synthesis by varying the reaction time t2. The measurement is performed based on the raw material gas supply amount and heating conditions in the present embodiment. As shown in (23B), it can be seen that heating for 8 minutes is optimal in the amount of material gas supply in the present embodiment.

(6C) in FIG. 6 shows ideal acetylene concentration distributions in the CNT synthesis region Z1 and the diffusion suppression region Z2. The conveyor belt 19 introduced into the temperature rising zone Z3 is rapidly passed through the diffusion suppression zone Z2 after being heated to the synthesis temperature in a state M2 where the C ₂ H ₂ gas concentration is extremely low, preferably 10 ppm or less. As a result, as indicated by M1 in (6C), the C ₂ H ₂ gas concentration that touches the catalyst layer 31 rises sharply, and the growth of highly oriented CNTs becomes possible in the CNT synthesis region Z1. In the present embodiment, the reduced partial cross-sectional shape and thickness for reducing the inside of the furnace of the diffusion suppressing bodies 6 and 7 shown in FIG. 3 are set appropriately to sufficiently diffuse the C ₂ H ₂ gas in the diffusion suppressing region Z2. It suppresses and enables smooth processing of highly oriented CNT growth.

The diffusion suppressing bodies 6 and 7 are arranged to face each other with a gap 8 therebetween to form a reduced partial cross-sectional shape. The lower diffusion suppressing body 7 may be configured to close the back side of the conveyor belt 19 as much as possible. Here, in order to synthesize highly oriented CNTs, the thickness of the diffusion suppressor 6 installed on the introduction side of the catalyst layer 31 is strictly set in order to prevent diffusion leakage of the raw material gas to the temperature rising region 3 side. There is a need to. For this setting, a model fluid simulation is performed for each type of diffusion suppressing body, and the appropriate thickness of the diffusion suppressing body 6 is determined by obtaining the C ₂ H ₂ gas concentration.

A model fluid simulation technique and analysis results executed in the CNT manufacturing apparatus of FIG. 1 will be described below.
In the model fluid simulation analysis, analysis is performed assuming a three-dimensional steady flow in the reactor 1, that is, a model fluid as a laminar flow continuum, and the concentration distribution due to the diffusion of the raw material gas before and after the gap 8 of the diffusion suppressing body 6 is calculated. Asked. In the analysis models used for some simulations described below, the same members as those in FIG. However, the positions of the gas discharge ports of the carrier gas supply pipe 10 and the source gas supply pipe 11 are changed according to the analysis contents.

In the analysis, continuity equations, equations of motion, energy transport equations, and mass fraction transport equations were solved.
FIG. 7 shows a CNT reaction processing unit set as an analysis model. In this analysis model, the partition plates W2 and W3 are arranged in the radiant heating region by the heating device 9, the partition plate W4 is provided on the He gas introduction side outside the radiant heating region, and the partition plate W1 is also provided on the exhaust side. . He gas is introduced from the He inflow surface 54, C ₂ H ₂ gas is introduced from the C ₂ H ₂ inflow surface 55, and exhaust gas is discharged from the exhaust surface 56. Since the reaction region 2 has symmetry, the vertical section including the center of the transparent quartz tube of the reaction furnace 1 is a half region where the plane of symmetry is a symmetry plane. The source gas and the carrier gas are C ₂ H ₂ and He, respectively.

  The transport equation of the scalar variable φ in the three-dimensional orthogonal coordinate system (x, y, z) can be described by the following general formula.

Where t is the time (s) u, v, w are the velocity in the x, y, and z directions (m / s), ρ is the density (kg / m ³ ), Γ is the diffusion coefficient, and S is the generation term. (Amount generated per unit time / unit volume). The x direction, the y direction, and the z direction correspond to the traveling direction of the transport belt 19, the belt width direction, and the direction perpendicular to the belt surface, respectively. In equation (1), the first term on the left side is an unsteady term, the second term to the fourth term are convection terms (convection terms), the first term to the third term on the right side are diffusion terms, and the fourth term is a generation term. . In the steady analysis, the time derivative of each variable is 0, so the non-stationary term is omitted, and the partial derivative term with respect to z disappears in the two-dimensional plane (x, y). Further, the expression (1) is described in the vector format as follows.

  In the formula (1), when φ is 1, a continuous formula (mass conservation law) is obtained.

Here, the first term Sm on the right side is a generation term, and means the mass generation amount per unit volume / unit time.

  In Equation (1), if φ is a velocity vector (u, v, w), a diffusion coefficient is Γ, and a viscosity coefficient μ (Pa · s), an equation of motion (momentum conservation law) is obtained.

  Here, p is a pressure (Pa). The fourth term on the right side of each equation is a pressure gradient term that is a kind of generation term, and the fifth term is a generation term that incorporates the generation of external force.

  In Equation (1), if φ is enthalpy h (J / kg) and the diffusion coefficient Γ is k / c, the energy transport equation is obtained.

Here, k is the thermal conductivity (W / m · K), and c is the specific heat (J / kg · K). When intended for fluid generally used pressure specific heat _{c p (J / kg · K} ) as the specific heat.

  The transport formula for chemical species i can be written as:

Here, ρ is a density (kg / m ³ ), mi is a mass fraction of the chemical species i, and J _i is a vector display of the diffusion flow rate (kg / m 2 · s). The diffusion flow rate J _i is generated due to the concentration gradient and the temperature gradient. In the case of laminar flow, the diffusion flow rate J _i can be expressed as follows.

Where D _{i, m} is the material diffusion coefficient (m ² / s) for chemical species i in the mixture,
D _{T, i} is the thermal diffusion coefficient (kg / (m · s)) of chemical species i. Since this analysis deals with a steady three-dimensional flow, the unsteady term is omitted in the following description.

  Next, the general scalar transport equation is converted into an algebraic equation that can be numerically solved by the finite volume method. In the finite volume method, first, a transport equation is integrated in each control volume to obtain a discretization equation, and a conservation law is expressed in units of control volumes.

  The discretization of the governing equation can be most easily expressed by considering the conservation equation (2) relating to the transport of the scalar quantity φ. Since this analysis deals with a steady three-dimensional flow, if the unsteady term is omitted, equation (2) becomes as follows.

  When formula (3) is integrated for an arbitrary control volume V, the following formula is established.

Here, A is an area vector A (A _x , A _y , A _z ), and the component display is omitted below.
When formula (4) is discretized for a certain control volume, it is as follows.

Here, the subscript f is the face number, N _faces is the number of _faces surrounding the cell, φ _f is the value of φ passing through the face f (convection term), and A _f is the area vector of the face f (A _f = ( A _fx , A _fy , A _fz ), and component display is omitted below.), Ρ _f φ _f · A _f is the mass flux passing through the face, grad φ _f is the gradient of φ in the face f, and V is the cell Volume.

  Furthermore, when equation (5) is linearized, the following equation is obtained.

Here, subscript nb adjacent cells are shown, a _P and a _nb are linearized coefficients of φ and φ _nb , and b is a constant term. A similar formula can be written for each cell in the grid. As a result, simultaneous algebraic equations are obtained.

For calculation of the convection terms in equation (5) is required face value of phi _f in (diffusion term is always a central difference secondary accuracy), it is necessary to interpolate from the stored cell center values. Interpolation of the face value is performed by the secondary accuracy upwind difference method. In the first-order upwind difference method, assuming that the cell center value is the cell average value and the same value in the entire cell, the face value φ _f is the cell center value of φ in the upwind cell.

In this analysis, pressure and velocity are coupled using the SIMPLE algorithm (see Seiichi Koshizuka, Computational Fluid Dynamics, Bafukan, 1997). It is necessary to obtain the flow field from the equation of motion for the analysis. However, in order to determine the flow field, the pressure field p needs to be known, and the pressure field p is only defined indirectly in the continuous equation. If the pressure field p is not known, the incomplete velocity fields u ^* , v ^* and w ^* obtained from the estimated pressure field p ^* from the equation of motion do not satisfy the continuous equation. In order to solve this problem, the initially estimated pressure field p ^* is improved (a combination of pressure and speed) so that the incomplete velocity fields u ^* , v ^* , and w ^* satisfy the continuous equation. It is necessary to continue.

  The equation of motion in the x direction and the equation of continuity can be described as follows.

  Based on the above discretization, Equation (7) is discretized as follows.

Here, the subscript nb indicates an adjacent cell, a _P and a _nb are linearized coefficients of u and _un , p _f1 and p _f2 are face pressures on two sides of the control volume, A is an area, and b is It is a constant term. To solve equation (9), face values for pressure and velocity are needed, but they are stored in the center of the cell. Therefore, the pressure face value is given by the following equation.

Here, p _c0 and p _c1 are face center pressures, and a _{p, c0} , a _{p, c1} are discretization coefficients. The speed is linearly averaged and the face value is obtained, so that it becomes a checkerboard-like distribution in which pressure cannot physically exist. Therefore, the speed is weighted and averaged. Further, when the equation (8) is discretized, it is as follows.

Here, _Jf is the mass flux passing through the face f, and _Af is the area of the face f. The exact pressure p is as follows

Suppose that it was corrected. Next, it is necessary to know how the velocity component changes with respect to this pressure change. Similarly, the velocity component at this time is

(U ′, v ′, and w ′ are called speed correction values). The speed correction values u ′, v ′, and w ′ can be obtained from the pressure correction value p ′. An equation for obtaining the velocity correction values u ′, v ′, and w ′ from the pressure correction value p ′ is called a velocity correction equation.
Based on the above, the SIMPLE algorithm proceeds with the calculation according to the following procedure.
1. Infer an incomplete pressure field p ^* .
2. Equation (8) is solved to obtain u ^* and v ^* and w ^* in the same manner.
3. The discrete equation is solved from the pressure correction equation obtained from Equation (9) to obtain the pressure correction value p ′.
4). The obtained p ′ is added to p ^* to obtain p.
5. Further, u ′, v ′, and w ′ are obtained from p ′ and the speed correction equation, and u, v, and w are obtained from Equation (21).
6). Solve discrete equations for other variables φ (enthalpy, mass fraction) and update fluid properties and generation terms that affect the flow field.
7). Using the corrected pressure p as a newly estimated pressure p ^* , the above procedure is repeated until convergence.

  In order to obtain a solution, it is necessary to solve the discretized equation of Equation (6). In this analysis, the discrete equation was solved by combining the Gauss-Seidel method and the algebraic multigrid (AMD) method.

In this analysis, characteristic values (physical property values) such as source gas (C ₂ H ₂ ) and carrier gas (He) were set and the analysis results were derived.
In the following, two types of gases, He as a carrier gas and C ₂ H _{2 as} a carbon source, are considered. Further, there are three types of solids, quartz glass of the quartz tube reactor 1 and quartz slider 32, Si when using the catalyst substrate, stainless steel (SUS) of the conveyor belt 19 or endless belt 34, and a total of five gases and solids. Defines physical properties. Here, the setting of each physical property value will be described.

The physical properties of He were determined as follows.
Constant pressure specific heat (cp _{, he} ): 5193 (J / kg · K)
Thermal conductivity (k _he ): kinetic theory definition (W / m · K)
Viscosity coefficient ( _μhe ): defined by dynamic theory (kg / m · s)
Molecular weight: 4.0026
Lennard-Jones characteristic length: 2.551mm
Lennard-Jones energy parameters: 10.22K

The physical property values of C ₂ H ₂ were determined as follows.
Constant pressure specific heat ( _{cp, c2h2} ): approximated by a polynomial.
300 ≦ T <1000: _{cp, c2h2} (T) = 6422.95581 + 4.85052T + −0.0051611108T ² + 2.8990371 × 10 ⁻⁶ T ³ + −6.1766 × 10 ⁻¹² T ⁴ ,
1000 ≦ T <5000: _{cp, c2h2} (T) = 11416.7169 + 1.7166374T + −0.00061078637T ² + 1.04938241 × 10 ⁻⁷ T ³ + −6.8866449 × 10 ⁻¹² T ⁴ (J / kg · K )
Thermal conductivity (k _c2h2 ): kinetic theory (W / m · K)
Viscosity coefficient (μ _c2h2 ): kinetic theory definition (kg / m · s)
Molecular weight: 26.04
Lennard-Jones characteristic length: 2.551mm
Lennard-Jones energy parameters: 10.22K
Moreover, it is necessary to handle a mixed gas of He and C ₂ H ₂ . As for the physical properties of this mixed gas, density, constant pressure specific heat, thermal conductivity, viscosity coefficient, material diffusion coefficient, and thermal diffusion coefficient were defined.
Density: Definition by the law of incompressible ideal gas (kg / m ³ )
Constant pressure specific heat: Depends on composition (J / kg · K)
Thermal conductivity: Definition by the mixing rule of ideal gas (W / m · K)
Viscosity coefficient: Definition by ideal gas mixing rule (kg / m · s)
Material diffusion coefficient: defined by kinetic theory (m ² / s)
Thermal diffusion coefficient: The following definition based on empirical rules

Where D _{T, i} is the thermal diffusion coefficient of chemical species i at temperature T, M _{w, i} is the molecular weight of chemical species i, X _i is the molar fraction of chemical species i, and Y _i is chemical species i. Mass fraction.
FIG. 24 is a graph showing changes in the material diffusion coefficient (24A) and the thermal diffusion coefficient (24B) of C ₂ H ₂ before and after the diffusion suppression region obtained for three types of furnace pressures (10, 100, 760 Torr). is there. As shown in (24A), the material diffusion coefficient of C ₂ H ₂ changes in inverse proportion to the pressure, and as shown in (24B), the thermal diffusion coefficient of C ₂ H ₂ does not depend on the pressure. .

The physical property value of stainless steel was determined as follows as an opaque body.
Density (ρ _SUS ): 7640 (kg / m ³ )
Specific heat (c _SUS ): A piecewise linear function approximated as follows.
_{(T, c SUS) = (} 300,499) (400,511) (600,556) (800,620) (1000,644) (J / kg · K)
Thermal conductivity (k _SUS ): a piecewise linear function approximated as follows (T, k _SUS ) = (300, 16) (400, 16.5) (600, 19) (800, 22.5) ( 1000, 25.7) (W / m · K)

The physical properties of quartz glass were determined as follows as a transparent body.
Density (ρ _qrz ): 2201 (kg / m ³ )
Specific heat (c _qrz ): 1052 (J / kg · K)
Thermal conductivity (k _qrz ): A piecewise linear function approximated as follows.
(T, k _qrz ) = (293.15, 1.38) (373.15, 1.47) (473.15, 1.55) (573.15, 1.67) (673.15, 1. 84) (122.15, 2.68) (W / m · K)

The boundary conditions in the analysis model were determined as follows. The reference pressure is 1.33 × 10 ³ Pa (10 torr).
First, on the He inflow surface 54, the flow rate was 3.121313 × 10 ⁻⁷ kg / s (210 sccm), and the temperature T was 298.15 K (25 ° C.).
For the inflow surface 55 of C ₂ H ₂ , the flow rate was 8.71344 × 10 ⁻⁷ kg / s (90 sccm), and the temperature T was 298.15 K (25 ° C.). The relative pressure on the exhaust surface 56 is 0 Pa.

On the heating surface of the surface of the quartz reaction tube (reactor 1), the external radiation energy was constant, and the temperature T was 973.15 K (700 ° C.). For the non-heated surface, the temperature was set as the heat insulation condition and the emissivity was set to 1.
The emissivity is 0.45 at the boundary between the gas phase and the stainless steel belt, and the emissivity is 0.22 at the boundary between the quartz slider 32 and the stainless steel belt.

  As a program for solving the discretization equation, general-purpose thermal fluid analysis software FLUENT (Version: 6.3.26) manufactured by ANSYS was used with a double precision solver. As a result of the analysis, the number of cells of the lattice was 2789256, the number of faces was 8633662, and the number of nodes was 3048317.

FIG. 8 shows a C ₂ H ₂ concentration distribution (8A) based on the analysis of the thermal fluid model, a schematic longitudinal section (8B) of the reactor 1 schematically showing a gas flow along the longitudinal direction of the reactor 1, and a slider 32. The schematic cross section (8C) of the reaction furnace 1 which shows a lower gas flow typically is shown.

In the C ₂ H ₂ concentration distribution diagram of (8A), broken lines 8a, 8b, 8c, and 8d are partition plates W1 to W4 (see FIG. 7), that is, a partition wall on the gas discharge side, a partition plate in the reaction region, Each position of the partition plate between the reaction region and the temperature rising region 82 and the temperature rising side partition (see (8B)) is shown. HZ represents a radiation heating region (reaction region) by the heating device 9. 8e shows the change in C ₂ H ₂ molar concentration (%) with respect to the position x in the longitudinal direction of the reactor 1. 8f shows the change of the furnace temperature (° C.) with respect to the position x.

The conveyor belt 19 is carried in from the right side of FIG. 8, and the furnace gas is discharged from the left side. Focusing on the partition W3 between the second reaction region from the right and the temperature rising region 82 filled with 100% He gas, a small amount of C ₂ H ₂ reaches the right He supply region and flows out. I understand that.

_Two flows of C ₂ H ₂ are supplied into the furnace. One is a flow 81 in the longitudinal direction of the reaction furnace 1 that flows under the partition plate W3 as shown in (8B). The other is a flow 57 that flows through the gap on the side of the slider 32 and flows to the lower part of the slider 32 as shown in (8C).

In order to satisfy the ideal C ₂ H ₂ concentration and temperature shown in (6C) of FIG. 6, the flow 83 flowing below the partition plate W3 shown in (8B), particularly the source gas supply section (source gas) The flow 81 flowing from the supply port 80 to the inflow side (right side) is preferably zero. The area of the order slider 32 horizontal partition plate W3 under the area (for example, 91.5mm ²⁾ larger than that, for example, by a 840.0mm ^_2, C ² _H ² gas does not flow in the longitudinal direction, the lower It can be made to flow only in the direction.

In the above area setting example, when the ratio of the mass flow rate of C ₂ H ₂ in each flow of (8B) and (8C) is obtained from the calculation result, it becomes 4.2: 95.8, and most C It can be seen that ₂ H ₂ gas flows downward. However, some of the C ₂ H ₂ gas also flows in the longitudinal direction. Due to this flow, only He on the inflow side (right side) is desired, and C ₂ H ₂ gas is present even in the temperature rising region. Can be seen from FIG. For this reason, in this embodiment, the diffusion suppressing bodies 6 and 7 are optimized to prevent the flow of C ₂ H ₂ gas to the temperature raising side.

In order to form an ideal C ₂ H ₂ concentration distribution in the CNT synthesis region and to continuously synthesize highly oriented CNTs, the basic requirement is to make the diffusion suppression region narrow and long, the conveyor belt 19 ( The gap other than the place where the catalyst base) passes is set to 0 as much as possible, and the carrier gas is supplied from the temperature raising side.

In order to satisfy the above three basic requirements, simulations were performed for various forms of the diffusion inhibitors, and the diffusion inhibitors 6 and 7 were optimized.
The first is the partition shape between the temperature rising region and the synthesis region, and a simulation was performed by changing the shape of the diffusion suppression region.
FIG. 9 shows a partition plate arrangement model of a diffusion suppressing body (partition plate) with different numbers or shapes of partition plates. (9A) to (9E) in FIG. 9 respectively show (1) no partition, (2) one partition plate 91, (3) three separated partition plates 92 in the diffusion suppression region (4). 5) A case where five separated partition plates 93 are installed, and (e) one long partition member 94 is installed. In each partition plate arrangement model, a partition wall 90 that partitions the lower portion of the slider 32 in a sealed manner in the diffusion suppression region is disposed.

(11A) and (11B) of FIG. 11 are perspective views of an installation example without partitioning of (9A) and an installation example of one partition plate 91 of (9B), respectively.
(12A) and (12B) of FIG. 12 are perspective views of an installation example of the three partition plates 92 of (9C) and an installation example of the long partition member 94 of (9E), respectively.
(13B) of FIG. 13 is a perspective view of an installation example of five partition plates 93 of (9D). In FIG. 11, FIG. 12, and (13 </ b> B), the inner wall of the reaction furnace 1 is indicated by reference numeral 95.

The C ₂ H ₂ concentration was calculated based on the above five partition plate arrangement conditions.
FIG. 10 shows the C ₂ H ₂ concentration distribution (molar fraction ppm) calculated based on the partition plate arrangement conditions of (9A) to (9E) of FIG. The alternate long and short dash line in the figure indicates the limit value (10 ppm) that needs to be suppressed in the temperature rising region, which is a condition for synthesizing highly oriented CNT.
From this calculation result, it can be seen that the one provided with the long partition (5) suppresses the diffusion most. Therefore, the diffusion suppression region is preferably as small and long as possible, and the number of partition plates is required to be at least one, and in particular, five is considered more preferable.

Regarding the point that no gap is provided in the diffusion suppression region other than the region where the belt passes, the diffusion of C ₂ H ₂ gas to the temperature rising region due to the gap other than the region where the conveyor belt 19 passes is likely to occur. It is preferable to eliminate unnecessary gaps in the reaction region in order to increase the size.

Finally, with regard to a method for introducing He serving as a carrier gas, in order to search for an optimum He introduction mode, the He introduction portion is changed from (1) a diffusion suppression region, (2) from a temperature rising region, and (3) a catalyst substrate. A simulation was carried out by changing the He introduction form into three types from the carry-in end of each gas, and the molar fraction distribution of each C ₂ H ₂ gas was obtained.

  FIG. 14 shows three examples in which the He introduction mode is changed when five partition plates 93 are installed.

  FIG. 14 (14 </ b> A) is a case where four He gas discharge ports 96 of the carrier gas supply pipe 10 are arranged in the diffusion suppression region by the five partition plates 93. FIG. 14B shows a case where five He gas outlets 96 are arranged in the temperature rising region in front of the diffusion suppressing region. FIG. 14C shows the case where He gas is introduced from a notch 98 in which the end of the temperature rising region of the carrier gas supply pipe 10 is greatly cut out. In the case of (14C), since He gas is supplied into the furnace from the notch 98, the piped carrier gas supply pipe 10 does not substantially function as a supply pipe and is illustrated as a dummy pipe. In FIG. 14, five source gas discharge ports 97 of the source gas supply pipe 11 are provided in the CNT synthesis region. Schematic perspective views of the installation examples of (14A), (14B) and (14C) in FIG. 14 are shown in (13A), (13B) and (13C) of FIG. 13, respectively.

In FIG. 17, as shown in FIG. 13 and FIG. 14, the introduction part of He is changed into three types: (1) from the diffusion suppression region, (2) from the temperature rising region, and (3) from the catalyst substrate carry-in end. ₂ shows the C ₂ H ₂ concentration distribution (molar fraction ppm) in the longitudinal direction of the reactor 1 calculated in the simulation. In FIG. 17, the C ₂ H ₂ concentration is a value 1 mm above the slider 32 surface.

From the C ₂ H ₂ concentration distribution of FIG. 17, the case (2) introduced from the temperature rising region and the case (3) introduced from the carry-in end of the catalyst substrate show the same concentration distribution, and are introduced from the diffusion suppression region ( Compared with 1), the concentration distribution decreases more steeply. Therefore, it is preferable to introduce from the temperature rising region or from the end. In the embodiment of FIGS. 1 and 4, the He discharge port is provided in the diffusion suppression region and the temperature raising region, but it may be introduced from the carry-in end of the catalyst substrate to simplify the device structure. .

We tested the effects of the type of carrier gas to the C ₂ H ₂ of the raw material gas.
The C ₂ H ₂ —Ar system simulation is performed to obtain the C ₂ H ₂ concentration distribution in a state where the diffusion inhibitor does not receive the diffusion suppressing action, that is, without the partition plate shown in (9A) of FIG. It was. The furnace pressure was 10 Torr.

The physical properties of Ar were determined as follows.
Constant pressure specific heat (cp _{, ar} ): 520.64 (J / kg · K)
Thermal conductivity (k _ar ): kinetic theory definition (W / m · K)
Viscosity coefficient (μ _ar ): defined by kinetic theory (kg / m · s)
Molecular weight: 39.948
Lennard-Jones characteristic length: 3.542 mm
Lennard-Jones energy parameters: 93.3K
Further, the boundary condition of the Ar inflow surface was defined as follows.
The flow rate of Ar was 3.111899 × 10 ⁻⁶ kg / s (210 sccm), and the temperature T was 298.15 K (25 ° C.).

FIG. 18 shows C ₂ H ₂ concentration distributions obtained in the case of using two types of carrier gases, He gas and Ar gas. In FIG. 18, the range of the diffusion suppression region is virtually shown corresponding to the diffusion suppression region when the partition plate 91 of (9B) in FIG. 9 is set.
In the case of He gas, since there is no diffusion suppressor near the boundary between the synthesis region and the diffusion suppression region, the C ₂ H ₂ concentration does not drop sharply, but in the case of Ar gas, it drops almost sharply to 10 ppm. is doing. This indicates that the Ar gas itself exerts a diffusion suppressing effect because the molecular weight of Ar is higher in each stage than He.

(19A) in FIG. 19 schematically shows the CNT manufacturing apparatus in FIG. 4, that is, a CNT synthesis processing section in which the diffusion suppressing bodies 6 and 7 formed of one partition plate are installed.
In this synthesis, CNTs were grown on the catalyst substrates 300 and 301 using Ar gas as a carrier gas. The catalyst substrate 300 was installed in the reaction region 302 partitioned by the partition walls 4 and the diffusion inhibitors 6 and 7, and the raw material gas C ₂ H ₂ was supplied to perform CNT synthesis. The catalyst substrate 301 was installed in the temperature rising region 303 partitioned by the partition walls 5 and the diffusion inhibitors 6 and 7, and the source gas C ₂ H ₂ was supplied to the reaction region 302 to perform CNT synthesis.

(19B) and (19C) in FIG. 19 are SEM (Scanning Electron Microscope) tomographic photographs of the catalyst substrates 300 and 301 after the CNT synthesis processing, respectively.
As shown in (19B), highly oriented CNTs 304 are formed on the catalyst substrate 300 synthesized in the reaction region 302. On the other hand, as shown in (19C), CNT growth is not observed on the surface 305 of the catalyst substrate 301 arranged in the temperature raising region 303 because the source gas C ₂ H ₂ leakage is extremely small.

(20A) and (20B) of FIG. 20 are SEM tomographic images of CNT synthesized using Ar gas as a carrier gas and C ₂ H ₂ as a source gas in the same manner as in the synthesis experiment of FIG. (20B) is an enlarged photograph of (20A).
(20C) and (20D) of FIG. 20 are SEM tomographic images of CNT synthesized using He gas as a carrier gas and C ₂ H ₂ as a source gas in the same manner as in the synthesis experiment of FIG. (20D) is an enlarged photograph of (20C).
From the SEM photograph of FIG. 20, it is clear that highly oriented CNTs can be formed by using He gas or Ar gas as the carrier gas.

  From the synthesis experiments shown in FIG. 19 and FIG. 20, when Ar gas is used as the carrier gas and He gas is used by interposing the diffusion suppressing bodies 6 and 7 between the reaction region 302 and the temperature raising region 303. It can be seen that high-quality CNT synthesis is possible as well. Furthermore, in terms of comparison of raw material costs, for example, nitrogen is inexpensive, but cyan may be generated, and Ar cheaper than He is suitable for producing low-cost CNTs.

The presence or absence of the influence of the blowing direction of the source gas in the reaction region 2 was verified.
(21A), (21B), and (21C) of FIG. 21 show the arrangement of the source gas supply pipe 307 used in the source gas spraying experiment, and respectively show a plan view, a side view, and a front view of the pipe arrangement.
(21C), (21D), and (21E) in FIG. 21 are SEM tomographic photographs of CNT synthesized by a raw material gas spraying experiment. FIG. 21F is a photograph of the imaging positions of (21C), (21D), and (21E).

In this raw material gas spraying experiment, the catalyst substrate 309 is placed on the SUS belt 306 in the reaction region, and the raw material gas is supplied above the catalytic substrate 309 in the belt longitudinal direction (x-axis direction) or belt width direction (y-axis direction). The tube 307 was arranged to supply the source gas C ₂ H ₂ . (21A), (21B), and (21C) of FIG. 21 show an arrangement example in which the source gas supply pipe 307 is arranged in the belt longitudinal direction (x-axis direction). The gas supply ports 308 of the source gas supply pipe 307 have an inner diameter of 0.5 mm, and five gas supply ports 308 are arranged at a pitch interval P of 10 mm. The distance H between the surface of the SUS belt 306 and the source gas supply pipe 307 is 5 mm. The catalyst substrate 309 has a Si substrate having a size of 20 × 20 mm and a thickness of 0.625 mm, and an Fe catalyst layer is formed on the Si substrate surface. The belt width of the SUS belt 306 is 30 mm.

  (21C), (21D), and (21E) in FIG. 21 show the CNT synthesis results when the source gas supply pipe 307 is arranged in the belt longitudinal direction (x-axis direction). The SEM tomograms (21C), (21D), and (21E) are respectively located at the left end, the center, and the right end of the gas supply port 308 of the source gas supply pipe 307 along the x-axis direction with respect to the catalyst layer of the catalyst substrate 309. The CNT formed in the place to do is shown. From these SEM photographs, it can be seen that the CNT growth unevenness does not occur due to the gas blowing by the gas supply ports 308 arranged in the x-axis direction.

  (22A), (22B), and (22C) of FIG. 22 show CNT synthesis results when the source gas supply pipe 307 is arranged in the belt width direction (y-axis direction). FIG. 22D is a photograph of the imaging positions of (22A), (22B), and (22C).

  The SEM tomographic images of (22A), (22B), and (22C) are such that the gas supply port 308 of the source gas supply pipe 307 is positioned at the upper end, the center, and the lower end along the y-axis direction with respect to the catalyst layer of the catalyst substrate 309. The CNT formed in the place to do is shown. From these SEM photographs, it can be seen that the CNT growth unevenness does not occur even when the gas is supplied by the gas supply port 308 arranged in the y-axis direction. Therefore, when the source gas supply pipe 307 is arranged in the belt longitudinal direction (x-axis direction) or the belt width direction (y-axis direction), the effect on the CNT growth due to the difference in the spraying direction is not noticeable in any case. It was. When both are compared, in the case of the arrangement in the belt width direction (y-axis direction), as shown in FIG. 5 (5B), the raw material gas is more uniform in the width direction than in the arrangement in the belt longitudinal direction (x-axis direction). There is an advantage of spraying. Further, when the apparatus is increased in size, it is difficult to form a long pipe in the x-axis direction. Therefore, the arrangement in the belt width direction (y-axis direction) has an advantage that the assembly is simplified. In view of the CNT growth state, sufficient CNT synthesis is possible even if the pitch interval P of the gas supply ports 308 is increased to about 20 mm.

  The present invention is not limited to the above-described embodiments and modifications, and includes various modifications and design changes within the technical scope without departing from the technical idea of the present invention. Needless to say.

  According to the present invention, high-quality carbon nanostructures such as CNT can be mass-produced, and are excellent in high conductivity, spring-like mechanical properties, electromagnetic wave activity, GHz electromagnetic wave shielding (absorbing) material, transparent electrode Carbon nanostructures suitable for membranes, vibration control materials, etc. can be provided at low cost.

DESCRIPTION OF SYMBOLS 1 Reaction furnace 2 Reaction area | region 3 Temperature rising area 4 Partition 5 Partition 6 Diffusion suppression body 6a Through hole 6b Through hole 6c Through hole 6d Through hole 7 Diffusion suppression body 8 Gap 9 Heating device 10 Carrier gas supply pipe 11 Raw material gas supply pipe 12 Supply port 13 Supply port 14 Carrier gas introduction port 15 Raw material gas introduction port 16 Cover body 17 Cover body 18 SUSU surface 19 Conveying belt 20 Winding roller 21 Treated conveying belt 22 Winding roller 23 Opening port 24 Main exhaust pump 25 Lower exhaust Pump 26 CNT scooping member 27 Telescopic arm 28 CNT recovery actuator device 29 Heat resistant resin layer 30 Al layer 31 Catalyst layer 32 Slider 33 Enlarged portion 34 Endless belt 35 Drive roller 36 Drive shaft 37 Drive roller 38 Rotation shaft 39 Catalyst substrate 40 catalyst substrate 41 catalyst substrate 42 CNT
43 catalyst substrate 44 claw member 45 robot hand device 46 telescopic arm 47 substrate recovery actuator device 48 spacer 49 narrow portion 50 CNT
51 CNT
52 Broken line 53 Thermocouple quartz pipe 54 Inflow surface 55 Inflow surface 56 Exhaust surface 57 Flow 80 Source gas supply part 81 Flow 82 Temperature rising region 83 Flow 90 Partition 91 Partition plate 92 Partition plate 93 Partition plate 94 Partition plate 95 Inner wall 96 Outlet 97 Discharge port 98 Notch 100 Furnace material 101 Upper plate 102 Diffusion suppressor 103 Spacer 104 Lower space 105 Carrier gas supply pipe 105a Through hole 106 Source gas supply pipe 106a Through hole 107 Branch pipe 108 Supply port 109 Through hole 110 Gap 300 Catalyst substrate 301 Catalyst substrate 302 Reaction region 303 Temperature rising region 304 Highly oriented CNT
305 Surface 306 SUS belt 307 Raw material gas supply pipe 308 Gas supply port 309 Catalyst substrate Z1 CNT synthesis region Z2 Diffusion suppression region Z3 Temperature rising region W1 Partition plate W2 Partition plate W3 Partition plate W4 Partition plate

Claims (12)

A reaction furnace provided with a reaction region and a temperature raising region; source gas supply means for supplying a source gas provided in the reaction region; carrier gas supply means for supplying a carrier gas to the temperature raising region; and the reaction region A heating means for heating the carbon nanostructure to a growth temperature, a temperature raising means for raising the temperature raising area, and a catalyst substrate is carried into the reaction furnace, and the temperature raising area and the reaction area are sequentially arranged. A carbon nanostructure manufacturing apparatus, comprising: a catalyst base transporting means for transporting, wherein the catalyst base that has passed through the temperature raising region is transferred to the reaction region, and carbon nanostructures are grown on the catalyst base by the source gas And reducing the cross section in the furnace, leaving a gap through which the catalyst substrate can pass, partitioning the boundary region between the temperature rising region and the reaction region, and the rising of the source gas supplied to the reaction region. The material gas diffusion suppression type carbon nanostructure manufacturing apparatus characterized by having a suppressing diffusion suppressing body diffusion into the region side. The diffusion suppressor comprises a single partition plate having a predetermined thickness or a plurality of partition plates having a predetermined total thickness that sharply reduces the concentration distribution of the source gas at a partition end in contact with the reaction region. The raw material gas diffusion suppression type carbon nanostructure manufacturing apparatus according to claim 1. Set the equation of motion of the model fluid as a laminar flow continuum that diffuses from the reaction region to the temperature rising region via the diffusion suppressor, the equation of continuity, and the mass fraction transport equation of the source gas. The characteristic value of the source gas is applied to the velocity and pressure of the model fluid derived from the equation to determine the concentration distribution of the source gas in at least the reaction region and the diffusion suppressor, and according to the determined concentration distribution The raw material gas diffusion suppression type carbon nanostructure manufacturing apparatus according to claim 2, wherein the predetermined thickness or the predetermined total thickness and the reduced partial cross-sectional shape of the diffusion suppression body are determined. The density of the model fluid is ρ, the viscosity coefficient is μ, the velocity is u (u is represented by u = (u _x , u _y , u _z )), the pressure of the model fluid is p, and the flow velocity u generation term (the generation amount per unit time and unit volume) S _u, mass fraction of m _i of the raw material gas, the diffusion flux J _i (J _i of the source gas, J _i = (J _ix, J _iy , J _iz ))), the equation of motion is ρ (u · grad) u = div (μgradu) −gradu + S _u ,
The continuous equation is
div (ρu) = 0,
The mass fraction transport formula of the source gas is
div (ρum _i ) = − divJ _i ,
The raw material gas diffusion suppression type carbon nanostructure manufacturing apparatus according to claim 3, wherein the concentration distribution is obtained by applying a characteristic value of the raw material gas to the pressure p and the velocity u. The concentration distribution of the source gas is indicated by a molar fraction of the source gas with respect to the carrier gas, and at least the molar fraction of the source gas at the partition end is 100 ppm or less. Raw material gas diffusion suppression type carbon nanostructure manufacturing equipment. The raw material gas diffusion suppression type carbon nanostructure manufacturing apparatus according to any one of claims 2 to 5, wherein the predetermined thickness or the predetermined total thickness is 15 mm or more. The raw material gas diffusion-suppressing carbon nanostructure manufacturing apparatus according to any one of claims 1 to 6, wherein the catalyst substrate transport means includes an endless belt that runs in the reaction furnace. The said endless belt is a raw material gas diffusion suppression type | mold carbon nanostructure manufacturing apparatus of Claim 7 currently formed from the SUS material. The catalyst substrate transporting means is configured by a roll-to-roll device that causes the belt body to travel in the reaction furnace while winding one end side of the belt body wound around the winding roller around the winding roller, and the surface side of the belt body The catalyst layer is formed into the catalyst base, the belt body is transferred from the temperature rising region through the gap to the reaction region, and the carbon nanostructure is grown on the catalyst layer. The raw material gas diffusion suppression type carbon nanostructure manufacturing apparatus according to any one of claims 1 to 6, wherein the carbon nanostructure is collected and the belt body is wound around the winding roller. The raw material gas diffusion suppression type carbon nanostructure manufacturing apparatus according to claim 9, wherein the belt body is formed of a SUS material. The catalyst substrate transport means comprises a source gas supply pipe provided with a plurality of supply ports for supplying the source gas to the reaction region in the width direction of the catalyst substrate, and the source gas supplied to the reaction region is supplied to the catalyst The raw material gas diffusion suppression type carbon nanostructure manufacturing apparatus according to any one of claims 1 to 10, further comprising: an outflow path that flows out to the back side of the substrate; and an exhaust unit that exhausts the raw material gas that flows out of the outflow path. . The raw material gas diffusion suppression type carbon nanostructure manufacturing apparatus according to any one of claims 1 to 11, wherein the carbon nanostructure is a brush-like carbon nanotube grown on the catalyst substrate.