JP5386125B2 - Carbon fiber manufacturing apparatus and carbon fiber manufacturing method - Google Patents

Description

  The present invention relates to a carbon fiber manufacturing apparatus and a carbon fiber manufacturing method. More specifically, the present invention relates to a carbon fiber manufacturing apparatus excellent in maintainability and compactness, and a carbon fiber manufacturing method using the manufacturing apparatus.

The use of carbon fiber is rapidly expanding in the aerospace industry and sports / leisure industry due to the material properties of light weight and high strength.
Conventionally, carbon fibers have been produced by spinning polyacrylonitrile, flameproofing, carbonization treatment, etc. In recent years, carbon fiber production methods by chemical vapor deposition (CVD) have made carbon fibers inexpensive and It was developed as a method that can be mass produced.
A fluidized bed manufacturing apparatus is used for manufacturing carbon fibers by this CVD method. That is, by filling the catalyst in a reaction vessel provided with a metal porous dispersion plate at the bottom, and supplying the carbon-containing gas and the inert gas for flow, the catalyst and the carbon-containing gas are in a fluid state. It is made to contact, and carbon fiber is pyrolyzed to produce carbon fiber.
Conventionally, various proposals have been made in order to efficiently generate carbon fibers while maintaining a fluid state. However, since the dispersion plate is clogged or deteriorated in a short time, it is necessary to frequently stop the reaction tank and clean or replace the dispersion plate, which is not efficient. In particular, such clogging and deterioration of the dispersion plate are conspicuous in a metal dispersion plate that serves as a catalyst for the carbon fiber formation reaction. Therefore, a durable dispersion plate material that can replace metal is studied. ing.
For example, a catalyst having a dispersion plate using a quartz sintered plate is filled with a catalyst, a carbon-containing gas is supplied from the bottom of the reactor, the catalyst is fluidized, and the solid catalyst and the carbon-containing gas are brought to a reaction temperature or higher. A method for producing carbon nanotubes by heating to (Patent Document 1) has been proposed.

However, even if such a quartz sintered plate sintered plate is used, it is known that the quartz sintered plate is likely to be blocked by long-term use. In addition, in the case of such an apparatus, when the dispersion plate is clogged, the entire reactor is once removed from the plant, or if the reactor is large, an operator needs to enter the inside, and maintenance work is complicated. There is also the problem of being.
In addition, when scaling up for industrial use, it is difficult to increase the size of the quartz sintered plate, and a metal material must be used. When a metal material is used for the dispersion plate, as described above, clogging of the dispersion plate becomes remarkable, so that frequent maintenance is required.

On the other hand, a manufacturing apparatus has also been proposed in which a fluidized bed is fluidized with a carbon-containing gas and an auxiliary gas without installing a dispersion plate (Patent Document 2).
However, in this apparatus, in order to maintain the fluidized bed, the gas flow becomes enormous and is not suitable for an increase in size. Moreover, in the apparatus described in Patent Document 2, it is also described that the gas is preheated with a heat exchanger before supplying the carbon-containing gas to the reactor. As a result, the apparatus becomes longer and is not compact. End up.

JP 2008-56523 A Special table 2007-519592

  The present invention has been made in view of the above circumstances, and the carbon fiber manufacturing apparatus has a double structure using an outer cylinder surrounding the inner cylinder, a dispersion plate is installed at the lower part of the inner cylinder, and the outer By providing a preheating heater in the cylinder, clogging of the dispersion plate is reduced, and even when the dispersion plate is clogged, it can be easily maintained, and a compact carbon with integrated preheating mechanism It is an object of the present invention to provide a fiber manufacturing apparatus and a carbon fiber manufacturing method using the manufacturing apparatus.

In order to achieve the above object, the inventors of the present invention have made extensive studies and completed the present invention. That is, the present invention is as follows.
1. An apparatus for producing a double-structured carbon fiber comprising an inner cylinder having a fluidized portion in which a granular catalyst and a carbon-containing gas react, and an outer cylinder surrounding the inner cylinder, wherein the carbon-containing gas is contained in the outer cylinder A carbon-containing gas supply pipe for supplying, a heater for preheating the carbon-containing gas provided in the outer cylinder, a dispersion plate provided at the bottom of the inner cylinder, and a reaction gas from the inner cylinder An apparatus for producing carbon fiber, comprising: a reaction gas discharge pipe for discharging.
2. 2. The carbon fiber manufacturing apparatus according to 1 above, wherein the ratio of the outer diameter of the inner cylinder to the inner diameter of the outer cylinder is 0.5 to 0.98.
3. 3. The carbon fiber manufacturing apparatus according to 1 or 2, wherein the ratio of the length of the inner cylinder to the length of the outer cylinder is 0.4 to 0.7.
4). 4. The carbon fiber production apparatus according to any one of 1 to 3, wherein the granular catalyst is a metal catalyst.
5. The carbon fiber manufacturing apparatus according to any one of the above 1 to 4, wherein a carbon-containing gas supply pipe is provided at the lower part of the outer cylinder.
6). The carbon fiber manufacturing apparatus according to any one of the above 1 to 5, wherein a carbon-containing gas supply pipe is provided at the top of the outer cylinder.
7). 7. The carbon fiber manufacturing apparatus according to any one of 1 to 6, wherein a lid on the top of the inner cylinder is detachable.
8). Using the manufacturing apparatus according to any one of 1 to 7 above, after supplying the carbon-containing gas to the outer cylinder and preheating it, through the dispersion plate, the inner cylinder having a fluidized portion where the granular catalyst and the carbon-containing gas react A method for producing carbon fiber, characterized in that carbon fiber is produced by supplying and then the reaction gas is discharged from the inner cylinder to the outside of the system.
9. 9. The method for producing carbon fiber as described in 8 above, wherein the preheating temperature of the carbon-containing gas is lower than the decomposition temperature of the carbon-containing gas, and the temperature of the fluidized part is equal to or higher than the decomposition temperature of the carbon-containing gas.
10. 10. The method for producing carbon fiber as described in 9 above, wherein the preheating temperature of the carbon-containing gas and the temperature of the fluidized portion are controlled by the supply rate to the carbon-containing gas production apparatus.
11. The method for producing carbon fiber according to any one of 8 to 10 above, wherein the carbon-containing gas is ethylene and the preheating temperature is 600 to 630 ° C.
12 12. The method for producing carbon fiber as described in 11 above, wherein a supply rate of ethylene to the outer cylinder is 0.03 to 5 m / s under a preheating temperature.

  The present invention reduces clogging of a dispersion plate provided in a carbon fiber manufacturing apparatus, and can be easily maintained even when the dispersion plate is clogged to obtain a large amount of carbon fiber at low cost. In addition, it is possible to provide a compact carbon fiber manufacturing apparatus in which a preheating mechanism is integrated, and a carbon fiber manufacturing method using the manufacturing apparatus.

The present invention is a double-structure carbon fiber manufacturing apparatus comprising an inner cylinder having a fluidized portion in which a granular catalyst and a carbon-containing gas react, and an outer cylinder surrounding the inner cylinder, A carbon-containing gas supply pipe for supplying a carbon-containing gas, a heater for preheating the carbon-containing gas provided in the outer cylinder, a dispersion plate provided at the bottom of the inner cylinder, and the inner cylinder And a reaction gas discharge pipe for discharging the reaction gas from the carbon fiber manufacturing apparatus.
The present invention will be described in detail with reference to FIG. FIG. 1 shows an example of the carbon fiber production apparatus of the present invention.
In FIG. 1, 1 is an inner cylinder, 2 is an outer cylinder surrounding the inner cylinder 1, 3 is a dispersion plate installed at the bottom of the inner cylinder 1, 4 is a heater provided at the outer periphery of the outer cylinder 2, 5 'is a carbon-containing gas supply pipe, 6 is a reaction gas discharge pipe (also serving as an inert gas supply pipe in some cases), 7 is a granular catalyst supply pipe, 8 is a powder extraction pipe, 9 is an inert gas supply pipe, Reference numeral 10 denotes a heat insulating material, and 11 denotes a lid of the inner cylinder 1 that is detachable. The carbon-containing gas supply pipes 5 and 5 ′ may be separately provided with an inert gas supply means and used together as the inert gas supply pipe 9.

The carbon fiber manufacturing apparatus of the present invention has a double structure using an inner cylinder 1 and an outer cylinder 2 surrounding the inner cylinder 1, and has an outer diameter r ₁ of the inner cylinder 1 with respect to an inner diameter r ₂ of the outer cylinder 2. The ratio is preferably about 0.5 to 0.98.
By making this ratio within the above range, when carbon fiber is produced using the production apparatus of the present invention, the volumetric efficiency is high, and even when the inner cylinder and the outer cylinder are thermally expanded, both can be in contact with each other. Low.
The ratio of the length l ₁ of the inner cylinder 1 to the length l ₂ of the outer cylinder 2 is preferably about 0.3 to 0.7 (in the case of the manufacturing apparatus of FIG. The length shall be up to the lower cone end).
By setting this ratio within the above range, the preheating portion in the outer cylinder 2 is secured, and the preheating effect can be sufficiently exhibited.
The inner cylinder 1 and the outer cylinder 2 can be freely separated by a flange or the like provided at the top.

A heater 4 is provided on the outer peripheral portion of the outer cylinder 2, and the distance l ₃ in the length direction thereof is adjusted so as to exert a preheating effect in the outer cylinder 2. When the gas is supplied from the lower carbon-containing gas supply pipe 5, it is provided to extend downward from the dispersion plate 3 provided at the bottom of the inner cylinder 1 in order to secure a preheating portion. Even when the carbon-containing gas supply pipe 5 ′ is provided at the top of the outer cylinder 2 and the carbon-containing gas is supplied from the gap between the inner cylinder 1 and the outer cylinder 2, it is preferable to provide a preheating part below the dispersion plate 3. .
The installation distance l ₃ in the length direction of the heater 4 is the volume in the outer cylinder 2 serving as a preheating part, the volume of the gap between the inner cylinder 1 and the outer cylinder 2, the type of carbon-containing gas, and the gas Therefore, it is preferable to make an experiment in advance.

A lid 11 of the inner cylinder 1 is detachably provided at the top of the carbon fiber manufacturing apparatus.
In FIG. 1, a powder extraction pipe 8 is provided in the vertical direction to take out the powder containing the carbon fibers and the particulate catalyst as the reactants from the substantially central portion of the inner cylinder 1. The powder extraction tube 8 can be moved up and down, and by positioning the inlet of the extraction tube 8 by a gripping means (not shown), the amount of extraction of the reactant can be arbitrarily determined. For example, the total amount of the reactant may be withdrawn, and in order to facilitate the formation of a fluidized part in the next operation, about 10 to 40% by mass of the reactant is left in the inner cylinder 1 and the remaining part can be taken out. Alternatively, the inlet of the powder extraction tube 8 may be set. By providing such a powder extraction pipe 8 and supplying an inert gas into the inner cylinder 1 from an inert gas supply pipe 9 at the bottom of the production apparatus, the reactant can be taken out.

As a material used for the inner cylinder 1 and the outer cylinder 2 used in the carbon fiber manufacturing apparatus, a material that mainly considers airtightness and heat resistance strength is used for the outer cylinder 2 by adopting a double structure. On the other hand, as the inner cylinder 1, a material mainly considering heat resistance and corrosion resistance may be used. For example, using ceramics such as boron nitride, silicon carbide and silicon nitride, stainless steel (SUS-304, 316, 310, 430, etc.), chromium / tungsten alloys such as Stellite (registered trademark), ceramic coating materials, etc. it can. Among these, stainless steel is preferable from the viewpoints of workability and corrosion resistance. The same material can be used for the powder extraction tube 8.
In addition, it is preferable to avoid the use of Ni in order to generate carbon fibers having different shapes. However, if it is absolutely necessary to use a Ni-based material, the surface in contact with the carbon-containing gas is polished. It is preferable. This is because by polishing, the surface roughness can be reduced, and the production of carbon fibers from Ni can be reduced.
As described above, by adopting a double structure as a carbon fiber manufacturing apparatus, airtightness and heat-resistant strength can be secured in the outer cylinder, so that variations in the material and structure of the inner cylinder increase.
The heater 4 is provided in the outer peripheral part and inner peripheral part of the outer cylinder 2, and can employ conventional heating means such as an electric furnace, an electric heating coil, and an infrared heater.
As the dispersion plate 3, a metal plate such as stainless steel can be used, but a quartz plate can also be used.
The heat insulating material 10 is not particularly limited, and those usually used can be used.

  As the carbon-containing gas supplied from the carbon-containing gas supply pipe 5 or 5 ′, hydrocarbons that are gases under carbon fiber generation reaction conditions can be used. Examples of such hydrocarbons include methane, ethane, ethylene, acetylene, propane, propylene, isopropylene, n-butane, butadiene, butene, pentane, pentene, n-hexane, n-octane, isooctane, and n-nonane. , N-decane, or mixtures thereof. Of these, ethylene is particularly preferable because it has a relatively low thermal decomposition temperature.

  The carbon-containing gas can be a mixture with an inert gas such as nitrogen, argon, hydrogen, or helium. The combined use of such a carbon-containing gas and an inert gas is preferable because the concentration of carbon can be controlled and there is an effect as a carrier gas.

As a granular catalyst which is supplied from the catalyst supply pipe 7 of the carbon fiber production apparatus of the present invention to the inner cylinder 1 and flows in the fluidized part to come into contact with the carbon-containing gas and causes a carbon decomposition reaction, gas phase process carbon is used. There is no particular limitation as long as it promotes the generation of fibers. In general, it is preferable to contain a transition metal element such as Fe, Co, and Ni, and more preferably to contain an Fe element. Furthermore, a supported catalyst having the above metal supported on a carrier is preferable. Moreover, you may contain the other transition metal element as a promoter. As such a co-catalyst element, Mo, W, Cr, V, Mn, Ti and the like are preferable, and combinations of two or more such as Mo and V, Mo and Cr, W and V, W and Cr are more preferable.
These catalysts can be used as precursor particles, metal or alloy particles, but are preferably supported on a carrier. As the catalyst carrier, any known compound can be used, but an inorganic substance that is stable under the reaction conditions is preferable. Examples of such preferred inorganic carriers include alumina, silica, alumina silicate, zeolite, diatomaceous earth, titania, silica titania, magnesia, spinel and the like.
The amount of catalyst metal supported on the carrier is usually about 0.1 to 40% by mass. The supporting method is not particularly limited, and a conventional impregnation method or ion exchange method can be employed.
In order to make the catalyst particles or the supported catalyst particles flow under reaction conditions, the particle diameter is preferably 1 to 1000 μm, more preferably 10 to 500 μm. The particle size of the catalyst particles and the supported catalyst particles can be adjusted to a preferred range by appropriately adjusting the catalyst adjustment conditions and the catalyst precursor compound and catalyst carrier used for catalyst adjustment. It is particularly preferable to adjust to a desired particle size range by pulverizing, crushing, and classifying.
The amount of the granular catalyst charged to the carbon-containing gas is usually about 300 to 2000 NL / (min · kg). When the charged amount is less than 300 NL / (min · kg), the reaction takes a long time, and thus the productivity is deteriorated. If it exceeds 2000 NL / (min · kg), the carbon fiber generation reaction ends early, but the ratio of the carbon-containing gas that does not contribute to the reaction increases, which is not economical.
In order to improve the fluidity of the fluidized portion and to prevent local heat generation of the granular catalyst, a flow aid can be added in addition to the catalyst. Such flow aids include magnesia, alumina, titania, and manufactured carbon fibers.

Although the carbon fiber manufacturing apparatus of the present invention has been described with reference to FIG. 1, the present invention is not limited to the above description. For example, instead of or in addition to providing the carbon-containing gas supply pipe 5 at the lower part of the outer cylinder. In addition, by providing a carbon-containing gas supply pipe 5 ′ at the top and supplying the carbon-containing gas therefrom, the carbon-containing gas can be preheated in the gap between the inner cylinder 1 and the outer cylinder 2, and this manufacturing apparatus is It becomes possible to make it more compact.
In FIG. 1, the shape of the inner cylinder 1 is tapered so that the cross-sectional area of the inner cylinder 1 decreases downward only, but not limited thereto, the cross-sectional area of the inner cylinder 1 is downward. The shape may be reduced continuously or intermittently toward the top, and only the upper part of the inner cylinder 1 may have a funnel shape having a larger cross-sectional area than the lower part. In short, any shape can be adopted as long as a fluid part is generated inside the inner cylinder 1 and a dispersion plate can be attached to the bottom of the fluid part.
As for the method of supplying the granular catalyst, the inner cylinder 1 may be filled in advance prior to the reaction, or the supply of the granular catalyst may be started simultaneously with the supply of the carbon-containing gas.

The present invention also provides an inner cylinder 1 having a fluidized part in which the granular catalyst and the carbon-containing gas react through the dispersion plate 3 after supplying the carbon-containing gas to the outer cylinder 2 and preheating using the manufacturing apparatus. To produce carbon fiber, and then the reaction gas is discharged from the inner cylinder to the outside of the system.
A method for producing carbon fibers will be specifically described using the production apparatus shown in FIG. First, while supplying an inert gas or the like from the inert gas supply pipe 9, the manufacturing apparatus is heated by the heater 4 until the preheating temperature is reached, and then the carbon-containing gas is supplied from the carbon-containing gas supply pipe 5 to the outer cylinder 2. The heater 4 is preheated by the preheating part generated at the lower part of the outer cylinder 2 surrounding the outer peripheral part. The preheating temperature is lower than the temperature at which the carbon-containing gas is brought into contact with the granular catalyst to cause a decomposition reaction and carbon fibers are generated. Next, the preheated carbon-containing gas is supplied into the inner cylinder 1 through the dispersion plate 3. In the inner cylinder 1, the carbon-containing gas fluidizes the catalyst introduced from the catalyst supply pipe 7 to generate a fluidized part, and the carbon fiber is formed by a pyrolysis reaction accompanied by heat generation due to contact between the granular catalyst and carbon. Heated above the temperature at which it is produced. As a result, carbon fibers are produced on the granular catalyst from the carbon-containing gas. The reaction gas that has finished the reaction is discharged out of the system from the reaction gas discharge pipe 6.
After a predetermined time has elapsed, the powder extraction tube 8 is opened, the reaction gas discharge tube 6 is closed, and the generated carbon fiber is discharged from the powder extraction tube 8 and is then returned to the bag filter, cyclone, centrifuge, or ceramic filter. The gas and the powder are separated and recovered. Alternatively, an inert gas such as nitrogen gas that does not affect the decomposition reaction is supplied from the inert gas supply pipe 9 instead of the carbon-containing gas, and the generated carbon fiber is discharged from the powder extraction pipe 8. Also good.

When the discharge of the carbon fiber is completed, if the dispersion plate is not clogged, the above process is repeated again, and if the dispersion plate is clogged, maintenance or replacement of the dispersion plate is performed.
The clogging of the dispersion plate can be grasped by measuring the pressure loss of the dispersion plate or by extracting the whole amount of the reaction product and observing it directly with the naked eye.
In the case of the manufacturing apparatus shown in FIG. 1, the maintenance is performed by opening the lid 11 at the top of the inner cylinder 1 and removing only the inner cylinder 1 to clean or replace the dispersion plate. After the maintenance is completed, the inner cylinder 1 is stored as it is, the lid is attached, and the operation is started again.
Thus, since it is not necessary to disassemble and disassemble the entire manufacturing apparatus, it is extremely excellent in maintainability.

In the above description, the preheating temperature of the carbon-containing gas and the temperature of the fluidized portion vary depending on the carbon raw material used. Therefore, it may be determined according to the carbon raw material to be used. For example, when ethylene gas is used as the carbon raw material, the preheating temperature is preferably 600 to 630 ° C. Within this temperature range, the thermal decomposition of ethylene is not significant, and almost no carbide is generated, so that the possibility of clogging the dispersion plate is reduced. After that, when ethylene gas is supplied to the fluidized portion of the inner cylinder 1 and comes into contact with the granular catalyst, an exothermic reaction occurs, easily reaching the ethylene decomposition temperature or more, and carbon fibers are generated.
In this case, it is also important to adjust the supply rate of the carbon-containing gas into the outer cylinder 2. In the case of ethylene gas, in order to realize the preheating temperature and the temperature of the fluidized part, The supply rate of the carbon-containing gas at the preheating temperature is preferably about 0.03 to 5 m / s. The linear velocity of the gas in the inner cylinder 1 is usually 0.05 m / s or more, preferably 0.10 m / s or more, although it depends on the granular catalyst used and its carrier. A fluidized part is formed.
These conditions can be obtained by experiments if the carbon-containing gas to be used is determined.

In the above, the produced carbon fiber is taken out through the powder extraction pipe 8 by supplying the carbon-containing gas from the carbon-containing gas supply pipes 5, 5 ′ or the inert gas supply pipe 9. As described above, instead of the inert gas supply pipe 9, a separate inert gas supply means is provided in the reaction gas discharge pipe 6, and an inert gas is supplied therefrom, and the reactant is taken out through the powder extraction pipe 8. It can also be done.
Further, in the manufacturing method of the present invention, the extraction is not limited to the method performed through the powder extraction tube 8. For example, the removable lid 11 provided on the top of the inner cylinder 1 of the manufacturing apparatus is opened and manually operated. The reactant may be removed. In addition, you may perform such taking-out of a reaction material for every batch operation. Further, it is possible to continuously recover the reaction product during the reaction. In this case, the carbon-containing gas and the granular catalyst are continuously supplied to the production apparatus at a constant supply rate, and the opening degrees of the reaction gas discharge pipe 6 and the powder extraction pipe 8 are adjusted, so that the carbon fiber is Collect continuously.
However, the batch type is preferable because the residence time (reaction time) can be made constant and the quality of the carbon fiber can be kept constant.
In this case, since there is a possibility that unreacted carbon-containing gas is entrained and discharged outside the system, the unreacted gas and carbon fiber are separated from the gas filter such as a bag filter or a centrifuge after the reaction gas is recovered. Separation may be performed using separation means, and the unreacted source gas may be supplied again to the production apparatus as the source gas.

As described in detail above, in the present invention, since the double structure is adopted as the carbon fiber manufacturing apparatus, the outer cylinder 2 can ensure airtightness and heat-resistant strength. Variations such as increase.
Further, since the decomposition of the carbon-containing gas occurs in the fluidized portion after being supplied to the inner cylinder 1, the periphery of the dispersion plate 3 is maintained below the decomposition temperature of the carbon-containing gas. Therefore, even if the metallic dispersion plate 3 is used, clogging on the surface of the dispersion plate 3 is unlikely to occur, and accordingly, the frequency of maintenance such as cleaning is reduced, and the carbon fiber production time is set longer. Can do. In addition, even when the dispersion plate 3 is clogged, it is possible to perform maintenance such as cleaning and replacement by removing only the inner cylinder 1, far more maintenance than disassembling the entire conventional manufacturing apparatus. Improves.
In addition, since the carbon-containing gas is supplied from the lower part of the reactor or the gap between the inner cylinder and the outer cylinder and preheated, the apparatus can be made more compact and has many excellent points.
The obtained carbon fiber is of high quality and can be used as a material for aerospace industry and sports / leisure industry.

EXAMPLES Next, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited at all by these examples.
(Preparation of supported catalyst)
1.8 parts by mass of iron (III) nitrate nonahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 1.5 parts by mass of methanol. Next, 0.05 parts by mass of ammonium metavanadate (manufactured by Kanto Chemical Co., Ltd.) and 0.075 parts by mass of ammonium heptamolybdate (manufactured by Wako Pure Chemical Industries, Ltd.) were dissolved to obtain a catalyst preparation solution. The catalyst preparation liquid was dropped and kneaded into 1 part by mass of commercially available gamma alumina (AKP-G015 manufactured by Sumitomo Chemical Co., Ltd.) to obtain a paste-like mixture. The paste-like mixture was dried with a vacuum dryer at 100 ° C. for 4 hours, pulverized with a mortar and classified to 45 μm to 250 μm to prepare a catalyst.

Example 1
Using the production apparatus shown in FIG. 1, vapor grown carbon fiber was produced as follows.
First, as a manufacturing apparatus, SUS430 having an upper outer diameter of 192 mm, an upper inner diameter of 190 mm, a bottom inner diameter of 128 mm, a bottom outer diameter of 130 mm, an opening diameter of 1.0 mmφ at the bottom, an opening ratio of 0.5%, and a thickness of 1 mm. A manufacturing apparatus having a double structure of a stainless steel inner cylinder (length 1440 mm) to which a dispersion plate is fixed and a SUS304 stainless steel outer cylinder (length 2880 mm) having an upper inner diameter of 200 mm and a tapered bottom is used. (The ratio of the outer diameter of the inner cylinder to the inner diameter of the outer cylinder is 0.96, and the ratio of the length of the inner cylinder to the length of the outer cylinder is 0.5). The heater 4 had a length of 1780 mm, and the outer periphery of the heater 4 was covered with a heat insulating material 10 to which an aluminum foil was attached.
First, the temperature inside the inner cylinder 1 (at 250 mm on the dispersion plate) is heated to 600 to 620 ° C. with the heater 4, and then nitrogen gas is entrained in the inner cylinder 1 to obtain 50 g of the granular catalyst in advance. The produced carbon fiber 250 g is charged on a dispersion plate, and then a mixed gas of ethylene 30 NL / min and hydrogen 30 NL / min is supplied from the raw material gas supply pipe 5 of the outer cylinder 2 to bring the solid catalyst solid catalyst particles into contact with ethylene. This produced carbon fiber.
The temperature of the preheating part in the outer cylinder 2 was 620 ° C., and the temperature in the flow part in the inner cylinder 1 15 minutes after the supply of the carbon-containing gas was 650 to 670 ° C. Moreover, the linear velocity of the preheating part in 620 degreeC was 0.104 m / s, the linear velocity of the inner cylinder 1 lower part was 0.265 m / s, and the linear velocity of the inner cylinder 1 upper part was 0.115 m / s. The reaction time was 60 minutes. After completion of the reaction time, nitrogen gas is supplied from the inert gas supply pipe 9, the powder extraction pipe 8 is opened, the reaction gas discharge pipe 6 is closed and the gas flow path is switched, and then the carbon fiber present in the inner cylinder 1 The catalyst and carbon fiber were collected in a bag filter from a powder extraction tube 8 whose inlet was fixed at a position where all of the catalyst was discharged. The reaction gas discharged from the bag filter was incinerated.
The batch processing time was 95 minutes in total, with 5 minutes of granular catalyst input, 60 minutes of reaction time, and 30 minutes of extraction. The recovered carbon fiber was 1650 g.
When this operation was repeated 50 batches, the pressure difference between the upper and lower sides of the dispersion plate gradually increased, and the recovered amount of carbon fiber decreased. Then, the temperature was lowered, the lid 11 was opened, and the state of the stainless steel dispersion plate 3 was observed. As a result, clogging of about half of the total area was observed, so the inner cylinder 1 was taken out and the dispersion plate 3 was replaced. The time required for exchanging the dispersion plate was 2 hours.

  According to the carbon fiber manufacturing apparatus and the carbon fiber manufacturing method of the present invention, high quality carbon fiber can be efficiently produced by reducing clogging of the dispersion plate and preheating the carbon-containing source gas. The carbon fiber thus obtained can be used as a material for the aerospace industry and sports / leisure industry.

It is a schematic block diagram which shows the one aspect | mode of the manufacturing apparatus of the carbon fiber of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inner cylinder 2 Outer cylinder 3 Dispersion plate 4 Heater 5, 5 'Carbon containing gas supply pipe 6 Reactive gas discharge pipe (inert gas supply pipe)
7 Catalyst supply pipe 8 Powder extraction pipe 9 Inert gas supply pipe 10 Heat insulating material 11 Lid

Claims (12)

An inner cylinder which particulate catalyst and a carbon-containing gas has a flow section that reacts, the production of carbon fiber having a double structure composed of an outer cylinder surrounding the inner cylinder has a preheating section for preheating the carbon-containing gas An apparatus comprising: a carbon-containing gas supply pipe for supplying the carbon-containing gas into the outer cylinder; a heater for preheating the carbon-containing gas provided in the outer cylinder; and the bottom of the inner cylinder And a reaction gas discharge pipe for discharging the reaction gas from the inner cylinder ,
The heater heats the preheating part below a decomposition temperature at which the carbon-containing gas and the granular catalyst come into contact with each other to cause a decomposition reaction to generate carbon fibers,
An apparatus for producing carbon fiber, wherein the temperature of the fluidized part is equal to or higher than the decomposition temperature .   The carbon fiber manufacturing apparatus according to claim 1, wherein the ratio of the outer diameter of the inner cylinder to the inner diameter of the outer cylinder is 0.5 to 0.98.   The carbon fiber manufacturing apparatus according to claim 1 or 2, wherein a ratio of the length of the inner cylinder to the length of the outer cylinder is 0.4 to 0.7.   The apparatus for producing carbon fiber according to any one of claims 1 to 3, wherein the granular catalyst is a metal catalyst.   The carbon fiber manufacturing apparatus according to any one of claims 1 to 4, wherein a carbon-containing gas supply pipe is provided at a lower portion of the outer cylinder.   The carbon fiber manufacturing apparatus according to any one of claims 1 to 5, wherein a carbon-containing gas supply pipe is provided at the top of the outer cylinder.   The carbon fiber manufacturing apparatus according to any one of claims 1 to 6, wherein a lid at the top of the inner cylinder is detachable.   An inner cylinder having a fluidizing section in which the granular catalyst and the carbon-containing gas react through a dispersion plate after supplying the carbon-containing gas to the outer cylinder and preheating using the manufacturing apparatus according to claim 1. To produce carbon fiber, and then discharge the reaction gas from the inner cylinder to the outside of the system.   The carbon fiber manufacturing method according to claim 8, wherein the preheating temperature of the carbon-containing gas is lower than the decomposition temperature of the carbon-containing gas, and the temperature of the fluidized portion is equal to or higher than the decomposition temperature of the carbon-containing gas.   The carbon fiber manufacturing method according to claim 9, wherein the preheating temperature of the carbon-containing gas and the temperature of the fluidized portion are controlled by a supply rate to the carbon-containing gas manufacturing apparatus.   The carbon fiber production method according to any one of claims 8 to 10, wherein the carbon-containing gas is ethylene and the preheating temperature is 600 to 630 ° C.   The method for producing a carbon fiber according to claim 11, wherein a supply rate of ethylene to the outer cylinder is 0.03 to 5 m / s under a preheating temperature.

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