JPS6392727A - Production of carbon fiber and apparatus therefor - Google Patents

Abstract

PURPOSE:To produce and collect carbon fiber grown in vapor phase, in high efficiency, preventing the deposition of carbon to production devices, etc., by supplying gas of a carbon compound and catalyst particles or gas of a catalyst raw material to a region irradiated with a laser beam. CONSTITUTION:A laser beam is radiated from one end to the other end of a reaction vessel 10. One end of the reaction vessel 10 is supplied with a carrier gas, gas of a carbon compound and a raw material gas for catalyst (or catalyst particle) and the other end of the reaction vessel 10 is provided with a carbon fiber collector 22. The gas of the carbon compound is preferably aliphatic or aromatic hydrocarbon gas and the catalyst is preferably a transition metal compound, especially an iron compound such as Fe(NO)4, FeCl3, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for producing carbon ia i (8) by a vapor phase growth method, and particularly to a method and apparatus using a laser beam.

[Prior Art] Conventionally, PAN-based and pitch-based carbon fibers have been commercially produced. However, the PAN system is expensive, and the pitch system has fatal drawbacks such as complicated processes and difficult quality control.

On the other hand, a vapor phase growth method has been proposed in recent years. Conventionally, vapor-grown carbon fibers are produced by placing a substrate made of porcelain such as alumina or graphite in an electric furnace, forming carbon growth nuclei, ultrafine particle catalysts such as iron or nickel on this, and then forming carbonization particles such as benzene on this. A method is known in which carbon IA fibers are grown on a substrate by introducing a mixed gas of hydrogen gas and hydrogen carrier gas and decomposing hydrocarbons at a temperature of 950° to 1300°C.

However, with this method, there are two issues: (1) non-uniformity in length is likely to occur due to subtle temperature unevenness on the substrate surface and the density of the surrounding taitt, and (2) gas as a source of carbon is consumed by the reaction. As a result, the diameter of the 1a fibers becomes considerably larger near the inlet and outlet of the reaction tube, and (1) the production occurs only on the substrate surface, so the central part of the reaction tube does not participate in the reaction and the yield is poor. ■ Continuous manufacturing is impossible because there are processes that must be carried out independently, such as dispersing ultrafine particles onto a substrate, reducing them, growing them, and then taking out the FA fibers, resulting in problems such as poor productivity. have

Therefore, a method for producing carbon ia fa was proposed in which a mixed gas of a carbon compound gas, an inorganic or organic transition metal compound gas, and a carrier gas was reacted at high temperature.
0-54998.6〇-224816, etc.).

[Problems to be solved by the invention] However, the above-mentioned Japanese Patent Application Laid-Open No. 60-54998.224
In methods such as 816, the reaction vessel is also heated, which causes problems such as by-products adhering to the walls of the vessel, resulting in a decrease in yield and difficulty in continuous operation. In addition, it is not easy to scale up, making it unsuitable for mass production, and requires an electric furnace for heating, resulting in high energy costs.

[Means and effects for solving the problems] In order to solve the above problems, the present invention brings carbon compound gas into contact with suspended catalyst particles under laser irradiation to form carbon into fibers. A method for producing carbon fiber, comprising: a reaction vessel having a reaction zone therein; a laser device that irradiates a laser beam toward the reaction zone; and a reaction vessel with the reaction zone in between. A means for introducing carrier gas, a means for introducing carbon compound gas, and a means for introducing catalyst particles or catalyst raw material gas are connected to one side, and carbon is connected to the other side of the reaction vessel with the reaction zone in between. The present invention provides a carbon fiber manufacturing method and apparatus, characterized by comprising a fiber collection means.

The present invention will be explained in more detail below.

The carbon compound in the present invention refers to all carbon compounds that can be gasified, and includes CCL, CHCl3CI2
Particularly useful compounds characterized by inorganic compounds such as Cl2, CH, C1%C01C52, etc. and organic compounds in general are aliphatic hydrocarbons and aromatic hydrocarbons.

In addition to these, nitrogen, oxygen, sulfur, fluorine, iodine, phosphorus,
Derivatives containing elements such as arsenic can also be used. Some specific examples of individual compounds include methane (natural gas may also be used), alkane compounds such as ethane, alkene compounds such as ethylene and butadiene, alkyne compounds such as acetylene, benzene, toluene, styrene, etc. aryl hydrocarbon compounds, aromatic hydrocarbons with condensed rings such as indene, naphthalene, and phenanthrene, cycloparaffin compounds such as cyclopropane and cyclohexane, cycloolefin compounds such as cyclopentene and cyclohexene, and alicyclic rings having condensed rings such as steroids. Formula hydrocarbon compounds, sulfur-containing aliphatic compounds such as methylthiol, methylethyl sulfide, dimethylthioketone, sulfur-containing aromatic compounds such as phenylthiol and diphenyl sulfide, sulfur-containing heterocyclic compounds such as benzothiophene and thiophene, and Although not individual substances, Fire Service Act dangerous substances such as gasoline, Class 4 petroleum, Class 2 petroleum such as kerosene, turpentine, camphor oil, and pine oil, Class 3 petroleum such as heavy oil, gear oil, cylinder oil Quaternary petroleum oils such as, etc. can also be used effectively. It goes without saying that mixtures of these can also be used.

In the present invention, the catalyst includes an inorganic transition metal compound,
Examples include inorganic compounds of Si, organic transition metal compounds, and organic compounds of St. What is this inorganic transition metal compound?
An inorganic compound of a transition metal that can be vaporized alone or a transition metal that is soluble in water or at least one type of water or organic solvent (a carbon raw material compound may be used as the organic solvent) or can be suspended as fine particles. The target is inorganic compounds of metals. As the transition metal, iron, nickel, cobalt, molybdenum, vanadium, palladium, etc. are preferable, and iron is particularly preferable. Examples of the former inorganic transition metal compound that can be vaporized alone include Fe(No)4. FeC
1t, Fl! (No)3C1, Fe(NO)2. F
Representative examples include e(NO)21FeF3. In addition to the compounds listed as the former, the latter include Fa (NOs
) 2. FeBr2゜Fe(HCOO)s, C2t
H4xFeN90+2. Fe(SO2)s Fe(S
CN)s.

Fe(NO)J)Is, Go(No)2CI, Nt
Representative examples include (No)CI, Pd(NO)2c12°NiC1, etc.

The organic transition metal compounds in the present invention include alkyl metals in which an alkyl group and gold scrap are bonded, allyl complexes in which an allyl group and a metal are bonded, and π-complexes in which a carbon-carbon double bond or triple bond is bonded to a metal. It is an organic transition metal compound typified by chelate type compounds. In addition, the translucent metals include scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, yttrium, zirconium, niobium, molybdenum, ruthenium, rhodium, palladium, tantalum, tungsten, rhenium, iridium, and platinum. Of these, those belonging to group (I) of the periodic table are particularly preferred, particularly iron, nickel, and cobalt, with iron being the most preferred.

Furthermore, in the presence of a sulfur-containing carbon compound or an inorganic sulfur compound, an inorganic compound of silicon can also be used. For example, the above-mentioned inorganic metal compounds in which the metal is replaced with Si or silicon carbide may be used. Furthermore, various organosilicon compounds may also be used.

The organic silicon compound includes, for convenience, silane and halogen silane in addition to organic compounds having a silicon-carbon bond. Examples of organic compounds having a carbon-silicon bond include organosilanes such as tetramethylsilane and methyltriphenylsilane; organohalogensilanes such as chlorodifluoromethylsilane and bromotripropylsilane; Alkoxysilanes; Organoacetoxysilanes such as diacetoxydimethylsilane and acetoxytripropylsilane; Organopolysilanes such as hexaethyldisilane, hexaphenyldisilane and octaphenylcyclotetrasilane; Organohydrogenosilanes such as dimethylsilane and triphenylsilane; Cyclosilane represented by SiH2)rl; organosilazane such as triphenylsilazane, hexaethyldisilazane, hexaphenylcyclotrisilazane; (SiH2N)I)organosilazane such as cyclosilazane diethylsilanediol and triphenylsilanol represented by n; Silanol; Organosilanols such as trimethylsilylacetic acid and trimethylsilylpyropionic acid; Organosilane carboxylic acids such as trimethylsilylacetic acid and trimethylsilylpropionic acid; Silicon isocyanates such as trimethylsilicon isocyanate and diphenylsilicon diisocyanate; Trimethylsilicon isothiocyanate and diphenyl Organosilicon isothiocyanates such as silicon diisothiocyanate; organosilicon esters such as triethylsilyl cyanide; silthians such as hexaethyldisilazane and tetramethyl siliconsilthian; cyclosylthian expressed as (siH2s)n; Examples include organosylmethylenes such as methyldisiloxane and octamethyltrisylmethylene; organosiloxanes such as hexamethyldisiloxane and hexapropyldisiloxane; however, compounds containing other carbon-silicon bonds may be used. Also,
It is also possible to use mixtures of these.

Note that, in the present invention, catalyst particles (for example, dried fine powder) that have been generated in advance as fine particles may be introduced into the reaction vessel.

The carrier gas in the present invention refers to all gases that are not directly involved in the reaction. For example, N2 gas,
The gas is mainly N2 gas, NH3 gas, Ar gas, He gas, R gas, or a mixture thereof. Among these, N2 gas is usually used.

Moreover, a component for enhancing the laser absorption effect may be added to the gas introduced into the container, such as a carrier gas.

In this case, the additive components depend on the wavelength of the laser used, but
For example, for a C02 laser, NH3 or C2H4 can be added as a laser absorption effect enhancer.

The present invention will be described in detail below with reference to preferred embodiments shown in the drawings.

FIG. 1 is a schematic cross-sectional view showing an example of an apparatus suitable for carrying out the present invention. Reference numeral 10 designates a reaction vessel (in this embodiment, a reaction tube), on one end of which a laser oscillator 12 for irradiating a laser beam is installed, and on the other end a laser absorption plate 14 is installed. Further, to the one end side, a pipe 16 for supplying a compound containing a substance to become catalyst particles, a pipe 18 for supplying a carrier gas, and a pipe 20 for supplying a gas of a carbon compound are connected. 1
In the middle of 6.18.20, respectively, the flow rate control device 16a,
18a and 20a are provided.

Further, a carbon fiber collector 22 is connected to the other end of the reaction tube 10, and an exhaust gas extraction pipe 22 is connected to the carbon fiber collector 22.
4 is connected.

In the present invention, the laser oscillator 12 is preferably one that emits light with a wavelength in the range of about 0.1 to 1000 μm, and specifically, for example, C02, YAG, ruby, semiconductor, excimer laser, etc. Can be adopted.

In the carbon fiber manufacturing apparatus configured as described above, a compound containing a substance that becomes catalyst particles introduced into the reaction vessel is excited by a laser beam and decomposed, and catalyst particles such as transition elements or SiC (normal Particle size is 0.1~10μ
m) is generated. Further, the raw carbon compound excited and decomposed by the laser beam is deposited on the fine particles, and carbon fibers grow.

In the present invention, the temperature of the wall of the reaction vessel in which fine particles are generated and carbon fibers are generated using these particles as growth points is considerably lower than that of a reaction vessel using a conventional external heating electric furnace.
No by-products will adhere to the vessel wall. Therefore, in the present invention, there is no need to limit the material of the reaction vessel to expensive materials with high corrosion resistance or high heat resistance. Additionally, since it uses a laser beam, it consumes less energy than a general external heating type electric furnace, resulting in lower energy costs. However, in the present invention, if necessary, an external heating means such as an external heating type electric furnace may be provided to surround the reaction vessel to heat the vessel wall of the reaction zone.

In this case, in order to prevent the product from adhering to the vessel wall, it is preferable to externally heat the vessel so that the vessel wall temperature is less than 600°C, particularly 550°C or less.

In the present invention, the size of the catalyst particles or the diameter and length of the carbon fibers can be adjusted by controlling the partial pressure, residence time, laser intensity, etc. of the raw material gas.

As described above, the reaction order in the reaction vessel is the generation of catalyst fine particles and the growth of carbon fibers, but there is no need to divide the inside of the reaction vessel into a fine particle generation zone and a carbon fiber growth zone.

However, if necessary, a carbon fiber growth zone may be formed by additionally providing a suitable external heating means as described above.

The carbon IIA fibers produced in the reaction vessel are introduced into the carbon fiber collector 22 together with a carrier gas. As this collection method, various conventionally known methods such as gravity sedimentation method and electrostatic precipitation method can be employed. Note that the carbon fiber collector 22 also plays a role of cooling the generated carbon fibers. According to the present invention, it is possible to easily produce carbon fibers that usually have a length of about 0.1 to 500 mm and a diameter of about 0.1 to 300 um.

The carrier gas extracted from the carbon fiber collector 22 is
It may be introduced into the exhaust treatment means and discharged as it is, but it may also be circulated and used after purification.

In the above apparatus, a laser absorption plate (for example, a water-cooled copper plate) 14 is installed at the end of the reaction tube 10, but if the optical path length is short, a reflection plate may be placed to lengthen the optical path length of the laser beam. may be configured.

FIG. 2 is a schematic cross-sectional view showing the configuration of a carbon fiber manufacturing apparatus according to a different embodiment of the present invention.

Reference numeral 30 indicates a reaction vessel, and in this embodiment, a reaction tube 32.
It is assembled by connecting 34, 36, and 38 into a rectangular frame. A prism 39 is provided at each corner of the rectangle, and a laser oscillator 12 is provided at the corner between the reaction tubes 32 and 38. In addition, a window plate made of Zn5e that only transmits the laser beam is provided at the connection between the reaction tubes 32 and 38.
and are blocked. Similar window plates 42 are used for reaction tubes 34 and 36.
It is also located at the connection point.

Connected to one end of the reaction tubes 32 and 36 are a compound supply pipe 16 containing a substance to become catalyst particles, a carrier gas supply pipe 18, and a carbon compound supply pipe 20, respectively. Flow rate control devices 16a, 18a, and 20a are provided in the middle.

Also, the end of the reaction tube 34 on the reaction tube 36 side and the reaction tube 38
Carbon 1a fa collectors 22a and 22b are connected to the ends of the reaction tube 32 side, respectively, and an exhaust gas outlet 24 is connected to the collectors 22a and 22b.

In the apparatus of FIG. 2 configured in this way, the piping 16
, 1B and 20 are introduced into the reaction tubes 32 and 34.
The carbon fibers are reacted within and generated, and the carbon fibers are collected by the collector 22a. Further, the carbon 11a fibers generated in the reaction tubes 36 and 38 are similarly collected by the collector 22b. In the apparatus shown in FIG. 2, the optical path length of the laser beam is large, and carbon fibers can be manufactured efficiently. In the above embodiment, the reaction tubes are connected in a rectangular shape to constitute the reaction vessel, but this may be in other shapes such as pentagonal or hexagonal. Furthermore, various connection methods may be employed, such as a connection method in which the reaction tubes 32 are reciprocated in a meandering manner as shown in FIG. 3, and a multi-type connection method in which reaction tubes 32 are arranged in parallel as shown in FIG.

FIG. 5 is a perspective view showing the configuration of a carbon fiber manufacturing apparatus according to a different embodiment of the present invention. In this embodiment, two flat plates 4
0, 42, laser reflecting plates 44, 46, and laser absorbing plate 48 constitute a reaction vessel 50. This reaction vessel 50
, a carbon compound gas, a carrier gas, and a compound gas containing a substance that will become catalyst particles are introduced from the gas introduction side 50a, and the laser oscillator 12 is connected to the laser reflection plate 44.
A laser is irradiated towards. This laser is reflected multiple times between reflection plates 44 and 46 as shown in FIG.
The gas is eventually absorbed by the laser absorption plate 48, but during this process, the above gas is excited and carbon fibers are generated. The generated carbon fibers are discharged from the outlet side 50b of the reaction vessel 50 together with the carrier gas and the remaining raw material gas, and the carbon IA fibers are collected by an appropriate collection means.

Note that the laser oscillator 12 may be moved in the longitudinal direction of the reaction container 50 so as to swing its head. In this way, the entire inside of the reaction vessel 50 can be irradiated with the laser beam, and the carbon fiber production reaction is further promoted.

Furthermore, instead of swinging the laser oscillator 12, a laser oscillator 12 that emits a laser beam in a diffusing direction may be used as shown in FIG. In this case, it is necessary to make all parts of the reaction vessel 50 other than the laser absorption temporary installation part a mirror surface to reflect the laser beam. Further, as shown in FIG. 8, by employing a curved mirror as the laser reflecting plate 44, the laser beam may be emitted toward the laser reflecting plate 44. Even in the case of FIG. 8, it is necessary to make the inner surface of the reaction vessel other than the laser absorption plate a mirror surface.

[Example] Hereinafter, preferred manufacturing examples will be described.

Example 1 In the apparatus shown in FIG. 1, carbon fibers were manufactured under the following conditions.

Laser m: 002 laser (10,591μ) original
Material: C2H4 Compound containing a substance that becomes catalyst particles: FeCl13 aqueous solution Carrier gas: H2 pressure Crab normal pressure residence time = 1 minute Raw material concentration: 5vo 1% 1nH2 Reactor: 20mmI Dx450mmL (made of quartz) The results are as follows. Ta.

Experimental result: Growth fiber 2061~1.0μmφ 100-1000μm above Yield rate: 25wt% Example 2 Carbon fibers were manufactured using the apparatus shown in FIG.

The main conditions and results are shown below.

Experimental conditions Laser: YAG laser (1,06 μm) Raw material:
Compound containing a substance that becomes benzene catalyst particles: FeSO4 aqueous solution carrier gas: H2 pressure Crab normal pressure residence time: 5 minutes (1 loop) Raw material concentration: 5vo1% inH2 Reactor: 20 mm DX 500 mm LX 4 (made of quartz) Experimental results: Growing tafa: 0.1~1.0μmφ100~200
0 μmL Yield: 30 to 35 wt% Example 3 Carbon 1a fibers were produced using the apparatus shown in FIG. The main conditions and results are shown below.

Experimental conditions Laser m: 002 laser (10,591ρ) original
Material: Ca Ha + H2S Compound containing substance to become catalyst particles: FeBra aqueous solution Carrier gas: H2 pressure Crab normal pressure residence time: 20 seconds Raw material concentration near, 5vo1%1nH2 Reactor: d = 10 mm, h = 1000 mm.

A = 200 mm (made of quartz) Experimental results Growing fibers: 0.1 to 1.0 μmφ, 100 to 2000 μmL Yield: 35 to 45 wt% In addition, in these Examples 1 to 3, the deposits on the vessel wall were It was not admonished.

[Effects of the Invention] As described above, according to the present invention, carbon fibers are manufactured by a vapor phase method using a laser, and (1) energy consumption is low and manufacturing costs are low.

■ The inner wall surface of the reaction vessel is at a low temperature, and its material can be made of an inexpensive material.

(2) It is difficult for by-products to adhere to the inner surface of the reaction vessel, making it suitable for continuous operation and operation of large reaction vessels.

(2) The quality of the carbon fiber obtained can be easily controlled by adjusting the pressure inside the reaction vessel, the partial pressure of each gas, residence time, laser intensity, etc.

■ Great production, easy to scale up.

Excellent effects such as these can be achieved.

[Brief explanation of the drawing]

FIGS. 1 and 2 are illustrations of an apparatus according to an embodiment of the present invention, FIGS. 3 and 4 are diagrams illustrating a reaction tube connection system, and FIG. 5 is a diagram showing a different embodiment of the apparatus. Perspective view, No. 6
The figure is an explanatory diagram of a laser beam optical path showing the reflection of a laser beam in the same device, and FIGS. 7 and 8 are cross-sectional views illustrating different embodiments of the apparatus. DESCRIPTION OF SYMBOLS 10... Reaction container, 12... Laser oscillator, 16... Catalyst supply pipe, 18... Carrier gas supply pipe, 20... Carbon compound supply pipe, 22.22a, 22b... Carbon fiber Collector. Agent Patent Attorney Tsuyoshi Shigeno Figure 1 Carrier Ganu 10 (2) Figure 5 Compound containing a substance that becomes catalyst particles Figure 6 Figure 7 Figure 8

Claims (2)

[Claims] (1) A method for producing carbon fibers, which comprises bringing carbon compound gas into contact with suspended catalyst particles under laser irradiation to precipitate carbon in the form of fibers. (2) A reaction container with a reaction zone inside, a laser device that irradiates a laser beam toward the reaction zone, and a carrier gas introduced on one side of the reaction container with the reaction zone in between. means, means for introducing carbon compound gas, means for introducing catalyst particles or catalyst raw material gas, and means for collecting carbon fibers connected to the other side of the reaction vessel across the reaction zone. Characteristic carbon fiber manufacturing equipment.