JP4452773B2 - Method and apparatus for producing carbon fine particles - Google Patents

Description

  The present invention relates to a method and apparatus for producing carbon fine particles, and more particularly to a method and apparatus for producing carbon fine particles typified by fullerene and carbon nanotubes easily and efficiently.

Carbon fine particles having a nano-size diameter in which carbon atoms are connected in a spherical or cylindrical shape are collectively called nanocarbon, and fullerenes and carbon nanotubes are known as typical nanocarbons.
Fullerenes are 60 or more hollow particles of about 1 nanometer in diameter which carbon atoms linked to the cage, for example C ₆₀ carbon atoms led 60 is a soccer ball-like about 0.7 nanometers in diameter Is a spherical molecule.
Such fullerenes have been demonstrated to exhibit unique electrochemical properties, gas adsorption properties, mechanical properties, and optical properties. Using these properties, anti-cancer using ultrasound and the like has been demonstrated. Applications such as pharmaceuticals such as agents, cosmetics that prevent skin aging, long-life lithium ion batteries, electrolyte membranes for gas storage and fuel cells, high-temperature superconducting materials, magnetic memory materials, lubricants, catalysts for chemical production, etc. Is expected.

The carbon nanotube is a carbon crystal in which a graphite sheet composed of a benzene ring of 6 carbon atoms is spirally rolled and grown into a cylindrical shape, and includes a diameter of about 1 nanometer to several tens of nanometers. There are various shapes having different thicknesses, number of layers, end shapes, and the like depending on various conditions such as manufacturing methods and raw materials.
Such carbon nanotubes show a variety of electrical, mechanical, chemical properties, etc. depending on their shapes, light sources using electron emission capability, FED expected as next-generation thin display, hydrogen storage capability It is expected to be applied to hydrogen storage materials, electrodes, and electrically conductive paints utilizing electrical conductivity for fuel cells for electric vehicles that utilize the electric field.

The carbon fine particles (nanocarbon) as described above have been conventionally produced by a laser ablation method, a chemical vapor deposition method (CVD method) using acetylene gas, a method by arc discharge using a carbon rod electrode as a raw material, or the like. .
Among these, the most common method is a method using arc discharge, and various specific methods have already been proposed (for example, see Patent Document 1).
Japanese Patent Application Laid-Open No. 7-187631

However, many of the prior arts represented by the disclosed technology described in Patent Document 1 use gas (vaporized gasoline) as a raw material, so the carbon density contained is low and production efficiency is poor. Moreover, since a separate facility for gasification is required, it cannot be said that the method can easily and economically obtain carbon fine particles.
Further, when a solid is used as the raw material, there is a possibility that air existing in the gaps of the solid raw material reacts with the generated carbon fine particles. Patent Document 1 describes a method of using argon gas to make the inside of the arc furnace oxygen-free when using liquid as a raw material, but argon gas is relatively expensive. Therefore, there was a problem that the cost would be high.
Further, since the carbon electrode itself is a main raw material for generating arc discharge, there is a problem that stable discharge cannot be obtained when the electrode is consumed with use.
Furthermore, when collecting the carbon fine particles contained in the gas obtained by arc discharge, a part of the gas is liquefied by the collector, and the carbon fine particles are dissolved in this liquid. There was a problem that a highly viscous liquid was generated. There is also a method for producing carbon fine particles by treating this highly viscous liquid, but this requires a separate process and equipment, leading to a decrease in manufacturing cost and efficiency.

  The present invention has been made to solve such problems of the prior art, and is a method capable of producing carbon fine particles easily and at low cost and continuously with an apparatus having a relatively simple structure. And to provide a device.

According to the first aspect of the present invention , a plurality of carbon particles are arranged between a pair of metal arc electrodes, and an arc discharge is generated by energizing the arc electrode in an oxygen-free atmosphere. The solid raw material made of synthetic resin is thermally decomposed and gasified by heating and high heat generated thereby, and the carbon fine particles contained in the obtained gas are recovered , and the carbonization contained in the gas after the carbon fine particle recovery The present invention relates to a method for producing fine carbon particles, which comprises subjecting a gas such as hydrogen to plasma pyrolysis by arc discharge .
The invention according to claim 2 relates to the method for producing carbon fine particles according to claim 1, characterized in that the atmosphere of the recovery part for recovering the carbon fine particles contained in the gas is maintained at a high temperature of 50 ° C. or higher.
The invention according to claim 3 relates to the method for producing carbon fine particles according to claim 1 or 2, wherein the gas after plasma pyrolysis is passed through an adsorbent to adsorb harmful components contained in the gas.
The invention according to claim 4 is characterized in that the gas that has passed through the adsorbent is circulated through a supply path of the solid raw material to the apparatus for performing the thermal decomposition, and is replaced with air that enters with the solid raw material. The method for producing carbon fine particles according to claim 3.
The invention according to claim 5 relates to the method for producing carbon fine particles according to any one of claims 1 to 4, wherein the oxygen-free atmosphere is an atmosphere containing nitrogen.

According to a sixth aspect of the present invention, there is provided a pyrolysis apparatus that contains a solid raw material made of synthetic resin and pyrolyzes and gasifies by high heat generated by arc discharge in an oxygen-free atmosphere, and the pyrolysis apparatus. Fine particle collector for collecting carbon fine particles contained in the obtained gas, and gas for thermally decomposing plasma such as hydrocarbons contained in the gas after collecting the carbon fine particles with the fine particle collector by arc discharge A decomposition device and an adsorption device that adsorbs harmful components contained in the gas released from the gas decomposition device , wherein the thermal decomposition device is disposed between at least a pair of metal arc electrodes and the arc electrodes. The present invention relates to a carbon fine particle manufacturing apparatus comprising a plurality of carbon particles .
The invention according to claim 7 relates to the carbon fine particle manufacturing apparatus according to claim 6 , wherein the carbon particles are arranged on a rotating plate .
The invention according to claim 8 is characterized in that a heat radiation preventing plate for preventing heat radiation to the supplied solid material is provided in front of the supply port for supplying the solid material made of synthetic resin. Item 6. The apparatus for producing carbon fine particles according to Item 6 or 7 .
The invention according to claim 9 relates to the apparatus for producing carbon fine particles according to any one of claims 6 to 8 , wherein the oxygen-free atmosphere is an atmosphere containing nitrogen .

A tenth aspect of the present invention relates to the carbon fine particle manufacturing apparatus according to any one of the sixth to ninth aspects, wherein a heating means for heating the inside of the fine particle collector is provided.
Invention, the gas decomposition apparatus, at least a pair of arc electrodes, one of claims 6 to 10, characterized in that it comprises a plurality of carbon granules disposed between the arc electrode according to claim 11 The present invention relates to a carbon microparticle production apparatus.
The invention according to claim 12 is provided with a replacement means for circulating the gas that has passed through the adsorbent to the supply path to the thermal decomposition apparatus for the solid raw material to replace the air that enters with the solid raw material. apparatus for producing carbon microparticle according to any one of claims 6 to 11,.
The invention according to claim 13 is characterized in that the replacement means is means for supplying the gas to a space between the raw material introduction valves respectively provided in the upstream portion and the downstream portion of the supply path. The carbon fine particle production apparatus according to 12 .

According to the present invention, by using a solid raw material made of a synthetic resin containing carbon at a higher density than conventional gas raw materials, a treatment for obtaining a high-pressure gas or a liquefied gas is not required, and handling is performed. Therefore, carbon fine particles can be produced efficiently at a low cost. In addition, since a solid raw material containing carbon is supplied separately from the arc electrode, it is possible to suppress wear of the electrode and to obtain a stable arc discharge over a long period of time.
In addition, by maintaining the atmosphere of the recovery unit for recovering the carbon fine particles contained in the gas at a high temperature of 50 ° C. or higher, the gas obtained by the thermal decomposition by the thermal decomposition apparatus is liquefied, and the carbon fine particles are contained in this liquid. It becomes possible to prevent a tar-like liquid from being dissolved, and the carbon fine particles can be efficiently recovered.
Moreover, the reaction of the produced carbon fine particles can be inactivated by performing the decomposition in an oxygen-free atmosphere containing nitrogen.
In addition, by hydrothermally plasma-decomposing gas such as hydrocarbon contained in the gas after the carbon fine particle recovery by arc discharge, by passing the gas after the decomposition through an adsorbent, adsorb harmful components contained in the gas, Harmful components are prevented from being discharged into the atmosphere, and the safety and environmental resistance are excellent.
Further, the gas that has passed through the adsorbent is circulated to the supply path of the solid raw material to the thermal decomposition apparatus and is replaced with the air that enters along with the solid raw material, so that air can be mixed into the thermal decomposition apparatus. Thus, the entire apparatus can be maintained in an oxygen-free atmosphere, and the produced carbon fine particles can be prevented from reacting with oxygen and combusted or gasified.

Further, the pyrolysis apparatus includes at least a pair of arc electrodes and a plurality of carbon particles disposed between the arc electrodes, so that the carbon particles generate heat during arc discharge, thereby causing thermal decomposition. It becomes possible to make it perform efficiently.
Further, since the carbon particles are arranged on the rotating plate, a large number of carbon particles can be stirred and heated uniformly, and it is possible to prevent the carbon particles from being consumed and to increase the thermal efficiency. Become.
In addition, by providing a heat radiation prevention plate for preventing heat radiation to the supplied solid raw material in front of the supply port for supplying the solid raw material made of synthetic resin, the solid heat is generated by the radiant heat from the carbon particles. It is possible to prevent the raw material from being decomposed at the supply port.
In addition, by having means for supplying exhaust gas to the space between the raw material input valves provided at the upstream and downstream portions of the supply path, it is possible to reliably prevent air from entering the thermal decomposition apparatus. Thus, an oxygen-free atmosphere in the apparatus can be maintained.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic diagram showing the overall configuration of a carbon fine particle production apparatus according to the present invention.
An apparatus for producing carbon fine particles according to the present invention includes a pyrolysis apparatus (1) that contains a solid raw material made of a synthetic resin and thermally decomposes and gasifies by high heat generated by arc discharge in an oxygen-free atmosphere; Included in the fine particle recovery device (2) for recovering the carbon fine particles contained in the gas obtained by the thermal decomposition apparatus (1), and in the gas after the recovery of the carbon fine particles by the fine particle recovery device (2) Gas decomposition apparatus (3) for thermally decomposing a gas such as hydrocarbons by arc discharge in an oxygen-free atmosphere, and an adsorption apparatus for adsorbing harmful components contained in the gas released from the gas decomposition apparatus (3) (4) is provided.

FIG. 2 is a schematic cross-sectional view showing the internal structure of the thermal decomposition apparatus (1).
The thermal decomposition apparatus (1) includes a processing unit (5) that is supplied with a solid material made of a synthetic resin and processed, and a gantry (6) provided below the processing unit (5).
The processing unit (5) is provided with a supply port (51) for supplying raw materials, a gas outlet (52) for taking out the generated gas, and an observation window (53) for observing the inside of the supply unit. In the illustrated example, the supply port (51) is provided at the ceiling, and the gas outlet (52) and the observation window (53) are provided at positions closer to the upper side of the peripheral wall.

An arc electrode (7) made of a pair of left and right metal rods is disposed below the processing unit (5), and a large number of spherical carbon particles (8) are interposed between the arc electrodes (7). Is arranged. As a metal material for forming the arc electrode (7), for example, stainless steel or tungsten is preferably used. A plurality of pairs of arc electrodes (7) can be provided. For example, a configuration in which three pairs of arc electrodes (7) are installed at intervals of 60 ° in the circumferential direction can be employed.
The arc electrode (7) is inserted into a cylindrical heat insulating material (9) having an inclined inner surface that is reduced in the shape of a mortar, and is arranged so that the tip portion slightly protrudes from the heat insulating material (9). The carbon particles (8) are arranged in a space surrounded by the inclined surface of the heat insulating material (9).
Further, a heat insulating material is built in the peripheral wall and ceiling surrounding the processing section (5).

A conical heat radiation prevention plate (10) is disposed in front (downward) of the supply port (51) with a slight gap from the supply port. The solid raw material does not fall straight down but falls downward from the periphery of the heat radiation prevention plate (10).
Thereby, it can prevent that a solid raw material decomposes | disassembles in a supply port (51) with the radiant heat from the carbon granule (8) provided in the perpendicular | vertical lower position of a supply port (51).
In addition, as a kind of solid raw material, what is necessary is just to contain carbon, However, Plastics, such as a thermosetting resin and a thermoplastic resin, are used suitably, Specifically, a polyethylene terephthalate (PET) and polyethylene (PE) Etc. are preferably used. In particular, it is preferable to use waste plastic such as a PET bottle as a raw material because waste can be effectively used. Further, the size of the solid raw material to be supplied is not particularly limited, but it is preferable that the solid raw material is crushed into chips, specifically about 20 to 30 mm.

  The carbon particles (8) are placed on a disk-shaped rotating plate (11) provided in the gantry (6). The rotating plate (11) is disposed so as to close the lower end portion of the center hole of the cylindrical heat insulating material (9) having a tapered inner surface as shown in the drawing, and the diameter thereof is at least a cylindrical heat insulating material. The diameter is larger than the lower end diameter of the center hole of (9).

The number and size of the carbon particles (8) can be appropriately set so that the space between the pair of arc electrodes (7) arranged to face each other is substantially filled. It is preferable to use a sphere having a diameter of at least 10 mm. This is because if the carbon particles (8) are too small, arc discharge is not performed well.
The rotating plate (11) rotates continuously or intermittently in a horizontal plane via a motor (12) and a gear (13) provided in the gantry (6). 11) A large number of carbon particles (8) placed thereon are stirred and heated uniformly.

The voltage applied to the arc electrode (7) is in the range of 20 to 50V and the current is in the range of 100 to 600A, preferably the voltage is 30 to 40V and the current is 450 to 500A.
When the arc electrode (7) is energized in this way, an arc discharge occurs between the electrode and the carbon particles, and the carbon particles (8) are heated by an electric current to become a red-hot state, 600 to 1000 ° C. Heated to a high temperature. This arc discharge is performed in an oxygen-free atmosphere.
Although not shown, a nitrogen gas supply port is provided in the processing unit (5), and the nitrogen gas is supplied to the processing unit (5) to perform arc discharge in an oxygen-free atmosphere containing nitrogen gas. A configuration can also be preferably adopted.
Thus, the solid raw material supplied in the processing part (5) which became high temperature state is thermally decomposed and gasified by being exposed to the high temperature of 600-1000 degreeC, and is discharged | emitted from a gas outlet (52).

In a normal arc discharge, the electrode is consumed because the carbon electrode itself is a raw material. However, according to the method of the present invention, since a solid material containing carbon is supplied separately from the arc electrode, the consumption of the electrode is reduced. It is possible to obtain a stable arc discharge over a long period of time.
Further, by disposing the carbon particles (8) between the arc electrodes, the carbon particles generate heat at the time of arc discharge, thereby enabling efficient thermal decomposition. In the present invention, the material disposed between the arc electrodes does not necessarily need to be a carbon particle, and a material that can be another heating element with less consumption can also be used.

The gas outlet (52) is connected to the inlet passage of the fine particle collector (2).
FIG. 3 is a schematic cross-sectional view showing the internal structure of the fine particle collector (2).
The fine particle collector (2) includes an inlet passage (21) for taking in gas containing carbon fine particles discharged from the gas outlet (52) of the thermal decomposition apparatus (1), and the inlet passage (21). And an outlet passage (22) for discharging the gas after the carbon fine particles are collected provided on the opposite side.
The inlet passage (21) and the outlet passage (22) are opened facing each other at a position near the upper side of the side wall of the particulate collection device (2), and the interior space of the particulate collection device (2) extends downward from the ceiling. A baffle plate (23) that hangs down is provided. The baffle plate (23) is provided to prevent the gas taken in from the inlet passage (21) from going to the outlet passage (22) as it is, and to make a detour downward.
Further, a collection tray (24) is disposed at the bottom of the internal space of the particulate collection device (2), and an opening / closing door (25) for taking out the collection tray (24) to the outside at a position closer to the lower side of the side wall. Is provided.

The gas containing carbon fine particles discharged from the gas outlet (52) of the thermal decomposition apparatus (1) is introduced into the internal space of the fine particle collector (2) from the inlet passage (21) and collides with the baffle plate (23). Then, when detouring downward, the carbon fine particles fall downward and are collected in the collection tray (24), and are discharged from the outlet passage (22) as gas containing no carbon fine particles.
The fine particle collector (2) is provided with heating means for heating the inside of the fine particle collector, and the gas containing carbon fine particles introduced into the internal space from the inlet passage (21) is supplied from the heating means. Heated by heat. As the heating means, a known heating device such as a heater is used, and the atmospheric temperature of the internal space is set to at least 50 ° C. or higher, preferably 150 to 200 ° C. by the heating device. However, the heating means is not necessarily provided, and natural heating may be performed at the temperature of the introduced gas itself.
By maintaining the internal space of the fine particle collector (2) in a high-temperature atmosphere in this way, the gas introduced from the inlet passage (21) is liquefied and a tar-like liquid in which carbon fine particles are dissolved in this liquid. It becomes possible to prevent becoming.

A gas decomposition device (3) is connected to the outlet passage (22) of the particulate collection device (2).
FIG. 4 is a view showing the structure of the gas decomposition apparatus (3), where (a) is a plan view, (b) is a cross-sectional view taken along line AA, and (c) is a cross-sectional view taken along line BB.
The gas decomposition apparatus (3) is provided with a gas inlet (31) and a gas outlet (32) on the left and right side walls, respectively, and a pair of arc electrodes projecting from the front and back side walls toward the internal space, respectively. (14) is provided. A lid (15) that can be opened and closed is provided on the upper surface.
The arc electrode (14) is composed of a pair of left and right metal rods, and a large number of spherical carbon particles (16) are arranged between the arc electrodes (14). As the metal material for forming the arc electrode (14), for example, stainless steel or tungsten is preferably used.

In the internal space of the gas decomposition apparatus (3), a heat insulating material (17) is provided along the bottom surface and the inner wall surface.
The arc electrode (14) is inserted into a heat insulating material (17) disposed so that the inclined inner surface inclined inward is opposed to the arc electrode (14), and the tip thereof is slightly from the heat insulating material (17). It arrange | positions so that it may protrude and the carbon particle (16) is arrange | positioned in the space pinched | interposed by the inclined surface of a heat insulating material (17).
About the number and magnitude | size of a carbon particle (16), the structure similar to a thermal decomposition apparatus (1) is employable.

The voltage applied to the arc electrode (14) is in the range of 20 to 50V and the current is in the range of 100 to 600A, preferably the voltage is 30 to 40V and the current is 450 to 500A.
When the arc electrode (14) is energized in this way, an arc discharge occurs between the electrode and the carbon particles, and the carbon particles (16) are heated by an electric current to be in a red hot state, and 600 to 1000 ° C. Heated to a high temperature. This arc discharge is performed in an oxygen-free atmosphere.
Gases such as hydrocarbons supplied from the gas inlet (31) into the internal space are subjected to plasma pyrolysis by arc discharge to become only a more stable gas component and are discharged from the gas outlet (52).

The adsorption device (4) is connected to the gas outlet (52) of the gas decomposition device (3).
FIG. 5 is a schematic cross-sectional view showing the internal structure of the adsorption device (4).
The adsorption device (4) has a gas inlet (41) and a gas outlet (42), and is held by a mesh material in an internal space serving as a passage from the gas inlet (41) to the gas outlet (42). (43) is arranged.
As a result, the gas released from the gas outlet (32) of the gas decomposition apparatus (3) is introduced into the gas inlet (41) of the adsorption apparatus (4) and passes through the zeolite (43). The harmful components contained therein are adsorbed and become harmless gas, which is discharged from the gas outlet (42).

  A vacuum pump (18) is connected to the gas outlet (42) of the adsorption device (4), and suction force is generated by driving the vacuum pump (18). By this suction force, the raw material supplied into the thermal decomposition apparatus (1) is sequentially sent to the fine particle collector (2), the gas decomposition apparatus (3), and the adsorption apparatus (4). In addition, the arrow in FIG. 1 has shown the gas flow of the whole apparatus.

A supply path (19) for sending the raw material to the supply port (51) is connected to the supply port (51) of the thermal decomposition apparatus (1). In the middle of the supply path (19), A circulation path (20) extending from the discharge port of the vacuum pump (18) is connected.
A raw material charging valve (54) is disposed in each of the upstream and downstream portions in the passage of the supply path (19). (Hereinafter, the upstream charging valve is referred to as a first charging valve, and the downstream charging valve is referred to as a second charging valve.) A circulation path (20) is connected between these raw material charging valves (54). Thus, the gas that has passed through the adsorption device (4) can be fed into the supply path (19).

Further, the circulation path (20) is branched in the middle to form a branch path (55), and the branch path (55) is downstream of the second input valve of the supply path (19) (on the pyrolysis device side). It is connected to the. The branch passage (55) is provided with an on-off valve (56), and an air intake passage (57) opened to the outside for connecting air is connected to the downstream side of the on-off valve (56). Yes.
In addition, check valves (58) and (60) for preventing the backflow of gas and air are disposed in the middle of the circulation path (20) and the air intake path (57).
The circulation path (20) is provided with a connection path (59) for connecting the space between the first input valve and the second input valve and the space upstream of the first input valve. It has been.

Each of the above paths constitutes a replacement means that circulates the exhaust gas that has passed through the adsorbent in the adsorption device (4) to the supply path for the solid raw material and replaces it with the air that enters with the solid raw material.
That is, after opening the first input valve and supplying the raw material into the supply path (19), a part of the exhaust gas is exchanged with the first input valve via the circulation path (20) and the connection path (59). By supplying the space between the second charging valve and the space upstream of the first charging valve, respectively, the air entering with the solid raw material is replaced, and then the second charging valve is opened to supply the raw material. It leads to the supply port (51) of the thermal decomposition apparatus (1).
At this time, the check valve (58) escapes a part of the exhaust gas generated in the apparatus by the decomposition process to prevent an excessive pressure rise, and at the same time, introduces the escaped part of the exhaust gas together with the solid raw material. And play a leading role to replace.
As a result, the air present in the gaps between the chip-like solid raw materials is replaced with the exhaust gas discharged from the adsorption device (4) in the supply path (19), and the air is mixed into the thermal decomposition device (1). This prevents the entire apparatus from being maintained in an oxygen-free atmosphere.

The on-off valve (56) is opened during operation of the apparatus, and a part of the exhaust gas that has passed through the adsorption device (4) is taken into the downstream of the second input valve of the circulation path (20) as a circulation gas. And supplied to the thermal decomposition apparatus (1).
After the operation is completed (after cooling), the on-off valve (56) is closed, and when the on-off valve (56) is closed, air (outside air) is taken in from the air intake path (57). That is, the check valve (60) serves to replace the exhaust gas in the apparatus with air during maintenance or the like. The check valve (60) disposed in the air intake path (57) may be a normal on-off valve. In this case, it may be closed during operation and opened after cooling.

Carbon fine particles were produced using the carbon fine particle production apparatus having the respective apparatuses shown in FIGS. 2 to 5 and having the configuration shown in FIG. 1 as a whole.
The manufacturing conditions were as follows.
As a raw material, 10 kg of material PET (crushed PET bottle) having a size of 20 to 30 mm was used.
Three pyrolyzers (1) were operated in parallel by applying a voltage of 35 V and a current of 500 A to the arc electrode (7). (This point is different from that shown in FIG. 1.)
The fine particle collector (2) was set so that the internal atmosphere was 150 ° C.
As the gas decomposition apparatus (3), one arc electrode (14) having a voltage of 40 V and a current of 200 A applied thereto was used.

As a result of elemental analysis using electron energy loss spectroscopy (EELS) of a transmission electron microscope (TEM) for 1 kg of the substance recovered in the fine particle collector (2) after operating the apparatus for 2 hours, 99% or more It was confirmed to be carbon.
Moreover, as a result of observing the recovered carbon with a scanning electron microscope (SEM), all of the particles are made of a spherical substance, and most of the particles have a size of 100 nm or less, and have a large particle size that can be confirmed slightly. Even the thing was a thing of about 200-300 nm.
A scanning electron microscope (SEM) photograph of the recovered carbon is shown in FIG. In addition, the photograph of FIG. 6 is 50000 times magnification.

  The present invention is used for producing nanocarbons such as fullerenes and carbon nanotubes which are expected to be applied to a wide range of uses.

It is the schematic which shows the whole structure of the manufacturing apparatus of the carbon particulate concerning this invention. It is a schematic sectional drawing which shows the internal structure of a thermal decomposition apparatus. It is a schematic sectional drawing which shows the internal structure of a microparticles | fine-particles collector. It is a figure which shows the structure of a gas decomposition apparatus, (a) is a top view, (b) is an AA sectional view, (c) is a BB sectional drawing. It is a schematic sectional drawing which shows the internal structure of an adsorption | suction apparatus. It is a scanning electron microscope (SEM) photograph of the collected carbon fine particles.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thermal decomposition apparatus 2 Fine particle collection device 3 Gas decomposition apparatus 4 Adsorption apparatus 7 Arc electrode 8 Carbon particle 10 Thermal radiation prevention plate 11 Rotary plate 51 Supply port 19 of thermal decomposition apparatus Supply path 20 Circulation path 21 Raw material input valve

Claims (13)

A plurality of carbon particles are arranged between a pair of metal arc electrodes, and the arc particles are generated by energizing the arc electrodes in an oxygen-free atmosphere and the carbon particles are heated, thereby generating high heat. The solid raw material made of synthetic resin is pyrolyzed and gasified, and the carbon fine particles contained in the obtained gas are recovered , and the gas such as hydrocarbons contained in the gas after the carbon fine particle recovery is arc-discharged. A method for producing carbon fine particles, characterized by plasma pyrolysis .   2. The method for producing carbon fine particles according to claim 1, wherein the atmosphere of the collection unit for collecting the carbon fine particles contained in the gas is maintained at a high temperature of 50 ° C. or higher. The method for producing carbon fine particles according to claim 1 or 2, wherein the gas after the plasma pyrolysis is passed through an adsorbent to adsorb harmful components contained in the gas.   4. The carbon fine particles according to claim 3, wherein the gas that has passed through the adsorbent is circulated through a supply path of the solid raw material to the apparatus for performing the thermal decomposition, and is replaced with air that enters with the solid raw material. Manufacturing method.   The method for producing carbon fine particles according to any one of claims 1 to 4, wherein the oxygen-free atmosphere is an atmosphere containing nitrogen. Included in the pyrolysis device that contains a solid raw material made of synthetic resin and thermally decomposes and gasifies by high heat generated by arc discharge in an oxygen-free atmosphere, and the gas obtained by the pyrolysis device Fine particle collector for collecting carbon fine particles, gas decomposition apparatus for thermally decomposing gas such as hydrocarbons contained in gas after collecting carbon fine particles by the fine particle collector by arc discharge, and the gas decomposition apparatus Comprising an adsorption device that adsorbs harmful components contained in the gas released from the pyrolysis device, wherein the pyrolysis device comprises at least a pair of metal arc electrodes and a plurality of carbon particles disposed between the arc electrodes. An apparatus for producing carbon fine particles, comprising: The apparatus for producing carbon fine particles according to claim 6, wherein the carbon particles are arranged on a rotating plate. 8. A carbon fine particle according to claim 6 or 7, wherein a heat radiation preventing plate for preventing heat radiation to the supplied solid material is provided in front of a supply port for supplying the solid material made of synthetic resin. Manufacturing equipment.   The apparatus for producing carbon fine particles according to any one of claims 6 to 8, wherein the oxygen-free atmosphere is an atmosphere containing nitrogen. The apparatus for producing carbon fine particles according to any one of claims 6 to 9, further comprising heating means for heating the inside of the fine particle collector. 11. The production of carbon fine particles according to claim 6, wherein the gas decomposition apparatus comprises at least a pair of arc electrodes and a plurality of carbon particles disposed between the arc electrodes. apparatus. 12. The apparatus according to claim 6, further comprising a replacement unit that circulates the gas that has passed through the adsorbent to a supply path to a solid raw material pyrolysis apparatus and replaces the air that enters along with the solid raw material. An apparatus for producing carbon fine particles according to claim 1. 13. The apparatus for producing carbon fine particles according to claim 12, wherein the replacement means is means for supplying the gas to a space between the raw material introduction valves respectively provided in the upstream portion and the downstream portion of the supply path. .

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