KR20060097940A - Carbon nano tubes mass fabrication device - Google Patents

Abstract

The present invention relates to a carbon nanotube mass synthesis apparatus using a continuous process of gas phase synthesis, and more particularly, to synthesize carbon nanotubes while introducing a catalytic metal from an outside air into a sealed reactor and continuously moving by a transfer screw. It relates to a carbon nanotube mass synthesis device. In accordance with a preferred embodiment of the present invention, the carbon nanotube mass-grown growth value has an interior blocked from outside air, and the catalyst, carbon source gas, and inert gas are introduced into the interior, and the synthesized carbon nanotubes are discharged from the interior. A carbon nanotube reservoir having an outlet and a heating means formed therein, a catalyst transfer mechanism installed inside the reactor, an inside of the reactor connected to the outlet of the reactor and shut off from outside air, and connected to the reactor to transfer gases into the reactor. It comprises a gas supply unit for supplying.

Carbon Nanotubes, Bulk Synthesis, Transfer Screw, Continuous Process

Description

Carbon Nanotube Mass Synthesis Device {CARBON NANO TUBES MASS FABRICATION DEVICE}

1 is a schematic view showing a carbon nanotube mass synthesis apparatus according to a preferred embodiment of the present invention,

Figure 2 is a perspective view schematically showing another form of the spiral feed screw of the carbon nanotube mass synthesis apparatus according to a preferred embodiment of the present invention,

3 is a perspective view showing the first stirring means of FIG.

4 is a front view showing the second stirring means of FIG.

Explanation of the Main References

1: reactor 20: spiral feed screw

30: catalyst supply mechanism 40: gas supply unit

50: carbon nanotube storage unit 70: carbon nanotube purification apparatus

The present invention relates to a carbon nanotube mass synthesis apparatus using a continuous process of gas phase synthesis, and more particularly, to carbon nanotubes using a gas phase synthesis method for synthesizing carbon nanotubes while continuously transporting a catalyst metal in a closed reactor from outside air. It is about mass sum growth.

Carbon nanotubes have a structure in which graphite sheets are rolled into a cylindrical shape and are classified into single-walled, double-walled and multi-walled carbon nanotubes according to the number of graphite surfaces.

Carbon nanotubes are lightweight, have excellent electrical properties, mechanical strength, chemical stability, and easy surface reactions, and are expected to be used in a variety of applications in the electronic information industry, energy, high-performance composites, and ultra-fine nano components. Therefore, a method of synthesizing high purity carbon nanotubes inexpensively and in bulk is required.

Representative methods for synthesizing carbon nanotubes in large quantities include an electric discharge method, a laser deposition method, a chemical vapor deposition method, or a vapor phase synthesis method. According to the electric discharge method or the laser deposition method, in addition to the carbon nanotubes, amorphous carbon materials are simultaneously produced during the synthesis of the carbon nanotubes, so that thermal or chemical purification is required to obtain high purity carbon nanotubes. Economical mass synthesis is difficult. In the synthesis of carbon nanotubes by chemical vapor deposition, it is possible to grow high-purity carbon nanotubes aligned with a substrate, but there is a problem that mass synthesis is difficult.

Therefore, the gas phase synthesis method has emerged as a method of mass synthesis of cheap carbon nanotubes. However, various gas phase synthesis methods reported to date contain a large amount of amorphous carbon particles in the synthesized carbon nanotubes, and it is difficult to purify them. In particular, when single-walled or double-walled carbon nanotubes are synthesized by vapor phase synthesis, the yield is very low and a large amount of amorphous carbon particles is considered to be not suitable for mass synthesis.

In addition, the carbon nanotube mass-synthesis growth value according to the gas phase synthesis method is a batch, in which a catalyst metal is injected into the reactor, the reactor is heated to react for a predetermined time, and the reactor is cooled. It is a way to synthesize. Such a synthesis apparatus has a high cost because it is necessary to repeat the individual process for each batch, the productivity is very low, and it is difficult to meet the same process conditions in each batch, there was a problem that the homogeneity of carbon nanotubes are inferior.

The present invention has been made to solve the above-mentioned problems of the prior art, the object of the present invention is to introduce the carbon nanotubes to synthesize the carbon nanotubes while introducing the catalyst metal from the outside air into the sealed reactor and continuously moved by the transfer screw To provide a tube mass synthesis device.

An object of the present invention described above is a reactor having an interior blocked from the outside air, the reactor, the inlet through which the catalyst, carbon source gas and inert gas is introduced, the outlet for discharging the synthesized carbon nanotubes from the inside and the heating means is formed; A catalyst transport mechanism installed inside the reactor; A carbon nanotube storage unit connected to the reactor outlet and having an interior blocked from outside air; And a gas supply unit connected to the reactor and supplying gases to the inside of the reactor.

In order to achieve the above object, it is preferable that a certain amount of the catalyst is added over time.

In addition, the device preferably further comprises a catalyst supply mechanism for blocking the outside air and introduce the catalyst into the reactor.

In the apparatus according to the present invention, it is preferable that a catalyst transfer mechanism is formed from the inlet to the outlet through which the catalyst is introduced.

In addition, the catalyst transfer mechanism is preferably a transfer screw.

In addition, the screw is provided with a spiral wing, the spiral wing is preferably installed to be adjacent to at least one surface inside the reactor.

In addition, the reactor is preferably formed with a cooling means.

The device according to the present invention preferably further comprises a carbon nanotube refining device connected to the carbon nanotube storage unit and having a suction device and an outlet opening to the outside air.

In addition, it is preferable that a stirring means is further formed at the bottom of the carbon nanotube storage unit.

In addition, the apparatus includes a carbon nanotube transport means connected to the carbon nanotube storage unit, an internal space, a blower that is connected to the internal space and blows air into the internal space, and is connected to the internal space and the suction mechanism and It is preferable to further include a carbon nanotube purification device consisting of a discharge mechanism having an outlet open to the outside air.

In addition, the carbon nanotube transfer means is connected to the inner space, it is preferable that a valve capable of selectively opening and closing between the carbon nanotube transfer means and the inner space is further formed.

In addition, it is preferable that a stirring means is further formed at the bottom of the inner space of the carbon nanotube refining apparatus.

Other objects, specific advantages and novel features of the invention will become more apparent from the following detailed description and the preferred embodiments associated with the accompanying drawings.

Hereinafter, the configuration of the carbon nanotube mass synthesis apparatus according to the preferred embodiment of the present invention will be described in detail.

1 is a schematic diagram showing the configuration of a carbon nanotube mass synthesis apparatus according to a preferred embodiment of the present invention. As shown in Figure 1, the carbon nanotube mass synthesis device according to the present invention (hereinafter referred to as 'device') is connected to the gas supply unit 40 to synthesize the carbon nanotubes (1), the reactor ( 1) a catalyst supply mechanism 30 connected to one side of the carbon nanotube storage unit 50 connected to the reactor 1 and a carbon nanotube purification unit 70 connected to the carbon nanotube storage unit 50. It is configured to include.

The reactor 1 has a cylindrical shape having a cylindrical space cut off from outside air, and a catalyst inlet 2 connected to the catalyst supply mechanism 30 is formed adjacent to the front end of the reactor 1, and hydrogen and an inert gas are Inlet gas inlets 3 are formed adjacent to the catalyst inlet 2 of the reactor 1. The reactor 1 is formed with a plurality of carbon source gas inlets 5 spaced from each other to the rear of the catalyst inlet 2 and the gas inlet 3, the carbon source gas inlet (5) is a carbon source gas containing It is connected to the carbon source gas tank 41. The reactor 1 is formed with a reactor side carbon nanotube outlet 7 opened downward at the bottom of the rear of the carbon source gas inlets 5. The reactor 1 is formed long in the longitudinal direction to facilitate the separation of the hydrogen gas and the carbon source gas into the front part and the rear part, respectively, but for simplicity of the substrate, the reactor 1 is briefly illustrated in the drawings. The shape is not limited by the dimensional ratio of the drawings. As long as the areas occupied by the hydrogen gas and the carbon source gas can be separated, the positions and quantities of the inlets can be appropriately changed, and thus the inlets are not limited to the positions and quantities adopted in the present embodiment.

The heating means 15 is provided outside the reactor 1 from the front end of the reactor 1 to the center part, and the cooling means 16 is provided outside the reactor 1 adjacent to the rear end of the reactor 1. Each position can be changed as long as the heating means 15 satisfies the condition located before the cooling means 16. The heating means 15 is equipped with a temperature sensor (not shown) to maintain the temperature inside the reactor 1 at 600 to 1200 ℃.

Inside the reactor 1, a spiral feed screw 20 is installed in the longitudinal direction. The helical feed screw 20 is composed of a shaft 21 and a spiral blade 22 formed around the shaft 21, the shaft 21 of the helical feed screw 20 is connected to a motor installed outside the reactor (1) Connected. The spiral feed screw 20 is installed so that the lower part of the spiral blade 22 maintains a predetermined distance from the bottom of the inside of the reactor 1. If the spacing between the spiral wing 22 and the bottom of the reactor 1 is large, catalysts are accumulated as much as the spacing, but this does not mean that the catalyst metal and carbon nanotubes cannot be transferred, but the catalyst metal and carbon nanotubes have a predetermined thickness. Will only build up on the floor. Axle 21 The shaft 21 of the helical feed screw 20 may be a rigid structure such as a metal bar, or may be a flexible flexible structure such as a wire rope. However, since the spiral feed screw 20 is used in a high temperature reactor 1, a material having excellent heat resistance, for example, a metal and ceramic material having good heat resistance is used.

The spiral feed screw 20 does not necessarily require a central axis 21, and as shown in FIG. 2, the spiral feed screw 25 is composed of only a spiral blade 27 having no shaft, similar to a coil spring shape. It is also possible to use. Even when the shaftless helical feed screw 25 is used, the end is connected to the motor shaft.

Catalyst supply mechanism 30 is for supplying a certain amount of catalyst into the reactor (1) is provided with a transfer screw 32 is formed therein a space for storing the catalyst and connected to the catalyst inlet (2) of the reactor (1) .

In the present embodiment, since the reactor 1 itself performs catalytic reduction, the catalyst reduction mechanism is not separately formed. However, to reduce the catalyst prior to introducing the catalyst into the reactor 1, the catalyst reduction mechanism is added to the catalyst supply mechanism 30. It is also possible to install.

The gas supply unit 40 includes a carbon gas tank 41 (carbon source gas tank) connected to the reactor 1, an argon gas tank or a nitrogen gas tank 42, and a hydrogen gas tank 43. The gas tanks each have a refiner (not shown). The purifier purifies the carbon gas mixture and the hydrogen gas mixture by adsorption, respectively, to supply high purity carbon source gas and hydrogen gas. Examples of the carbon source gas include methane, ethane, ethylene, acetylene, propylene, butane, butylene, butadiene, nucleic acid, heptane, toluene, benzene, xylene, gasoline, propane, liquefied propane gas (LPG), liquefied natural gas (LNG) ), Naphtha, carbon monoxide and alcohols. Argon, nitrogen, etc. may be used as the inert gas, but is not limited thereto.

The carbon nanotube storage unit 50 is connected to the reactor 1 through the reactor-side carbon nanotube outlet 7 and has an inner space that is blocked from outside air. The installed gas discharge pipe 55 is formed and the gas discharge pipe 55 is connected to the suction pump 58 opened to the outside air. The gas discharge pipe 55 is provided with an opening / closing valve 57 that can be opened and closed. Therefore, when the suction pump 58 is not operated, the carbon nanotube storage unit is locked through the gas discharge pipe 55 by locking the opening / closing valve 57. 50) can prevent air from entering. A storage side side carbon nanotube outlet 52 is formed on the bottom of the carbon nanotube storage unit 50, and the first stirring means 53 for uniformly stiring the carbon nanotubes above the storage side side carbon nanotube outlet 52 is provided. Is installed.

3 is a plan view from above of the first stirring means 53 installed in the carbon nanotube storage unit 50 of the carbon nanotube mass synthesis apparatus according to the preferred embodiment of the present invention. As shown in FIGS. 1 and 3, the first stirring means 53 comprises a plurality of radially extending stirring blades 54 and connected to the motor. The stirring blades 54 of the first stirring means 53 may be inclined with respect to the bottom surface, but may also be vertically formed. The first stirring means 53 may control the motor to continuously operate the mass synthesizer while it is operating or to intermittently operate it to include a rest period.

Under the carbon nanotube storage unit 50, a transfer screw 62 connected to the carbon nanotube outlet 52 of the storage unit side is installed, and the transfer screw 62 has a connection pipe 63 provided with an on / off valve 64. Is connected to the carbon nanotube purification apparatus 70 to be described later.

The carbon nanotube refining device 70 includes a collecting part 71 having a funnel structure having an internal space blocked from outside air, and a carbon nanotube outlet 73 is formed at the lower part of the refining device, and the collecting part 71 is formed. The second stirring means 75 is formed inwardly. As shown in FIG. 4, the second stirring means 75 includes a stirring blade 76 having a frame structure in which a through hole 76 is formed, and is connected to a motor to enable rotation. The carbon nanotube refining apparatus 70 includes an air injection mechanism 85 including a blower for blowing external air into the collecting unit 71, and includes gases containing air from inside the carbon nanotube refining apparatus 70. It includes a gas exhaust mechanism to discharge to the outside. The gas discharge mechanism of the carbon nanotube refining mechanism 70 includes a gas discharge pipe 79 provided with a bag filter 78 and an opening / closing valve 80 and includes a suction pump 81 that sucks gas from the gas discharge pipe 79. Equipped.

The carbon nanotube outlet 73 of the purification unit side of the collecting unit 71 is connected to a transfer screw 89 for discharging the synthesized carbon nanotubes.

Hereinafter, a process of synthesizing carbon nanotubes using the apparatus of the present invention will be described.

After raising the temperature of the reactor 1 to 600-1200 ° C. by the heating means 15, injecting argon, which is an inert gas, through the gas inlet pipes 3 of the reactor 1, into the reactor 1. The gases present are released to the carbon nanotube storage unit 50 through the carbon nanotube outlet 7 of the reactor side, and the foreign matter inside the reactor 1 is removed, so that the inside of the reactor 1 becomes an inert gas atmosphere. Gases introduced into the carbon nanotube storage unit 50 are discharged to the outside through the gas discharge pipe 55 of the carbon nanotube storage unit 50.

Then hydrogen is introduced into the reactor (1).

The catalyst supply mechanism 30 introduces a catalyst carrier having a catalyst metal oxide or catalyst metal oxide having a size of 1 to 50 nm into the reactor 1 filled with hydrogen gas and passes through the carbon source gas inlet 5. Into the inside of the carbon source gas. First, the catalytic metal introduced into the reactor 1 is reduced by reacting with the hydrogen gas charged at the front end of the reactor 1. The catalyst carrier may be in the form of particles, and may be made of magnesium oxide (Mg0), alumina (Al ₂ O ₃ ), zeolite, or silica, and the catalyst metal particle oxide may be nano-pores of the catalyst carrier. The supporting method may be the sol-gel method (sol-gel method), the coprecipitation method (precipitation method), or the supporting method (impregnation method). At this time, if the hydrogen gas is excessively supplied into the reactor 1, the pressure of the hydrogen gas at the front end of the reactor 1 is increased, so that the carbon source gas is pushed backward, so that only hydrogen gas is present at the front end of the reactor 1. Done.

The catalytic metal reduced at the front end of the reactor (1) is moved to the rear of the reactor (1) by the helical transfer screw (20), and the catalytic metal moved by the helical transfer screw (20) reacts with carbon source gas to form carbon. Synthesize nanotubes. The synthesized carbon nanotubes are cooled to room temperature by the cooling means 16 while passing through the rear end of the reactor 1. Since the catalyst metal and the synthesized carbon nanotubes are agitated by the helical transfer screw, the carbon nanotubes are prevented from adhering to each other to reduce homogeneity. Of course, by adjusting the carbon source gas flow rate and the synthesis temperature when the carbon nanotubes are synthesized, the growth rate, diameter, and crystallinity of the carbon nanotubes may be controlled.

The synthesized carbon nanotubes are moved to the carbon nanotube storage unit 50 through the reactor-side carbon nanotube outlet 7 formed at the rear end of the reactor 1. Since the reactor-side carbon nanotube outlet 7 is always open, the carbon nanotube storage unit 50 is introduced with not only the synthesized carbon nanotubes but also carbon source gas and hydrogen gas inside the reactor 1.

Since the catalyst metal continuously introduced into the reactor 1 through the catalyst supply mechanism 3 is continuously synthesized into carbon nanotubes, mass synthesis of carbon nanotubes is possible.

The gas introduced into the carbon nanotube storage unit 50 together with the synthesized carbon nanotubes is operated by the suction pump 58 installed in the gas discharge pipe 55 of the carbon nanotube storage unit 50. Through the carbon nanotubes are filtered and only the gases are discharged to the outside. The filtered carbon nanotubes leave the carbon nanotube outlet 52 of the storage unit side by the first stirring means 53 and are introduced into the refining mechanism through the transfer screw 62.

Opening and closing valve 64 above the carbon nanotube refining mechanism 70 to remove residual gases such as hydrogen contained in the carbon nanotubes from the carbon nanotubes introduced into the collecting portion 71 of the carbon nanotube refining mechanism 70. A) stirs the carbon nanotubes to the second stirring means (75) while introducing outside air into the blower in a closed state. Air from the outside blows and dilutes the residual gases contained in the carbon or notubes, and the remaining gases are sucked by the gas suction device included in the carbon nanotube refining device 70 together with the air introduced into the outside and discharged again. . The reason for blocking the on-off valve 64 installed between the carbon nanotube refining mechanism 70 and the transfer screw 62 is that the air introduced by the blower penetrates the carbon nanotube storage unit 50 and the reactor 1. It is to prevent you from doing.

The carbon nanotubes thus purified through the carbon nanotube refining mechanism exit the refining mechanism 70 by the carbon nanotube outlet 73 of the refining mechanism side of the collecting part 71 and the intended position by the transfer screw 89. Are sent to.

In the apparatus according to the present invention, the carbon source gas is prevented from entering the front end of the reactor 1 by blowing excess hydrogen gas through the gas inlets 3 installed at the front end of the reactor 1 during the carbon nanotube synthesis process. . As a result, the catalytic metal can be prevented from reacting with the carbon source gas before being reduced.

In the device according to the embodiment of the present invention, the transfer screw used as the catalyst transfer mechanism continuously transfers the synthesized carbon nanotubes and the catalyst metal. In particular, the spiral blades 22 of the helical transfer screw 20 are used to transfer the catalyst metal. As it pushes forward and pushes in the circumferential direction, the catalyst metal is evenly stirred to smoothly react the catalyst metal with the carbon source gas.

The spiral blade 22 of the transfer screw, which is a catalyst transfer mechanism, is formed adjacent to the bottom surface of the reactor 1 to push forward catalyst metal accumulated in the reactor 1, but it must adhere closely to the bottom surface of the reactor 1. It is not. For example, if the spiral wing 22 is spaced 1 cm from the inner bottom of the reactor 1, only about 1 cm of catalytic metal or carbon nanotubes will accumulate and will not interfere with the synthesis of carbon nanotubes. .

In addition, in the present embodiment, the spiral blades 22 are continuously formed, but a plurality of spiral blades 22 may be arranged at a predetermined interval in an appropriate structure for performing a transfer function, for example, spirally.

Although the catalyst supply mechanism 30 of the apparatus according to the embodiment of the present invention allows a certain amount of catalyst to be added in the process of synthesizing the carbon nanotubes of the apparatus, the present invention is not limited thereto. May fluctuate, in which case the output of carbon nanotubes will fluctuate.

Although the apparatus according to the preferred embodiment of the present invention adopts the catalyst supply mechanism 30 having the transfer screw, the present invention is not limited thereto, and the catalyst can be introduced into the reactor 1 in a state of being blocked from outside air. As long as there is a catalyst supply mechanism 30 can be various modifications.

The catalyst transfer mechanism of the apparatus according to an embodiment of the present invention may be formed over the entire length of the reactor 1 or includes a section from the catalyst inlet 2 to the carbon nanotube outlet of the reactor 1. It is possible to be formed over a variety of ranges so as to satisfy.

In the apparatus according to the present invention, the cooling means 16 is installed in the reactor 1, but the present invention is not limited thereto, and the cooling means 16 is also formed in another configuration such as the carbon nanotube storage part 50. It is possible.

In the apparatus according to the present invention provided with a carbon nanotube refining mechanism 70 is connected to the carbon nanotube storage unit 50, the present invention is not limited to this, the purification of the synthesized carbon nanotubes through a separate process In this case, it is also possible to omit the carbon nanotube purification apparatus 70 from the apparatus of the present invention.

Since the stirring means formed in the apparatus of the present invention are intended to facilitate the purification and transfer, it is also possible to omit the stirring means in the apparatus of the present invention and to replace the stirring means of the apparatus with another type.

In the apparatus according to the embodiment of the present invention, the on-off valve is installed in the gas discharge pipe, but this is to prevent the inflow of air from the outside when the suction pump is not operated, it is also possible not to install the on-off valve in the gas discharge pipe. .

Although the reactor 1 is horizontally formed in the apparatus according to the embodiment of the present invention, it is also possible to arrange the reactor 1 inclined so that the front end portion of the reactor 1 in which the catalytic reduction reaction is performed is positioned higher than the rear end portion. In this case, due to the difference in specific gravity, light hydrogen is collected at the front of the reactor 1 and heavy carbon source gas is collected at the rear of the reactor 1 so that hydrogen and carbon source gas can be properly separated.

In the embodiment of the present invention, the reactor 1 has a cylindrical shape, but the present invention is not limited thereto, and one reactor for transferring catalyst metal and carbon nanotubes stacked on the inner bottom surface of the reactor 1 by a screw may be used. (1) can be formed in various structures, and other forms are also possible, for example, satisfying the condition that the inner lower surface of the reactor 1 has a semi-circular cross section.

Although the present invention has been described in connection with the above-mentioned preferred embodiments, it is possible to make various modifications or variations without departing from the spirit and scope of the invention. Accordingly, the appended claims will cover such modifications and variations as fall within the spirit of the invention.

The present invention is a continuous production process of the gas phase synthesis method and is a method for mass synthesis of single-walled, double-walled, multi-walled carbon nanotubes. The apparatus of the present invention can continuously mass-produce carbon nanotubes, and control single-walled, double-walled and multi-walled carbon nanotubes by controlling the catalyst, reaction temperature, type and amount of carbon source gas, screw feed rate and hydrogen amount. Mass synthesis is possible.

Claims (12)

A reactor having an interior blocked from outside air and having an inlet through which a catalyst, carbon source gas, and inert gas are introduced, an outlet for discharging the synthesized carbon nanotubes from the inside, and a heating unit; A catalyst transport mechanism installed inside the reactor; A carbon nanotube storage unit connected to the reactor outlet and having an interior blocked from outside air; And And a gas supply unit connected to the reactor and supplying gases to the inside of the reactor. The carbon nanotube synthesizing apparatus according to claim 1, wherein the catalyst is added with a predetermined amount with time. The apparatus of claim 1, wherein the apparatus further comprises a catalyst supply mechanism that blocks the outside air and introduces the catalyst into the reactor. The apparatus of claim 1, wherein the catalyst transfer mechanism is formed from an inlet to which the catalyst is introduced among the inlets to the outlet. 5. The apparatus of claim 4, wherein the catalyst transfer mechanism is a transfer screw. 6. The apparatus of claim 5, wherein the screw has a spiral blade and the spiral blade is installed adjacent to at least one surface of the reactor. The apparatus of claim 1 wherein the reactor is further formed with cooling means. The apparatus of claim 1, further comprising a carbon nanotube refining device connected to the carbon nanotube storage unit and having a suction device and an outlet open to the outside. 9. The apparatus of claim 8, wherein stirring means is further formed at the bottom of the carbon nanotube storage part. According to claim 1 or 8, Carbon nanotube transport means connected to the carbon nanotube storage unit, and the inner space, the blower connected to the inner space and blows air into the inner space, and the inside The apparatus further comprises a carbon nanotube refining device which is connected to the space and comprises a discharge device having an inlet device and an outlet open to the outside. 11. The apparatus of claim 10, wherein the carbon nanotube transfer means is connected to the internal space, and a valve capable of selectively opening and closing between the carbon nanotube transfer means and the internal space is further formed. The apparatus of claim 10, wherein a stirring means is further formed at the bottom of the inner space of the carbon nanotube refining apparatus.

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