Apparatus for synthesizing carbon nanotube

The present invention relates to a carbon nanotube synthesizer, and more specifically, it is synthesized by passing only a reaction gas that does not react with carbon nanotube synthesis in a vertical carbon nanotube synthesizer and discharging it through an exhaust unit. Emissions of carbon nanotubes or catalysts relate to a carbon nanotube synthesizer with a blocking section formed to block it.

Carbon nanotubes (CNTs) are allotropes of carbon consisting of a large amount of carbon present on the earth, and one carbon is combined with different carbon atoms into a hexagonal honeycomb shape to form a tube morphology. It is a substance, and it is a substance in a region where the diameter of the tube is extremely small at the level of several nanometers. Carbon nanotubes have excellent mechanical properties, electrical selectivity, excellent field emission characteristics, and high-efficiency hydrogen storage medium properties, and are attracting attention as new materials for the next generation.

Such carbon nanotubes can be produced by advanced synthetic techniques, and the synthetic methods include electrolysis (Arc-discharge), laser vaporization, and plasma enhanced chemical vapor deposition (Plasma Enhanced Chemical Vapor). Deposition (PECVD), thermochemical vapor deposition (Thermal Chemical Vapor Deposition), electrolysis method, flame synthesis method, etc. are known.

Generally, the steps for producing carbon nanotubes are a catalyst coating step in which a catalyst is applied to a substrate on which carbon nanotubes are synthesized, and a catalyst coated substrate is placed in a reactor to react a reaction gas with the coated catalyst. It is divided into a carbon nanotube synthesis step for synthesizing carbon nanotubes and a recovery step for recovering the carbon nanotubes synthesized on the substrate.

Carbon nanotube synthesizers can be divided into horizontal and vertical types depending on the form in which the reactor that provides the space for synthesizing carbon nanotubes is placed. Due to its advantages such as properties, the development of a carbon nanotube synthesizer having a vertical reactor is being actively promoted.

On the other hand, the morphology of carbon nanotubes is divided into single-walled nanotubes (SWNTs) and multi-walled nanotubes (MWNTs) according to the number of bonds forming the walls that form the tubes, and in particular, single-walled nanotubes. The form in which nanotubes are bundled (Bundle type) is called a rope type nanotube (Rope Nanotube). The morphology of such carbon nanotubes can be determined by the morphology of the catalyst that reacts with the reaction gas, that is, the shape, density, particle size, etc. of the catalyst, and the morphology of the catalyst used can be determined by the method of producing the catalyst.

In a vertical carbon nanotube synthesizer, a catalyst is positioned inside the reactor, a reaction gas is injected into the catalyst, and the catalyst is suspended in the reactor by the injection pressure for synthesis. At this time, the upper part of the reactor is formed with an exhaust part that discharges the reaction gas remaining after reacting and the residual gas, but the upper part of the reactor is synthesized so that only the reaction gas is discharged through the exhaust part. A blocking part is formed to prevent the carbon nanotubes and the catalyst from being discharged.

At this time, the reaction gas is effectively discharged to the outside, the synthesized carbon nanotubes and the catalyst are blocked so as not to be discharged to the outside, and a blocking portion is provided to prevent the carbon nanotubes and the catalyst from being laminated on the blocking portion. Need to provide. This is because the synthesized carbon nanotubes and the catalyst, which are not released to the outside by the blocking part, fall inside the reactor again and are synthesized, so that the productivity can be improved.

<p> The present invention has been devised to improve the above-mentioned problems, and an object of the present invention is to achieve each cell (diagonal structure) in a vertical carbon nanotube synthesizer. The purpose is to form a blocking blade in the cell) and effectively discharge the reaction gas remaining after the reaction, and the synthesized carbon nato tube and catalyst provide a blocking part that effectively blocks the discharge. The object of the present invention is not limited to the object mentioned above, and other purposes not mentioned above will be clearly understood by those skilled in the art from the following description.</p>

<p> In order to achieve the above object, the carbon nanotube synthesizer according to the embodiment of the present invention is formed in a reactor formed vertically long by providing a space in which carbon nanotubes are formed and outside the reactor. The heating unit that heats the reactor, the gas supply unit that injects the reaction gas for synthesizing the carbon nanotubes by reacting with the catalyst located inside the reactor, and the upper portion of the reactor are connected. The reaction gas that does not react with the synthesis of the carbon nanotubes is discharged to the outside, and only the reaction gas that is formed inside the reactor and does not react with the synthesis of the carbon nanotubes is discharged to the exhaust part and synthesized. Including a blocking portion that blocks the discharge of the carbon nanotube or catalyst, the blocking portion is divided into a plurality of polygonal structures in cross section, and each of the separated cells is inclined downward. A blocking wing is formed.</p>

<p> According to the carbon nanotube synthesizer of the present invention as described above, there is one or more of the following effects.</p><p> First, the advantage is that carbon nanotubes or catalysts synthesized by forming blocking blades in each cell separated by a polygonal structure can effectively block the discharge to the outside of the reactor. There is.</p><p> Second, there is also the advantage that the carbon nanotubes or catalyst synthesized by the inclined breaker can be guided to flow downward to prevent the carbon nanotubes or catalyst from being laminated on the upper surface of the breaker.</p><p> Thirdly, the blocking blades formed in each cell separated by a polygonal structure have a small area, which has an advantage that synthetic carbon nanotubes or catalysts can be prevented from being laminated.</p><p> Fourth, there is an advantage that the productivity can be improved because the carbon nanotubes and the catalyst synthesized on the blocking blade are not laminated and fall again on the reactor to be synthesized again.</p>

The specific content of the embodiments is included in the detailed description and figures.

The advantages, features, and methods of achieving them of the present invention will become clear with reference to the embodiments described in detail below with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and can be embodied in various forms different from each other. The present embodiment is provided solely for the purpose of fully informing a person having ordinary knowledge in the technical field to which the present invention belongs, so that the disclosure of the present invention is complete. The invention is defined only by the scope of the claims. Throughout the specification, the same reference numerals shall refer to the same components.

Hereinafter, the present invention will be described with reference to a diagram for explaining a carbon nanotube synthesizer according to an embodiment of the present invention.

FIG. 1 is a perspective view generally showing the structure of the carbon nanotube synthesizer according to the embodiment of the present invention, and FIG. 2 is a vertical sectional view roughly showing the structure of the carbon nanotube synthesizer according to the embodiment of the present invention. FIG. 3 is a diagram showing an example of a catalyst charging unit in the carbon nanotube synthesizer according to the embodiment of the present invention, and FIG. 4 is a stirrer in the carbon nanotube synthesizer according to the embodiment of the present invention. 5 is a perspective view showing the shape of the above, FIG. 5 is a diagram showing a blocking portion of the honeycomb structure according to an embodiment of the present invention, and FIG. 6 is a diagram showing blocking in cells separated by the honeycomb structure in FIG. It is a perspective view which shows that the wing was formed, FIG. 7 is a cross-sectional view for explaining the blocking part in the carbon nanotube synthesis apparatus by one Embodiment of this invention, and FIG. 8 is one of the present invention. It is sectional drawing which shows the blocking part formed by the multilayer structure in the carbon nanotube synthesis apparatus by embodiment.

The carbon nanotube synthesizer 100 according to an embodiment of the present invention may include a reactor 110, a heating unit 120, a gas supply unit 130, an exhaust unit 150, and a blocking unit 180. Further, the stirrer 140 and the catalyst charging unit 160 may be further included.

The Reaction tube 110 provides a space for carbon nanotubes to be synthesized and can be formed vertically long. The reactor 110 can be provided in a generally vertical cylindrical shape, but can be made of a heat resistant material such as quartz or Graphite. The reactor 110 is divided into a main body 110a where synthesis is performed, a lower 110b where the catalyst (M) is located, and an upper 110c where the exhaust 150 is formed. The cylindrical reactor 110 is the reactor 110. Means the shape of the main body 110a. Inside the reactor 110, a stirrer 140 may be formed that uniformly mixes the reaction gas and the catalyst (M).

The heating unit 120 is installed outside the reactor 110 and can heat the reactor 110 to heat the inside of the reactor 110 to the process temperature required for synthesizing carbon nanotubes. Preferably, the main body 110a where the synthesis takes place is heated in the reactor 110. As the carbon nanotube synthesis step proceeds, the inside of the reactor 110 is maintained at a high temperature of about 500 ° C or higher, preferably 650 ° C to 1000 ° C. The heating unit 120 can use a heat ray (not shown) having a coil shape so as to surround the outer wall of the reactor 110, but the configuration of the heating unit 120 is not limited to this and can be changed by those skilled in the art.

As shown in FIG. 2, the lower part of the reactor 110 can contain the catalyst (M) used for the synthesis of carbon nanotubes by reacting with the reaction gas. The catalyst (M) can be a metal powder or a vaporized metal, but preferably a magnetic material such as iron (Fe), cobalt (Co), nickel (Ni), etc. as the catalyst (M) in the form of a metal powder. Use abandoned metal compounds with.

On the other hand, a catalyst charging section 160 for supplying the catalyst (M) can be connected to the lower section 110b of the reactor 110.

As shown in FIG. 3, the catalyst charging unit 160 is a catalyst supply line 161 for supplying the catalyst (M) from the catalyst storage unit 162 for storing the manufactured catalyst (M) and the catalyst storage unit 162 to the inside of the reactor 110. May include. FIG. 3 shows an example in which the screw is rotated inside the catalyst supply line 161 to quantitatively charge the catalyst (M) into the reactor 110 according to the pitch of the screw. The method of supplying the catalyst (M) to the inside of the reactor 110 is not limited to this, and the catalyst (M) is supplied by various methods such as a method of injecting the catalyst (M) into the inside of the reactor 110. be able to. On the other hand, although not shown, the catalyst reducing part may be connected to the catalyst storage part 162, but the catalyst reducing part is a catalyst (M) oxidized by a drying process, a plastic process, etc. in the manufacturing process of the catalyst (M). Can play a role in reducing treatment.

As described above, the reactor 110 can be formed in a generally vertical cylindrical shape, and the main body 110a can be provided in a vertical cylindrical shape as a space in which carbon nanotubes are substantially synthesized.

Then, as illustrated in FIG. 4, the lower portion 112 of the reactor 110 containing the catalyst (M) can have various shapes in order to increase the floating characteristics of the catalyst (M). Preferably, as illustrated in FIG. 2, the lower portion 110b of the reactor 110 is formed in a cylindrical shape so as to be inclined so that the cross-sectional area becomes narrower toward the bottom. Here, the cone shape may be a shape including a cone shape, a taper shape, and the like.

As shown in FIG. 2, by forming the lower portion 110b of the reactor 110 in an inclined conical shape, if the reaction gas is injected toward the catalyst (M) by the gas supply portion 130 described later, the upper portion is formed by the reaction gas. The catalyst (M) suspended in the reactor (M) can come down along the side wall of the main body 110a of the reactor 110 and be uniformly mixed with the lower part 110b of the reactor 110 again. Therefore, the empty space of the catalyst (M) entering the lower portion 110b of the reactor 110 is filled, and the injection pressure of the reaction gas injected from the gas supply nozzle 130 naturally and repeatedly floats in the space inside the reactor 110. Can be done.

With reference to FIG. 2, the upper portion 110c of the reactor 110 may be formed to have a diameter larger than that of the main body 110a. This increases the cross-sectional area of the upper part 110c and lowers the flow velocity of the catalyst (M) or the synthesized carbon nanotubes reaching the upper part 110c so that it does not flow out to the exhaust part 150 but falls to the main body part 110a again. Because. The flow of catalyst (M) or reaction gas inside the reactor 110 is illustrated in FIG.

The gas supply unit 130 injects a reaction gas for synthesizing carbon nanotubes by reacting with a catalyst (M) located inside the reactor 110. Referring to FIG. 2, the gas supply unit 130 is installed long so as to go from the upper part 110c of the reactor 110 toward the lower part 110b containing the catalyst (M), and reacts with the catalyst (M) to synthesize carbon nanotubes. The reaction gas can be injected downward toward the catalyst (M). The catalyst (M) stored in the lower part 110b of the reactor 110 may float due to the injection pressure of the reaction gas injected through the gas supply part 130.

As the reaction gas, a gas containing carbon such as acetylene, ethylene, methane, benzene, xylene, cyclohexane, carbon monoxide or carbon dioxide can be used. The reaction gas can be decomposed into radicals by thermal decomposition inside the reactor 110, and such radicals react with the catalyst (M) suspended from the lower part 110b of the reactor 110 to synthesize carbon nanotubes. be able to.

On the other hand, the gas supply unit 130 can adjust the flow rate of the reaction gas according to the form of the catalyst (M), that is, the shape, density, and size of the catalyst (M). Therefore, as shown in FIG. 2, a pressurizing pump for supplying the reaction gas to the gas supply unit (not shown) is on the supply pipe 131 connecting the gas supply unit 130 and the gas storage unit 132 for storing the reaction gas. And a flow rate control valve 133 that regulates the flow rate of the reaction gas supplied to the gas supply unit may be installed. The configurations of the gas supply unit 130, the supply pipe 131, the pressurizing pump and the flow rate control valve 133 are not limited to this, and can be variously changed by those skilled in the art.

On the other hand, apart from the gas supply unit 130, a flow machine supply unit (not shown) for supplying the flow machine inside the reactor 110 can be provided. The fluidized body prevents the carbon nanotubes produced by the reaction of the reaction gas and the catalyst (M) from falling to the lower part of the reactor 110 due to the increase in weight due to the growth of the carbon nanotubes, and forms a fluidized area inside the reactor 110. The reaction between the reaction gas and the catalyst (M) can be activated. Inert gases such as helium, spartan, argon and the like can be used as such fluids and, as required, gases such as methane, acetylene, carbon monoxide or carbon dioxide or such gases and argon gas. It is also possible to use a mixed gas of.

The exhaust unit 150 can discharge unreacted gas that is connected to the upper portion 110c of the reactor 110 and does not react to the synthesis of carbon nanotubes to the outside of the reactor 110. That is, after the carbon nanotube synthesis step is completed through the exhaust unit 150, the residual gas or the like can be discharged to the outside. Such residual gas may include a portion of the synthesized carbon nanotubes or catalyst (M), which is separated by a barrier 180 formed inside the upper 110c of the reactor 110. The cutoff unit 180 can separate the carbon nanotubes and the catalyst (M) contained in the residual gas and discharge only the gas to the outside. Since the discharged residual gas can be harmful, such residual gas can be treated by a scrubber (not shown) connected to the exhaust unit 150 and discharged to the outside.

Inside the reactor 110, a stirrer 140 may be installed so as to uniformly mix the reaction gas and the catalyst (M) inside the reactor 110. As shown in FIG. 2, the stirrer 140 can be installed so as to surround the nozzle-shaped gas supply unit 130 which is long installed below the central axis of the reactor 110 from the upper portion 110c of the reactor 110.

As the stirrer 140, an impeller having a large number of blades and rotating can be used. As shown in FIG. 4, the stirrer 140 has a cylindrical body 141 with a hollow shaft 143 surrounding the gas supply nozzle 130, and a plurality of blades 142 may be formed around the body 141. The plurality of wings 142 may be arranged at equal intervals around the cylindrical main body 141, and may be arranged in multiple stages along the length direction of the main body 141. Further, the wings 142 of each stage may be arranged so as to intersect each other. The number and arrangement of blades 142 can be changed by those skilled in the art according to conditions such as the size of the reactor 110, the type of reaction gas, and the form of the catalyst (M).

The stirrer 140 rotates around the hollow shaft 143 with a constant period, and the reaction gas inside the reactor 110 and the catalyst (M) can be uniformly mixed. Therefore, the stirrer 140 can prevent the problem of the synthesized carbon nanotubes adhering to the wall surface of the reactor 110, and can increase the layer expansion coefficient of the catalyst (M). Although not shown, a drive unit for rotating the stirrer 140 may be connected to one end of the stirrer 140.

A cutoff portion 180 is formed on the hollow shaft 143 of the stirrer 140, and the cutoff portion 180 can rotate together with the rotation of the stirrer 140.

The recovery unit 190 discharges the carbon nanotubes synthesized connected to the lower portion 110b of the reactor 110 to the outside of the reactor 110 so that the carbon nanotubes can be recovered. Preferably, after the carbon nanotube synthesis step is completed, the gate (not shown) installed in the recovery unit 190 is opened to maintain the recovery unit 150 at a negative (-) pressure so that the carbon nanotubes synthesized are exposed to the outside. Discharge and collect. At this time, the recovery unit 190 can be cooled below a certain temperature in order to recover the synthesized carbon nanotubes. Although not shown, the recovery unit 190 may be equipped with a pump for adjusting the pressure and a valve for adjusting the recovery amount of carbon nanotubes.

The blocking unit 180 shuts off the emission of the synthesized carbon nanotubes or the catalyst (M) by discharging only the unreacted gas formed inside the reactor 110 and not reacting with the synthesis of the carbon nanotubes through the exhaust unit 150. As shown in FIG. 2, the blocking portion 180 is formed inside the upper portion 110c of the reactor 110. The reaction gas, carbon nato tube, and catalyst (M) that have risen through the main body 110a of the reactor 110 reach the cutoff 180, but the reaction gas is discharged through the exhaust 150 through the cutoff 180. The carbon nanotubes and the catalyst (M) are separated from the reaction gas by the blocking part 180 and fall under the reactor 110 again.

Hereinafter, the configuration of the blocking unit 180 according to the embodiment of the present invention will be described in detail with reference to FIGS. 5 to 8.

The cross section of the blocking portion 180 is divided by a plurality of polygonal structures, and blocking blades 184 and 186 inclined downward may be formed in each polygonal structure. FIG. 5 illustrates a honeycomb structure having a hexagonal cross section as an example of the blocking portion 180. For reference, the blocking blades 184 and 186 are not shown in FIG. 5, but the blocking blades 184 and 186 will be described later with reference to FIGS. 6 and 7. Although not shown, the blocking portion 180 may have a plurality of quadrangular structures rather than a honeycomb structure having a hexagonal cross section as shown in FIG.

Then, blocking blades 184 and 186 are formed in each cell 182 separated by a polygon. FIG. 6 is a perspective view showing one cell 182 separated by a honeycomb structure in FIG. 5, but two blocking blades 184 and 186 inclined downward from two opposite sides of the hexagon are formed. It turns out that it will be done. As shown in FIG. 7, the two blocking blades 184 and 186 may have different lengths extending from the two sides. Preferably, as shown in FIG. 7, the long blocking blade 184 is formed so as to be located below the vertical end of the short length blocking blade 186. That is, when viewed from below the vertical of the blocking portion 180, there is no empty space between the blocking blades 184 and 186. Therefore, all the carbon nanotubes and the catalyst (M) rising vertically from the main body 110a of the reactor 110 hit the blocking blades 184 and 186 and fall under the reactor 110 again. If the long blocking blade 184 is not located below the vertical end of the short blocking blade 186, there is a space between the blocking blades 184 and 186 when viewed from below the vertical of the blocking portion 180. The carbon nanotubes and a part of the catalyst (M) rising vertically from the main body 110a of the reactor 110 can easily pass through the blocking part 180 and be discharged to the outside through the exhaust part 150. it can.

The tilt angles of the blocking blades 184, 186 can be the same, but preferably 60 degrees. Since the inclination of the blocking blades 184 and 186 is large, the carbon nanotubes or the catalyst (M) are not laminated on the upper surface of the blocking blades 184 and 186 and flow downward. Therefore, the carbon nanotubes or the catalyst (M) that have descended into the reactor 110 again along the blocking blades 184 and 186 can go through the synthesis process again, so that the production amount of the carbon nanotubes can be improved.

Further, in the present invention, since the blocking blades 184 and 186 are formed in the cells 182 separated by the polygonal structure, the areas of the blocking blades 184 and 186 are small. Therefore, carbon nanotubes or catalysts (M) are not easily laminated on the upper surfaces of blocking blades 184, 186. In the drawings, the tilt angles of the blocking blades 184 and 186 on both sides are shown to be the same, but it is needless to say that the tilting angles of the blocking blades 184 and 186 can be configured to be different. For example, a short length cutoff wing 186 can be configured to have a small downward tilt angle, and a large length cutoff wing 184 can be configured to have a relatively large downward tilt angle.

Further, the blocking portion 180 of the carbon nanotube synthesizer 100 according to the embodiment of the present invention can be formed in a multilayer structure in the vertical direction of the reactor 110 as shown in FIG. By being formed in a multi-layer structure, the emission of the catalyst (M) and the carbon nanotube can be blocked by double or triple, and the performance of preventing the emission of the carbon nanotube or the catalyst (M) can be further improved. ..

Further, as shown in FIG. 1, the blocking unit 180 may have a structure in which it is connected to the outer main body 141 of the stirrer 140 and rotates with the rotation of the stirrer 140. By rotating the blocking unit 180 together with the stirrer 140, it is possible to form a backflow at the blocking blades 184 and 186 to more effectively prevent the emission (M) of carbon nanotubes and catalysts to the exhaust unit 150.

The operation of the carbon nanotube synthesizer 100 according to the embodiment of the present invention configured as described above will be briefly described as follows.

First, when the carbon nanotube synthesis process is started, power is supplied to the heating unit 120 to start heating the reactor 110, and the inside of the reactor 110 can be heated at a process temperature of about 650 ° C to 1000 ° C. .. Further, the reduced catalyst (M) can be supplied to the lower portion 110b of the reactor 110 through the catalyst charging portion 160.

When the internal temperature of the reactor 110 reaches the process temperature, the reaction gas can be supplied to the inside of the reactor 110 through the gas supply unit 130 and injected downward toward the lower portion 110b of the reactor 110. The catalyst (M) and the synthesized carbon nanotubes are suspended above the reactor by the injection pressure of the reaction gas. The reaction gas can be decomposed into radicals by thermal decomposition inside the reactor 110, and such radicals can react with the catalyst (M) suspended from the lower portion 110b of the reactor 110 to synthesize carbon nanotubes. When the step of synthesizing the carbon nanotubes in the reactor 110 is completed, the supply of the reaction gas can be interrupted from the gas supply unit 130. On the other hand, during the synthesis of the carbon nanotubes, the stirrer 140 rotates with a constant cycle to uniformly mix the reaction gas and the catalyst (M) inside the reactor 110, and the synthesized carbon nanotubes are produced. It is possible to prevent the reactor 110 from adhering to the inner wall surface. At this time, as described above, the unreacted reaction gas is discharged through the shutoff section 180 and the exhaust section 150 in the upper section 110c of the reactor 110, and the carbon nanotubes and the catalyst (M) suspended above are shut off. It is separated from the reaction gas from part 180 and falls under the reactor 110 again to undergo synthesis.

When the synthesis of the carbon nanotubes is completed, the synthesized carbon nanotubes can be recovered through the recovery section 190 connected to the lower section 110c of the reactor 110.

A person having ordinary knowledge of the technical field to which the present invention belongs can understand that the present invention can be carried out in other specific forms without changing its technical idea or essential features. .. Therefore, it should be understood that the above embodiments are exemplary in all respects and are not limiting. The scope of the present invention is indicated by the scope of claims rather than the detailed description, and all modified or modified forms derived from the meaning, scope, and equivalent concept of the scope of claims are included in the scope of the present invention. Must be interpreted as included.

<figref num="1">It is a perspective view which shows roughly the structure of the carbon nanotube synthesis apparatus by one Embodiment of this invention.</figref><figref num="2">It is a vertical cross-sectional view which shows roughly the structure of the carbon nanotube synthesis apparatus by one Embodiment of this invention.</figref><figref num="3">It is a figure which shows an example of the catalyst input part in the carbon nanotube synthesis apparatus by one Embodiment of this invention.</figref><figref num="4">It is a perspective view which shows the shape of the stirrer in the carbon nanotube synthesis apparatus by one Embodiment of this invention.</figref><figref num="5">It is a figure which shows the blocking part of the honeycomb structure by one Embodiment of this invention.</figref><figref num="6">FIG. 5 is a perspective view showing a cell in which a blocking blade is formed in a cell separated by a honeycomb structure in FIG.</figref><figref num="7">It is sectional drawing for demonstrating the blocking part in the carbon nanotube synthesis apparatus by one Embodiment of this invention.</figref><figref num="8">It is sectional drawing which shows the blocking part formed by the multilayer structure in the synthesis apparatus of carbon nanotube by one Embodiment of this invention.</figref>

Code description

110 reactor 120 heating part 130 Gas supply unit 140 stirrer 150 Exhaust section 180 cutoff