KR101932499B1

KR101932499B1 - Apparatus for preparing carbon nanotube fiber and process for preparing carbon nanotube fiber using same

Info

Publication number: KR101932499B1
Application number: KR1020150083389A
Authority: KR
Inventors: 오유진; 최용진; 송동수
Original assignee: 주식회사 엘지화학
Priority date: 2015-06-12
Filing date: 2015-06-12
Publication date: 2018-12-27
Also published as: KR20160146300A

Abstract

The present invention relates to a carbon nanotube fiber manufacturing apparatus and a carbon nanotube fiber manufacturing method using the same.

Description

Technical Field [0001] The present invention relates to a carbon nanotube fiber manufacturing apparatus and a method of manufacturing carbon nanotube fiber using the carbon nanotube fiber manufacturing apparatus,

Carbon nanotubes (CNTs), which are a kind of carbon isotopes, have a diameter of several to several tens of nanometers and are several hundreds of micrometers to several millimeters long, and have been reported in the journal Nature by Iijima in 1991 , Physical properties and high aspect ratio have been studied in various fields. The inherent properties of these carbon nanotubes are due to the sp2 bond of carbon, stronger than iron, lighter than aluminum, and exhibit electrical conductivity similar to that of metals. According to the number of nanotubes, single-wall carbon nanotubes (SWNTs), double-wall carbon nanotubes (DWNTs), multi-walled carbon nanotubes (Multi- Wall carbon nanotube (MWNT), and can be divided into zigzag, armchair, and chiral structures depending on the asymmetry / chirality.

Methods for fabricating carbon nanotube (CNT) fibers include forest radiation and direct radiation. The forest sputtering is performed by depositing a catalyst on a substrate, synthesizing a CNT forest in a direction perpendicular to the substrate, pulling CNTs at the end of the substrate with a tweezers or a tape, etc., CNT fiber. This method has the disadvantage that it can not increase the production amount because the continuous process is impossible.

On the other hand, according to Korean Patent No. 10-1286751 of the prior art, hydrogen is generally used as a carrier gas in the production of carbon nanotube (CNT) fibers. Therefore, the inside of the reactor is mostly hydrogen, but a part of the carbon source supplied from the feed solution exists. The activity of the catalyst is low and the residence time is short in the process of producing the CNT fiber, so that unreacted hydrocarbon gas exists in the reactor. When high-purity hydrogen gas is discharged to the reactor outlet, the production cost can be reduced by recycling the hydrogen gas. However, there is a problem that this process is difficult when unreacted hydrocarbons are present.

Korean Patent No. 10-1286751

In the conventional method for producing carbon nanotube (CNT) fiber, there is a problem in that unreacted hydrocarbon gas is present inside the reactor because the retention time of the catalyst is short and efficient reaction is difficult.

An object of the present invention is to provide an apparatus for manufacturing a cylindrical carbon nanotube fiber which recycles hydrogen gas discharged through removal of unreacted hydrocarbons remaining in the reactor to improve the economical efficiency of the reaction.

In order to accomplish the above object, the present invention provides a cylindrical high temperature reactor main body having a reaction zone; An inlet for injecting carbon material and hydrogen into the reaction zone of the body; Heating means for heating the reaction region; A discharge port for discharging the carbon nanotube fibers installed at the lower end of the main body; An exhaust port for exhausting the unreacted gas remaining in the reaction zone between the heating means and the exhaust port or the exhaust port downstream of the heating means; And an unreacted gas processing device connected to the exhaust port and installed outside the reactor main body.

According to a preferred embodiment of the present invention, the unreacted hydrocarbon recycle apparatus comprises a chamber; Heating means for heating the chamber; A mesh net comprising a transition metal; And a screw conveyor provided at both ends of the mesh network.

The carbon nanotube fiber discharging port may include winding means for collecting and collecting the carbon nanotube fibers discharged from the lower end of the cylindrical high temperature reactor main body. The hydrogen introduced from the inlet may be introduced into the reaction zone at a linear velocity capable of forming a laminar flow, and the inlet may include a spray nozzle for injecting the carbon material and a dispersion plate for injecting hydrogen. In addition, the carbon material may be a catalyst precursor dispersed in a gaseous or liquid carbon compound, and the carbon material may further include a catalytic activator.

Another aspect of the present invention provides a method for producing carbon nanotube fibers using the apparatus of the present invention and carbon nanotube fibers produced using the apparatus of the present invention.

INDUSTRIAL APPLICABILITY The present invention can provide a cylindrical carbon nanotube fiber manufacturing apparatus having an increased reaction efficiency. Further, when the apparatus for producing carbon nanotube fibers according to the present invention is used, unreacted hydrocarbons are removed from the inside of the reactor, and high-purity hydrogen gas is recycled to reduce the production cost.

1 shows an apparatus for producing carbon nanotube fibers according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail. The following detailed description is merely an example of the present invention, and therefore, the present invention is not limited thereto.

In the drawings, like reference numerals are used for similar elements.

The term "and / or" includes any one or a combination of the plurality of listed items.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it is to be understood that other elements may be directly connected or connected, or intervening elements may be present.

The singular expressions include plural expressions unless otherwise specified.

The terms "comprises", "having", or "having" mean that there is a feature, a value, a step, an operation, an element, a component or a combination thereof described in the specification, Does not exclude the possibility that a number, a step, an operation, an element, a component, or a combination thereof may be present or added.

The term "carbon nanotube fibers" in the present specification refers to both carbon nanotubes grown in a fiber form or formed by fusing a plurality of carbon nanotubes in a fiber form.

Techniques for producing carbon nanotube fibers include solution spinning, array spinning, aerogel spinning and / or film twisting or rolling. The present invention follows a process of directly spinning carbon nanotube fibers or ribbons from carbon nanotube aerogels formed immediately after the introduction of carbon material in a reactor by using chemical deposition (CD).

The direct spinning is carried out by adding a catalyst to a carbon source and injecting the carbon nanotube into a vertical furnace at a constant rate together with hydrogen to synthesize carbon nanotubes in a heating furnace, Is a process for continuously producing carbon nanotube fibers.

The catalyst precursor of the present invention is a substance which is not contained in the catalyst cycle but is changed into an active catalyst (or produces an active catalyst) in the course of the catalytic reaction, and in the present invention, the catalyst precursor forms a catalyst Then, CNT is synthesized.

The conventional method of producing carbon nanotube (CNT) fibers has a problem that the activity of the catalyst is low, the residence time of the reaction gas is short and the efficient reaction is difficult, and unreacted hydrocarbon gas exists in the reactor.

Accordingly, the present inventors have made extensive efforts to solve the above-mentioned problems, and have found that this problem can be solved by including an unreacted gas processing apparatus.

That is, a cylindrical high temperature reactor body having a reaction region in which a carbon material and hydrogen react; An inlet for injecting carbon material and hydrogen into the reaction zone of the body; Heating means for heating the reaction zone; A carbon nanotube fiber discharge port installed at a lower end of the main body; An unreacted gas exhaust port remaining in the reaction region between the heating means and the exhaust port or the exhaust port downstream thereof; And an unreacted gas processing device connected to the exhaust port and installed outside the reactor main body.

Hereinafter, the present invention will be described more specifically with reference to the drawings.

FIG. 1 illustrates an apparatus for manufacturing carbon nanotube fibers according to an embodiment of the present invention. Referring to FIG. A cylindrical high-temperature reactor main body 11 having a reaction zone; An inlet 10 for injecting carbon material and hydrogen into the reaction zone of the body; Heating means (13) for heating the reaction zone; A discharge port 14 for discharging the carbon nanotube fibers installed at the lower end of the main body; An exhaust port (15) for exhausting unreacted gas in the reaction zone between the heating means and the exhaust port; And an unreacted gas processing unit (16) connected to the exhaust port and installed outside the reactor body.

And a winding means (17) for winding a continuous aggregate of the carbon nanotubes produced at the lower end of the reaction region (12) to form fibers. The inlet 10 may include a spray nozzle for injecting a carbon material and a dispersing plate for injecting hydrogen. The inlet may be an injection nozzle, but is not limited thereto.

The apparatus may further include a carbon material supply unit for supplying carbon material to the reactor body 11 at the inlet 10, and a hydrogen supply unit for supplying hydrogen. The carbon material supply unit may include a mixing unit for dispersing the catalyst precursor in the gaseous or liquid carbon compound, and a carrier pump for supplying the carbon material formed in the mixing unit to the carbon material injection nozzle. The hydrogen introduced from the inlet may flow into the reaction zone at a linear velocity so as to form laminar flow. For this purpose, a dispersion plate may be used. The hydrogen may be introduced into the reactor main body 11 through the inlet 10 from a hydrogen supply unit having a gas tank and flow rate control means. The flow rate control means adjusts the gas flow rate so that hydrogen is supplied at a linear velocity at which laminar flow can be formed.

Specifically, the carbon material and hydrogen flow into the reactor through the inlet. When the catalyst precursor contained in the carbon material is supplied to the reactor, a catalyst is formed. The formed catalyst flows from the upper end to the lower end of the reactor to form carbon nanotubes and grow or fuse to form carbon nanotube fibers. At this time, the catalyst particles on which the CNTs have grown move to the bottom, and the formed CNT fibers are radiated to the winding means through the discharge port. The unreacted gas containing hydrogen and / or unreacted hydrocarbon is discharged through the exhaust port. The catalyst is discharged together with the CNT because the CNT grows, and the unreacted catalyst is also buried in the CNT and discharged.

The unreacted gas exhaust port remaining in the reaction region may be provided between the heating means and the discharge port or at the rear end of the CNT fiber discharge port. The unreacted gas may include unreacted hydrocarbon and hydrogen, and the unreacted hydrocarbon and hydrogen may be separated and discharged through an unreacted gas processing unit connected to the exhaust port and installed outside the reactor body.

According to a preferred embodiment of the present invention, the unreacted gas processing apparatus includes a chamber; Heating means for heating the chamber; A mesh net comprising a transition metal; A screw conveyor provided at both ends of the mesh net; And a gas exhaust port. The unreacted gas may include unreacted hydrocarbons and hydrogen. The unreacted hydrocarbons react with the transition metal in a mesh network and are discharged through a screw conveyor, and the hydrogen may be discharged through a gas exhaust port.

That is, the unreacted gas treating apparatus collects and processes the unreacted hydrocarbons remaining in the reactor by using a transition metal having a high carbon solubility, and allows hydrogen to be reused. More specifically, the unreacted hydrocarbon contained in the unreacted gas may be introduced into the mesh network through the screw conveyor, reacted with the transition metal, and then discharged through the screw conveyor. The hydrogen contained in the unreacted gas flows into the mesh network through the screw conveyor and is discharged through the gas exhaust port 26 without reacting with the transition metal. 1, the unreacted gas flows into the mesh net 23 including the chamber part 21 and the low-priced transition metal 24 through the screw conveyor 25a. The low-cost transition metals 24 provided in the mesh net 23 absorb the unreacted hydrocarbons contained in the unreacted gas and form metal carbides. The carbonized metal is discharged to the outside through the screw conveyor 25b on the opposite side. Hydrocarbons are removed from the collected unreacted gas, and remaining hydrogen is directly discharged from the chamber 21 to be reused. Some of the hydrogen discharged from the chamber 21 reduces the metal oxide carrying the metal carbide to hydrogen to remove hydrocarbons, and the transition metal can be reused. The heat source required for this reaction is available by burning some hydrogen, thus enabling a continuous process with little additional cost.

In the present invention, the chamber is a place where unreacted gases are collected, and a mesh network including a transition metal is provided in the chamber. The transition metal may include at least one selected from the group consisting of iron (Fe), nickel (Ni), and cobalt (Co). A mesh network is used to react the transition metal with unreacted hydrocarbons in the chamber. The average mesh size of the mesh network increases proportionally with the chamber size and may be approximately the same as the diameter of the chamber size, but is not limited thereto. The heating means 22 for heating the chamber may be the same as the heating means 13 surrounding the reactor body and the chamber 21 may be heated to 1,000 to 3,000 占 폚. The high temperature region of the chamber may preferably maintain a temperature of 1,000 to 2,000 DEG C, 1,000 to 1,500 DEG C or 1,000 to 1,300 DEG C, and more preferably 1,100 to 1,200 DEG C. [ The temperature of the high temperature region of the chamber influences the transition metal being injected to control the carbon solubility of the transition metal. The screw conveyor moves the transition metal from the outside to the mesh net, and discharges the metal carbide formed in the mesh net to the outside.

According to a preferred embodiment of the present invention, the carbon nanotube fiber outlet may include winding means for collecting and collecting the carbon nanotube fibers discharged from the lower end of the cylindrical high temperature reactor main body. That is, when the carbon material is continuously injected, the carbon nanotubes synthesized in the reaction region 12 collect the aggregate at the lower end of the reactor body and the heating furnace while forming a continuous aggregate into a cylindrical shape, And wound up by a take-up means (17) to form fibers.

The winding means 17 may include at least one selected from a spindle, a reel, a drum, and a conveyor. However, the present invention is not limited to this, and any means capable of stably winding the discharged carbon nanotube fibers can be used. The winding temperature and speed influence the orientation of the carbon nanotubes in the fiber in the fiber axis direction, thus determining the thermal, electrical and physical properties of the carbon or nanotube fibers. Preferably, it can be wound at a temperature of 15 to 120 DEG C in the range of 5 to 100 rpm.

In addition, the carbon nanotube fiber discharge port 14 may be provided with an inert gas injection port to form an inert gas curtain surrounding the continuous carbon nanotube fiber aggregate.

According to a preferred embodiment of the present invention, the carbon nanotube fiber manufacturing apparatus may further include a hydrogen recirculation device for recirculating hydrogen discharged from the gas exhaust port to the cylindrical high temperature reactor main body. The hydrogen recirculation device 30 is introduced into the cylindrical high-temperature reactor main body, and unreacted hydrogen remaining after the reaction is separated from unreacted hydrocarbon in the unreacted gas processing device and collected. The hydrogen recycling apparatus may be re-injected in accordance with the ratio of the carbon material injected into the inlet.

On the other hand, the carbon material may include not only a liquid phase but also a gaseous carbon compound. The liquid or gaseous carbon compound diffuses as a carbon source as a catalyst and is synthesized into carbon nanotubes. The molecular weight distribution, concentration, viscosity, surface tension, dielectric constant and properties of the solvent used are taken into consideration.

According to a preferred embodiment of the present invention, the liquid or gaseous carbon compound is selected from the group consisting of methane, ethylene, acetylene, methyl acetylene, vinyl acetylene, ethanol, methanol, propanol, acetone, xylene, chloroform, ethyl acetic acid, And one or more selected from the group consisting of polyethylene glycol, ethyl formate, mesitylene, tetrahydrofuran (THF), dimethylformamide (DMF), dichloromethane, hexane, benzene, carbon tetrachloride and pentane. Specifically, the liquid carbon compound may be at least one selected from the group consisting of ethanol, methanol, propanol, acetone, xylene, chloroform, ethyl acetate, diethyl ether, polyethylene glycol, ethyl formate, mesitylene, tetrahydrofuran And may include one or more selected from the group consisting of formamide (DMF), dichloromethane, hexane, benzene, carbon tetrachloride, and pentane. (C ₂ H ₅ OH), xylene (C ₈ H ₁₀ ), diethyl ether [(C ₂ H ₅ ) ₂ _O ], polyethylene glycol [(CH ₂ -CH ₂ -O) ₉ ] 1-propanol _{(CH 3 CH 2 CH 2 OH} ), acetone (CH ₃ OCH _3), ethyl formate (CH ₃ CH ₂ COOH), benzene (C ₆ H _6), hexane (C ₆ H ₁₄₎ and mesitylene [C ₆ H ₃ (CH ₃ ) ₃ ]. The gas-phase carbon compound may include at least one selected from the group consisting of methane, ethylene, acetylene, methyl acetylene, and vinyl acetylene.

According to a preferred embodiment of the present invention, the carbon material may be a catalyst precursor dispersed in a liquid or gaseous carbon compound. The carbon material may be mixed with 0.5 to 5 wt%, preferably 1 to 5 wt%, or 1.5 to 4 wt% of the catalyst precursor to the liquid or gaseous carbon compound. If an excess catalyst precursor is used in comparison with the liquid or gaseous carbon compound of the carbon material, the catalyst acts as an impurity, and it is difficult to obtain high purity carbon nanotube fibers. It may also be a factor that hinders the thermal, electrical and / or physical properties of the carbon nanotube fibers. In the present invention, the catalyst precursor may include at least one selected from the group consisting of metallocene including ferrocene, iron, nickel, cobalt, platinum, ruthenium, molybdenum, vanadium and oxides thereof, no. The catalyst precursor may also be in the form of nanoparticles. And preferably in a metallocene form such as ferrocene, which is a compound containing iron, nickel, cobalt and the like; Iron such as iron chloride (FeCl ₂ ); cobalt; And a nickel atom may be used as the catalyst precursor.

According to a preferred embodiment of the present invention, the carbon material may further comprise a catalytic activator. Generally, carbon nanotubes are synthesized by diffusion of carbon into the catalyst in the molten state of the catalyst, followed by precipitation of the carbon nanotubes. The catalyst activator is used as a promoter in the synthesis of carbon nanotubes to increase the carbon diffusion rate, Thereby synthesizing carbon nanotubes. As the catalytic activator, thiophene (C ₄ H ₄ S) may be used. Thiophene reduces the melting point of the catalyst and removes the amorphous carbon, allowing synthesis of high purity carbon nanotubes at low temperatures. The content of the catalytic activator may also affect the structure of the carbon nanotubes. For example, when 1 to 5% by weight of thiophene is mixed with ethanol as the carbon compound, multiwall carbon nanotube fibers are obtained And when the thiophene is mixed with ethanol in an amount of 0.5% by weight or less, single-walled carbon nanotube fibers can be obtained. According to a preferred embodiment of the present invention, the catalyst precursor and the catalytic activator may be liquid in the liquid carbon compound, and may be vapor in the vapor carbon compound. Therefore, the liquid carbon compound can be injected by dissolving the catalyst precursor or the catalytic activator, and vaporized into the gas-phase carbon compound to be injected into the gas form.

Another aspect of the present invention provides a method for producing carbon nanotube fibers using the carbon nanotube fiber manufacturing apparatus of the present invention. Specifically, (a) preparing a carbon material in which a catalyst precursor is dispersed in a gaseous or liquid carbon compound; (b) preparing hydrogen; (c) the carbon material is injected in the lower direction from the upper end of the reactor having the high-temperature region together with the hydrogen to radiate the carbon material while moving to the high-temperature region by the hydrogen, thereby forming a continuous aggregate of carbon nanotubes ; And (d) winding the continuous aggregate of carbon nanotubes at the lower end of the reactor to form fibers. The unreacted gas remaining in the reaction zone may be treated to recycle hydrogen.

The present invention also provides a carbon nanotube fiber produced using the carbon nanotube fiber manufacturing apparatus of the present invention.

10: inlet 11: reactor body 12: reaction zone 13: heating means
14: exhaust port 15: exhaust port 16: unreacted gas processing device 17: winding means
21: chamber 22: heating means 23: mesh net 24: transition metal 25a, 25b: screw conveyor 26: gas exhaust port 30: hydrogen recirculation device

Claims

A cylindrical high-temperature reactor body having a reaction zone;
An inlet for injecting carbon material and hydrogen into the reaction zone of the body;
Heating means for heating the reaction region;
A discharge port installed at a lower end of the main body to discharge the carbon nanotube fibers;
An exhaust port for exhausting the unreacted gas remaining in the reaction zone between the heating means and the exhaust port or the exhaust port downstream of the heating means; And
And an unreacted gas processing unit connected to the exhaust port and installed outside the reactor body,
The unreacted gas processing apparatus
chamber;
Heating means for heating the chamber;
A mesh net comprising a transition metal;
A screw conveyor provided at both ends of the mesh net; And
And a gas outlet.

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The method according to claim 1,
Wherein the transition metal comprises at least one selected from the group consisting of iron (Fe), nickel (Ni), and cobalt (Co).

The method according to claim 1,
Wherein the unreacted gas comprises unreacted hydrocarbon and hydrogen,
Wherein the unreacted hydrocarbon reacts with the transition metal in a mesh network and is discharged through a screw conveyor, and the hydrogen is discharged through a gas exhaust port.

The method of claim 4,
Further comprising a hydrogen recirculation device for recirculating the hydrogen discharged from the gas exhaust port to the cylindrical high temperature reactor main body.

The method according to claim 1,
Wherein the inlet comprises a carbon material supply unit for supplying a carbon material and a hydrogen supply unit for supplying hydrogen.

The method according to claim 1,
Wherein the outlet has winding means for winding up and collecting the carbon nanotube fibers discharged from the lower end of the cylindrical high temperature reactor main body.

The method of claim 7,
Wherein the winding means comprises at least one selected from a spindle, a reel, a drum, and a conveyor.

The method according to claim 1,
Wherein hydrogen introduced from the inlet is introduced into the reaction zone at a linear velocity capable of forming laminar flow.

The method according to claim 1,
Wherein the inlet comprises an injection nozzle for injecting a carbon material and a dispersing plate for injecting hydrogen.

The method according to claim 1,
Wherein the heating means is a heating furnace surrounding the reactor main body, and the reaction region is heated to 1,000 to 3,000 占 폚.

The method according to claim 1,
Wherein the carbon material is a catalyst precursor dispersed in a gaseous or liquid carbon compound.

The method of claim 12,
Wherein the carbon material further comprises a catalytic activator.

Claim 12
Wherein the catalyst precursor comprises at least one selected from the group consisting of metallocene including ferrocene, iron, nickel, cobalt, platinum, ruthenium, molybdenum, vanadium and oxides thereof.

The method of claim 12,
The gaseous or liquid carbon compound may be at least one selected from the group consisting of methane, ethylene, acetylene, methyl acetylene, vinylacetylene, ethanol, methanol, propanol, acetone, xylene, chloroform, ethyl acetic acid, diethyl ether, polyethylene glycol, ethyl formate, Wherein the carbon nanotube fiber comprises at least one selected from the group consisting of THF, dimethylformamide (DMF), dichloromethane, hexane, benzene, carbon tetrachloride, and pentane.

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