KR101951368B1

KR101951368B1 - Apparatus for preparing carbon nanotube fiber and process for preparing carbon nanotube fiber using same

Info

Publication number: KR101951368B1
Application number: KR1020150105177A
Authority: KR
Inventors: 오유진; 송동수; 이영호; 김지은; 김주한; 최용진
Original assignee: 주식회사 엘지화학
Priority date: 2015-07-24
Filing date: 2015-07-24
Publication date: 2019-02-22
Also published as: KR20170011836A

Abstract

The present invention relates to an apparatus for manufacturing carbon nanotube fibers and carbon nanotube fibers 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,

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

Carbon nanotubes (CNTs), 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, reported in the journal Nature in 1991 by Dr. Iijima, Due to its physical properties and high aspect ratio, research has been conducted 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 radiation is obtained by depositing a catalyst on a substrate, synthesizing a CNT fork in a direction perpendicular to the substrate, and pulling the CNT at the end of the substrate with a tweezers or a tape, It is a method to radiate CNT fiber while leaving. This method has the disadvantage that it can not increase the production amount because the continuous process is impossible.

On the other hand, the direct spinning method involves dissolving and dispersing a catalyst precursor in a solvent such as ethanol or xylene, injecting a solution containing a catalyst precursor and a carrier gas at the upper side of the vertical type high temperature furnace , The CNTs formed in the high-temperature region of the furnace are bundled together like aerogels, and the fibers are formed and come down to the lower portion of the reactor. In order to stably produce continuous fibers using this method, the injection method of the solution in which the catalyst precursor is dispersed is very important.

However, in the conventional solution injection method, since the carrier gas supply part and the solution supply part including the catalyst precursor are attached together, the catalyst precursor is converted into a catalyst suitable for CNT fiber formation, There is a problem that it is difficult. That is, the residence time of the spinning solution containing the catalyst precursor and the transfer gas is short, and the spinning solution is not evaporated, so that the spinning solution which is not vaporized flows into the reactor as it is.

Ya-Li Li, et al. Science 304, 276 (2004) Krzysztof Koziol, et al. Science 318, 1892 (2007)

In the conventional method for producing carbon nanotube (CNT) fiber, a catalyst precursor is converted into a catalyst suitable for CNT fiber formation, and a proper residence time can not be obtained. In order to produce the synthesized CNT fiber stably, it is necessary to keep the catalyst precursor in the section with a proper residence time for changing to the catalyst.

An object of the present invention is to provide a carbon nanotube fiber manufacturing apparatus in which reaction efficiency is increased. That is, the retention time of the transfer gas and the spinning solution becomes sufficient before the present invention is injected into the reactor. As a result, the spinning liquid is vaporized and the catalyst precursor is vaporized and introduced into the reactor. Therefore, the carbon nanotube fiber can be stably changed in the reactor as a catalyst.

In order to achieve the above object, the present invention provides a vertical reactor body having a reaction zone; A first transfer gas inlet connected to an upper end of the vertical reactor body; A spinning liquid inflow part connected to a part of the first transfer gas inflow part; And a second transfer gas inflow part connected to one end of the spinning liquid inflow part, wherein at least one selected from the first transfer gas inflow part, the spinning liquid inflow part and the second transfer gas inflow part is heated And the infusion liquid is vaporized to be introduced into the first transfer gas inflow section.

According to a preferred embodiment of the present invention, the length of the spinning liquid inflow part may be calculated by the following equation (1).

[Equation 1]

The evaporation rate of the spinning liquid of Equation (1) can be calculated by the following equation (2).

&Quot; (2) "

In Equation (2) above,

h _c is the heat transfer coefficient of the spinning solution, λ is the latent heat of the spinning solution, ΔT is the temperature difference between the inside and outside of the spinning solution inlet, and A is the surface area of spinning solution droplet.

In addition, the spinning solution may be one in which a catalyst precursor is dispersed in a liquid carbon compound, and the spinning solution may further comprise a catalytic activator. According to a preferred embodiment of the present invention, the transport gas may be a hydrocarbon gas, an inert gas, a reducing gas, or a mixed gas thereof.

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 carbon nanotube fiber manufacturing apparatus in which the reaction efficiency is increased. Accordingly, the carbon nanotube fiber manufacturing apparatus of the present invention can increase the yield of carbon nanotube fibers by increasing the reaction efficiency of the carbon nanotube fibers. That is, the retention time of the transfer gas and the spinning solution becomes sufficient before the present invention is injected into the reactor. As a result, the catalyst precursor becomes a vaporized catalyst precursor immediately before the catalyst is grown in the reactor, and is introduced into the reactor. Therefore, it is possible to produce carbon nanotube fibers with stable reaction efficiency.

Further, by using the apparatus for producing carbon nanotube fibers according to the present invention, carbon nanotube fibers having excellent reaction efficiency and excellent strength and elasticity can be obtained. Therefore, it is desirable to use a reinforcing material of a multifunctional composite material, a strain / damage sensor using a stable and repeated piezoresistive effect, a transmission line using high conductivity, a high specific surface area, an electrochemical device using excellent mechanical characteristics and electrical conductivity, It is expected to be applicable to various fields such as microelectrode materials, supercapacitors, and actuators.

FIG. 1 shows a conventional apparatus for producing carbon nanotube fibers.
2 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, film twisting / rolling methods, and the like. The present invention follows a process of directly spinning carbon nanotube fibers or ribbons from the carbon nanotube aerogels formed immediately after the injection of the spinning liquid in the reactor using chemical vapor deposition (CVD).

In the direct spinning, carbon nanotubes are synthesized in a heating furnace by injecting carbon nanotubes at a constant rate in a vertical furnace together with a carrier gas by adding a catalyst to the carbon source, and pure carbon nanotubes Carbon nanotube fibers are continuously produced.

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 prior art carbon nanotube (CNT) fiber manufacturing apparatus includes a spinning liquid supply unit including a catalyst precursor and a transfer gas supply unit attached together, and a spinning solution and a transfer gas are directly mixed and injected.

FIG. 1 illustrates a conventional apparatus for producing carbon nanotube fibers. The carbon nanotube fiber manufacturing apparatus includes a reactor main body having a reaction zone, and a transfer gas inlet. The spinning solution is injected into the transfer gas inlet through a syringe containing needles to produce carbon nanotube fibers. Such a conventional apparatus for producing carbon nanotube fibers has a problem in that it is difficult to obtain stable retention time because the catalyst precursor contained in the spinning solution can not obtain the residence time necessary for conversion into a catalyst suitable for CNT fiber formation.

As an example of a catalyst suitable for the above, ferrocene is mainly used as a catalyst precursor. In the reactor, the ferrocene is thermally decomposed to form iron atoms, and the formed iron atoms are aggregated and converted into catalysts in the form of iron nanoparticles. This reaction is shown in Reaction Scheme 1 below.

[Reaction Scheme 1]

_{Fe (C 5 H 5) 2} → Fe + xC + yH 2

However, since it is necessary to have a temperature of 500 ° C or more, preferably 1000 ° C or more in order to be a catalyst that is an iron nanoparticle, it flows into the first transfer gas inflow part, enters into the reactor, and grows into iron nanoparticles. At this time, a suitable catalyst in which the catalyst precursor has been converted means a state where it is a vaporized catalyst precursor immediately before growing into iron nanoparticles.

Accordingly, the inventors of the present invention have found an apparatus for producing carbon nanotube fibers that vaporizes a spinning solution and mixes the spinning solution with a first transfer gas.

That is, a vertical reactor body having a reaction zone; A first transfer gas inlet connected to an upper end of the vertical reactor body; A spinning liquid inflow part connected to a part of the first transfer gas inflow part; And a second transfer gas inflow part connected to one end of the spinning liquid inflow part, wherein at least one selected from the first transfer gas inflow part, the spinning liquid inflow part and the second transfer gas inflow part is heated And the infusion liquid is vaporized and introduced into the first transfer gas inflow portion. The spinning solution may have a catalyst precursor dispersed in the liquid carbon compound.

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

2 is a cross-sectional view illustrating an apparatus for manufacturing carbon nanotube fibers according to an embodiment of the present invention. More specifically, the reactor includes a vertical reactor body 10 having a reaction zone; A first transfer gas inlet (11) connected to an upper end of the vertical reactor body; A spinning liquid inflow part (12) connected to a part of the first transfer gas inflow part; And a second transfer gas inlet (13) connected to one end of the spinning liquid inlet, wherein the spinning liquid inlet and the second transfer gas inlet are provided with an inlet heating means (14).

The catalyst precursor contained in the spinning liquid is injected through the spinning liquid inlet and vaporized while moving with the second transfer gas. And then mixed with the first transfer gas, converted into a catalyst in the reactor, and formed into a carbon nanotube while flowing. The formed carbon nanotubes grow or fuse to form carbon nanotube fibers (CNTs). The CNT fiber thus formed is radiated to the winding means through the discharge port.

According to a preferred embodiment of the present invention, the inflow heating means is preferably provided in the spinning liquid inflow section and the first transfer gas inflow section.

The inlet portion heating means may be a heating furnace enclosing the inlet portion, and the reaction region may be heated to 100 to 500 ° C. The hot zone of the inlet can preferably maintain a temperature of 100 to 300 ° C or 100 to 400 ° C, more preferably 200 to 300 ° C. The temperature in the hot zone of the inlet influences the rate at which the spinning solution is vaporized and diffused into the second transport gas to control the rate at which the liquid catalyst precursor is converted to the gaseous catalyst precursor.

The spinning liquid inflow portion will be described.

According to a preferred embodiment of the present invention, the length of the spinning liquid inflow part can be calculated by the following equation (1).

[Equation 1]

In the case of the prior art, by injecting the spinning solution directly through the needle into the carrier gas inlet, the spinning solution was injected into the reactor before it was vaporized. However, in the present invention, before the spinning solution containing the catalyst precursor is mixed with the first carrier gas by the length of the spinning liquid inlet calculated by Equation 1, And travels a certain distance. Therefore, the residence time can be controlled so that the catalyst precursor dispersed in the spinning solution is supplied to the vapor phase catalyst precursor suitable for CNT fiber formation.

According to a preferred embodiment of the present invention, the rate of evaporation of the spinning solution can be calculated by the following equation (2).

&Quot; (2) "

In Equation (2) above,

In the present invention, the spinning solution fed into the spinning solution inlet may be fed at a rate of 5 to 50 ml / hr, preferably 5 to 40 ml / hr or 5 to 30 ml / hr or 5 to 20 ml / hr Lt; / RTI > The infusion rate of the spinning solution may be varied depending on the kind of the spinning solution and / or the size of the reactor.

The diameter of the spinning liquid inflow portion may be 1/4 to 1/2 inch and the length of the spinning liquid inflow portion may be 2.8 to 8.3 cm. However, it is not limited thereto. For example, if the spinning fluid feed rate is 5 to 15 ml / hr and the flow rate of the second transport gas is 300 sccm, the length of the spinning liquid inlet may be 2.8 to 8.3 cm.

The spinning liquid inflow part may be connected to a part of the first transfer gas inflow part at a slope of 30 to 90 °. But it is not limited thereto.

Next, the first transfer gas inflow section will be described.

In the present invention, the first transfer gas inflow part is connected to the upper part of the vertical reactor body, and the spinning solution injecting part is connected to a part thereof. The diameter of the first transfer gas inlet may be 1/4 to 1/2 inch and the length may be 1 to 20 cm. However, it is not limited thereto.

In the present invention, the first transport gas controls the amount of the carbon nanotube to be injected into the reactor by diluting the spinning solution during the synthesis of carbon nanotubes, and the purity of the carbon nanotube fibers produced by reacting with the generated amorphous carbon or excess impurities, . That is, the first transport gas serves to dilute the spinning solution and improve the purity of the carbon nanotube fibers.

Next, the second transfer gas inflow section will be described.

Conventionally, a transfer gas is introduced through one transfer gas inlet. However, in the present invention, in addition to the first transfer gas, the second transfer gas is introduced through the second transfer gas inlet separately connected to a part of the spinning liquid inlet. This is because the spinning liquid flowing through the spinning liquid inflow portion is combined with the second transfer gas and is transferred to the low-stage reactor through the first transfer gas inflow portion. Therefore, the residence time of the second transfer gas injected into the second transfer gas inlet is the residence time of the spinning solution. That is, the second conveying gas serves to convey the vaporized liquid.

According to a preferred embodiment of the present invention, the second transfer gas inflow part may be connected to one end of the spinning solution inflow part at a slope of 30 to 90 °. But it is not limited thereto. In the present invention, the residence time of the spinning liquid and the transfer gas varies depending on the diameter of the second transfer gas inflow portion, the length of the second transfer gas inflow portion, and the flow rate of the second transfer gas. This is expressed by the following equation (3).

&Quot; (3) "

The diameter of the second transfer gas inlet may be 1/4 to 1/2 inch, and the length may be 1 to 10 cm. However, it is not limited thereto.

The first transfer gas and the second transfer gas may be a hydrocarbon-based gas, an inert gas, a reducing gas, or a mixed gas thereof. The inert gas may be, for example, argon (Ar) gas and / or nitrogen (N ₂ ) gas, and the reducing gas may be, for example, hydrogen (H ₂ ) gas and / or ammonia (NH ₃ ) But is not limited thereto.

The first transfer gas and the second transfer gas may be the same or different.

Next, the vertical reactor main body will be described.

The vertical reactor body of the present invention may be of any type as long as it can be used normally. According to a preferred embodiment of the present invention, a heating means for heating the vertical reactor body may be provided.

In the present invention, the reactor heating means may be a heating furnace surrounding the reactor body, and the reaction region may be heated to 1,000 to 3,000 ° C. The high temperature region of the reactor 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 in the high temperature region of the reactor influences the rate at which carbon is diffused into the catalyst to control the growth rate of the carbon nanotube. When synthesizing carbon nanotubes by chemical vapor deposition, generally, the higher the synthesis temperature, the higher the crystallinity and strength as the growth rate of carbon nanotubes increases.

When the spinning solution is continuously injected, the carbon nanotubes synthesized inside the reaction zone are collected in the reactor body in the reactor body while forming a continuous aggregate into a cylindrical shape, and are taken out to the outside of the high temperature region and wound into a winding means.

According to a preferred embodiment of the present invention, the vertical reactor body includes a discharge port for discharging the carbon nanotube fibers at the lower end thereof, and the discharge port is formed by winding the carbon nanotube fibers discharged from the lower end of the vertical reactor body And a winding means for collecting the wire.

The winding means may include at least one selected from a spindle, a reel, a bobbin, a drum, and a conveyor, but is not limited thereto, 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, it is preferable that an inert gas injection port is provided in the discharge portion of the carbon nanotube fibers to form an inert gas curtain surrounding the circumference of the continuous carbon nanotube fiber aggregate. The discharge unit may include an outlet for discharging the generated carbon nanotube fibers and an exhaust line for discharging the transferred gas.

On the other hand, the liquid carbon compound contained in the spinning solution is synthesized into carbon nanotubes by diffusing as a carbon source as a catalyst, and is used in consideration of the molecular weight distribution, concentration, viscosity, surface tension, dielectric constant and properties of the solvent used.

According to a preferred embodiment of the present invention, the liquid carbon compound is selected from the group consisting of ethanol, methanol, propanol, acetone, xylene, chloroform, ethyl acetic acid, diethyl ether, polyethylene glycol, ethyl formate, mesitylene, tetrahydrofuran THF), dimethylformamide (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 ].

According to a preferred embodiment of the present invention, the spinning solution may be prepared by dispersing a catalyst precursor in a liquid carbon compound. The spinning solution may be mixed with 0.5 to 5% by weight, preferably 1 to 5% by weight, or 1.5 to 4% by weight of the catalyst precursor with respect to the liquid carbon compound. If an excess catalyst precursor is used in comparison with the liquid carbon compound of the spinning solution, it is difficult for the catalyst to act as an impurity 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.

According to a preferred embodiment of the present invention, the catalyst precursor may include at least one selected from the group consisting of metallocenes including ferrocene, iron, nickel, cobalt, platinum, ruthenium, molybdenum, vanadium and oxides thereof , But is not limited thereto. 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 spinning solution 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. Therefore, the liquid carbon compound can be injected by melting the solid catalyst precursor or solid catalyst activator.

According to a preferred embodiment of the present invention, the carrier gas may be a hydrocarbon gas, an inert gas, a reducing gas or a mixture thereof. The inert gas may be argon, nitrogen, or a mixed gas thereof, and the reducing gas may be hydrogen, ammonia, or a mixed gas thereof.

The present invention provides a carbon nanotube fiber produced using the above production apparatus.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the embodiments of the present invention described below are illustrative only and the scope of the present invention is not limited to these embodiments. The scope of the present invention is indicated in the claims, and moreover, includes all changes within the meaning and range of equivalency of the claims. In the following Examples and Comparative Examples, "%" and "part" representing the content are based on weight unless otherwise specified.

Example

Thiophene 0.8% by weight Acetic acid 97.6% by weight and ferrocene 1.6% by weight were mixed. The first transfer gas and the second transfer gas used hydrogen. The reaction temperature of the first transfer gas inlet portion and the spinning liquid inlet portion was maintained at 300 ° C and the reactor main body temperature was maintained at 1173 ° C. The flow rate of the spinning solution was 12 ml / hr (0.0034 cm ³ / s), the flow rate of the first conveying gas was 2.0 L / min and the flow rate of the second conveying gas was 380 cm ³ / min (linear velocity 5 cm / s) .

(3/8 inch in diameter and 20 cm in length) connected to the upper end of the vertical reactor body, a spinning liquid inlet (diameter: 3/8 inch and length: 20 cm) connected to a part of the first transfer gas inlet, (1/4 inch in diameter and 6.8 cm in length) and a second transfer gas inlet (1/4 inch in diameter and 10 cm in length) connected to one end of the spinning liquid inlet, the first transfer gas inlet and the spinning liquid inlet The carbon nanotube fiber manufacturing apparatus shown in FIG. 2 having heating means for heating the reactor main body and a discharge port provided at the lower end of the main body for discharging the carbon nanotube fibers was used.

Specifically, the length of the spinning liquid inflow portion is 6.8 cm, the inner diameter of the first transfer gas inflow portion is 3/8 inch, the inner diameter of the second transfer gas inflow portion is 1/4 inch, the outer diameter of the first transfer gas inflow portion, Was maintained at 300 DEG C using a heating tape.

Comparative Example

The same procedure as in Example 1 was carried out except that the carbon nanotube fiber manufacturing apparatus of FIG. 1 was used without the second transfer gas, the second transfer gas inlet and the spinning liquid inlet.

Experimental Example One

The lengths of the CNT fibers prepared in the above Examples and Comparative Examples were measured by multiplying the circumference of the bobbin by the winding speed (rpm).

The length of the CNT fibers prepared in the examples was 200 m or more, but the lengths of the CNT fibers produced in the comparative examples were less than 50 m or not produced. In view of the lengths of the CNT fibers produced in Examples and Comparative Examples, in the production apparatus of the present invention, the catalyst precursor present in the spinning solution is sufficiently vaporized and converted into a catalyst before being mixed with the first transfer gas and introduced into the reactor, Can be achieved efficiently.

Experimental Example 2

The reason why the lengths of the carbon nanotube fibers produced in the above Examples and Comparative Examples were different was confirmed by using the above-mentioned Equations 1 and 2.

The composition of the spinning solution is calculated considering only acetone since most of it is acetone. Usually a drop of liquid is 1 / 20cc If so, a drop of acetone to 1 / 20cc, the droplet diameter of the spinning liquid (D) 0.0045m, a surface area A = πD ² = 0.0000636m ^2. The temperature of the droplet is at room temperature (25 占 폚) and the temperature of the spinning liquid inlet is 300 占 폚, so the temperature difference? T = (300-25) = 275 占 폚. The Prandtl number (Pr) is calculated using the heat capacity (C _p ), the viscosity ( μ ) and the thermal conductivity (k) of acetone.

[Equation 1]

Then, the heat transfer coefficient h _c is calculated using the flow rate v, viscosity, μ and density _d of the hydrogen at the second transfer gas inlet, .

[Equation 2]

The evaporation rate of the spinning solution is calculated using the above-mentioned equation (2).

[Equation 3]

As a result, it can be seen that the injection rate of the spinning liquid is 0.0034 cm ³ / s, the time required for complete evaporation is about 1.36 seconds, and the spinning solution has a reaction inlet length of 6.8 cm or more to have a residence time of 1.36 seconds .

Therefore, in the embodiment using the apparatus for producing carbon nanotube fibers, in which the spinning solution has an inlet length of 7.5 cm, since the catalyst precursor dispersed in the spinning solution is sufficiently vaporized and changed into a catalyst before being mixed with the first transfer gas, It can be seen that the carbon nanotube fibers are formed long.

However, in the comparative example, a carbon nanotube fiber manufacturing apparatus without a second feed gas inlet and a spinning liquid inlet was used. It can be seen that the spinning solution was mixed with the transfer gas without residence time and was introduced into the reactor.

The following equation 4 shows the rate at which the spinning solution flows into the reactor and evaporates.

[Equation 4]

It can be seen that the inner volume of the spinning solution has a volume of about 0.05 cm ³ , and therefore the inner temperature of the reactor is not evaporated at a high temperature of 1173 ° C. for about 4 seconds. Since the dropping time of the droplet varies depending on the length of the reactor, it is usually about 1 second, so that the spinning solution passing through the high temperature region is observed in the droplet, so that it can be seen that the catalyst precursor is not sufficiently converted into the catalyst. That is, it can be seen that the catalyst precursor was not vaporized and was still solid. Therefore, it can be seen that carbon nanotube fibers shorter than those in the Examples were produced in Comparative Examples.

10: reactor body 11: first transfer gas inlet 12: spinning liquid inlet
13: second conveying gas inflow part 14: inflow part heating means

Claims

A vertical reactor body having a reaction zone;
A first transfer gas inlet connected to an upper end of the vertical reactor body;
A spinning liquid inflow part connected to a part of the first transfer gas inflow part; And
A second transfer gas inlet connected to one end of the spinning liquid inlet; Lt; / RTI >
And an inflow portion heating means for heating at least one selected from the first transfer gas inflow portion, the spinning liquid inflow portion and the second transfer gas inflow portion,
In the spinning liquid, the catalyst precursor is dispersed in the liquid carbon compound,
The spinning liquid is vaporized and flows into the first transfer gas inflow portion,
Wherein the catalyst precursor contained in the spinning liquid is injected through the spinning liquid inlet, the second transport gas flowing through the second transporting gas inlet and the catalyst precursor vaporized while moving the catalyst precursor, The CNTs are mixed with the first transfer gas and converted into catalysts in the reactor to form carbon nanotubes. The CNTs are grown or fused to form carbon nanotube fibers (CNTs) Is discharged through a discharge part included in the lower end of the vertical reactor body,
The discharge portion, which is provided with an inlet for inert gas,
A discharge port through which the carbon nanotube fibers are discharged,
And an exhaust line for discharging the remaining first and second transfer gases.

The method according to claim 1,
Wherein the length of the spinning liquid inflow part is calculated by the following equation (1): < EMI ID = 1.0 >
[Equation 1]

The method of claim 2,
Wherein the spinning liquid evaporation rate is calculated by the following equation (2).
&Quot; (2) "

In Equation (2) above,
h _c is the heat transfer coefficient of the spinning solution, λ is the latent heat of the spinning solution, ΔT is the temperature difference between the inside and outside of the spinning solution inlet, and A is the surface area of spinning solution droplet.

The method according to claim 1,
Wherein the spinning liquid inflow portion is connected to a part of the first transfer gas inflow portion at a slope of 30 to 90 degrees.

The method according to claim 1,
Wherein the second transfer gas inlet is connected to one end of the spinning solution inlet at a slope of 30 to 90 degrees.

The method according to claim 1,
Wherein the inflow section heating means is a heating furnace enclosing the inflow portion and is heated to 100 to 500 占 폚.

delete

The method according to claim 1,
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 (THF), dimethylformamide Methane, hexane, benzene, carbon tetrachloride, and pentane.

The method according to claim 1,
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 according to claim 1,
Wherein the spinning solution further comprises a catalytic activator.

The method according to claim 1,
And a reactor heating means for heating the vertical reactor main body.

The method of claim 11,
Wherein the reactor heating means is a heating furnace enclosing the reactor main body, and the reaction region is heated to 1,000 to 3,000 占 폚.

The method according to claim 1,
And a discharge port for discharging the carbon nanotube fibers at a lower end of the vertical reactor main body, and the discharge port includes a winding means for winding up and collecting the carbon nanotube fibers discharged from the lower end of the vertical reactor main body Carbon nanotube fibers.

14. The method of claim 13,
Wherein the winding means comprises at least one selected from a spindle, a reel, a drum, and a conveyor.