Patent Description:
Nano-size materials have recently become a major research source due to their unique optical and electrical properties and their potential use in electronics or photoelectronic engineering. The field of nanostructured material or nanostructure includes both of multi-dimensional nanostructures such as nanotubes and self-assemblies and technology development applying thereof. The nanostructures can be classified into inorganic nanostructures, organic nanostructures, polymer inorganic nanostructures, porous high surface area nanostructures and bio-related nanostructures depending on materials. The inorganic nanostructures are structures getting attention in relation to mainly semiconductors, and quantum structures, single electronic devices, next-generation memory devices and self-recording media researches are included therein. The organic nanostructure field includes fullerene, carbon nanotubes, carbon nanofibers, diamond thin film, organic EL and the like. The polymer inorganic nanostructures have two major fields: nanostructured polymers and ceramic particles of nanoparticle. The porous high surface area nanostructures include activated carbon fibers, zeolites and photocatalytic particles. The bio-related nanostructures include drug delivery systems, biomimetic devices, high sensitive nanosensor materials and the like.

In particular, carbon nanotubes have been subject to numerous studies for years due to their unique physical and electrical properties. The carbon nanotubes exhibit subconductor, conductor or semiconductor properties according to the chirality of the tube itself, carbon atoms are connected by strong covalent bonds, which makes tensile strength about <NUM> times larger than steel, the carbon nanotubes has excellent flexibility and elasticity as well as chemical stability. The carbon nanotubes are industrially important in the manufacture of composite materials due to their size and specific physical properties, and have high utilization in electronic materials, energy materials and other fields. For example, the carbon nanotubes can be applied to electrodes of electrochemical storage devices such as secondary batteries, fuel batteries or super capacitors, electromagnetic wave shielding materials, field emission displays, or gas sensors.

Because the nanostructured materials are provided in the form of powder of tens of micrometer in the actual process, they can cause harmfulness to the human body and malfunction of electrical products due to dusting in the process. In particular, in the case of carbon-based organic nanostructures, it is difficult to be dispersed due to large difference from polymers desired to mix in the apparent density.

In order to solve these problems, the nanostructured material may be compressed, and as a method for compressing carbon nanotubes, usually a method of palletization is provided due to increase of the density and easy of handling and transportation.

The carbon nanotube product, for example, a pellet-type carbon nanotube product is convenient to be used in various processing devices. In order to granulating or pelletizing carbon nanotubes, two different conventional methods, i.e., a method of wet-type pelletizing carbon nanotubes followed by drying thereof and a method of dry-type pelletizing, are used.

In general, the dry-type palletization uses a pelletization drum which comprises a horizontally positioned rotation tube, and the inside of the tube is referred to as a palletization chamber. Granulation of the carbon nanotube powder is performed by pre-condensing powder for industrial use and tumbling down thereof from the wall of a tube rotating in the pelletization drum for granulation. The powder is agglomerated by Van-der-Waals force and electrostatic force making the dry-type pelletization possible, and for the dry-type pelletization, usually pressure of several tons is applied. Thus, there is a problem that pellets may be rebroken during the manufacturing process.

The wet-type pelletizing process is performed mainly by a liquid bridge between carbon nanotubes and the capillary force. In the past, when mixing the carbon nanotubes by the wet-type pelletization, excessive solvents such as water or ethanol are added due to bad distribution of moisture and a binder, and the added solvents are generally hot-air dried, or heat-dried by using a rotary drum dryer or an agitated pan, or a conveyer. However, in the case of the method using a rotary drum or an agitated pan, there is a worry that the product may be damaged by a rotor, and in the case of the method using a conveyer, the spatial efficiency is deteriorated. In the case of the general hot-air drying, the drying efficiency is largely deteriorated.

<CIT> describes an apparatus for manufacturing carbon compounds, comprising a first electrode proximate a second electrode and defining a gap therein between for producing carbon compounds; a first chamber extending around said gap and defining a first effective cross-section and a second effective cross-section, said second effective cross-section being downstream of said first effective cross-section and having a size less than said first effective cross-section; a second chamber in fluid communication with said first chamber; a gas inlet in fluid communication with said first chamber; and a gas entering through said gas inlet, flowing through said first chamber and across said gap, said gas carrying the carbon compounds into said second chamber.

<CIT> describes a method and apparatus for producing organic nanotubes, wherein an organic nanotube material dispersion solution consisting of an organic nanotube material and an organic solvent is pressurized and caused to pass through a very narrow orifice. A tank contains an organic nanotube material dispersion solution consisting of an organic nanotube material and an organic solvent. A pump pressurizes the organic nanotube material dispersion solution from the tank so that the organic nanotube material dispersion solution is carried under high pressure. A cylindrical casing is used for continuously flowing the organic nanotube material dispersion solution carried from the pump under pressure. An orifice is placed in the cylindrical casing. An organic nanotube precipitation pipe is coupled to an outlet of the cylindrical casing; and drying means following the organic nanotube precipitation pipe.

<CIT> describes a nanocarbon and carbonized material continuous production apparatus provided with a first-stage drying means to dry an organic matter treated material, a middle-stage carbonization and pyrolytic liquid recovery means to carbonize and pyrolyze the dried organic matter treated material and to recover the resultant pyrolytic liquid, and a latter-stage nanocarbon formation means to form nanocarbon from the recovered pyrolytic liquid, wherein nanocarbon and activated carbon are continuously produced from the organic matter treated material.

<CIT> describes an apparatus for segregating particulate material, comprising a fluidizing bed having a receiving inlet for receiving the particulate material feed, an inlet opening for receiving a fluidizing stream, a discharge outlet for discharging a fluidized particulate material product stream, and a discharge outlet for discharging a non-fluidized particulate material stream; a source of fluidizing stream at a temperature of about <NUM>° F or less operatively connected to the inlet opening for introducing the fluidizing stream into the fluidizing bed to achieve separation of the fluidized particulate material product stream from the non-fluidized particulate material stream; and a conveyor means for transporting the non-fluidized particulate material from inside the fluidized bed to the outside of the fluidized bed through the discharge outlet. The fluidized particulate material product stream contains a reduction in the contaminant relative to the particulate material feed stream, and the non-fluidized particulate material stream contains an increase in the contaminant relative to the particulate material feed stream.

Accordingly, in order to solve the existing problems, the present invention is objected to provide a device which reduces damage or breakage of a product when drying or collecting a carbon nanotube pellet or aggregate and also has excellent drying efficiency.

In order to solve the above technical problem, the present invention provides a device for drying and collecting a carbon nanotube product comprising:.

According to one embodiment, the gas inlet part may be installed between the drying part and the product collecting part, and
the valve may comprise:.

The opening part of the first valve may allow gas from the gas inlet part to flow into the drying part while preventing the product from flowing out to the collecting part during the product drying process in the drying part.

The carbon nanotube product may be a carbon nanotube pellet or a carbon nanotube aggregate.

Further, the drying part may be vertical column type.

The first valve or the second valve may be each independently a butterfly valve or a damper valve.

The first valve may have a plurality of opening parts on the surface of a wing part of the butterfly valve or the damper valve.

Further, a mesh sheet through which the carbon nanotube product can't be communicated but only a fluid can be communicated may be put over a part or a whole of the opening part.

Further, a bubble cap may be covered over a part or a whole of the opening part.

Further, the device may further comprise a preheater for preheating the gas to be flowed into the gas inlet part.

Further, the device may further comprise a flow rate controller for controlling the follow rate of the gas to be flowed into the gas inlet part.

Further, a gas outlet may be installed on top of the drying part to control pressure in the drying part.

Further, a third valve may be installed at the bottom of the product collecting part to discharge a product.

Further, a second gas inlet part may be installed at the product collecting part to introduce gas which helps discharge of a product.

Further, the present invention provides a method for manufacturing a carbon nanotube product by using the aforementioned device.

Specifically, the method may comprise the steps of:.

Further, the gas inlet part may be installed between the drying part and the product collecting part, and.

According to one embodiment, the method for manufacturing a carbon nanotube product may further comprise the steps of:.

According to one embodiment, the exhaust gas discharged from the gas outlet may be incinerated. Further, the reactive exhaust gas generated at a pyrolysis process for manufacturing a carbon nanotube product may also be incinerated when incinerating the exhaust gas.

Other details of embodiments of the present invention are described in the following detailed specification.

The device for drying and collecting a carbon nanotube pellet or aggregate according to the present invention can accelerate solvent evaporation by inserting and dispersing high temperature gas into a drying column as well as by a heat source inside and outside of the column, and can quickly remove the evaporated solvent. Further, the device can proceed drying and collecting processes while minimizing product breakage by regulating the gas flow rate and controlling flow of the product in the column. As a result, a product can be obtained in the final percentage of water content of <NUM>% or less and the damage rate of less than <NUM>%.

It is to be understood that when one element is referred to as being "connected to" or "coupled to" another element, it may be connected directly to or coupled directly to another element with the other element intervening therebetween.

Singular forms include plural forms unless the context clearly indicates otherwise.

It will be further understood that terms "include", "have", or the like, used in the present specification are to specify the presence of features, numerals, steps, operations, components, parts mentioned in the present specification, or a combination thereof, but do not preclude the presence or addition of one or more other features, numerals, steps, operations, components, parts, or a combination thereof.

The term "carbon nanotube" used in the present specification may refer to a singular or plural carbon nanotube, and the term may include a fiber form formed by a plurality of carbon nanotubes.

Hereinafter, with reference to drawings, embodiments of the present invention are described in detail in a manner that one of ordinary skill in the art may perform the embodiments without undue difficulty. The present invention may be embodied in various forms, and the scope of the present invention is not limited to examples provided herein.

The device according to the present invention comprises:.

In the present invention, the carbon nanotube product may refer to a carbon nanotube pellet or a carbon nanotube aggregate.

<FIG> schematically illustrates a device for drying and collecting a carbon nanotube product, wherein a gas inlet part is installed between the drying part and the product collecting part, according to one embodiment of the present invention. Namely, <FIG> illustrates a structure designed to make gas flow from bottom to top of the drying part. However, the present invention is not limited thereto and also contains a structure wherein the gas flows from top to bottom of the drying part. When the gas flow from top to bottom of the drying part, the heat transferred from the furnace wrapping the heating part can be directly transferred to the gas, and therefore drying can be conducted with the gas of higher temperature.

<FIG> illustrates a device for drying and collecting a carbon nanotube product <NUM> comprises:.

The drying part <NUM> may be vertical column type, and equipped with a heating means <NUM> for heating the drying part. As illustrated in <FIG>, the heating means <NUM> may be a furnace wrapping the drying part <NUM>, but not limited thereto.

The device illustrated in <FIG> preferably further comprises a preheater <NUM> for preheating the gas to be flowed into the gas inlet part <NUM>, and a flow rate controller <NUM> for controlling the follow rate of the gas to be flowed into the gas inlet part <NUM>. The gas introduced in to the gas inlet part <NUM> is used to prevent agglomeration of a product in the drying part <NUM> and to promote drying the product in the drying part <NUM> by adding additional heat. Accordingly, the gas may preferably be inert gas which does not react with the product. Nitrogen gas is most preferred, but not limited thereto.

Further, a gas outlet <NUM> may be installed on top of the drying part <NUM> to control pressure in the drying part <NUM> by controlling the amount of the discharged gas <NUM>.

On the other hand, whether the product in the drying part <NUM> reaches a predetermined dried state or not can be checked by a method of measuring the temperature change in the drying part <NUM> (i.e., check whether there is little temperature change) or a method of measuring moisture in the exhaust gas discharged from the outlet <NUM> (e.g., using a hygrometer) to check whether the moisture content is within a certain level or not, but not limited thereto. The exhaust gas discharged from the gas outlet <NUM> may mainly contain nitrogen or water, but if an organic solvent is used instead of water when preparing a CNT pellet, the gas may contain a large quantity of the solvent evaporated during the product drying process. The gas may be evaporated or incinerated. However, if the gas is unreactive or flame retardant, the incineration efficiency may be deteriorated. It is also possible to incinerate this unreactive and flame retardant exhaust gas together with the exhaust gas discharged from the carbon nanotube synthesis process, i.e., the flammable reactive exhaust gas containing hydrogen, hydrocarbon and the like. Namely, when the reaction of the carbon nanotube synthesis process is finished, the reactive exhaust gas remained in a reaction system or a reactive exhaust gas feeding line can be incinerated by purging the gas with the unreactive and flame retardant gas discharged from the process according to the present invention, and therefore, backfiring into the reactive exhaust gas feeding line can be prevented and also the combustion efficiency can be increased.

<FIG> is a schematic diagram for describing constitution of the gas inlet part <NUM> and the product collecting part <NUM> in more detail.

The gas inlet part <NUM> is equipped with a nozzle <NUM> for spraying the introduced gas upward toward the drying part <NUM> thereby feeding the gas through the opening part of the first valve <NUM>, preferably. The shape of the nozzle <NUM> may refer to <FIG>.

Further, as illustrated in <FIG>, the first valve <NUM> is installed at to bottom of the drying part <NUM>, whereunder the gas inlet part <NUM> and the second valve <NUM> are installed.

The product collecting part <NUM> may be located below the second valve <NUM>, and for easier product collecting, the second gas inlet <NUM> and the third valve <NUM> may be installed at the bottom of the product collecting part <NUM>. The gas introduced through the second gas inlet <NUM> is sprayed through the spray nozzle <NUM> to prevent agglomeration of the product during the product discharging process. The shape of the spray nozzle <NUM> may be the same as illustrated in <FIG>, but not limited thereto. The gas to be introduced may preferably be inert gas and there is no need to preheat the gas.

<FIG> illustrate an example of the first valve <NUM>. The valve may be a butterfly valve or a damper valve. The first valve has a central axis <NUM>. Accordingly, the valve is rotatable and foldable on the axis and therefore, the valve is openable.

In order to prevent the product flowing out during product drying, the butterfly valve or the damper valve is used. However, the valve blocks the gas flow when the valve is closed, and therefore hot air flow of the upper part of the valve (drying part) is reduced. Thus, it causes reduction of the drying efficiency. The opening part <NUM> of the first valve <NUM> may improve the drying efficiency by allowing hot air flow through introduction of the gas from the gas inlet part <NUM> to the drying part <NUM>, while preventing the product from discharging to the collecting part <NUM> during the product drying process in the drying part <NUM>.

For the second valve <NUM> or the third valve <NUM>, a butterfly valve or a damper valve without an opening part can be used. Namely, as illustrated in <FIG>, the first valve may have a plurality of opening parts <NUM> on the surface of a wing part <NUM> of the butterfly valve or the damper valve.

Further, not illustrated herein, a mesh sheet through which the carbon nanotube product can't be communicated but only flow can be communicated may be put over a part or a whole of the opening part <NUM>.

According to another embodiment, as illustrate in <FIG>, a bubble cap <NUM> may be covered over a part or a whole of the opening part <NUM>.

According to the present invention, by placing the first valve <NUM> and the second valve <NUM> at the bottom of the drying part <NUM>, it is possible to feed hot air into the drying part by using the high temperature gas while first valve <NUM> is closed. Thus, the drying process can be proceeded efficiently. Further, during the collecting process of the dried product, it is possible to open the first valve <NUM> to introduce the product into the gas inlet <NUM>, and then to close the first valve <NUM> and to open the second valve <NUM> to introduce the product into the collecting part <NUM>. Thus, without stopping the drying process or lowering the temperature, it is possible to proceed the drying process and the product collecting process continuously.

The device illustrated in <FIG> was assembled by using a lab-scale cylinder-type high temperature dryer (Internal diameter <NUM> quartz tube), and <FIG> and <FIG> show the results of tests performed with the device. Test conditions are as listed in the following Table <NUM>.

Namely, the tests were performed at the same conditions except for changing the drying time, and the drying rate, the percentage of water content and the bed temperature change were observed.

<FIG> shows the drying rate and the bed temperature according to the drying time, and <FIG> shows the percentage of water content according to the drying time.

Claim 1:
A device (<NUM>) for drying and collecting a carbon nanotube product comprising:
a drying part (<NUM>), which receives a carbon nanotube product to be dried and dries the product;
a product collecting part (<NUM>), which is installed at the bottom of the drying part (<NUM>);
a gas inlet part (<NUM>), which is installed between the drying part (<NUM>) and the product collecting part (<NUM>), for flowing gas into the drying part (<NUM>); and
an openable valve (<NUM>), which is installed between the drying part (<NUM>) and the product collecting part (<NUM>), for introducing the product into the gas inlet part (<NUM>) when the valve (<NUM>) is opened, and wherein the valve (<NUM>) has a plurality of opening parts (<NUM>) allowing fluid communication, wherein the opening parts (<NUM>) of the valve (<NUM>) allow hot air gas flow from the gas inlet part (<NUM>) into the drying part (<NUM>) while preventing the product from discharging to the collecting part (<NUM>) during the product drying process in the drying part (<NUM>) while the valve (<NUM>) is closed.