Method of producing carbon nanotubes in fluidized bed reactor

1. A method of producing carbon nanotubes by supplying a catalyst and a carbon source to a fluidized bed reactor,

wherein the fluidized bed reactor has an expanded zone,

wherein a linear flow velocity of a raw material supplied to the fluidized bed reactor is equal to or higher than a terminal velocity of internal materials in the fluidized bed reactor,

wherein the linear flow velocity of the raw material is equal to or more than 25 times a minimum fluidization velocity of the internal materials, and

wherein the linear flow velocity of the raw material in the expanded zone is less than the terminal velocity of the internal materials.

2. The method according to claim 1 , wherein the flow velocity of the raw material is 20 cm/s or higher.

3. The method according to claim 1 , wherein the carbon source is one or more selected from the group consisting of saturated and unsaturated hydrocarbons having 1 to 4 carbon atoms.

4. The method according to claim 1 , wherein the catalyst is a metal catalyst.

5. The method according to claim 4 , the metal catalyst is any one metal selected from the group consisting of iron (Fe), molybdenum (Mo), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), nickel (Ni), cobalt (Co), copper (Cu), cadmium (Cd), zinc (Zn), ruthenium (Ru), lead (Pd), silver (Ag), platinum (Pt) and gold (Au), or any one selected from alloys thereof.

6. The method according to claim 1 , wherein the carbon nanotubes have a diameter of 0.4 nm to 10 nm.

7. The method according to claim 1 , wherein the carbon nanotubes are comprised of 1 to 10 layers.