초록 ▼

The present invention relates to a method for continuous production of carbon nanotubes in a nano-agglomerate fluidized bed, which comprises the following steps: loading transition metal compounds on a support, obtaining supported nanosized metal catalysts by reducing or dissociating, catalytically

The present invention relates to a method for continuous production of carbon nanotubes in a nano-agglomerate fluidized bed, which comprises the following steps: loading transition metal compounds on a support, obtaining supported nanosized metal catalysts by reducing or dissociating, catalytically decomposing a carbon-source gas, and growing carbon nanotubes on the catalyst support by chemical vapor deposition of carbon atoms. The carbon nanotubes are 4˜100 nm in diameter and 0.5˜1000 μm in length. The carbon nanotube agglomerates, ranged between 1˜1000 μm, are smoothly fluidized under 0.005 to 2 m/s superficial gas velocity and 20˜800 kg/m3 bed density in the fluidized-bed reactor. The apparatus is simple and easy to operate, has a high reaction rate, and it can be used to produce carbon nanotubes with high degree of crystallization, high purity, and high yield.

대표청구항 ▼

The invention claimed is: 1. A method for continuous production of carbon nanotubes in a nano-agglomerate fluidized bed, comprising: 1) loading transition metal oxide on a support to form a transition metal catalyst; 2) adding said transition metal oxide catalyst into a catalyst activation reactor,

The invention claimed is: 1. A method for continuous production of carbon nanotubes in a nano-agglomerate fluidized bed, comprising: 1) loading transition metal oxide on a support to form a transition metal catalyst; 2) adding said transition metal oxide catalyst into a catalyst activation reactor, flowing a mixture of (i) nitrogen and hydrogen or (ii) a mixture of nitrogen and carbon monoxide into the reactor at 500-900° C. to reduce nanosized transition metal oxide particles to nanosized metal particles, wherein the volume ratio of hydrogen or carbon monoxide to nitrogen is 1:0.3 to 1:1, the space velocity during the reduction reaction is from 0.3 h-1 to 3h-1 and the catalyst is in the form of nano-agglomerates, which have diameters between 1˜1000 μm; and 3) transporting the catalyst into a fluidized-bed reactor, flowing a mixture of (a) a carbon-source-gas which is a gas of lower hydrocarbons having less than 7 carbon atoms, (b) nitrogen and (c) either hydrogen or carbon monoxide into the reactor at 500-900° C., wherein the volume ratio of hydrogen or carbon monoxide:carbon-source-gas:nitrogen equals 0.4-1:1:0.1-2, the space velocity during the reaction is 5-10000 h-1 , the superficial gas velocity is 0.08-2 m/s, the bed density is maintained at 20-800 kg/m3, and the nano-agglomerates of the catalyst and the carbon nanotube product are kept in a dense-phase fluidization state to form carbon nanotube agglomerates, each having a diameter between 1 μm and about 1000 μm, as a result, crystalline carbon nanotubes are obtained from the fluidized-bed reactor, wherein the carbon nanotubes are free of amorphous carbon deposits. 2. The method of claim 1, wherein the catalyst support is superfine glass beads, SiO2, Al2O3 or carbon nanotubes. 3. The method of claim 1, wherein the transition metal oxide is Fe-Cu oxide, Ni-Cu oxide, Co-Mn oxide or Ni oxide. 4. A method of claim 1, which is carried out in a nano-agglomerate fluidized bed reaction apparatus, which apparatus comprises a main reactor (1), a catalyst activation reactor (6), a gas distributor (2), a gas-solid separator (7) and a product degassing section (9), wherein the catalyst activation reactor (6) is connected to the main reactor (1), the gas distributor (2) is placed in the bottom of the main reactor (1), the gas-solid separator (7) is arranged at the top of the main reactor (1), the main reactor (1) is provided with heat exchange tubes (3) and means for feeding gases at its bottom, and the product degassing section (9) is connected to the main reactor (1) through a product outlet (5). 5. The method of claim 1, which is carried out in a fluidized-bed reactor, which comprises a main reactor (1), a gas distributor (2), a gas-solid separator (7) and a product degassing section (9), the main reactor (I) is connected to a catalyst activation reactor (61, the gas distributor (2) is placed in the bottom of the main reactor (1), the gas-solid separator (7) is arranged at the top of the main reactor (1), the main reactor (1) is provided with heat exchange tubes (3) and a gas feeder at its bottom, and the product degassing section (9) is connected to the main reactor (1) through a product outlet (5). 6. The method of claim 1, wherein the carbon nanotubes obtained from the fluidized-bed reactor form a carbon nanotube agglomerate, which comprises: a plurality of transition metal nanoparticles; a solid support, wherein said plurality of metal nanoparticles and said support are combined to form a plurality of catalyst nano agglomerates; and a plurality of multi-walled carbon nanotubes deposited on said plurality of catalyst nano agglomerates. 7. The method of claim 6, wherein the carbon nanotube agglomerate has a diameter of about 1 μm to about 1000 μm. 8. The method of claim 6, wherein said plurality of catalyst nano agglomerates have a diameter of about 1 μm to about 1000 μm. 9. A method for continuous production of carbon nanotubes in a nano-agglomerate fluidized bed, comprising: 1) placing a catalyst support in the fluidized-bed reactor, wherein the diameters of the agglomerates of the catalyst support are in the range of 1-1000 μm and the bed density of the reactor is 20-1500 kg/m3 so that the catalyst support can be fluidized; 2) dissolving a metallocene compound in a low carbon number organic solvent; 3) heating the above solution to a temperature higher than the boiling point of the organic solvent to vaporize the solution; and 4) feeding the above vaporized catalyst precursor into the fluidized-bed reactor, flowing a mixture of (a) a carbon-source-gas which is a gas of lower hydrocarbons having less than 7 carbon atoms, (b)nitrogen and (c) either hydrogen or carbon monoxide into the reactor at 500-900° C., wherein the volume ratio of hydrogen or carbon monoxide:carbon-source-gas:nitrogen equals 0.4-1:1:0.1˜2, the space velocity during the reaction is 5-10000 h-1 , the superficial gas velocity is 0.005-2 m/s, and the stuffs in the reactor are kept in a dense-phase fluidization state to form carbon nanotube agglomerates, each having a diameter between 1 μm and about 1000 μm, as a result, crystalline carbon nanotubes are obtained from the fluidized-bed reactor, wherein the carbon nanotubes are free of amorphous carbon deposits. 10. The method of claim 9, wherein the catalyst support is superfine glass beads, SiO2, Al2O3 or carbon nanotubes. 11. The method of claim 9, which is carried out in a fluidized-bed reactor, which comprises a main reactor (1), a gas distributor (2), a gas-solid separator (7) and a product degassing section (9), the gas distributor (2) is placed in the bottom of the main reactor (1), the gas-solid separator (7) is arranged at the top of the main reactor (1), the main reactor (1) is provided with heat exchange tubes (3) and a gas feeder at its bottom, and the product degassing section (9) is connected to the main reactor (1) through a product outlet (5). 12. The method of claim 9, wherein the carbon nanotubes obtained from the fluidized-bed reactor form a carbon nanotube agglomerate, which comprise a plurality of transition metal nanoparticles; a solid support, wherein said plurality of transition metal nanoparticles and said solid support are combined to form a plurality of catalyst nano agglomerates; and a plurality of multi-walled carbon nanotubes deposited on said plurality of catalyst nano agglomerates. 13. The method of claim 12, wherein the carbon nanotube agglomerate has a diameter of about 1 μm to about 1000 μm. 14. The method of claim 12, wherein said plurality of catalyst nano agglomerates have a diameter of about 1 μm to about 1000 μm. 15. A method of claim 9, which is carried out: in a nano-agglomerate fluidized bed reaction apparatus, which apparatus comprises a main reactor (1), a catalyst activation reactor (6), a gas distributor (2), a gas-solid separator (7) and a product degassing section (9), wherein the catalyst activation reactor (6) is connected to the main reactor (1), the gas distributor (2) is placed in the bottom of the main reactor (1), the gas-solid separator (7) is arranged at the top of the main reactor (1), the main reactor (1) is provided with heat exchange tubes (3) and a gas feeder at its bottom, and the product degassing section (9) is connected to the main reactor (1) though a product outlet (5).