Continuous manufacturing apparatus and method for carbon nanotubes having gas separation units

Abstract

The present invention relates to a continuous manufacturing apparatus for a carbon nanotube having gas separation units and a continuous manufacturing method for a carbon nanotube using the same. According to the present invention, the present invention has an effect to provide the continuous manufacturing apparatus of the carbon nanotube and continuous manufacturing method using the same, in which it makes possible to perform a rapid processing; has excellent productivity and excellent conversion rate of carbon source; can significantly reduce the cost of production; can reduce energy consumption because a reactor size can be decreased as compared with capacity; and a gas separation unit that not generate a waste gas.

Claims

1. A continuous carbon nanotube manufacturing apparatus, comprising: i) a reactor for synthesizing the carbon nanotube; ii) a separator for separating a mixed gas and the carbon nanotube transferred from the reactor; iii) a heat exchanger between the reactor i) and the separator ii); iv) a gas separation unit for removing, in part or in whole, a component gas from the mixed gas, the gas separation unit comprising one or more hollow tubular polymer membranes constructed to separate hydrogen from the mixed gas at a temperature of 50 C. or below; and v) a re-circulation pipe for recirculating the mixed gas, without the component gas separated by the gas separation unit, to the reactor; vi) a catalyst supplier connected to an upper part of the reactor, the catalyst supplier comprising a hopper; and vii) a reaction gas supplier connected to a bottom part of the reactor, wherein the apparatus comprises a sole product discharging pipe for discharging the product produced by the reactor i), and wherein the heat exchanger is in direct communication with the sole product discharging pipe.

2. The continuous carbon nanotube manufacturing apparatus according to claim 1, wherein the one or more polymer membranes are produced with more than one polymer selected from the group consisting of polysulfone, polycarbonate, polyimide, and polystyrene.

3. The continuous carbon nanotube manufacturing apparatus according to claim 1, wherein reactor i) is a chemical vapor deposition reactor.

4. The continuous carbon nanotube manufacturing apparatus according to claim 3, wherein the chemical vapor deposition reactor is a rotary kiln reactor or a fluidized bed reactor.

5. The continuous carbon nanotube manufacturing apparatus according to claim 4, wherein the rotary kiln reactor or the fluidized bed reactor are connected with a catalyst supply pipe for supplying a catalyst; a reaction gas supply pipe for supplying a carbon source, a reducing gas, and an inert gas.

6. The continuous carbon nanotube manufacturing apparatus according to claim 5, further comprising a preheater for preheating the reaction gas to a temperature of 200 to 500 C.

7. The continuous carbon nanotube manufacturing apparatus according to claim 1, wherein the separator of ii) is a cyclone.

8. The continuous carbon nanotube manufacturing apparatus according to claim 1, wherein the heat exchanger is constructed to cool the mixed gas and the carbon nanotube transferred from the reactor to a temperature of 40 to 50 C.

9. The continuous carbon nanotube manufacturing apparatus according to claim 1, wherein the continuous manufacturing apparatus of the carbon nanotube further includes a flow controlling device constructed to control the amount of a reaction gas supplied to the reactor and the amount of component gas removed from the gas separation unit.

10. The continuous carbon nanotube manufacturing apparatus according to claim 1, wherein the continuous manufacturing apparatus of the carbon nanotube further includes a flow controlling device constructed to control the amount of a reducing gas supplied to the reactor and the amount of the reducing gas passed through the gas separation unit.

11. The continuous carbon nanotube manufacturing apparatus according to claim 1, wherein the continuous manufacturing apparatus does not comprise any apparatus for incinerating waste gas.

12. The continuous carbon nanotube manufacturing apparatus according to claim 1, wherein the reactor is a vertical fluidized bed reactor constructed to provide a fluidization velocity of 0.03 to 30 cm/s.

13. The continuous carbon nanotube manufacturing apparatus according to claim 1, further comprising a filter arranged in an expander part of the reactor.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) The above and other objects, features and advantages of the present invention will become apparent from the following description of preferred embodiments given in conjunction with the accompanying drawings, in which:

(2) FIG. 1 is a process chart showing a specific example of a continuous CNT manufacturing apparatus according to the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

(3) Hereinafter, preferable examples will be described in order to helping the understanding of the present invention, but the following Examples are only for indicating the present invention, and the spirit of the present invention is not limited thereto.

(4) Furthermore, a specific example of the continuous CNT manufacturing apparatus according to the present invention is roughly shown in FIG. 1. FIG. 1 only shows device required for describing the present invention, and other definite devices, including any pump, an additional valve, any pipe etc, that are required for performing the present method are omitted.

EXAMPLES

Example 1

(5) <Production of CNT Catalyst>

(6) Flask A including 37.039 g of Co(NO.sub.3).sub.2-6H.sub.2O dissolved in 200 ml of aqueous solution and Flask B including 32.30 g of (NH.sub.4).sub.6MO.sub.7O.sub.24-4H.sub.2O dissolved in 200 ml of aqueous solution were prepared to add to Flask C including 50 g of Al.sub.2O.sub.3 (D50=76 micron, pore volume: 0.64 cm.sup.3/g, surface area: 237 m.sup.2/g, the product available from Saint Gobain Company), and then stirred for at least 60 minutes to sufficiently support a catalyst active metal precursor into Al.sub.2O.sub.3. And then, it was vacuum-filtered by using 10 micron filter paper or 4 glass filter to separate a filter cake supported with the catalyst active metal precursor and then washed with a distilled water to collect. The filter cake collected was dried for 24 hours at a oven of 120 C. The dried catalyst was fired for 3 hours at 600 C. to produce the catalyst.

(7) <Production of CNT>

(8) As shown in FIG. 1, 5 g of the CNT catalyst was supplied inside the reactor through a catalyst gas supplier connected to the upper part of a vertical fluidized bed reactor having a diameter of 55 mm and a height of 1 m to fill 5 g of the catalyst inside the reactor, and then a reaction gas (C.sub.2H.sub.4:H.sub.2:N.sub.2=1:1:1) was injected to the reactor in a velocity of 3000 ml/min through a reaction gas supply pipe connected to the bottom part of the reactor, provided that it was injected after increasing the temperature to 500 C. through a preheater, to synthesize CNT for 1 hour at 800 C.

(9) The reaction was performed by selectively separating 50% out of a hydrogen gas discharged in a mixed gas (un-reacted carbon source C.sub.2H.sub.4, inert gas N.sub.2, initial injected reducing gas H.sub.2, H.sub.2 generated as the byproduct) separated from CNT product through a cyclone as a continuous reaction in two parallel connection polymer membranes (48 mm diameter, 27 inch length, hollow type polycarbonate membrane, the product available from IGS Company), and recirculating to the reaction gas supply pipe through the recirculation pipe passed through a flow control valve to produce CNT.

(10) After 1 hour reaction, CNT collected to a CNT collector has a yield [(Weight of CNT collected Weight of Catalyst injected)/Weight of Catalyst injected100] of 950% based on catalyst input, and at this time, the average external diameter of CNT obtained from the above was 30 nm.

Example 2

(11) CNT was produced by using the same method with the above Example 1, except that the composition of the reaction gas in the above Example 1 was changed to C.sub.2H.sub.4:H.sub.2:N.sub.2=1:2:1 and 35% out of hydrogen gas in the mixed gas discharged from the reactor was selectively separated and discharged in the polymer membrane.

(12) The reaction could be possible to safely operate by selectively removing only H.sub.2 as the byproduct and recirculating the mixed gas consisting of the remained H.sub.2, N.sub.2, and 4.8% of un-reacted C.sub.2H.sub.4 to the reaction gas supply pipe. In addition, the used amounts of H.sub.2 and N.sub.2 were minimized by reacting without an additional supply of H.sub.2 and N.sub.2 by performing a continuous operation through adding only C.sub.2H.sub.4 corresponding 85% of initial amount injected to the reaction gas supply pipe.

(13) After 1 hour reaction, CNT collected to the CNT collector has a yield of 1020% as compared with catalyst input, and at this time, the average external diameter of CNT obtained from the above was 30 nm.

Example 3

(14) CNT was produced by using the same method with the above Example 1, except that the composition of the reaction gas in the above Example 1 was changed to C.sub.2H.sub.4:H.sub.2:N.sub.2=1:3:1 and 29% out of hydrogen gas in the mixed gas discharged from the reactor was selectively separated and discharged in the polymer membrane.

(15) The reaction could be possible to safely operate by selectively removing only H.sub.2 as the byproduct and recirculating the mixed gas consisting of the remained H.sub.2, N.sub.2, and 3.6% of un-reacted C.sub.2H.sub.4 to the reaction gas supply pipe. In addition, the used amounts of H.sub.2 and N.sub.2 were minimized by reacting without an additional supply of H.sub.2 and N.sub.2 by performing a continuous operation through adding only C.sub.2H.sub.4 corresponding 85% of initial amount injected to the reaction gas supply pipe.

(16) After 1 hour reaction, CNT collected to the CNT collector has a yield of 780% as compared with catalyst input, and at this time, the average external diameter of CNT obtained from the above was 30 nm.

Example 4

(17) CNT was produced by using the same method with the above Example 1, except that the composition of the reaction gas in the above Example 1 was changed to C.sub.2H.sub.4:H.sub.2:N.sub.2=1:4:1 and 24% out of hydrogen gas in the mixed gas discharged from the reactor was selectively separated and discharged in the polymer membrane.

(18) The reaction could be possible to safely operate by selectively removing only H.sub.2 as the byproduct and recirculating the mixed gas consisting of the remained H.sub.2, N.sub.2, and 3.3% of un-reacted C.sub.2H.sub.4 to the reaction gas supply pipe. In addition, the used amounts of H.sub.2 and N.sub.2 were minimized by reacting without an additional supply of H.sub.2 and N.sub.2 by performing a continuous operation through adding only C.sub.2H.sub.4 corresponding 83% of initial amount injected to the reaction gas supply pipe.

(19) After 1 hour reaction, CNT collected to the CNT collector has a yield of 630% as compared with catalyst input, and at this time, the average external diameter of CNT obtained from the above was 30 nm.

Example 5

(20) CNT was produced by using the same method with the above Example 1, except that the composition of the reaction gas in the above Example 1 was changed to C.sub.2H.sub.4:H.sub.2:N.sub.2=1:5:1 and 20% out of hydrogen gas in the mixed gas discharged from the reactor was selectively separated and discharged in the polymer membrane.

(21) The reaction could be possible to safely operate by selectively removing only H.sub.2 as the byproduct and recirculating the mixed gas consisting of the remained H.sub.2, N.sub.2, and 3.2% of un-reacted C.sub.2H.sub.4 to the reaction gas supply pipe. In addition, the used amounts of H.sub.2 and N.sub.2 were minimized by reacting without an additional supply of H.sub.2 and N.sub.2 by performing a continuous operation through adding only C.sub.2H.sub.4 corresponding 80% of initial amount injected to the reaction gas supply pipe.

(22) After 1 hour reaction, CNT collected to the CNT collector has a yield of 580% as compared with catalyst input, and at this time, the average external diameter of CNT obtained from the above was 30 nm.

Example 6

(23) 3 g of the CNT catalyst produced from the above Example 1 was filled to 15 cm reaction module having a cylinder type, of which both sides connected to a rotary drum reactor having a diameter 55 mm and a height of 60 cm were produced with 10 micron mesh, and then supplied inside the reactor. The reaction gas (C.sub.2H.sub.4:H.sub.2:N.sub.2=1:2:1) was preheated at 500 C. through a preheater in a velocity of 1500 ml/min through the reaction gas supply pipe, and then injected to the above reactor. The reactor was tilted at an angle of 30 degree, and then rotated in a velocity of 30 rpm. The reaction was progressed for 1 hour at 800 C. to synthesize CNT.

(24) The reaction was performed by selectively separating 36% out of a hydrogen gas discharged in the mixed gas (un-reacted carbon source C.sub.2H.sub.4, inert gas N.sub.2, initial injected reducing gas H.sub.2, H.sub.2 generated as the byproduct) separated from CNT product through the cyclone as a continuous reaction in the polymer membrane that is a module of hollow type produced with polystyrene, and recirculating to the reaction gas supply pipe through the recirculation pipe passed through a flow distribution controller to produce CNT.

(25) After 1 hour reaction, CNT collected to the CNT collector has a yield of 870% based on catalyst input, and at this time, the average external diameter of CNT obtained from the above was 30 nm.

Example 7

(26) CNT was produced by using the same method with the above Example 6, except that the composition of the reaction gas in the above Example 6 was changed to C.sub.2H.sub.4:H.sub.2:N.sub.2=1:3:1 and 29% out of hydrogen gas in the mixed gas discharged from the reactor was selectively separated and discharged in the polymer membrane.

(27) The reaction could be possible to safely operate by selectively removing only H.sub.2 as the byproduct and recirculating the mixed gas consisting of the remained H.sub.2, N.sub.2, and 4.2% of un-reacted C.sub.2H.sub.4 to the reaction gas supply pipe. In addition, the used amounts of H.sub.2 and N.sub.2 were minimized by reacting without an additional supply of H.sub.2 and N.sub.2 by performing a continuous operation through adding only C.sub.2H.sub.4 corresponding 85% of initial amount injected to the reaction gas supply pipe.

(28) After 1 hour reaction, CNT collected to the CNT collector has a yield of 700% as compared with catalyst input, and at this time, the average external diameter of CNT obtained from the above was 30 nm.

Example 8

(29) <Production of CNT Catalyst>

(30) Flask A including 37.039 g of Co(NO.sub.3).sub.2-6H.sub.2O dissolved in 300 ml of aqueous solution and Flask B including 32.30 g of (NH.sub.4).sub.6Mo.sub.7O.sub.24-4H.sub.2O dissolved in 300 ml of aqueous solution were prepared to add to Flask C including 50 g of MgO (Particle size: 44106 micron, available from Aldrich Company), and then stirred for at least 60 minutes to sufficiently support a catalyst active metal precursor into Al.sub.2O.sub.3. And then, it was vacuum-filtered by using 10 micron filter paper to separate a filter cake and then washed with a distilled water to collect. The filter cake collected was dried for 24 hours at a oven of 120 C. The dried catalyst was fired for 3 hours at 600 C. to produce the CNT catalyst.

(31) <Production of CNT>

(32) 5 g of the CNT catalyst was supplied inside the reactor through a catalyst gas supplier connected to the upper part of a vertical fluidized bed reactor having a diameter of 55 mm and a height of 1 m, and then a reaction gas (C.sub.2H.sub.4:H.sub.2:N.sub.2=1:2:1) was injected to the reactor in a velocity of 3000 ml/min through a reaction gas supply pipe connected to the bottom part of the reactor, provided that it was injected after increasing the temperature to 500 C. through a preheater, to synthesize CNT for 1 hour at 800 C.

(33) The reaction was performed by selectively separating 34% out of a hydrogen gas discharged in a mixed gas (un-reacted carbon source C.sub.2H.sub.4, inert gas N.sub.2, initial injected reducing gas H.sub.2, H.sub.2 generated as the byproduct) separated from CNT product through a cyclone as a continuous reaction in the polymer membrane that is a module of hollow type produced with polyimide, and recirculating to the reaction gas supply pipe through the recirculation pipe passed through a flow control valve to produce CNT.

(34) After 1 hour reaction, CNT collected to a CNT collector has a yield of 1060% based on catalyst input, and at this time, the average external diameter of CNT obtained from the above was 25 nm.

(35) Accordingly, the present invention allows realizing the process for continuously produce CNT by supplying only a shortage of ethylene without an additional supply of H.sub.2 and N.sub.2 out of the reaction gas components initially injected.

Example 9

(36) CNT was produced by using the same method with the above Example 8, except that the composition of the reaction gas in the above Example 8 was changed to C.sub.2H.sub.4:H.sub.2:N.sub.2=1:3:1 and 29% out of hydrogen gas in the mixed gas discharged from the reactor was selectively separated and discharged in the polymer membrane.

(37) The reaction could be possible to safely operate by selectively removing only H.sub.2 as the byproduct and recirculating the mixed gas consisting of the remained H.sub.2, N.sub.2, and 3.8% of un-reacted C.sub.2H.sub.4 to the reaction gas supply pipe. In addition, the used amounts of H.sub.2 and N.sub.2 were minimized by reacting without an additional supply of H.sub.2 and N.sub.2 by performing a continuous operation through adding only C.sub.2H.sub.4 corresponding 84% of initial amount injected to the reaction gas supply pipe.

(38) After 1 hour reaction, CNT collected to the CNT collector has a yield of 810% as compared with catalyst input, and at this time, the average external diameter of CNT obtained from the above was 25 nm.

Example 10

(39) CNT was produced by using the same method with the above Example 8, except that the composition of the reaction gas in the above Example 8 was changed to C.sub.2H.sub.4:H.sub.2:N.sub.2=1:4:1 and 24% out of hydrogen gas in the mixed gas discharged from the reactor was selectively separated and discharged in the polymer membrane.

(40) The reaction could be possible to safely operate by selectively removing only H.sub.2 as the byproduct and recirculating the mixed gas consisting of the remained H.sub.2, N.sub.2, and 3.6% of un-reacted C.sub.2H.sub.4 to the reaction gas supply pipe. In addition, the used amounts of H.sub.2 and N.sub.2 were minimized by reacting without an additional supply of H.sub.2 and N.sub.2 by performing a continuous operation through adding only C.sub.2H.sub.4 corresponding 81% of initial amount injected to the reaction gas supply pipe.

(41) After 1 hour reaction, CNT collected to the CNT collector has a yield of 670% as compared with catalyst input, and at this time, the average external diameter of CNT obtained from the above was 25 nm.

Example 11

(42) 3 g of the CNT catalyst produced from the above Example 8 was supplied inside the reactor through 15 cm reaction module having a cylinder type, of which both sides connected to a rotary drum reactor having a diameter 55 mm and a height of 60 cm were produced with 10 micron mesh. The reaction gas (C.sub.2H.sub.4:H.sub.2:N.sub.2=1:2:1) was injected to the reactor in a velocity of 1500 ml/min through the reaction gas supply pipe. The reactor was tilted at an angle of 30 degree, and then rotated in a velocity of 30 rpm. The reaction was progressed for 1 hour at 800 C. to synthesize CNT.

(43) The reaction was performed by selectively separating 36% out of a hydrogen gas discharged in the mixed gas (un-reacted carbon source C.sub.2H.sub.4, inert gas N.sub.2, initial injected reducing gas H.sub.2, H.sub.2 generated as the byproduct) separated from CNT product through the cyclone as a continuous reaction in two parallel connection polymer membranes (48 mm diameter, 27 inch length, hollow type polycarbonate membrane, the product available from IGS Company), and recirculating to the reaction gas supply pipe to produce CNT.

(44) After 1 hour reaction, CNT collected to the CNT collector has a yield of 860% based on catalyst input, and at this time, the average external diameter of CNT obtained from the above was 25 nm.

Example 12

(45) CNT was produced by using the same method with the above Example 11, except that the composition of the reaction gas in the above Example 11 was changed to C.sub.2H.sub.4:H.sub.2:N.sub.2=1:3:1 and 32% out of hydrogen gas in the mixed gas discharged from the reactor was selectively separated and discharged in the polymer membrane.

(46) The reaction could be possible to safely operate by recirculating the mixed gas consisting of H.sub.2, N.sub.2, and 2.9% of un-reacted C.sub.2H.sub.4 to the reaction gas supply pipe and at the same time, selectively recirculating 3% of H.sub.2 to the reaction gas supply pipe. In addition, the used amounts of H2 and N2 were minimized by reacting without an additional supply of H.sub.2 and N.sub.2 by performing a continuous operation through adding only C.sub.2H.sub.4 corresponding 88% of initial amount injected to the reaction gas supply pipe.

(47) After 1 hour reaction, CNT collected to the CNT collector has a yield of 690% as compared with catalyst input, and at this time, the average external diameter of CNT obtained from the above was 25 nm.

Example 13

(48) CNT was produced by using the same method with the above Example 11, except that the composition of the reaction gas in the above Example 11 was changed to C.sub.2H.sub.4:H.sub.2:N.sub.2=1:4:1 and 27% out of hydrogen gas in the mixed gas discharged from the reactor was selectively separated and discharged in the polymer membrane.

(49) The reaction could be possible to safely operate by recirculating the mixed gas consisting of H.sub.2, N.sub.2, and 3.3% of un-reacted C.sub.2H.sub.4 to the reaction gas supply pipe and at the same time, selectively recirculating 3% of H.sub.2 to the reaction gas supply pipe. In addition, the used amounts of H.sub.2 and N.sub.2 were minimized by reacting without an additional supply of H.sub.2 and N.sub.2 by performing a continuous operation through adding only C.sub.2H.sub.4 corresponding 83% of initial amount injected to the reaction gas supply pipe.

(50) After 1 hour reaction, CNT collected to the CNT collector has a yield of 570% as compared with catalyst input, and at this time, the average external diameter of CNT obtained from the above was 25 nm.

Example 14

(51) <Production of CNT Catalyst>

(52) Flask A including 54.25 g of F(NO.sub.3).sub.2-6H.sub.2O dissolved in 200 ml of aqueous solution and Flask B including 32.30 g of (NH.sub.4).sub.6Mo.sub.7O.sub.24-4H.sub.2O dissolved in 200 ml of aqueous solution were prepared to add to 5 g of SiO2 (D50=55 micron, Surface area: 550 m.sup.2/g, Merk 9385); vacuum-filtered by using 10 micron filter paper to separate a filter cake; and washed with a distilled water to collect. The filter cake collected was dried for 24 hours at a oven of 120 C. The dried catalyst was fired for 3 hours at 600 C. to produce the CNT catalyst.

(53) <Production of CNT>

(54) 5 g of the CNT catalyst was initially supplied in a certain amount inside the reactor through a catalyst gas supplier connected to the upper part of a vertical fluidized bed reactor having a diameter of 55 mm and a height of 1 m, and then continuously supplied; a reaction gas (C.sub.2H.sub.4:H.sub.2:N.sub.2=1:2:1) was injected to the reactor from the bottom part of the reactor in a velocity of 3000 ml/min through a supply pipe, provided that it was injected after increasing the temperature to 500 C. through a preheater, to synthesize CNT for 1 hour at 800 C.

(55) The reaction was performed by recirculating a filtered mixed gas (un-reacted carbon source C.sub.2H.sub.4, N.sub.2 and H.sub.2) including 31% out of a hydrogen gas discharged in a mixed gas (un-reacted carbon source C.sub.2H.sub.4, inert gas N.sub.2, initial injected reducing gas H.sub.2, H.sub.2 generated as the byproduct) separated from CNT product through a cyclone as a continuous reaction through the polymer membrane (48 mm diameter, 27 inch length, hollow type polycarbonate membrane, the product available from IGS Company) through the re-circulation pipe, and at the same time selectively separating and circulating further 2% of hydrogen through the re-circulation pipe to the reaction gas supply pipe to produce CNT.

(56) After 1 hour reaction, CNT collected to a CNT collector has a yield of 930% based on catalyst input, and at this time, the average external diameter of CNT obtained from the above was 25 nm.

(57) From the result of analyzing by GC (Gas Chromatography) in the re-circulation pipe after selectively separating H.sub.2, it could be known that the stable operation could be possible by only further supplying a shortage of ethylene without an additional supply of H.sub.2 and N.sub.2 out of the reaction gas components initially injected and CNT could be continuously produced.

Example 15

(58) CNT was produced by using the same method with the above Example 14, except that the composition of the reaction gas in the above Example 14 was changed to C.sub.2H.sub.4:H.sub.2:N.sub.2=1:3:1 and 24% out of hydrogen gas in the mixed gas discharged from the reactor was selectively separated and discharged in the polymer membrane.

(59) The reaction could be possible to safely operate by recirculating the mixed gas consisting of H.sub.2, N.sub.2, and 4.8% of un-reacted C.sub.2H.sub.4 to the reaction gas supply pipe and at the same time, selectively recirculating 3% of H.sub.2 to the reaction gas supply pipe. In addition, the used amounts of H.sub.2 and N.sub.2 were minimized by reacting without an additional supply of H.sub.2 and N.sub.2 by performing a continuous operation through adding only C.sub.2H.sub.4 corresponding 80% of initial amount injected to the reaction gas supply pipe.

(60) After 1 hour reaction, CNT collected to the CNT collector has a yield of 790% as compared with catalyst input, and at this time, the average external diameter of CNT obtained from the above was 25 nm.

Example 16

(61) CNT was produced by using the same method with the above Example 14, except that the composition of the reaction gas in the above Example 14 was changed to C.sub.2H.sub.4:H.sub.2:N.sub.2=1:4:1 and 21% out of hydrogen gas in the mixed gas discharged from the reactor was selectively separated and discharged in the polymer membrane.

(62) The reaction could be possible to safely operate by recirculating the mixed gas consisting of H.sub.2, N.sub.2, and 4.2% of un-reacted C.sub.2H.sub.4 to the reaction gas supply pipe and at the same time, selectively recirculating 2% of H.sub.2 to the reaction gas supply pipe. In addition, the used amounts of H.sub.2 and N.sub.2 were minimized by reacting without an additional supply of H.sub.2 and N.sub.2 by performing a continuous operation through adding only C.sub.2H.sub.4 corresponding 78% of initial amount injected to the reaction gas supply pipe.

(63) After 1 hour reaction, CNT collected to the CNT collector has a yield of 600% as compared with catalyst input, and at this time, the average external diameter of CNT obtained from the above was 25 nm.

Example 17

(64) 3 g of the CNT catalyst produced from the above Example 14 was supplied inside the reactor through 15 cm reaction module having a cylinder type, of which both sides connected to a rotary drum reactor having a diameter 55 mm and a height of 60 cm were produced with 10 micron mesh. The reaction gas (C.sub.2H.sub.4:H.sub.2:N.sub.2=1:2:1) was injected to the reactor in a velocity of 1500 ml/min through the reaction gas supply pipe after preheating at 500 C. The reactor was tilted at an angle of 30 degree, and then rotated in a velocity of 30 rpm. The reaction was progressed for 1 hour at 800 C. to synthesize CNT.

(65) The reaction was performed by recirculating a filtered mixed gas (un-reacted carbon source C.sub.2H.sub.4, N.sub.2 and H.sub.2) including 35% out of a hydrogen gas discharged in a mixed gas (un-reacted carbon source C2H4, inert gas N.sub.2, initial injected reducing gas H.sub.2, H.sub.2 generated as the byproduct) separated from CNT product through a cyclone as a continuous reaction through the hollow type polysolfone as the polymer membrane through the re-circulation pipe to the reaction gas supply pipe to produce CNT.

(66) After 1 hour reaction, CNT collected to a CNT collector has a yield of 860% based on catalyst input, and at this time, the average external diameter of CNT obtained from the above was 25 nm.

Example 18

(67) CNT was produced by using the same method with the above Example 17, except that the composition of the reaction gas in the above Example 17 was changed to C.sub.2H.sub.4:H.sub.2:N.sub.2=1:3:1 and 29% out of hydrogen gas in the mixed gas discharged from the reactor was selectively separated and discharged in the polymer membrane (48 mm diameter, 27 inch length, hollow type polycarbonate, the product available from IGS Company).

(68) The reaction could be possible to safely operate by recirculating the mixed gas consisting of H.sub.2, N.sub.2, and 3.6% of un-reacted C.sub.2H.sub.4 to the reaction gas supply pipe. In addition, the used amounts of H.sub.2 and N.sub.2 were minimized by progressing the reaction without an additional supply of H.sub.2 and N.sub.2 by performing a continuous operation through adding only C.sub.2H.sub.4 corresponding 85% of initial amount injected to the reaction gas supply pipe.

(69) After 1 hour reaction, CNT collected to the CNT collector has a yield of 680% as compared with catalyst input, and at this time, the average external diameter of CNT obtained from the above was 25 nm.

Example 19

(70) CNT was produced by using the same method with the above Example 17, except that the catalyst produced from the above Example 14 in the above Example 17 was used; the composition of the reaction gas was changed to C.sub.2H.sub.4:H.sub.2:N.sub.2=1:4:1 and 24% out of hydrogen gas in the mixed gas discharged from the reactor was selectively separated and discharged in the polymer membrane.

(71) The reaction could be possible to safely operate by recirculating the mixed gas consisting of H.sub.2, N.sub.2, and 3.5% of un-reacted C.sub.2H.sub.4 to the reaction gas supply pipe. In addition, the used amounts of H.sub.2 and N.sub.2 were minimized by progressing the reaction without an additional supply of H.sub.2 and N.sub.2 by performing a continuous operation through adding only C.sub.2H.sub.4 corresponding 85% of initial amount injected to the reaction gas supply pipe.

(72) After 1 hour reaction, CNT collected to the CNT collector has a yield of 550% as compared with catalyst input, and at this time, the average external diameter of CNT obtained from the above was 25 nm.

(73) The conversion rates of carbon sources in the above Examples 1 to 19 were at least 98%.

Example 20

(74) In addition, 25 g of Al.sub.2O.sub.3 metal supported catalyst supported with 5 wt % of Mo and 15 wt % Co produced in a way as the above Example 1 was filled in the reactor. After preheating ethylene, nitrogen, and hydrogen as the reaction gas at 500 C., 28.2 gmol of the ethylene, 28.2 gmol of the nitrogen, and 84.7 gmol of the hydrogen were injected per one hour as the flow rate to the reactor through the gas distributor, respectively. And then, the temperature was controlled at 800 C. and then manipulated to synthesize the desired CNT.

(75) As a result, 0.502 kg of CNT per one hour was produced in the reactor. The ethylene in the reaction gas was consumed by the reaction and the hydrogen was generated as the byproduct so that the composition of the mixed gas was changed, and then as the flow rate, 7.3 gmol of the etylene, 28.2 gmol of the nitrogen, and 126.5 gmol of the hydrogen were discharged from the reactor per one hour, respectively in the outlet part of the reactor.

(76) And then, in order to secure the temperature of less than 50 C. that is the range capable of operating of the polymer membrane for the low temperature, the mixed gas and CNT discharged after cooling at 40 to 50 C. through the heat exchanger were separated through the cyclone; for the separated mixed gas, only hydrogen in a such amount that is generated as the byproduct in the reactor was selectively separated in the single polymer membrane (48 mm diameter, 27 inch length, hollow type polycarbonate membrane, the product available from IGS Company) and then re-circulated to the reactor supply pipe through the re-circulation pipe to significantly reduce 21 gmol per one hour of the amount of the ethylene gas that is lately supplied to the reactor.

(77) Meanwhile, for the mixed gas re-circulated to the inlet of the reactor, it was confirmed that 7.2 gmol of the ethylene, 27.4 gmol of the nitrogen, and 84.7 gmol of the hydrogen were measured per one hour. The above values were shown that the original feed rate of the reaction gas was largely reduced as the rates of 26% of ethylene, 98% of nitrogen, and 99% of hydrogen as compared with the case of incineration of whole conventional discharging gas so that the production cost of desired CNT could be significantly reduced.

(78) The following Table 1 shown the composition and flow rate of the mixed gas discharged from the reactor, and the following Table 2 shown the composition and flow rate of the mixed gas discharged from the polymer membrane.

(79) TABLE-US-00001 TABLE 1 Reactor Outlet Gas Amount of Reactor Discharging Gas 3.63 Nm.sup.3/h Content in Supply Gas (%) H.sub.2 78.1 C.sub.2H.sub.4 4.5 N.sub.2 17.4

(80) TABLE-US-00002 TABLE 2 Gas Separation Unit (Polymer Membrane) Outlet Gas Each Contents in H.sub.2 >98.6% (Hydrogen Generation Gas (%) Recovery Rate 33.04%) Un-reacted C.sub.2H.sub.4 ~0.2% Remained N.sub.2 ~1.2% Flow of Product Gas Selectively Separated 0.96 Nm.sup.3/h Through Separation Unit

Example 21

(81) The same process with Example 20 was repeated, except that 26.2 gmol of the ethylene, 26.2 gmol of the nitrogen, and 104.7 gmol of the hydrogen per one hour as the flow rate were supplied to the reactor, respectively, as the reaction gas after preheating at 500 C., and the single polystyrene was used as the polymer membrane in the above Example 20.

(82) As a result, it was confirmed that for the gas composition discharged from the reactor, 5.2 gmol of the ethylene, 26.2 gmol of the nitrogen, and 146.6 gmol of the hydrogen per one hour as the flow rate were discharged, respectively, and also for the composition of the mixed gas re-circulated to the inlet of the reactor, 5.1 gmol of the ethylene, 25.4 gmol of the nitrogen, and 104.7 gmol of the hydrogen per one hour as the flow rate were measured, respectively.

(83) The above values were shown that the original feed rate of the reaction gas was largely reduced as the rates of 20% of ethylene, 98% of nitrogen, and 99% of hydrogen as compared with the case of incineration of whole conventional discharging gas so that the production cost of desired CNT could be significantly reduced.

(84) The following Table 3 shown the composition and flow rate of the mixed gas discharged from the reactor, and the following Table 4 shown the composition and flow rate of the mixed gas discharged from the polymer membrane.

(85) TABLE-US-00003 TABLE 3 Reactor Outlet Gas Amount of Reactor Discharging Gas 3.99 Nm.sup.3/h Content in Supply Gas (%) H.sub.2 82.4 C.sub.2H.sub.4 2.94 N.sub.2 14.7

(86) TABLE-US-00004 TABLE 4 Gas Separation Unit (Polymer Membrane) Outlet Gas Each Contents in H.sub.2 >98.6% (Hydrogen Generation Gas (%) Recovery Rate 33.04%) Un-reacted C.sub.2H.sub.4 ~0.2% Remained N.sub.2 ~1.2% Flow of Product Gas Selectively Separated 0.96 Nm.sup.3/h Through Separation Unit

Example 22

(87) The same process with Example 20 was repeated, except that 27.5 gmol of the ethylene, 27.5 gmol of the nitrogen, and 137.6 gmol of the hydrogen per one hour as the flow rate were supplied to the reactor, respectively, as the reaction gas after preheating at 500 C., and the single polyimide of hollow type was used as the polymer membrane in the above Example 20.

(88) As a result, it was confirmed that for the gas composition discharged from the reactor, 6.6 gmol of the ethylene, 27.5 gmol of the nitrogen, and 179.4 gmol of the hydrogen per one hour as the flow rate were discharged, respectively, and also for the composition of the mixed gas re-circulated to the inlet of the reactor, 6.5 gmol of the ethylene, 26.7 gmol of the nitrogen, and 137.6 gmol of the hydrogen per one hour as the flow rate were measured, respectively.

(89) The above values were shown that the original feed rate of the reaction gas was largely reduced as the rates of 24% of ethylene, 98% of nitrogen, and 99% of hydrogen as compared with the case of incineration of whole conventional discharging gas so that the production cost of desired CNT could be significantly reduced.

(90) The following Table 5 shown the composition and flow rate of the mixed gas discharged from the reactor, and the following Table 6 shown the composition and flow rate of the mixed gas discharged from the polymer membrane.

(91) TABLE-US-00005 TABLE 5 Reactor Outlet Gas Amount of Reactor Discharging Gas 4.78 Nm.sup.3/h Content in Supply Gas (%) H.sub.2 84.02 C.sub.2H.sub.4 3.1 N.sub.2 12.9

(92) TABLE-US-00006 TABLE 6 Gas Separation Unit (Polymer Membrane) Outlet Gas Each Contents in H.sub.2 >98.6% (Hydrogen Generation Gas (%) Recovery Rate 23.3%) Un-reacted C.sub.2H.sub.4 ~0.2% Remained N.sub.2 ~1.2% Flow of Product Gas Selectively 0.96 Nm.sup.3/h Separated Through Separation Unit

Comparative Example 1

(93) The same method with the above Example 2 was performed, except that 100% of the mixed gas separated by the cyclone in the above Example 2 was re-circulated without passing through the polymer membrane, the distributor, and the like, and only ethylene (C.sub.2H.sub.4) corresponding to 85% of initial amount injected to the reaction gas supply pipe was added.

(94) The continuous operation was tried in the reaction, but 2 mole of hydrogen (H.sub.2) produced as the byproduct of the reaction per 1 mole of ethylene was continuously accumulated in the reactor so that the pressure in the reactor was increased; made it difficult to smoothly inject C.sub.2H.sub.4; and hence the stable operation could not be possible within 20 minutes.

Comparative Example 2

(95) The same method with the above Example 2 was performed, except that all of the polymer membrane and re-circulation pipe were omitted and the same composition and content of the reaction gas was continuously supplied to the reactor in the above Example 2.

(96) The reaction had a significantly high cost of CNT production because the consumption level of ethylene was 37 times higher and the consumption level of nitrogen was 80100 times higher, and the consumption level of hydrogen was at least 100 times higher than these of the above Example 2.

(97) After one-hour reaction, CNT collected in the CNT collector had a yield of 840% and a conversion rate of 80% based on catalyst input, and the average external diameter of CNT obtained was 30 nm.

Test Example

(98) The reaction condition, the conversion rate of the carbon source, and CNT yield of the above Examples 1 to 19 were measured as the following methods, and the results were shown in the following Table 7 and Table 8.

(99) Conversion Rate of Carbon Source (%): an injecting amount of ethylene gas to the reactor and a discharging amount of ethylene gas from the outlet of the reactor were measured by using Gas Chromatography and then the conversion rate was calculated as the following formula:
Conversion Rate of Carbon Source=(Flow of Ethylene Gas Injected to Reactor (gmol/hr)Flow of Ethylene Discharged from Reactor (gmol/hr))100/Flow of Ethylene Injected to Reactor (gmol/hr)

(100) Gas Separation Efficiency (%): The compositions at a front end and a back end of the membrane were measured by using Gas Chromatography and the separation efficiency was calculated based on the following formula:
Gas Separation Efficiency (%)=Gas Flow filtration-removed by Polymer Membrane (gmol/hr)100/Gas Flow flowed to Polymer Membrane (gmol/hr)

(101) CNT Yield (%): A weight of catalyst was subtracted from a weight of CNT amount collected after the reaction by using a precise electronic scale, and then the catalyst yield was calculated based on the following formula:
Catalyst Yield (%)=(Total Weight of Carbon Product Recovered (g)Mass of Catalyst (g))100/Mass of Catalyst (g)

(102) TABLE-US-00007 TABLE 7 Supply H.sub.2 Gas C.sub.2H.sub.4 Catalyst Gas Supplying Velocity Separation Conversion CNT Reactor Use Composition (ml/ Efficiency Rate Yield Example Type Catalyst Amount C.sub.2H.sub.4 H.sub.2 N.sub.2 min) (%) (%) (%) 1 FBR CoMo/ 5 g 1 1 1 3000 20 90 950 2 Al.sup.2O.sub.3 5 g 1 2 1 3000 33 98.7 1020 3 5 g 1 3 1 3000 28 98.4 780 4 5 g 1 4 1 3000 24 98 630 5 5 g 1 5 1 3000 20 98.2 580 6 Rotary CoMo/ 3 g 1 2 1 1500 35 98.5 870 7 klin Al.sup.2O.sub.3 3 g 1 3 1 1500 29 98.2 700 type 8 FBR CoMo/ 5 g 1 2 1 3000 34 98 1060 9 MgO 5 g 1 3 1 3000 29 99 810 10 5 g 1 4 1 3000 24 98.5 670 11 Rotary CoMo/ 3 g 1 2 1 1500 36 99.2 860 12 klin MgO 3 g 1 3 1 1500 29 99 690 13 type 3 g 1 4 1 1500 24 98 570 14 FBR FeMo/ 5 g 1 2 1 3000 31 98.4 930 15 SiO.sub.2 5 g 1 3 1 3000 24 98.3 790 16 5 g 1 4 1 3000 21 98 600 17 Rotary FeMo/ 3 g 1 2 1 1500 35 99 860 18 klin SiO.sub.2 3 g 1 3 1 1500 29 99.2 680 19 type 3 g 1 4 1 1500 24 98.5 550

(103) TABLE-US-00008 TABLE 8 Gas H.sub.2 Gas C.sub.2H.sub.4 Catalyst Supplying Supply Separation Conversion CNT Com. Reactor Use Composition Velocity Efficiency Rate Yield Example Type Catalyst Amount C.sub.2H.sub.4 H.sub.2 N.sub.2 (ml/min) (%) (%) (%) 1 FBR CoMo/Al.sup.2O.sub.3 5 g 1 2 1 3000 Gas Separation NA 2 5 g 1 2 1 3000 Gas 80 80 Separation- NA

(104) As shown in the above each of Examples, Table 7 and Table 8, it could be confirmed that the CNT manufacturing apparatus and method according to the present invention (Examples 1 to 19) had excellent conversion rate and also excellent CNT yield so that the cost of production could be significantly reduced and was an environmentally friendly way because a waste gas was not be generated.

(105) Furthermore, it could be also confirmed that Examples 20 to 22 that use the single polymer membrane of hollow type allow separating effectively through controlling the pressure and input amount even if using single membrane when the polymer membrane itself has high separation efficiency.