Patent ID: 6413487
Filing Date: 2002-07-02
Classification: B01J,B82Y,C01B,D01F,Y02P,Y10S

Abstract:
A process for producing carbon nanotubes, comprising:feeding catalytic particles into a reactor wherein the catalytic particles comprise a support material and a catalyst, the catalyst effective in catalyzing the conversion of a carbon-containing gas into carbon nanotubes; removing air from the catalytic particles; reducing the catalytic particles by exposing the catalytic particles to reducing conditions forming reduced catalytic particles; preheating the reduced catalytic particles to a reaction temperature; catalytically forming carbon nanotubes by exposing the reduced catalytic particles to a carbon-containing gas heated to the reaction temperature and under elevated pressure for a duration of time sufficient to cause catalytic production of carbon nanotubes thereby forming reacted catalytic particles bearing the carbon nanotubes; flushing the carbon-containing gas from the reacted catalytic particles; cooling the reacted catalytic particles; removing amorphous carbon deposited on the reacted catalytic particles by exposing the reacted catalytic particles to oxidizing conditions burning the amorphous carbon and forming semi-purified catalytic particles; treating the semi-purified catalytic particles to separate the support material from the catalyst; treating the catalyst to separate the carbon nanotubes from the catalyst; recovering and recombining the support material and the catalyst to regenerate catalytic particles; and feeding the regenerated catalytic particles into the reactor.