Continuous production of single-walled carbon nanotubes using a supported floating catalyst

Using catalytic decomposition, a technique for the production of singe-walled carbon nanotubes (SWCNTs) is reported with a production rate up to 6 g h(-1) after purification, and scaling capability up to 220 g h(-1). This is achieved by injection of pre-prepared alumina supported catalyst powder into a modified vertical floating reactor. The product is collected in several cyclones connected in series. Wide range Raman studies (laser excitations from lambda = 1064 to 488 nm) and temperature programmed oxidation measurements of the samples collected from the different cyclones show that SWCNTs were separated in situ by tube diameter. This is attributed to the different residual times of the catalyst in the reaction zone depending on particle diameter. A series of computational fluid dynamics calculations of the flow and heat transfer in the reactor, as well as modeling of catalyst particle transport reveals the parametrical dependence of the process. (c) 2007 Elsevier Ltd. All rights reserved.