An apparatus for continuous production of aligned carbon nanotubes is disclosed. The apparatus includes a reactor, an injector for delivering a feed solution into the reactor, and a conveyor for passing through the reactor a substrate on which nanotubes may be formed and grown. The apparatus further may include an inert, porous medium through which the feed solution may be passed. The apparatus produces aligned carbon nanotubes of a predetermined external diameter, and is suitable for large scale production of aligned carbon nanotubes in an industrial setting.