Abstract
Fischer-Tropsch synthesis reaction was conducted in gas phase, liquid phase and supercritical phase, respectively, with the same Co-based catalyst. Its characteristics in different reaction phase were compared experimentally and theoretically, mainly from the viewpoint of mass transfer. Under the same reaction conditions, the gas phase reaction exhibited the highest reaction rate while the liquid phase reaction showed the lowest.
Reactant diffusion efficiency in different reaction phase were found to be in the following orders: gas phase>supercritical phase>liquid phase. This point was emphasized with the comparison of apparent activation energy, and catalyst effectiveness factor. In the meanwhile, the influence of catalyst pellet size or catalyst pore size was investigated. Supercritical phase reaction gave highest olefin selectivity, regardless of carbon number. This phenomenon was attributed to the quick desorption of the olefin from catalyst surface and its rapid diffusion occurring inside catalyst pellet, to the advantage of supercritical fluid.
