Application of Plasma Technology in Fischer-Tropsch Catalysis for the Production of Synthetic Fuels

Abstract

A short review of our results is presented on the use of high temperature plasma technology in producing catalysts for application in Fischer- Tropsch synthesis (FTS). Nanometric carbon-supported catalysts based primarily on Co and Fe with various metal formulations were synthesized using an induction suspension plasma-spray (SPS) system. The active catalytic species of the metals and the C-matrix support composing both graphitic (G) and amorphous (D; disordered) carbon were all simultaneously generated in situ within the plasma. The Co/C catalyst was the most active when tested for FTS with high selectivity towards the longer hydrocarbon chains. At 220 °C, 2MPa pressure; gas hourly specific velocity of over 3,600cm3 .h-1 .g-1 of catalyst, it indicated ~40% CO conversion with the following selectivity expressed as % in the products: 30% gasoline (C5-C12), 45% diesel (C13-C20), and 21% waxes (C21+), with less than 4% CH4 and trace amounts of CO2 . Other catalysts tested include Fe/C, bimetallic Co-Fe/C formulations and those promoted with Ni, Mo, and Au-Ni. It has been shown that particle size influences FTS when using plasma-synthesized catalysts: thus, particles in the mean size range of 9-11nm were more selective towards the diesel fraction and waxes, while larger particles of mean size of 14-21nm produced more gasoline. Since SPS technology is a relatively new approach in catalyst synthesis, being a one-step process potentially offers an overall higher efficiency and new prospects for the commercial production of synthetic fuels through FTS.