Abstract: The Fischer-Tropsch synthesis (FTS) reaction over the fused iron catalyst in the presence of supercritical media was investigated in a fixed-bed reactor. Compared with the gas-phase FTS reaction, the presence of supercritical media resulted in an increase in CO conversion, olefin selectivity, and C5+selectivity, but a decrease in CH4 selectivity owing to the fact that diffusion was easier in the supercritical media and less inactive carbon was deposited on the catalyst surface. The effects of supercritical media, temperature, pressure, H2/CO ratio, and syngas flow rate on the supercritical phase FTS reaction were investigated. The n-pentane, n-hexane, n-heptane, and n-octane had similar effects on the FTS reaction. The performance of FTS reaction could be improved when the reaction temperature and pressure were higher than the critical points of the media owing to the better mass and heat transportation in supercritical media.

Key words: fused iron catalyst, supercritical fluid, normal paraffin, Fischer-Tropsch synthesis, syngas