Fischer–Tropsch Synthesis at High Conversions on Al2O3-Supported Co Catalysts with Different H2/CO Levels

Fischer-Tropsch experiments with different H2/CO ratios at high CO conversions have been carried out over an alumina-supported 20wt%Co-0.5wt%Re catalyst in a stainless steel fixed-bed reactor at 210 oC and 20 bar and with H2/CO ratios between 1.04 and 2.56. The results indicate that for H2/CO ratios above 2.1, CO conversion levels up to at least 85% can be obtained without significant short-term deactivation or loss of selectivity towards heavier hydrocarbons. Except for very low conversion anomalies, the data collapse into a single trendline for selectivity to C5+ products versus average hydrogen partial pressure in the reactor irrespective of the H2/CO feed ratio. The present results are important for development of small scale biomass to liquids plant based on a once-through process concept in order to avoid recycle streams.