Influence of Gas Feed Composition and Pressure on the Catalytic Conversion of CO₂to Hydrocarbons Using a Traditional Cobalt-Based Fischer−Tropsch Catalyst

The hydrogenation of CO2 using a traditional Fischer−Tropsch Co−Pt/Al2O3 catalyst for the production of valuable hydrocarbon materials is investigated. The ability to direct product distribution was measured as a function of different feed gas ratios of H2 and CO2 (3:1, 2:1, and 1:1) as well as operating pressures (ranging from 450 to 150 psig). As the feed gas ratio was changed from 3:1 to 2:1 and 1:1, the production distribution shifted from methane toward higher chain hydrocarbons. This change in feed gas ratio is believed to lower the methanation ability of Co in favor of chain growth, with possibly two different active sites for methane and C2−C4 products. Furthermore, with decreasing pressure, the methane conversion drops slightly in favor of C2−C4 paraffins. Even though under certain reaction conditions product distribution can be shifted slightly away from the formation of methane, the catalyst studied behaves like a methanation catalyst in the hydrogenation of CO2.