COx Fixation to Elementary Building Blocks: Anaerobic Syngas Fermentation vs. Chemical Catalysis

Heterogeneous catalysis and anaerobic syngas fermentation represent two different approaches for the conversion of synthesis gas into chemicals and fuels. This review provides a unique comparison of different reaction paths for the fixation of CO2, CO and H-2 into elementary building blocks such as methanol, acetic acid and ethanol. Operating conditions, reactor engineering, influence of gas impurities, yields, conversion efficiencies as well as downstream product recovery are compared. It was found that mass-specific productivity ranges in the same order of magnitude for both technologies, while space-time yield of heterogeneous catalysis is up to three orders of magnitude higher.