To synthesize liquid fuels on precipitated Fe catalyst with CO2-containing syngas gasified from biomass

Abstract

Fischer-Tropsch (FT) synthesis is an effective method to produce liquid fuels from biomass. This chapter reports the study on precipitated Fe catalysts for conversion of CO2-containing syngas to liquid fuels. The influences of promoter Zn, K, and Cu on CO2 activation were analyzed by CO2 temperature-programmed- desorption (CO2-TPD). Cu has no strong effect to activate CO2. K increases mainly CO2 adsorption and is inferior to Zn in producing CO. The catalysts with high Zn/K ratio or low K content possess desorbed CO peak around 930 K in CO2-TPD and decreased CO2 selectivity resulted from CO2 addition in FT synthesis. The Fe catalyst with high Zn/K ratio shows high C2+ hydrocarbon selectivity for CO2 hydrogenation, too. It indicates that the CO2 contained in syngas is able to be activated by suitable promoter(s) for hydrocarbon synthesis at low temperature. The correlation between promoter composition and catalyst reactivity found for SiO2-free Fe catalysts is effective for SiO2-added Fe catalysts.