Iron-Based Fischer-Tropsch Synthesis for the Efficient Conversion of Carbon Dioxide into Isoparaffins

摘要

Iron-based Fischer-Tropsch (FT) synthesis in combination with hydroisomerization in the presence of zeolites for the synthesis of isoparaffins from CO2/H-2 was conducted in a fixed-bed reactor. Relative to supported iron catalysts, the precipitated one efficiently converted intermediate CO into hydrocarbons by supplying a high density of FT active sites on the catalyst surface. Removing water by interstage cooling and promoting the CO conversion step in the FT synthesis were effective approaches in achieving a high CO2 conversion, because of an increase in the driving force to the reaction equilibrium. Particle mixing of 92.6Fe7.4K with either 0.5Pd/ or HZSM-5 zeolite effectively hydroisomerized the resulting FT hydrocarbons into gasoline-range isoparaffins. Particularly, HZSM-5 displayed a higher isoparaffin selectivity at approximately 70%, which resulted from easier hydrocracking and hydroisomerization of the olefinic FT primary products.