Kinetic Study of the Fischer-Tropsch Synthesis and Water Gas Shift Reactions over a Precipitated Iron Catalyst

Fischer-Tropsch 5 . , $H_2$ /CO 0.5~2, 60~80 ml/min, $255{\sim}275^{\circ}C$ 1.5 MPa . F-T ( $r_{FT}$ ) CO Eley-Rideal , WGS ( $r_{WGS}$ ) formate . , F-T WGS $CO_2$ , power law CO . , ( $r_{FT}$ , $r_{WGS}$ , $-r_{CO}$ ) . 【The kinetics of the Fischer-Tropsch synthesis and water gas shift reactions over a precipitated iron catalyst were studied in a 5 channel fixed-bed reactor. Experimental conditions were changed as follows: synthesis gas $H_2$ /CO feed ratios of 0.5~2, reactants flow rate of 60~80 ml/min, and reaction temperature of $255{\sim}275^{\circ}C$ at a constant pressure of 1.5 MPa. The reaction rate of Fischer-Tropsch synthesis was calculated from Eley-Rideal mechanism in which the rate-determining step was the formation of the monomer species (methylene) by hydrogenation of associatively adsorbed CO. Whereas water gas shift reaction rate was determined by the formation of a formate intermediate species as the rate-determining step. As a result, the reaction rates of Fischer-Tropsch synthesis for the hydrocarbon formation and water gas shift for the $CO_2$ production were in good agreement with the experimental values, respectively. Therefore, the reaction rates ( $r_{FT}$ , $r_{WGS}$ , $-r_{CO}$ ) derived from the reaction mechanisms showed good agreement both with experimental values and with some kinetic models from literature.】