Characterization and catalytic performance of CeO 2-Co/SiO 2 catalyst for Fischer-Tropsch synthesis using nitrogen-diluted synthesis gas over a laboratory scale fixed-bed reactor

Abstract

The surface species of CO hydrogenation on CeO 2-Co/SiO 2 catalyst were investigated using the techniques of temperature programmed reaction and transient response method. The results indicated that the formation of H 2O and CO 2 was the competitive reaction for the surface oxygen species, CH 4 was produced via the hydrogenation of carbon species step by step, and C 2 products were formed by the polymerization of surface-active carbon species (-CH 2-). Hydrogen assisted the dissociation of CO. The hydrogenation of surface carbon species was the rate-limiting step in the hydrogenation of CO over CeO 2-Co/SiO 2 catalyst. The investigation of total pressure, gas hourly space velocity (GHSV), and product distribution using nitrogen-rich synthesis gas as feedstock over a laboratory scale fixed-bed reactor indicated that total pressure and GHSV had a significant effect on the catalytic performance of CeO 2-Co/SiO 2 catalyst. The removal of heat and control of the reaction temperature were extremely critical steps, which required lower GHSV and appropriate CO conversion to avoid the deactivation of the catalyst. The feedstock of nitrogen-rich synthesis gas was favorable to increase the conversion of CO, but there was a shift of product distribution toward the light hydrocarbon. The nitrogen-rich synthesis gas was feasible for F-T synthesis for the utilization of remote natural gas.