Effect of Re and Al2O3 Promotion on the Working Stability of Cobalt Catalysts for the Fischer–Tropsch Synthesis

Abstract

The results of the working stability studies of cobalt catalysts based on SiO2 and Al2O3 promoted with Re and Al2O3 in the synthesis of hydrocarbons from CO and H2 in continuous tests for 200–300 h are presented. The prepared catalysts were characterized by transmission electron spectroscopy, temperature-programmed reduction with hydrogen, temperature-programmed desorption of CO, and X-ray fluorescence spectroscopy and tested at a temperature 200°C, a pressure of 0.1 MPa, and a GHSV of 100 h–1. It was determined that a cobalt–silica catalyst promoted with Al2O3 had the highest activity. It was established that the addition of Al2O3 to a cobalt–silica catalyst increased the conversion of CO and selectivity for C5+ hydrocarbons and inhibited the agglomeration of Co particles under the action of a reaction atmosphere in the Fischer–Tropsch synthesis. It was found that the initial conversion of CO increased by a factor of 2 upon the introduction of 0.1 wt % rhenium into the Co/γ-Al2O3 catalyst; however, the rate of its deactivation increased in this case due to an almost twofold increase in the size of cobalt particles in the course of synthesis after operation for 300 h.