Catalytic performances of cobalt-based ultrafine particles prepared by chemical reduction in slurry-phase Fischer–Tropsch synthesis

Abstract

For the purpose of developing the catalysts for slurry phase Fischer–Tropsch synthesis, fundamental studies of catalysis by ultrafine particles (UFP) of Co were carried out using a slurry bed reactor. Co UFP prepared by the method of chemical reduction in liquid phase was more active for this reaction than a precipitated Co catalyst, due to its nonporous structure. The addition of Cr, Ti, Mn, Mo, or Zr onto Co UFP was found to be effective to enhance the catalytic activity. Among these UFP catalysts, Co–Cr UFP exhibited the highest activity. The space time yield of hydrocarbons on Co–Cr UF P prepared in the mixed solution of H 2O and CH 3OH was 14.9 g g-cat −1 h −1. The increased activity was attributed to a decrease in particle size of Co. Distribution of hydrocarbons produced was also dependent on the particle size. The selectivity for CH 4 was lowered and that for C 5 + hydrocarbons was enlarged by a decrease in particle size.