The formation of surface cobalt structures was investigated for a number of β-SiC-supported Fischer–Tropsch catalysts.

A comparative analysis of industrial zeolite-containing cobalt catalysts for Fischer-Tropsch synthesis with a number of physicochemical parameters is performed. Catalysts containing a heat-conducting additive (aluminum flakes or exfoliated graphite) were tested in an industrial size single-tube reactor (length—6000 mm, inner diameter—12 mm). The testing results of a sample without heat-conducting additive are presented for comparison. It is shown that a catalyst based on support, containing exfoliated graphite is preferable for industrial application at high gas hour space velocities of the syngas due to its higher thermal stability and liquid hydrocarbon productivity.

Some kinetic parameters of Fischer–Tropsch synthesis (FTS) were determined in the presence of a granular cobalt/zeolite catalyst. Usually, kinetic studies of granular catalysts are considered to be complicated by external and internal diffusion. We managed to obtain a catalyst with a special structure of the active surface, where sites active in FTS are isolated from each other due to the environment of inactive spinel CoAl₂O₄ and inter-site transport is provided by an extensive intragranular graphitic network serving simultaneously as a heat-conductive medium. As a result, FTS proceeded in the kinetic region. It was found that the reaction kinetics obey the Arrhenius law; whereas, the activation energy is different in different temperature ranges, i.e., 118.2 kJ/mol in the range of 180–210 °C, and 173.6 kJ/mol in the range of 232–243 °C. This behavior is determined by the presence of zeolite, which becomes active in the secondary transformations of FTS products at temperatures beyond 210 °C.