Fischer–Tropsch synthesis over one eggshell-type Co/SiO2 catalyst in a slurry phase reactor

The eggshell type cobalt catalyst (Co/SiO2) was prepared via a spray method. Characterization of surface information between cobalt and the support of silica gel was obtained by SEM and EPMA techniques. The discrete cobalt particle sizes were calculated based on XRD analysis. The prepared eggshell Co/SiO2 catalysts were investigated for Fischer–Tropsch (FT) synthesis in a slurry-phase reactor and compared with conventional impregnated catalyst under the conditions of P = 1.0 MPa, T = 503 K, W/F = 5.0 g-cat h/mol and H2/CO = 2. Results indicated that eggshell Co/SiO2 catalyst was inclined to generate long chain hydrocarbons and had relatively low CH4 selectivity. The parameters that respond to the performance of FT synthesis had been upgraded when compared with those of a conventional impregnated catalyst. In generated hydrocarbons for 1800 μm supported catalyst, CH4 selectivity decreased from 22.98% to 9.68%, and C5+ selectivity increased from 61.66% to 79.45%. Meanwhile, the chain growth probabilities (α) also increased from 0.84 to 0.90. According to H2-chemisorption and space-time yield (STY), the turnover frequency (TOF) of each catalyst was calculated. The higher TOF value of eggshell catalyst means better FT synthesis performance than is available using conventional impregnated catalyst.

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► Eggshell Co/SiO2 catalyst was prepared by spray method.
► Cobalt was deposited on the external surface of silica gel in the eggshell catalyst.
► The catalyst was conducted FT synthesis in a slurry phase reactor.
► The high TOF value of eggshell catalyst indicated good performance of FT synthesis.