An active and selective production of gasoline-range hydrocarbons over bifunctional Co-based catalysts

Abstract

Catalytic performance of several bifunctional cobalt-based catalysts in slurry-phase Fischer–Tropsch synthesis has been investigated at 1 MPa and 230 °C. The catalysts were prepared according to the conventional impregnation method using SiO 2, Al 2O 3, montmorillonite (K10 ®), and various zeolites (USY, ZSM-5 and MCM-22) as a support. When an acidic support was applied, the formation of heavier hydrocarbons was retarded and the carbon number distribution was shifted to gasoline range (C 4–C 12). Montmorillonite loaded with Co (Co/MONT) was a good catalyst, showing higher the CO conversion than Co/SiO 2 and Co/Al 2O 3. MCM-22 exhibited a superior performance to other zeolitic supports. With decreasing aluminum content, the activity of Co/MCM-22 catalysts was remarkably enhanced and the selectivity to methane and isoparaffins decreased. Besides the high CO conversion (55–60%), C 4 + isoparaffins were produced more selectively over Co/MCM-22 (43–53%) than Co/USY (43.5%) and Co/ZSM-5 (36%). Compared to the results under supercritical conditions, the slurry-phase conditions are more suitable for an active and selective production of gasoline-range hydrocarbons through the Fischer–Tropsch synthesis over MCM-22 supported Co catalysts.