Preliminary evaluation of a commercially viable Co-based hybrid catalyst system in Fischer-Tropsch synthesis combined with hydroprocessing

Syngas conversion via the Fischer-Tropsch synthesis (FTS) protocol provides a promising alternative to flaring or re-injection of associated petroleum gas to monetize it. The most attractive method for this is direct conversion of syngas into transportation fuels over hybrid catalyst systems comprising both a catalyst for FTS and a zeolite component that catalyzes hydroprocessing (HP) of primary hydrocarbons. Here we describe a hybrid catalyst system in which a pre-formed silica-supported cobalt catalyst for FTS and a ZSM-5 zeolite component as an HP catalyst reside within a single extruded particle, in nanoscale vicinity to each other, while the sizes of the extrudates are suitable for their commercial application. The prepared hybrid catalysts were tested for their performance in a bench-scale fixed bed reactor operating at T = 240-250 °C, P = 1.0-2.0 MPa, GHSV = 1000 h −1 and H 2 /CO = 1-3 and showed higher activities in both FTS and HP as compared with some recently reported catalysts. The prepared catalysts were characterized by temperature-programmed desorption of hydrogen (H 2 -TPD) and ammonia (NH 3 -TPD), X-ray diffraction (XRD) using synchrotron radiation, high-resolution transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). As has been shown by TEM, the procedure applied to prepare the hybrid catalyst system does not change the size distribution of cobalt nanoparticles in the resulting hybrid catalyst as compared with the parent FTS catalyst. A hybrid catalyst for one-step conversion of syngas into liquid hydrocarbons, mainly gasoline and diesel, is proposed.