Co and Co/Ru based catalysts synthesized by FSP for the industrial Gas-to-Liquid Fischer-Tropsch process

The GTL - FT process converts syngas, a mixture of H2/CO with a molar ratio equal to 2, into hydrocarbons [1]. A 10%wtCo and a 10%wtCo - 0.1%wtRu based catalysts supported on silica were prepared by Flame Spray Pyrolysis (FSP), chatacterized by BET, SEM, TEM, TPR, XRD and tested at different temperature in a FT bench scale plant using a Packed Bed Reactor (PBR). FSP allows to obtain metal oxides with high surface area and high thermal stability thanks to the dispersion, vaporization and pyrolysis of the precursors solution [2]. The solution is composed of Co(CH3COO)2·4H2O (Fluka), Si(OC2H5)4 (Fluka) dissolved in a 1/1 (vol/vol) mixture of CH3CH2COOH (Fluka)/p-xylene (Sigma Aldrich). The synthesis of the bimetallic catalyst is accomplished by FSP followed by the addition of Ru by impregnation using Ru3(CO)12 (Sigma Aldrich) as a precursor. The TPR profiles (Figure 1) of both samples show two different peaks at T= 320-360°C (Co3O4CoO) and T= 700-800°C (CoOCo) [1]. Figure 1 also highlights that the insertion of Ru decreases both peaks temperatures by ca. 20°C. The samples were tested at T= 225-260°C, P= 2.0 MPa, H2/CO= 2 (mol/mol) with sl/h/gcat= 3.0. The results summarized in Table 1 show that Co-Ru is more active in therms of CO conversion and C2+yeld if compared with the monometallic one. The non-promoted catalyst shows higher selectivity to >C7 with respect to the Ru-doped catalyst. Finally, the selectivity toward the reaction products is not largely influenced in the range of temperature tested.