Fischer-Tropsch synthesis in slurry-phase reactors over Mn- and Zr-modified Co/SiO2 catalysts

Fischer-Tropsch (F-T) synthesis was carried out in a gas-flowed slurry-phase reaction system over Mn- and Zr-modified CO/SiO2 catalysts. A 0.5 L stirred tank slurry reactor (STSR) was used for catalyst screening and a 12.5 L slurry bubble column reactor (SBCR) was used for trial pilot operation. While using the 0.5 L reactor for catalyst screening, Co supported on the SiO2 With an average pore size of 10 nm showed a high catalytic performance for the F-T synthesis due to the suitable Co particle size in the catalyst. Zr promoter improved the activity and Mn promoter improved the stability Of Co/SiO2 catalyst for the F-T synthesis. H-2-TPR profiles indicated that Zr and Mn promoters improved the reduction degree Of Co3O4 particles (on SiO2 surface) to Co-0 active species in H-2 flow at low temperature. While using the 12.5 L reactor for trial pilot operation over Mn-Zr-Co/SiO2 catalyst, the space-time yield (STY) Of C5+ hydrocarbons (liquid fuel) showed almost the same values when various solvents (n-C16H34, n-C14H30, diesel from petrol station, F-T crude oil) were used. Diesel and F-T crude oil are suitable for using in a large-scaled F-T synthesis plant owing to the low prices. Mn-Zr-Co/SiO2 catalyst achieved a STY Of C5+ hydrocarbons larger than 1000 g-C5+ kg-cat(-1) h(-1) in the 12.5 L reactor. The production capacity of liquid fuel from the 12.5 L reactor reached to 15,6 L per day (assumed for 24 h continuous operation). The stirring was very important for the F-T synthesis both reaction in the 0.5 L reactor and reaction in the 12.5 L reactor. The shape of slurry reactor also influenced the CO conversion for the F-T synthesis: reaction in the 12.5 L SBCR gave a higher CO conversion than that of reaction in the 0.5 L STSR (at the same W/F value under the same stirring speed) because the slender column reactor (SBCR) extended the residue time of reaction gas in the slurry-phase containing catalyst. (C) 2009 Elsevier B.V. All rights reserved.