Fischer-Tropsch synthesis over an alumina-supported cobalt catalyst in a fixed bed reactor – Effect of process parameters

• Published in: Catalysis today 2021-06, Vol.369, p.150-157
• Main Authors: Gavrilović, Ljubiša, Jørgensen, Erik A., Pandey, Umesh, Putta, Koteswara R., Rout, Kumar R., Rytter, Erling, Hillestad, Magne, Blekkan, Edd A.
• Format: Article
• Language: English
• Subjects: Alumina; Cobalt; Fischer-Tropsch; Process parameters; Water
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2020.07.055

The evaluation of the Fischer-Tropsch experiment with H2/CO = 2.13 at 210 °C with changes in CO conversion and water addition. [Display omitted] •Co-based catalyst developed WGS activity at low H2/CO ratio.•Water has a positive effect on C5+ selectivity for all H2/CO ratios.•Re-oxidation of cobalt is proposed as the main deactivation mechanism caused by water. Fischer-Tropsch synthesis has been investigated over a commercial type cobalt-based catalyst (20 %Co/0.5 %Re/γ-Al2O3) by varying the H2/CO ratio (2.55–1.12), CO conversion (15–75 %), reaction temperature (210 °C, 230 °C), and by adding water to the syngas. The experiments were conducted in a fixed bed reactor with the main purpose of obtaining experimental data to be used in the development and fitting of a mechanistic model. A positive effect of water on the catalyst activity was found for experiments with a H2/CO ratio higher than 1.7. Water was found to always increase the C5+ selectivity regardless of the H2/CO ratio. Increasing conversion led to increased C5+ selectivity. The selectivity to CO2 was significantly enhanced at higher conversions (high water partial pressure), particularly with the lowest H2/CO = 1.12, interpreted as the emergence of water-gas shift activity. Re-oxidation of cobalt, probably limited to small cobalt particles, is proposed as the main deactivation mechanism caused by water while a steeper deactivation curve was found for higher temperature, indicating that sintering also may play a role.