The impact of Al2O3 promoter on an efficiency of C5+ hydrocarbons formation over Co/SiO2 catalysts via Fischer-Tropsch synthesis

• Published in: Catalysis today Vol. 279; pp. 107 - 114
• Main Authors: Savost’yanov, Alexander P., Yakovenko, Roman E., Sulima, Sergey I., Bakun, Vera G., Narochnyi, Grigoriy B., Chernyshev, Victor M., Mitchenko, Sergey A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2017
• Subjects: Al2O3 promoter; C5+ selectivity; Co/SiO2 catalyst; Fischer-Tropsch synthesis; Particle size; Fischer-Tropsch synthesis; Particle size; Co/SiO2 catalyst; Al2O3 promoter; C5+ selectivity
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2016.02.037

[Display omitted] •Al2O3 dopant to Co/SiO2 Fischer-Tropsch catalyst promotes synthesis of C5nH10n+2.•The highest promotion effect was detected at 1wt.% of Al2O3 loading into Co/SiO2.•Al2O3 addition into Co/SiO2 catalyst alters dispersion of the formed Co° particles.•Co° particles of 8nm mean size were formed at 1wt.% of Al2O3 loading. The influence of doping of Co/SiO2 catalysts with alumina on a performance of Fischer-Tropsch synthesis (FTS) was studied by extended FTS trials in a fixed-bed tubular pilot-scaled reactor. The addition of small amount of Al2O3 causes apparent promotional effect on the catalysts activity and C5+ hydrocarbons selectivity. The largest promotion effect was observed for the catalysts with 1wt.% of alumina loading. The modification of the catalyst with alumina (1wt.%) changes molecular weight distribution of the resultant C5+ paraffins with increasing the fraction of C8–C25 and decreasing the fraction of longer chain hydrocarbons. The addition of a proper amount of alumina into Co/SiO2 catalyst alters Co° particle size distribution making it narrower with the maximum at 8nm and the same mean value for Co° particle size. A volcano-like dependence of CO chemisorption on alumina loadings with a maximum at 1wt.% was observed. Relatively high CO chemisorption at the proper amount of alumina decreases the ratio of surface hydrogen to carbon monoxide and in such a way promotes formation of C5+ hydrocarbons.