Effects of surfactant and promoters on the catalytic performance of Co-catalysts supported on γ‑Al2O3 granules for Fischer−Tropsch synthesis

Abstract

A series of supports were synthesized using two methods of sol-gel and oil-drop. In this work, the simultaneous effects of P123 surfactant, promoters (cerium, zirconium, and boron), and ethanol solvent on catalytic activity for the Fischer–Tropsch Synthesis (FTS) were studied. Cobalt catalysts were prepared using the incipient wetness impregnation method on γ-alumina granules for FTS in a fixed-bed reactor. All the prepared granules Co catalysts were characterized using FTIR, BET, XRD, TPR, FESEM, EDS, and ICP techniques. The FTS operation condition was carried out at T = 503 K, P = 15 bar, H2/CO = 2, and space velocity 5.1 NL g–1 h-1. The obtained results clearly showed that the catalytic evaluation of the Co catalysts supported on γ-alumina, with respect to the activity and selectivity of C5+ products were increased by the addition of surfactant and promoters in FTS. Also, the Co catalysts supported with γ-alumina P123 surfactant were more active than the Co catalysts supported with γ-alumina. Furthermore, the morphologies of the γ-alumina supported granules were changed by surfactant and promoters and the presence of CeO2 on the surface of the supports favors the reducibility of cobalt oxide with a shift down in reduction temperature of about 50 °C. Meanwhile, the addition the simultaneous of P123 surfactant and Ce promoter with ethanol solvent remarkably influenced the improvement of activity, selectivity, and stability of the catalyst as well. Ce promoter reduced the methane selectivity by increasing the chain-growth probability (α-value).

Keywords

• Sol–gel
• P123 surfactant
• γ-alumina granules
• Cobalt catalyst
• Fischer–Tropsch synthesis
• Anderson–Schulz–Flory (ASF) plot