Coal fly ash derived SBA-15 supported Co/Fe catalysts for Fischer-Tropsch synthesis

This research article investigates the conversion of syngas (CO + H 2 ) using Zr/Ru-promoted Co–Fe-based Fischer–Tropsch catalysts supported on SBA–15 mesoporous silica synthesized from coal fly ash (CFA). The support and catalysts are characterized using X-ray Diffraction (XRD), H 2 –Temperature Programmed Reduction (H 2 -TPR), Energy Dispersive X-ray Spectroscopy (EDX), and High-Resolution Transmission Electron Microscopy (HRTEM). The main surface phases are identified as Co 3 O 4 and Fe 2 O 3 for Co-rich and Fe-rich bimetallic catalysts, respectively. Catalyst performance is evaluated in a fixed-bed tubular reactor under conditions of syngas (H 2 /CO ∼ 2:1) at 220 °C, 30 bar pressure, and a gas hourly space velocity (GHSV) of 500 h −1 for hydrocarbon synthesis. The Zr–Ru promoted Co-based catalyst achieves a higher CO conversion of 80.3 %, while the Zr–Ru promoted Co-rich bimetallic catalyst demonstrates superior selectivity (∼88.7 %) for liquid hydrocarbons (C 5+ ). Catalyst stability is assessed through analysis of CO conversion over time, and spent catalysts are further characterized by XRD to understand phase changes during the course of reaction. • Different combination of Co and Fe catalysts has been synthesized and tested its performance in Fixed bed reactor. • Zr and Ru promoter has been incorporated on the surface of the catalyst to maximize the C 5+ hydrocarbon. • The maximum CO conversion and middle distillate (C 6 - C 20 ) selectivity is observed as 80.3 % and 88.7 % respectively for Zr and Ru promoted Cobalt rich mono and bimetallic catalyst respectively. • This study also helpful to optimize the Co and Fe composition to maximize C 5+ hydrocarbon and minimize the methane.