Silica-Gel-Supported Cobalt Catalysts for the Selective Synthesis of Long-Chain Hydrocarbons (C19+)

Abstract

This study investigates a silica-gel-supported cobalt catalyst for synthesizing long-chain hydrocarbons (C₁₉₊) from CO and H₂. The process conditions were varied within the following ranges: pressure, 1.5–3.5 MPa; gas hourly space velocity (GHSV), 300–830 h^–1; H₂/CO ratio, 2.0–2.3; and temperature, 187–213°C. Catalytic testing revealed a correlation between the catalyst deactivation rate and the content of C₁₉₊ hydrocarbons in the products. When the C₁₉₊ content increased from approximately 40 to 55 wt %, the deactivation rate increased more than tenfold. Under optimized conditions (H₂/CO = 2.3, P = 2.0 MPa, T = 193°C), the C₁₉₊ content reached ~46–50 wt %, and the deactivation rate was minimized. A long-term stability test over 500 h was used to project a catalyst cycle length, which was found to be at least 4000 h. The study results provide a foundation for optimizing Fischer–Tropsch process conditions to maximize catalyst lifetime and selectivity toward heavy hydrocarbons, supporting the recommendation of the proposed catalyst for industrial implementation.