Reaction pathway and kinetic modeling of Fischer-Tropsch synthesis over an alumina supported cobalt catalyst in supercritical-hexane.

A kinetic model for Fischer-Tropsch synthesis (FTS) was developed in a supercritical-hexane (SCH) environment over a commercial 15% CO/Al2O3 catalyst in a fixed-bed-reactor. The model assumed that SCH has more significant influence on the chain propagation and chain termination stages than the initial stages (adsorption of CO and H2 on the catalyst surface and chain initiation). SCH promoted in-situ extraction during FTS and provided vacant sites that promote both adsorption of CO and H2 and incorporation of alpha-olefins in the chain growth. The suggested trend in chain growth agreed well with the SCH-FTS experimental findings. The model was applicable to the following reaction conditions: synthesis gas space velocity of 93.75-281.25/hr, 230-260deg;C, 40-65 bar, and H2/CO feed ratios of 1:1-2:1, with a hexane/synthesis gas molar ratio of 3:1/1:1. The results were compared to conventional gas phase FTS operation under the similar conditions without hexane solvent. This is an abstract of a paper presented at the 227th ACS National Meeting (Anaheim, CA 3/28/2004-4/1/2004).

Reaction pathway and kinetic modeling of Fischer-Tropsch synthesis over an alumina supported cobalt catalyst in supercritical-hexane. Conference Paper