A Fugacity Based Kinetic Model for Supercritical Fischer –Tropsch Synthesis Over Cobalt-Based Catalytic Systems

摘要

A kinetic model for Fischer-Tropsch synthesis (FTS) in both conventional reactionmedia (gas-phase) and non-conventional media (near-critical and supercritical solventmedia) was derived from experimental data generated from a commercial aluminasupported cobalt catalyst (15% Co/Al2O3). The model was developed based on partialpressures assuming ideal gas phase as well as based on fugacity coefficients toaccount for the non-ideality in the near critical and supercritical phase. The estimatedkinetics parameters from the fugacity-based model were compared to the kineticsparameters obtained from the ideal gas assumption using the partial pressure basedkinetic model. Similarly, the fugacity-based model successfully predict the methaneformation rates for gas phase as well as near critical and supercritical phase FTS. It wasobserved that the fugacity-based models more accurately predicted the carbonmonoxide consumption rate in gas-phase as well as near critical and supercritical FTSconditions. Our qualitative conclusion is that fugacity-based model will also do a betterjob than the partial pressure based model in predicting the chain growth probability ofthe cobalt catalyst since it can better account for the non-ideality of the reaction in thegas-phase FTS (high pressures operation) and in the near-critical and supercriticalphase.