Modeling and Optimization of Selectivity and Activity of Co/Al2O3 Catalyst in the Fischer Tropsch Synthesis

In this paper, main effects and the interactions of operating conditions were investigated using response surface methodology and statistical analysis in the presence of Co/Al2O3 catalyst in a CSTR reactor. Analysis of variance demonstrated that the second-order polynomials adequately predicted the responses. The selectivity of CO2, CH4, and CO conversion increased by the decrement of syngas flow rate. Increasing the pressure to 22 bar led to the increasing of CO conversion and CO2 selectivity; indicating the promotion of the water-gas-shift reaction in these conditions. Rising syngas flow rate caused decreasing the CO conversion and increasing C5+ selectivity. Minimum CO2 selectivity was achieved at the syngas flow rate and pressure of 61.9 Nl/h and 15 bar, respectively. Multi-objective optimization showed that minimum CO2 selectivity (2%) and methane selectivity (16.4%), as well as maximum CO conversion (53.8 %) and C5+ selectivity (68.3%) obtained at the syngas flow rate and pressure of 47.8 Nl/h and 15 bar, respectively.