Industrial & Engineering Chemistry Research, Vol.47, No.3, 889-899, 2008
Feasibility of reactive distillation for Fischer-Tropsch synthesis
Fischer-Tropsch synthesis (FTS) is an area that is receiving revived interest worldwide as a technology alternative to produce transportation fuels as well as chemicals from syngas. SASOL and Shell are two of the major players who operate FT reactors on a commercial scale. To have a balance between gasoline and diesel production, one needs to have both the low temperature (LTFT) and high-temperature (HTFT) processes operating in parallel. Heat-removal from the exothermic FT reactions was the main driver in the development of conventional FT reactors (fixed-bed, fluidized bed, or slurry type). However, the focus has recently shifted toward the product distribution as well. Reactive distillation (RD) is a proven reactive separation method that can enhance yields as well as improve product selectivity in multiple reactant/product systems. This paper aims to check if FTS is feasible in RD from a theoretical viewpoint. In-built thermodynamic procedures and power-law kinetics of Aspen Plus, along with a simplified kinetic model that predicts product distribution, were used in performing the simulations. Simulation results of the conventional reactors are compared with RD, and it is seen that the performance of RD is at par or better than the conventional reactors in terms of conversion, yield, and product distribution. Within the RD mode for FTS, results of some of the alternate column configurations are presented. The results indicate that FTS can be a potential candidate to be implemented using RD.