Synthesis, Modeling and Exergy Analysis of Atmospheric Air Blown Biomass Gasification for Fischer-Tropsch Process

The main objective of the present work is to investigate the combination of an atmospheric and a pressurised air blown biomass gasifier towards Fischer-Tropsch (FT) synthesis of second generation biofuels and co-production of power. The complete process was simulated in AspenPlus (TM) software including sub-models for the gasification, gas cleaning and conditioning as well as for the FT reactor. A sensitivity analysis on exergetic performance was performed mainly examining the recycling of FT-tail gas. For the base case of 80% FT CO conversion without any recirculation, the exergetic efficiency was found to be 34.3% with atmospheric gasification and 30.64% for pressurised gasification. Recirculation of the non-reacted CO, H-2 as well as light gas products of the FT-reactor back to the atmospheric gasifier can increase the overall efficiency up to 48.1 %.