Biomass to Liquids (BtL) Process Simulation, Economics and Environmental Impact Assessment for a 3000 bbl/d Plant

Abstract

The biomass to liquids process (BtL) is an interesting path to produce synthetic petroleum via biomass gasification and Fischer Tropsch (FT) synthesis. The scope of this work is to describe, to simulate and to assess the economic and the environmental impact of the BtL multistep process. The process simulation tool is CheOpe, the economics have been estimated via Aspen Process Economic Analyzer V7.2.1 and the environmental assessment via GaBi V6.0. In this study, cobalt-based catalyst kinetics are simulated in a FT slurry bubble column reactor. The feedstock for FT is the syngas obtained from biomass gasification. The first step is a syngas reforming followed by a water gas shift (WGS) section to adjust the H2 to CO ratio to about 2 (required for FT catalysis) and then by a Rectisol® island to remove the acid gases (H2S, poison for FT catalysis, and CO2, inert gas in FT reaction). Finally, after the FT reaction section, the last step is the upgrading (UPG) of FT products to produce diesel and naphtha. An estimation of CAPEX for a 3000 bbl/d capacity plant has been carried out. Estimated investment costs are about M€ 400. This result has been paired with a life cycle assessment (LCA) in order to complete a decisional frame. LCA points out the environmental advantages in the use of BtL-fuels in the reduction of CO2 global emissions, if compared to the ones relevant to fossil fuels. This result respects the recent EU Directives limits.