Techno-economic assessment of bio-oil aqueous phase-to-liquids via Fischer-Tropsch synthesis and based on supercritical water reforming

High energy demand along with large capital costs have been the main drawbacks of Fischer-Tropsch plants, which may call into question the economic viability of the Fischer-Tropsch process. The second issue is the focus of this paper, which presents a techno-economic assessment of biofuels production by a low-temperature Fischer-Tropsch synthesis with electricity as a co-product from supercritical water reforming of the bio-oil aqueous phase. A plant size of 60 t/h was considered and a heat-integrated process was designed to be energy self-sufficient, which includes syngas production and upgrading, as well as liquid fuels production by Fischer-Tropsch synthesis and refining. The simulation and optimization was performed with the aid of Aspen Plus, and some case-studies were performed. Using a feeding concentration of 25 wt%, 2.74 t/h biofuels and 5.72 MWe were obtained. In this case, by performing a discounted cash flow analysis, with 10% rate of return and 100% equity financing, the minimum selling prices for the refined FT-gasoline, FT-diesel and FT-jet fuel were 1.20, 0.93 and 0.26 €/kg (0.84, 0.75 and 0.20 €/L), respectively, which are competitive prices with respect to the market values of the equivalent fossil fuels. Likewise, the decrease in the selling prices as the plant capacity increases was also analyzed.