Techno-Economic Assessment of Chemical Looping Gasification of Biomass for Fischer-Tropsch Crude Production with Net-Negative CO2 Emissions: Part 2

This work presents a techno-economic analysis of a used as the primary gasification process for biofuel production through Fischer-Tropsch synthesis (FTS). Two different gas cleaning process configurations, cold-gas cleanup and hot-gas cleanup process trains, are explored, along with off-gas utilization possibilities, to study their influence on the process economics of an integrated CLG-FT process plant. Off-gas recirculation to increase Fischer-Tropsch (FT) crude production has a significant influence on reducing the levelized production costs for FT crude. The results indicate that the specific production cost estimated for a CLG-FT plant with a hot-gas cleanup train is roughly 10% lower than the case with a cold-gas cleanup train, while the total plant costs remain relatively the same for all plant configurations. In addition to this, the former has a considerably higher overall system energy efficiency of 63%, roughly 18% more than the latter, considering the co-production of FT crude, district heating, and electricity. The specific investment costs range from 1.5 to 1.7 M euro 2018/MWLHV, and the specific FT crude production cost ranges from 120 to 147 euro 2018/MWhFT. Roughly 60% of total carbon fed to the process is captured, enabling net-negative CO2 emissions. A CO2 price for negative emissions would significantly reduce the specific fuel production costs and would, hence, be competitive with fossil-based liquid fuels.