Synergistic Biomass and Natural Gas Conversion to Liquid Fuel with Reduced CO2 Emissions

Abstract Towards reducing the CO 2 emissions associated with the transportation sector, we investigate the design of carbon and energy efficient processes for integrated biomass and natural gas (NG) conversion to liquid fuel. A process superstructure considering biomass conversion via gasification/Fischer-Tropsch (FT) synthesis and fast- hydropyrolsis/hydrodeoxygenation, and NG conversion via reforming followed by FT synthesis is established. Subsequently, a mixed integer nonlinear programming model (MINLP) is formulated to identify the process configurations that maximize the energy output as liquid fuel for different ratios of NG to biomass carbon feeds ( δ ng ). For 1 % ≤ δ ng ≤ 150 %, the optimal process configurations are capable of producing ~5–14 % more liquid fuel output than the combined fuel output of individual standalone processes converting the same amount of biomass and NG. This synergy originates from synthesizing additional liquid fuel by combining the residual biomass carbon with the excess hydrogen per carbon available from the NG feed. These integrated processes are also estimated to achieve up to 80 % reductions in greenhouse gas (GHG) emissions relative to petroleum-based fuels.