433540 Co-Processing Biomass and Natural Gas into Clean Transportation Fuels at Small Scale: A Techno-Economic Assessment

Monday, November 9, 2015: 4:43 PM
257B (Salt Palace Convention Center)
Anna K. Hailey1, Johannes C. Meerman2, Eric D. Larson2 and Yueh-Lin Loo1, (1)Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, (2)Princeton Environmental Institute, Princeton University, Princeton, NJ

Concerns over climate risks, price volatility, and energy insecurity associated with petroleum-derived fuels motivate the search for alternatives. Liquid fuels derived from domestic natural gas and sustainable biomass can help mitigate these concerns. Biomass is a dispersed resource best suited for smaller-scale conversion plants. We explore the economic viability of smaller-scale production of synthetic diesel and gasoline from biomass or biomass and natural gas. Our three designs each process 2,000 dry tonnes of biomass per day and incorporate an indirectly-heated gasifier and tar cracker, a microchannel Fischer-Tropsch (FT) reactor for liquid-fuels production, and capture of CO2 for storage (CCS) by injection into spent shale gas wells. Our base design uses only biomass. In a second design, we take advantage of the synergistic opportunity to blend H2-poor syngas from biomass gasification with H2-rich syngas from natural gas reforming to obtain the 2:1 H2:CO ratio needed for FT synthesis. The feed to this plant is 10% natural gas on an energy basis. In a third design, we increase the natural gas content to 50% of the feed to augment the heat input to the gasifier to increase biomass carbon conversion to fuels. We also explore the impact of post-combustion CO2 capture in addition to the baseline pre-combustion capture. The biomass-only case provides 80 gallons of energy-equivalent gasoline per dry tonne of biomass (gge/t), with strongly negative greenhouse gas (GHG) emissions. The second design provides 100 gge/t, with neutral to negative GHG emissions; the latter occurs when additional post-combustion capture is utilized. The third design provides 170 gge/t, with positive to neutral GHG emissions. Even at these levels, the emissions do not exceed 50% of the emissions of plants producing equivalent petroleum-derived fuels. The economics of fuels production for the three designs were investigated under different assumed GHG emission prices. Despite its smaller scale, at high GHG emissions prices (> $100/tCO2), the biomass-only design with additional post-combustion capture provides the lowest production costs that rival production costs of petroleum fuels even at $100 per barrel crude oil prices due to its strongly negative emissions.

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See more of this Session: Biofuels Production: Design, Simulation, and Economic Analysis
See more of this Group/Topical: Sustainable Engineering Forum