Integration of chemical looping and Fischer-Tropsch processes for efficient biomass to liquid fuel production and carbon dioxide sequestration.

Decarbonizing hard-to-electrify transportation sectors requires biomass-to-liquids pathways that integrate carbon management without excessive process complexity. This study presents a fully integrated chemical looping Fischer-Tropsch (CLFT) pathway in which Fischer-Tropsch (FT) tail gas is directly incorporated into the chemical looping system using a circulating Fe-Ti oxygen carrier (OC). By restructuring the reduction stage into two sequential moving-bed reactors and oxidizing the FT tail gas within the redox cycle prior to biomass gasification, the process enables inherent CO2 separation and autothermal operation while generating high-purity syngas suitable for direct FT synthesis. This integration eliminates the need for solvent-based CO2 capture, extensive water-gas shift conditioning, and external oxygen supply required in conventional biomass gasification systems. Process simulations demonstrate stable autothermal performance at combustor temperatures near 950°C, producing syngas purities of 85-86% and sequestration-ready CO2 streams exceeding 95% purity. Carbon efficiency to liquid fuels reaches approximately 37% for corn cob biomass under optimized conditions. Bench-scale experimental validation in a 2.5 kWth moving-bed reactor confirms high-purity CO2 production and syngas compositions consistent with Aspen Plus predictions. A techno-economic analysis at a commercial scale of 2000 tonnes/day (tpd) yields a minimum fuel selling price of 2.75 $/GGE under federal incentive scenarios and 3.55 $/GGE without incentives. Sensitivity analysis identifies biomass feedstock cost and capital investment as dominant economic drivers. The results demonstrate that staged chemical looping integration provides a technically feasible and economically competitive pathway for carbon-managed liquid fuel production.