Exploring bimetallic oxygen carriers for biomass chemical looping gasification: A comprehensive thermodynamic evaluation

• Exploring CoO, NiO, CuO, and Mn 3 O 4 -based Ferrite OCs for CL-BG systems. • 26.67 % CuO in Fe-AM shows maximum improvement across all OC compositions. • ∼29 % lowering in OC circulation and ∼9 % increase in syngas yield achieved. • CuO-Fe 2 O 3 OC increases liquid fuel yield by 50 % when integrated with F.T. process. The increasing demand for energy and the urgency of reducing CO 2 emissions have accelerated the development of renewable energy technologies. Among these, chemical looping biomass gasification (CL-BG) presents a promising pathway for sustainable syngas (CO + H 2 ) production. This study presents a comprehensive thermodynamic evaluation of iron-based bimetallic oxygen carriers (OCs) for CL-BG systems using ASPEN Plus simulation software. By systematically varying the composition of transition metal oxides (CuO, CoO, NiO, Mn 3 O 4 ) in combination with iron oxide (Fe 2 O 3 ) and silicon carbide (SiC) as an inert support, the performance of over 60 OCs was analyzed under isothermal and adiabatic conditions. Isothermal operation of the reducer revealed a significant reduction in the reducer heat duty for CuO-modified OCs. Key process parameters, including syngas yields, oxygen carrier circulation rate, and OC conversion, were evaluated at optimal operating regions where autothermal operation (no requirement of external heat) has been established for the CL-BG system. The results revealed that OC composition with 26.67 % of the active material (AM) of the OC substituted by CuO exhibited the most significant improvement, enabling a ∼29 % reduction in oxygen carrier circulation rate and a ∼9 % increase in syngas yield. The CL-BG process was further integrated with a Fischer-Tropsch (F.T.) unit to assess process-level implications of using composite OCs for liquid fuel synthesis. Results demonstrate that the OC composition with 26.67 % CuO in the AM reduces auxiliary resource demands (steam, oxygen) and enhances product yields (gasoline and diesel), achieving ∼50 % higher fuel yield compared to Fe 2 O 3 OC. This study provides a robust framework for designing composite metal OCs tailored for scalable and efficient chemical looping systems for sustainable chemical production.