Integrated simulation and life cycle assessment of CO ₂ to gasoline conversion: reactor level optimization and environmental trade offs

Abstract The conversion of carbon dioxide (CO 2 ) into gasoline-range hydrocarbons offers a dual benefit of carbon mitigation and the production of synthetic fuels. This work develops an integrated process simulation and life cycle assessment (LCA) framework for CO 2 -to-gasoline synthesis using Aspen HYSYS, explicitly coupling the Reverse Water Gas Shift (RWGS) and Fischer–Tropsch (FT) pathways. Two RWGS reactor configurations, a Gibbs reactor and a plug-flow reactor (PFR), are modeled and compared based on product yield, energy requirements, and cradle-to-gate environmental performance. The PFR achieves a gasoline output of 314.9 kg h −1 from 1,100 kg h −1 of CO 2 , a 4.3-fold increase relative to the Gibbs reactor, but requires 18.4 % more cold utility and higher hydrogen input. LCA using ReCiPe 2016 Midpoint (H) v1.13 and a functional unit of 1,000 t of CO 2 processed shows that this reactor-level efficiency gain is accompanied by 17 % higher climate-change impacts (31.8 vs. 27.1 million kg CO 2 -eq) and a 4.3-fold increase in human toxicity, driven by electricity use and Ni/Co catalyst production. Photochemical ozone formation and fossil resource depletion are also significantly higher in the PFR case. The study demonstrates that optimizing CO 2 utilization at the reactor level does not automatically minimize life cycle burdens, and highlights the importance of integrating detailed process simulation with LCA when designing CO 2 valorization routes.