Integrated Multiscale Optimization of Sustainable Aviation Fuel Systems: Coupling Supply Chain with Intensified Alcohol-to-Jet Process Upgrading

Sustainable aviation fuel (SAF) deployment requires simultaneous coordination of spatially distributed biomass supply chains and nonlinear conversion technologies. This study develops an integrated multiscale optimization framework for SAF production in Mexico using second-generation sugarcane bagasse as the lignocellulosic resource for alcohol-intermediate production, followed by an intensified Alcohol-to-Jet (ATJ) upgrading stage targeting Mexico City Airport. A multi-period mixed-integer linear programming model optimizes harvest-area selection, biorefinery location, biomass allocation, inventory, production, and distribution, while an Aspen Plus model of an intensified Alcohol-to-Jet (ATJ) process with reactive distillation is optimized using Differential Evolution with Tabu List. In this framework, the ATJ block is not modeled as direct biomass-to-jet conversion. In the base case, ethanol is used as the representative alcohol intermediate. Therefore, the upstream biomass-to-alcohol section is represented through an effective bagasse-to-ethanol coefficient, whereas the Aspen Plus–DETL model explicitly describes the downstream ethanol-to-ATJ-range hydrocarbon blendstock upgrading section through dehydration, ethylene oligomerization, hydrogenation, and fractionation. Process yield, production cost, environmental impact, and feasible capacity are fed back into the supply chain model, making process performance endogenous rather than fixed. Results show that the decoupled supply chain baseline favors large production capacities, reducing TAC from approximately 1010 to 340 USD/tSAF and system-level EI99 from 1.110 to 1.059 kPt EI99/tSAF as capacity increases from 80,000 to 490,000 tSAF/year. This corresponds to an environmental reduction of approximately 5.2%. In contrast, isolated ATJ optimization exhibits nonlinear scale-dependent behavior, with process-only EI99 decreasing from approximately 1.70 to 0.55 kPt EI99/tSAF. The integrated framework identifies an intermediate capacity region of 120,000–300,000 tSAF/year, with TAC values of approximately 3400–6800 USD/tSAF and total EI99 values of approximately 0.78–1.31 kPt EI99/tSAF. The integrated base case at 200,000 tSAF/year has an EI99 value of approximately 1.063 kPt EI99/tSAF.