Multiobjective Optimization of Biomass-to-liquids Processing Networks

This paper addresses the optimal design and planning of biomass-to-liquids (BTL) supply chains under economic and environmental criteria. The supply chain consists of multisite distributed-centralized BTL processing networks. The economic objective is measured by the total annualized cost, and the measure of environmental performance is the life cycle greenhouse gas emissions. A bi-criterion, multi-period, mixed-integer linear programming model is proposed that takes into account diverse conversion pathways and technologies, feedstock seasonality, geographical diversity, biomass degradation, infrastructure compatibility, and government incentives. The model simultaneously predicts the optimal network design, facility location, technology selection, capital investment, production planning, inventory control, and logistics management decisions. The problem is solved with the ε-constraint method, and the resulting Pareto curve reveals how the optimal annualized cost and the BTL processing network structure change under different specifications of environmental performance. The proposed approach is illustrated through a county-level case study for the state of Iowa.