Design of an Optimal Biorefinery

In this paper we propose a biorefinery optimization model that can be used to find the optimal processing route for the production of ethanol, butanol, succinic acid and blends of these chemicals with fossil fuel based gasoline. The approach unites transshipment models with a superstructure, resulting in a Mixed Integer Non-Linear Program (MINLP). We consider a specific problem based on a network of 72 processing steps (including different pretreatment steps, hydrolysis, fermentation, different separations and fuel blending steps) that can be used to process two different types of feedstock. Numerical results are presented for four different optimization objectives (maximize yield, minimize costs, minimize waste and minimum fixed cost), while evaluating different cases (single product and multi-product).