Simultaneous design and scheduling of a semicontinuous/batch plant for ethanol and derivatives production

The interest on renewable fuels has greatly increased in the last years. Particularly, ethanol production arises as a good solution to many current economic-environmental problems. Yeast production from the ethanol residuals constitutes a sustainable alternative. Usually, this kind of plants is designed using single product campaigns. However, since yeast degradation is fast and a continuous supply must be assured, the mixed product campaign policy is the most appropriate. Besides, a stable context can be assumed to justify this approach that takes advantage of the special structure of the plant. Therefore, in this paper, a mixed integer linear programming model is formulated for simultaneous design and scheduling of a semicontinuous/batch plant for ethanol and derivatives production. The optimal plant configuration, unit sizes, number of batches of each product in the campaign and its sequencing is obtained in order to fulfill the ethanol and yeast demands minimizing the investment cost.

► A MILP model for designing sequential multipurpose plants is proposed.
► Scheduling is simultaneously solved using mixed product campaigns.
► The model is applied to an ethanol plant.
► Yeast production is also considered as a sustainable alternative.
► Novel scheduling constraints are formulated and several tradeoffs can be assessed.