In this paper we address the topic of energy and water optimization in the production of bioethanol from corn and switchgrass. We show that in order for these manufacturing processes to be attractive

there is a need to go beyond traditional heat integration and water recycling techniques. Thus

we propose a strategy based on mathematical programming techniques to model and optimize the structure of the processes

and perform heat integration including the use of multi-effect distillation columns and integrated water networks to show that the energy efficiency and water consumption in bioethanol plants can be significantly improved. Specifically

under some circumstances energy can even be produced and the water consumption can be reduced below the values required for the production of gasoline.