The absolute majority of methods for conceptual process design have been devel­oped for processes of basic chemical and petro-chemical industries. Most of these approaches are especially oriented to the design of separation schemes, particularly distillation trains. For this reason, there is a paramount interest in the application of these methodologies to biotechnological processes, which are of a complex and highly multicomponent nature. None of the described approaches can be applied in a generic way to any type of synthesis problem, even more so in the case of biological processes. Considering this, the application of a minimum of two strate­gies or synthesis procedures is required to undertake the design of processes for fuel ethanol production with a high technoeconomic and environmental perfor­mance. In this way, a higher amount of possibilities can be covered allowing the creativity during the design process that is the source of innovation. Therefore, the employment of synthesis strategies that systematically compile and utilize the accumulated knowledge around a research subject, such as fuel ethanol, directly contributes to screening and filtering the best alternative process configurations.

Further, some of the approaches mentioned above were applied to the genera­tion of different process flowsheets with a high technical, economic, and envi­ronmental performance. Thus, both the hierarchical decomposition method and optimization-based strategies were used for the main process steps needed for ethanol production. For specific process steps, such as the synthesis of separation and ethanol dehydration scheme, the analysis of the statics and the exergy balance were also employed. These issues will be discussed in following chapters.