Basic concepts and elements in the design of thermally coupled distillation systems

Abstract The separation stage is one of the most critical steps in a chemical process because it is at this stage where the product sales requirements are reached or where some important raw materials are recovered and reused. Nowadays, around 90% and 95% of the separations required in the chemical industry are carried out by distillation, which become it in the most used process separation, in particular for platform chemicals such as furfural. However, the distillation processes are characterized by enormous energy requirements, for this reason, a current tendency in separation processes is the search for new distillation schemes that can substantially reduce the energy consumption. In this sense, the thermally coupled distillation sequences are considered as some of the most important advances in the distillation field because this kind of arrangements can provide energy savings between 30% and 50% compared with the distillation sequences conventional, in the case of ternary mixtures. This chapter addresses some basic concepts for the design of thermally coupled distillation systems such as the remixing effect as well as current design methodologies, which can be easily implemented in process simulator programs.