An Approach for Solvent Selection in Extractive Distillation Systems Including Safety Considerations

The selection of solvents in the chemical industry is typically based on performance and economic considerations. Other relevant aspects, such as the safety implications of a given solvent, are generally left for consideration after the design of the process has been completed. In this work, an approach for solvent selection including safety considerations at the design stage of the process is presented. The safety component is included through a consequence analysis using an average distance for the risk of death as the major parameter. The approach is applied to the design of extractive distillation systems, for which a preselection step for the solvent is used, followed by the formulation of a multiobjective optimization problem in which both economic and safety aspects are taken into account. The approach is applied for the purification of bioethanol, for which solvents that offer the best cost–safety compromise are identified.