Evaluation of Solvent Recovery Options for Economic Feasibility through a Superstructure-Based Optimization Framework

As the chemical market continues to expand, environmental concerns have increased due to excessive disposal of organic solvents. To date, there is no comprehensive mitigation plan to completely handle such a volume of solvent waste generated annually by the chemicals sector. These organic solvents can account for up to 90% of the process by mass and are often discarded after a single use. Incineration, the most widely used process for solvent disposal, is not a green method because of the release of harmful pollutants and greenhouse gases to the environment. A systematic framework for solvent recovery has been developed to overcome the drawbacks of the existing disposal methods. This framework uses a superstructure-based approach that considers the simultaneous comparison of multiple separation technologies for solvent recovery. The viability of this framework was tested using two representative case studies of varying complexities. These case studies were analyzed and formulated as mixed-integer nonlinear programming optimization problems. In both cases, solvent recovery is an economically favorable choice to conventional incineration. Herein, we demonstrate the capability of our solvent recovery framework to obtain economically viable solvent recovery pathways.