Optimal design of solvent blends for environmental impact minimization

A systematic procedure proposed here selects optimal solvent blends for nonreactive, multicomponent absorption processes accounting for plant-wide point source environmental interactions. This approach, based on the optimal design technique for pure solvents developed in our earlier work, involves the identification of all agent-based operations (such as gas absorption and liquid extraction) within the process of interest, the determination of a list of candidate solvent blends satisfying separation task operational and environmental constraints, and the selection of an optimal solvent blend candidate based on global plant-wide process and environmental constraints. The procedure features new property and operational feasibility constraints, a refined task-based problem formulation, and a new solution strategy. Two examples are presented to demonstrate the approach, and trade-offs between cost and environmental impact objectives are discussed.