A hierarchical optimization approach for the conceptual design of extraction-distillation processes is presented. The approach includes the solvent selection and flowsheet synthesis using pinch-based short-cut apparatus models which take into account of the material balances and piece-wise linearized thermody- namics (MLT models) and is limited to ternary systems. MLT models enable fast and robust identification of feasible flowsheet-solvent combinations and op- timization thereof. Performant solvents are found by assessing process stream tables. Promising solvent-flowsheet combinations are evaluated using flowsheet simulation with detailed models, whereby the MLT results are in good agree- ment with the results of the detailed models. The approach is presented alongan example of the separation of acetic acid and water.
Hierarchical Design of Extraction-distillation Processes using Short-cut Apparatus Models with Piece-wise Linearized Thermodynamics
