Hierarchical Design of Extraction-distillation Processes using Short-cut Apparatus Models with Piece-wise Linearized Thermodynamics

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.

Modeling and Flowsheet Simulation of Vibrated Fluidized Bed Dryers

Drying in fluidized beds is an important step in the production of powdered materials. Especially in the food and pharmaceutical industry, fluidized bed dryers are often vibrated to improve the drying process. In the current work, a continuous fluidized bed drying model is implemented in the novel, open-source flowsheet simulation framework Dyssol. The new model accounts for the hydrodynamic characteristics of all Geldart groups as well as the impact of mechanical vibration on the drying process. Distributed particle properties are considered by the model. Comprehensive validation of the model was conducted for a wide range of process parameters, different materials, dryer geometries and dimensions as well as the impact of vibration. Particle properties are predicted accurately and represent the broad experimental data well. A sensitivity analysis of the model confirmed grid independence and the validity of underlying model assumptions.