Micro-scale Distillation and Microplants in Process Development

The purpose of this work was to evaluate the feasibility of using micro scale units for the process development projects. The work consisted of three tasks; the measurement of thermodynamic equilibria, the development of a micro distillation column, and the use of microplants in process development. In the first task new thermodynamic data was measured; 361 vapor-liquid equilibria points for 10 binary mixtures, 83 vapor pressure points for pure compounds, 27 excess enthalpy of mixing, and 27 excess volume of mixing. The results were validated against literature values. Phase equilibria measurements were additionally validated using thermodynamic consistency, and by comparing the total pressure at equimolar composition. The results of phase equilibria measurements were modeled using Soave-Redlich-Kwong equation of state, and Hayden-O'Connel equation to calculate the vapor phase fugacity, and Non-Random Two Liquid, Wilson, Universal Quasi-Chemical and Universal Quasi-Chemical Functional Group models to calculate liquid phase relative activity coefficients. Results obtained from modeling were compared against literature values with good accuracy. A novel micro distillation column was developed based on a planar design using open-cell metal foam as column packing. Operation of the column was tested both as a heat-pipe and as part of a modular distillation unit. In the heat-pipe operation the column operation was controlled via surface temperatures. In the modular operation reboiler and condenser were located outside the column, which is the approach more commonly used in the chemical industry. The quality of data obtained from a microplant for the process development was evaluated using etherification as a model reaction. For this purpose the dynamic change in stream compositions, the reaction equilibrium, and the separation of product from feedstock was measured and modeled. The modeled results corresponded accurately with the experiments. This indicates that when the essential process steps are included in the trial plant the process model can be rigorously validated based on data obtained from micron scale piloting.