(158j) Improving the Unit Operations Lab: Design Methods and Process Simulation as Basic Tools in the Distillation of Binary Mixtures

The teaching of unit operations for undergraduate students of chemical engineering starts in the classroom and is reinforced in the laboratory. The theory studied in class requires a practical exercise that is representative and allows the application of the most important concepts. In addition, the implementation of tools like computer simulation completes the learning experience. The first aspect to take into account in a distillation experiment is the adequate selection of the mixtures. Preferably, it should be easy to separate, non hazardous and low cost. From a variety of binary mixtures, the systems ethanol?water and water?ethylene glycol were selected based on their physical and chemical properties. The measurement and control of the process variables is also a point to considerate. The design with shortcut methods allows the student to understand the basic concepts of distillation through the use of graphics. The simulation offers a tool to predict the process of distillation, by manipulating and adjusting the parameters involved in it. Both design and simulation give a fuller vision of what can be expected in the laboratory. The distillation column in the pilot plant at UDLA,P represents the environment that gives the student the chance to understand the distillation process, to verify the factors that affect it and how the variable manipulation determines the results. The design with the McCabe ? Thiele method makes possible to study the operation conditions for the experiment and see the effects of the change of these conditions; obtaining results for reflux ratio, feed thermal condition and purity of the products. The computer simulation with Aspen Plus© helps with the prediction of the results of the designed experiment. Temperature profiles, phase compositions and plate efficiencies are some of the values that can be obtained. The integration of all these tools in the distillation courses has given excellent results, especially in a better use of the time dedicated to teaching, and the improvement of the concepts understanding by the chemical engineering students.