Control Analysis of Alternative Design Configurations for Bioethanol Purification

This study presents a control analysis of different design configurations for the separation of bioethanol. Starting from a four-column configuration, a three-column configuration with a liquid recycle and a two-column configuration with a side stream vapor recycle are considered as design cases. For each configuration, the designed control structures including inferential temperature control loops are evaluated based on their step responses against two different types of disturbances. The results indicate that stable control is obtained for all configurations. In addition to the lower capital and energy costs, the dynamic performance of the two-column configuration is found to be competitive in terms of transient deviations and ultimate steady-state values when compared to that of other configurations. (Graph Presented).