Optimal Operation and Control of Four-Product Dividing-Wall (Kaibel) Distillation Column

Due to globalization and increased market competition, the process industry is seeking to maximize productivity at minimal operational cost. Distillation operation alone accounts for a significant amount of the world’s energy consumption. This consumption can be greatly reduced by using a complex distillation column configuration, such as a fully thermally coupled distillation column or divided-wall distillation column, over conventional arrangements. The divided-wall column offers potential energy and capital investment savings. In this study, it was shown that energy savings of up to 25% can be achieved by using a four-product divided-wall distillation column (Kaibel) compared with conventional column arrangements. The reported capital investment associated with a four-product divided-wall column is approximately 30%. However, design and operation remain a challenge due to the large number of design and operational degrees of freedom. Divided-wall columns can be used for multicomponent separation as well. This research demonstrated the steady-state and dynamic behavior of a Kaibel distillation column using commercial simulation software, i.e., Aspen HYSYS. A self-optimizing control scheme was implemented to reject disturbances during operation and to meet the required product specifications for a Kaibel distillation column.