Abstract
Dividing-wall distillation columns offer large potential energy savings over conventional column sequences, typically up to 30% for three-product (Petlyuk) columns and 40% for four-product (Kaibel) columns. However, the energy required for a separation depends on using an optimal vapor split. Hence, the energy saving potential may be lost if the column is operated away from its optimal point, for example, due to feed composition changes. This work demonstrates experimentally that the vapor split can be effectively used as a degree of freedom during operation, for example, for temperature control in the prefractionator section. Together with an adjustable liquid split, the vapor split control allows for minimizing the energy requirements.