Energy Efficient Distillation by Combination of Thermal Coupling and Heat Integration

Abstract

Abstract Conventional heat-integration between adjacent columns, as well as thermal coupling and the equipment-integrated implementation in a dividing wall column are successful concepts for the improvement of the energy efficiency of distillation processes. While especially dividing wall columns have made a considerable impact in industrial application, further heat integration is prevented by the bidirectional transfer of liquid and vapor streams that impede a necessary pressure variation for modification of the boiling temperatures. This limitation can however be overcome by the modification of thermal couplings to one-directed liquid only transfer. While this concept has been proposed almost 20 years ago, it has received limited attention so far. In order to evaluate the prospect of this combination, the current article exploits a combination of a shortcut-based screening and a rigorous economic optimization, in order to evaluate a heat-integrated side-rectifier with liquid only transfer modification in comparison with a range of alternative options. The application to an exemplary case study highlights the huge potential of this combination, showcasing the possibility to save half of the energy required for a non-integrated configuration and even more than 30% compared to fully thermally coupled configurations, depending on the feed composition.