Economic feasibility of heat pumps in distillation to reduce energy use

An i-butane/n-butane mixture was selected to analyze several distillation assisted heat pump processes when compared to conventional distillation. This conventional process, along with top vapour recompression, bottom flashing and absorption heat pumps, were simulated using the HYSYS software platform, in order to determine economically the best alternative. Distillation with both top vapour recompression and bottom flashing heat pumps allows reduction of operation (energy) costs by 33% and 32%, respectively. This improves the economic potential (incorporating capital costs) by 9% and 10%, respectively. Due to the large steam consumption, when compared to the conventional case, the absorption heat pump is not suitable for this system.