Distillation is the most extensively used separation process in the chemical industry. It is highly energy intensive and has relatively low thermodynamic efficiency. Increasing energy prices and recent advances in process intensification have motivated the researchers to explore more energy efficient and environment friendly processes. Heat-pump assisted distillation is one such alternative that can potentially address these issues.

            In this study, we present a systematic methodology for designing and improving vapor recompression distillation (VRC) schemes using commercial process simulator Aspen Plus®. The proposed methodology is then applied to an industrial scale i-butane/n-butane fractionator as a case study. In the base VRC configuration, the quality of low-grade heat from the overhead vapor is improved using a heat pump and then used to boil the bottoms liquid in the reboiler. Up to 38% savings in direct operating/energy costs and up to 24% savings in the net total annualized cost relative to the conventional column are observed. Further improvements are made by topological changes including feed location, heat integration, and recycle streams. For each VRC configuration, optimization of key design variable and operational parameters is performed to find an optimum configuration.