A model developed originally for crude oil distillation units has been applied to a standalone internally heat integrated distillation column (HIDiC) to evaluate emissions levels and to generate design options for direct carbon dioxide emissions reduction. Simulations indicate that for propylene-propane separation, an ideal (no reboiler) HIDiC enables a reduction in emissions of 83% and of 36%, compared to conventional and heat pump alternatives, respectively. Integrating a turbine to drive the compressor, in conjunction with a suitable fuel is the key to the minimization of the emissions associated with the operation of a HIDiC. Importantly, while substantial emission reductions are achieved, the process economics are improved. (C) 2005 Elsevier Ltd. All rights reserved.