Distillation is the most widely-used but the most energy-consuming separation process in chemical industries. The internally Heat-Integrated Distillation Columns (HIDiC) are one of the most promising technologies for the energy saving of conventional distillation processes. However, the mass and heat transfer phenomena in the HIDiC are still unclear. To analyze the phenomena, a simulator with rate-based model was developed for HIDiC. Tthe separation performance of the HIDiC was affected by the internal heat exchange. The internal heat exchange might suppress the mass transfer. This is an abstract of a paper presented at the 2007 AIChE Annual Meeting (Salt Lake City, UT 11/4-9/2007).