Energy Efficiency Limitations of the Conventional Heat Integrated Distillation Column (HIDiC) Configuration for Binary Distillation

In the recent literature, a typical heat integrated distillation column (HIDiC), with heat integration at multiple locations between the rectifying and stripping sections, is often claimed to be more energy efficient than a single binary distillation column. However, we find that there are many binary feed separations where HIDiC is less energy efficient than simple heat pump schemes using only one or two heat transfer locations. Furthermore, we show that the energy efficiency of HIDiC cannot be solely decided based on the feed composition or product purities. A better performance indicator is the temperature profile along the height of the rectifying section relative to the corresponding temperature profile in the stripping section. On the basis of the analysis of these temperature profiles, we suggest a novel method to reduce heat transfer locations between the two distillation sections of HIDiC with negligible, if any, negative impact on the overall energy efficiency.