Energy conserving effects of dividing wall column

The energy-conserving performance of dividing wall column (DWC) is discussed in this paper. The heat transfer through the dividing wall is considered and the results are compared with that of common heat insulation dividing wall column (HIDWC). Based on the thermodynamic analysis of heat transfer dividing wall column (HTDWC) and HIDWC, both computer simulation and experiments are employed to analyze the energy-conserving situation. Mixtures of n-hexane, n-heptane and n-octane are chosen as the example for separation. The results show that the energy consumption of HTDWC is 50.3% less than that of conventional distillation column, while it is 46.4% less than that of HIDWC. It indicates that DWC is efficient on separating three-component mixtures and HTDWC can save more energy than HIDWC. Thus it is necessary to consider the heat transfer while applying DWC to industry.

Graphical AbstractBack-mixing often happens when separating three-component mixture in direct sequence column and indirect sequence column. This phenomenon will cause the energy loss, then increase the energy consumption. The situation is improved in both HTDWC and HIDWC since component B is concentrated in the central column and the back-mixing is avoided. Figures (a) and (b) illustrate how the back-mixing wastes the energy. The results of computer simulation and experiments show that the energy consumption of HTDWC and HIDWC is less than that of conventional distillation column. It can be concluded that DWC enhances the energy-saving by eliminating back-mixing.Figure optionsDownload as PowerPoint slide