(326c) Structural Design and Separation Characteristic of Divided Wall Column by the Shortcut Method

It is suggested an efficient structure design method with interrelation of optimization by the internal separation characteristic for the initial structure design stage of divided wall distillation column. In the structural design of divided wall column (DWC), the main design factors affecting the overall performance are the position of feed tray, divided wall section, and side-stream tray as well as the total number of trays in main and prefractionator sections. In the proposed method, the main factors of structural design in DWC can be easily obtained from a shortcut method by using the Fenske-Underwood equation via employing three conventional simple column's configuration while the existing structural design method requires a lot of efforts for the design of DWC. One of the optimal design factors, the internal-flow in DWC is related to the reflux ratio of the 1st column, and it is also related to each composition of components separated at the top and bottom of the 1st column. This relation clearly has a benefit as the tray position is very simple and efficient by applying on the DWC structure design. Further, the optimal design condition and energy consumption is compared by applying the proposed method on divided wall column and by using the optimal internal-flow via. a case study in simulation. The energy consumption is also studied by changing the composition of intermediate component in feed mixture. The simulation result shows that the energy consumption of DWC using the shortcut method shows an acceptable difference from the global optimal design case. The DWC designed by the proposed method saves energy approximately from 29% to 34% more over the conventional sequential two column system.