Extractive distillation column

[Harry20]

Hello everyone, does anyone know how to determine the number of trays and minimum reflux ratio of an extractive distillation column. I was given the task to design one for the separation of Dimethylcarbonate and Methanol azeotrope. I can’t approach it like I would a simple distillation column. Any advice is welcomed

 

[pmoneysh]

There is no straightforward equation to estimate the minimum no of trays/reflux ratio for extractive distillation. Take a good initial guess for number of trays and observe its effect (vary the tray no.) on duty of reboiler and condenser. You might get a curved line. Higher duty-more operating cost, Hihger number of trays-more capital cost. You can show the graph to your advisor how you estimated the optimum number of trays. Reflux ratio is often varied to meet the product specification upon fixing the tray no. and solvent flow.