Separation of a Partially Miscible Mixture Shown by Graphical Method

Consider a binary mixture of water and nitromethane at 1 atm. This mixture exhibits the vapor-liquid equilibrium behavior of partially miscible mixtures (equilibrium data is available in [1]). Thus, in order to separate water from nitromethane, one has to use a two-column system with an intermediate decanter. This Demonstration shows the required operational setup, which will produce two product streams: a pure water stream and a water-free stream.

Assume that the feed to the first column is a saturated vapor containing water flowing at and that the feed to the second column is a saturated liquid containing water flowing at . The bottom compositions are set to water and water for columns 1 and 2, respectively.

External mass balances give the flow rates of the bottom products of both columns, and .

The Demonstration uses the McCabe and Thiele graphical method to compute the number of stages for both columns. You can set the two reboil ratios.