The large-scale column in Example 16-4 is fed a saturated liquid with mole fraction \(\mathrm{z}=0.5\), and separation is essentially complete ( \(\mathrm{x}_{\text {dist }} \sim 1.0\) and \(\left.\mathrm{x}_{\text {bot }} \sim 0\right)\). Assume the Murphree vapor efficiency calculated in Example \(16-4, \mathrm{E}_{\mathrm{MV}}=0.97\), is constant in the large-scale column (plug flow trays). Calculate \(\mathrm{E}_{\mathrm{pt}}\) and \(\mathrm{K}_{\mathrm{y}} \mathrm{a}\) in the stripping section at \(\mathrm{x}=0.10\) and \(\mathrm{x}=0.30\) and in the enriching section at \(\mathrm{x}=0.9\) and at \(\mathrm{x}=0.7\). Compare your value at \(\mathrm{x}=0.7\) with the value calculated in Example \(16-4\) as a check on your procedure.

Example 16-4

A small distillation column separating benzene and toluene gives a Murphree vapor efficiency of 0.65 in the rectifying section where L/V = 0.8 and Xbenz = 0.7. The tray is perfectly mixed and has a liquid head of 2.0 in. Assume n = 0.9. The vapor flux is V/A = 25.0 lbmol/(h ft). (a) Calculate Kya. (b) Estimate EMV for a large-scale column where the trays are plug flow and the liquid head, h, becomes 2.5 in. Other parameters are constant.