19. A distillation column is separating a feed that is 20 mol% methanol, 50 mol% n. propanol, and 30 mol% n-butanol. Feed is 750 kmol/h. We want a 92 mol% recovery of methanol in the distillate and 95% recovery of n-propanol in the bottoms. Use L/D = 10. Feed is a saturated liquid. The column has a total condenser and a partial reboiler. As a guess, assume that n-butanol does not distribute (it all exits in the bot- toms), Do not do iterations to improve this guess. If we choose n-propanol as the ref- erence, the relative volatilities are methanol = 3.58, n.propanol -1.0, and n-butanol 0.412. Assume relative volatilities are constant. Do not use Aspen Plus. This calcula. tion is simple enough that it can be done by hand or with a spreadsheet (with or with out Visual Basic for Applications (VBA]) or with MATLAB. a. Find D, B. X.diw and X.doc b. Step off stages using the second stage above the partial reboiler (the third equilib- rium contact from bottom) for feed location and find the total number of stages and the calculated distillate mole fractions