Explore the sensitivity of Eq. (7-35) in Example 7-3 at \(X=0.455\) by determining \(\mathrm{Y}\) and \(\mathrm{N}\) as the value of the constant 0.99357 changes. Try constant values of \(0.990,0.993\), and 0.994 .

Equation (7-35)

Example 7-3

Estimate the total number of equilibrium stages and the optimum feed plate location required for the distillation problem presented in Examples 7-1 and 7-2 if the actual reflux ratio is set at L/D = 2.

Example 7-1 

A distillation column with a partial reboiler and a total condenser is separating a saturated vapor feed that is 40.0 mol% benzene (B), 30.0 mol% toluene (T), and 30.0 mol% cumene (C). Recovery of toluene in the distillate is 95%, and recovery of cumene in the bottoms is 98%. Reflux is a saturated liquid, and constant molal overflow (CMO) is valid. Pressure is at 1.0 atm. Relative volatilities are constant. Choosing toluene as the reference component, α_B-T = 2.25 and α_C-T = 0.21. Find the number of equilibrium stages required at total reflux, the recovery fraction of benzene in the distillate and in the bottoms, and the mole fractions in the distillate and bottoms.

Example 7-1 

For the distillation problem given in Example 7-1, find the minimum reflux ratio. Use a basis of 100.0 kmol/h of feed.

Transcribed Image Text:

Y= 1-X0.0031 1-0.99357X0.0031