Test: Differential Distillation - Chemical Engineering MCQ

Explanation: In flash vaporization only small portion of liquid gets flashed.

Explanation: Still is the distillation column used for differential distillation.

Explanation: Here, the liquid mixture is filled in the still for certain time to attain the vapour liquid equilibrium.

Explanation: Since the low volatile component has high boiling point it will be the final portion.

Explanation: Cuts are the place where the different volatile components are stored.

Explanation: The first two high volatile components are stored in two cuts and the low volatile remains in the still itself.

Explanation: For the differential distillation to get the effective distillation the process must be slow to attain the vapour- liquid equilibrium.

Explanation: If pre-cooling occurs, the vapour gets condense in the still itself so there will be alter in equilibrium.

Explanation: Rayleigh proposed the numerical analysis of the batch distillation.

Explanation: Using Rayleigh equation, we can estimate
ln (F/W)= 1.657
F= 313 mol/hr.

Explanation: Using Rayleigh equation,
Ln (F/W) = Area under the curve
= 1
F= 163.

Explanation; F*xf= D*yd+ W*xw
Yd= 0.62.

Answer: For a constant pressure process, the will be a constant relative volatility. So from modified Rayleigh method we can determine relative volatility,
Log(F*xf/W*xw)= A log ( F(1-xf)/W(1-xw)), where A- constant relative volatility
A= 2.43.

Explanation: From the Rayleigh equation for differential condenser, we get distillate rate = 22.

Explanation: Using Rayleigh equation, we can estimate
ln (F/W)= 1.657
F= 313 mol/hr then
D= 253 mol/hr.