Engineering Questions with Answers - Multiple Choice Questions

# Distillation Design MCQ’s – Analytical X-Y Diagram -Smoker’s Equation

1 - Question

Smoker proposed an analytical closed form formula, to calculate
a) Reflux ratio
b) Number of trays
c) Number of stages
d) Number of feeds

Explanation: In 1938, Smoker proposed an analytical closed form formula to calculate the number of stages in a binary distillation column

2 - Question

. The analytical formula fails to predict the
a) Equilibrium Stages
b) Reflux ratio
c) Feed inlet and outlet
d) Boil up

Explanation: The analytical formula fails to predict the Equilibrium Stages with reasonable accuracy, while reflux and boil up are predicted as ratio.

3 - Question

. In the below diagram, the minimum reflux can be seen as ______ using smoker’s equation.

a) 1.567
b) 1.425
c) 1.2
d) Can’t be specified

Explanation: By tracking the locus to the x axis of smoker’s line reflux is seen to be intersecting at the abscissa of 1.425 on the x axis.

4 - Question

Smoker’s equation is convenient to use, in binary separations with
a) Large number of stages
b) Small number of stages
c) Independent stages
d) Dependent stages

Explanation: Smoker’s equation is convenient to use in binary separations with large number of stages, while Fenske’s for the minimum number of trays

5 - Question

Smoker’s equation is based on assumption?
a) Constant molar overflow and volatility
b) Constant Molar overflow and viscosity
c) Constant feed and stages
d) Constant Pressure

Explanation: Smoker’s equation is based on assumption of Constant molar overflow and volatility, while McCabe and Ponchan are based on Constant molar overflow only.

6 - Question

If NR is 5.44 and NS is 3.42. Total stages are
a) 2.02
b) 1.8
c) 8.86
d) 1.59

Explanation: as NR + NS = 5.44 + 3.42 = 8.86.

7 - Question

According to smoker’s equation, b is given as
a) R+1
b) xD/R+1
c) xD/y
d) y/R+1

Explanation: According to smoker’s equation b is given as xD/R+1, where XD is the moles of liquid distilled with the rate of reflux R.

8 - Question

According to smoker’s equation, C is given as
a) 1 + (α -1) k
b) 1 -(α -1)k
c) 1 -(α +1)k
d) α -1

Explanation: According to smoker’s equation C is given as 1 + (α -1) k, where k value is calculated from bottom and top sections of the column.

9 - Question

Calculate b? If xD= 0.95 and R=8
a) 0.445
b) 0.118
c) 0.2375
d) 0.568

Explanation: AS xD/R+1 = 0.95/8+1= 0.2375.

10 - Question

If reflux ratio is 3, then slope m is estimated as
a) 0.75
b) 1
c) 0.66
d) 0.90