Engineering Questions with Answers - Multiple Choice Questions

# Distillation Design MCQ’s – Mccabe Thiele Diagram-Construction

1 - Question

The component balance of the component A is given as
a) FzF= DxD + Wxw
b) FzF= DxD – Wxw
c) FzF= DxD/Wxw
d) FzF= DxD *Wxw

Explanation: According to McCabe Thiele method material balance over is given as FzF= DxD + Wxw, where F is the total feed.

2 - Question

If F= 200 kmol/h and ZF=0.4, XD=0.95, XW=0.04 and R=2.0, Then D is
a) 88.1
b) 22.6
c) 79.1
d) 158.2

Explanation: Using equation FzF= DxD + Wxw substituting values we get D=79.1.

3 - Question

The very First step of McCabe method is?
a) Plot the equilibrium curve
b) Plot diagonal curve
c) Plot Operating line
d) Plot stripping line

Explanation: Firstly we plot the Equilibrium diagram from the given equilibrium data, then the diagonal curve and then plot the operating line.

4 - Question

Calculate Boil up? If vapor flow and bottom withdrawal are 237.3 and 120.9 respectively
a) 1.5
b) 2.9
c) 2.111
d) 1.963

Explanation: As boil up is ratio of vapor flow and bottom withdrawal then 237.3/120.9 = 1.963.

5 - Question

If ZF¬=0.58 and also feed contains 35% mole of the liquid, then intercept of y axis is
a) 0.892
b) 0.205
c) 0.707
d) Can’t be calculated

Explanation: As – (ZF/q-1) using values -0.58/ (0.35-1) = 0.892.

6 - Question

If ZF=0.6 and also feed contains 72% mole of the liquid, then intercept of x axis is
a) 0.744
b) 0.899
c) 0.833
d) 1.2

Explanation: As (ZF/q) using values 0.6/ (0.72) = 0.833.

7 - Question

Calculate minimum reflux? If intercept is 0.56 and XD= 0.96
a) 0.174
b) 0.125
c) 0.21
d) 0.28

Explanation: As 0.56=XD/ (RM+1) = 0.96/ (RM+1) M= 0.174

8 - Question

Slope of rectifying line is given by
a) R/XD
b) R/(R+1)
c) F/ (D+W)
d) R/(R+1)

Explanation: The rectifying line slope is always given as ratio of Reflux ratio plus unity i.e. R/(R+1), While R/XD gives us the reflux to liquid ratio for the operation.

9 - Question

If xD=0.95, xW= 0.04 and α=2.5. Find total trays?
a) 7
b) 6.7
c) 7.7
d) 6

Explanation: Using Fenske’s equation total number of trays to be calculate are 5.7 as Nm + 1 then 5.7+1 = 6.7 which is the final answer.

10 - Question

A Pinch point may occur at intersection of feed line and
a) Stream line
b) Stripping line
c) Rectifying line
d) Equilibrium line