Engineering Questions with Answers - Multiple Choice Questions

# Separation Processes MCQ’s – Multicomponent Flash, Bubble Point and Dew Point Calculations

1 - Question

What is a flash?
a) It is a single-equilibrium stage distillation where the feed is partially vaporized to give a vapor feed rich in more volatile components.
b) It is a double-equilibrium stage distillation where the feed is partially vaporized to give a vapor feed rich in more volatile components
c) It is a single-equilibrium stage distillation where the feed is completely vaporized to give a vapor feed rich in more volatile components
d) It is a single-equilibrium stage distillation where the feed is partially vaporized to give a vapor feed rich in less volatile components
Explanation: A flash is a single-equilibrium stage distillation where the feed is partially vaporized to give a vapor feed rich in more volatile components.

2 - Question

When is flashing a replacement for distillation?
a) When the relative velocity is high
b) When the relative velocity is low
c) When the relative volatility is high
d) When the relative volatility is low
Explanation: Unless the relative volatility is high, flashing is not a replacement for distillation.

3 - Question

What is the condition for phase equilibrium?
a) Pv=PL
b) TV=TL
c) yi=kixi
d) Fzi=Vyi + Lxi
Explanation: The correct equation for phase equilibrium isyi=kixi.

4 - Question

What is the condition for thermal equilibrium?
a) Pv=PL
b) TV=TL
c) yi=kixi
d) Fzi=Vyi + Lxi
Explanation: The correct equation for thermal equilibrium is TV=TL.

5 - Question

What is the condition for mechanical equilibrium?
a) Pv=PL
b) TV=TL
c) yi=kixi
d) Fzi=Vyi + Lxi
Explanation: The correct equation for mechanical equilibrium is Pv=PL.

6 - Question

What is the equation for component material balance?
a) Pv=PL
b) TV=TL
c) yi=kixi
d) Fzi=Vyi + Lxi
Explanation: The correct equation for component material balance isFzi=Vyi + Lxii.

7 - Question

What is the equation for total energy balance?
a) Pv=PL
b) F=V + L
c) yi=kixi
d) Fzi=Vyi + Lxi
Explanation: The correct equation for total energy balance is F= V + L.

8 - Question

What is the dew point quation?
a) ∑ ziki=0
b) ∑ zi/ki=0
c) ∑ ziki=1
d) ∑ zi/ki=1
Explanation: The dew point equation is∑ zi/ki=1.

9 - Question

What is the bubble point equation?
a) ∑ ziki=0
b) ∑ zi/ki=0
c) ∑ ziki=1
d) ∑ zi/ki=1
Explanation: The dew point equation is∑ zi/ki=1.

10 - Question

What is true about vapor- liquid equilibrium?
a) Vapor is at its dew point and liquid at its bubble point
b) Vapor at its bubble point and liquid at its dew point
c) Both the liquid and vapor at dew point
d) Both the liquid and vapor at bubble point