Engineering Questions with Answers - Multiple Choice Questions
Distillation Design MCQ’s – Minimum Reflux for System Containing Distributed Monkeys
1 - Question
Light non-keys end up as a
a) Final product
b) Feed outlet
c) Bottom end product
d) Overhead product
View Answer
Answer: d
Explanation: Light non-keys always end up as an overhead product, while heavy keys at bottom product of the column.
2 - Question
Heavy non-keys end up as a
a) Final product
b) Feed outlet
c) Bottom end product
d) Overhead product
View Answer
Answer: c
Explanation: Heavy non-keys always end up as a Bottom end product, this occurs due to volatility difference in the components.
3 - Question
The reflux ratio corresponding to the minimum total cost is called as
a) Optimum reflux ratio
b) Minimum reflux ratio
c) Final Ratio
d) Total Reflux Ratio
View Answer
Answer: a
Explanation: The reflux ratio corresponding to the minimum total cost is called as Optimum reflux ratio and the final cost related is called as final ratio.
4 - Question
The concentration of multi component mixture in mass transfer process, can be represented by
a) Mass concentration
b) Molar concentration
c) Molar density
d) Each quantity is important
View Answer
Answer: d
Explanation: The concentration of multi component mixture can be represented by all molar forms independent of property, so concentration as well as density are equally important.
5 - Question
HETP is numerically equal to HTU, If and only if operating line
a) Lies below the equilibrium line
b) Lies above equilibrium line
c) At equilibrium line
d) Is far from equilibrium line
View Answer
Answer: c
Explanation: HETP is numerically equal to HTU if and only if operating line is parallel to equilibrium line, this means NTU i.e. number of transfer units are unity.
6 - Question
In binary system, Separation is very efficient when relative volatility is
a) 1
b) >1
c) <1
d) Zero
View Answer
Answer: b
Explanation: If α >1 efficiency of separation increases, if separation is difficult then α < 1 and if no separation is possible then α= 0.
7 - Question
In batch distillation, with constant reflux overhead product composition
a) Increases with time
b) Decreases with time
c) Does not vary with time
d) Does vary with time
View Answer
Answer: b
Explanation: As batch operation feed reduces with given time thus reflux decreases, as batch distillation contains a limited amount of feed.
8 - Question
Which of the following assumes constant molal vaporization and overflow?
a) McCabe Thiele method
b) Ponchan Savarit Method
c) Enthalpy concentration method
d) Plate absorption method
View Answer
Answer: a
Explanation: The McCabe Thiele method assumes constant molal vaporization and overflow, while the Ponchan Savarit Method is based on the enthalpy balance of components.
9 - Question
The McCabe Thiele method
a) Uses molal units for material and energy balance
b) Uses weight fractions to express liquid and vapor composition
c) Can use any type of units
d) Is more accurate than ponchan savarit method
View Answer
Answer: b
Explanation: The McCabe Thiele method uses weight fractions to express liquid and vapor composition for calculations.
10 - Question
If q is interpreted to be fraction of feed stream that is liquid, then for saturated liquid feed
a) q =0
b) q <0
c) q >l0
d) q =1
View Answer
Answer: b
Explanation: For saturated liquid feed q is always less than 0 and for saturated gas feed q is greater than 0.