Engineering Questions with Answers - Multiple Choice Questions

# Distillation Design MCQ’s – Reflux Stage Relationships

1 - Question

Fenske’s Equation can be written as
a) Nmin = S/ ln α
b) Nmin = ln S/ ln α
c) Nmin – 1 = ln S/ ln α
d) Nmin + 1 = ln S/ ln α

Explanation: The Fenske’s equation is given by this equation Nmin = ln S/ ln α, where N is the number of trays and alpha is the relative volatility.

2 - Question

The term S in the Fenske’s equation, is given as
a) (xLKxHK)D(xLKxHK)B
b) (xLKxHK)D(xLKxHK)L(xLKxHK)R
c) (xLKxHK)L(xLKxHK)V
d) (xLKxHK)HK(xLKxHK)LK

Explanation: The term S in the Fenske’s equation is given as (xLKxHK)D(xLKxHK)B, representing High and Low keys of the gas and liquid phases.

3 - Question

N√αN this equation is called as
a) Sorel’s Method
b) Polson Equation
c) Fenske’s Equation
d) Gilliland Equation

Explanation: Fenske’s Equation that is rigorous, Gilliland Equation are used and based on the trial and error basis

4 - Question

Calculate ln S? If XLK=0.41 and XHK = 0.005 and XL= 0.417 and XH= 0.01, then
a) 9.45
b) 8.90
c) 8.137
d) 7.98

Explanation: As ln (0.41/0.005) (0.417/0.01) = 8.137.

5 - Question

A non-key component may be distributed if
a) Close to that of one key
b) The Specified separation is sloppy
c) Intermediate between keys
d) Intermediate one key

Explanation: For distributed systems the Specified separation is sloppy, while for the distributed system it is close to that of one key

6 - Question

In a distillation operation, the reflux ratio may vary between
a) Zero and one
b) Zero and infinity
c) Minimum and infinity
d) One and two

Explanation: L0/D Varies from zero to one, as the ratio cannot be more than one because that will cause the failure of the column.

7 - Question

Most distillation columns are designed for reflux ratio between
a) 3 to 5 Rmin
b) 1.2 and 1 .7 Rmin
c) 2 to 10 Rmin
d) 0.2 to 0.7 Rmin

Explanation: This is the most suitable for 1.2 and 1.7 Rmin times reflux ratio, this also reduces the operating and the final cost of the system.

8 - Question

If Component is non-distributed, then
a) DR >1
b) DR<1
c) DR=0
d) DR=∞

Explanation: If component is non-distributed then DR >1 contained entirely distillate, while if components are distributed they are entirely withdrawn.

9 - Question

If Component is distributed, then
a) 0< DR> 1
b) 0< DR< 1
c) DR= 0
d) DR < 0

Explanation: If Component is distributed then 0< DR< 1, DR is recovery component, if DR = 0 then there exists no distributed components in the systems.

10 - Question

Underwood’s equation can be used to find
a) Distributed components
b) Non distributed components
c) Reflux for components
d) Non reflux components