Distillation Design Questions and Answers – Reflux Stage Relationships

This set of Distillation Design Multiple Choice Questions & Answers (MCQs) focuses on “Reflux Stage Relationships”.

1. 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
View Answer

Answer: b
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. 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
View Answer

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

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

4. 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
View Answer

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

5. 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
View Answer

Answer: b
Explanation: For distributed systems the Specified separation is sloppy, while for the distributed system it is close to that of one key.
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6. 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
View Answer

Answer: a
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. 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
View Answer

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

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1 contained entirely distillate, while if components are distributed they are entirely withdrawn.

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

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

Answer: a
Explanation: Underwood’s equation can be used to find Distributed components (n) including key.

Sanfoundry Global Education & Learning Series – Distillation Design.
To practice all areas of Distillation Design, here is complete set of 1000+ Multiple Choice Questions and Answers.

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Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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