Separation Processes Questions and Answers - Extractive Distillation

1. If broth flow rate is 200kg/hr and solvent flow rate is 300kg/hr and POD is of diameter 1m and length 7m, what is the residence time?
a) 28s
b) 20s
c) 40s
d) 35s

Answer: c
Explanation:ttme= pi*(D2/4)L/F+S, ttime = 3.14*(1/4)7/500=40s.

2.If broth flow rate is 200kg/hr and solvent flow rate is 300kg/hr and POD is of diameter 3m and length 5m, what is the residence time?
a) 200s
b) 250s
c) 230s
d) 254s

Answer: a
Explanation: ttme= pi*(D2/4)L/F+S, ttime = 3.14*(9/4)5/500=254s.

3. If broth flow rate is 200kg/hr and solvent flow rate is 500kg/hr and POD is of diameter 1m and length 5m, what is the residence time?
a) 28s
b) 20s
c) 30s
d) 35s

Answer: b
Explanation: ttme= pi*(D2/4)L/F+S, ttime = 3.14*(1/4)5/700=20s.

4. Which distillation is used to separate azeotropes and close boiling mixtures?
a) Extractive distillation
b) Salt distillation
c) Pressure-swing distillation
d) Reactive distillation

Answer: a
Explanation: Extractive distillation is used to separate azeotropes and close boiling mixtures.

5. If the feed is ______ boiling azeotrope the solvet enters the column with the feed.
a) Maximum
b) Minimum
c) Low
d) High

Answer: a
Explanation:If the feed is maximum boiling azeotrope the solvet enters the column with the feed.

6. Why is water the preferred solvent for separating acetone and methanol?
a) Because it does not form hydrogen bonding
b) Because it does not react with it
c) Because water is an universal solvent
d) Because water does not form binary or ternary azeotropes with acetone or methanol.

Answer: d
Explanation: Water is the preferred solvent for separating acetone and methanol because water does not form binary or ternary azeotropes with acetone or methanol.

7. What happens due to presence of appreciable water?
a) Phase activity coefficient of acetone increases and that of methanol decreases
b) Phase activity coefficient of acetone decreases and that of methanol increases
c) Phase activity coefficient of both methanol and acetone increases
d) Phase activity coefficient of both decreases

Answer: a
Explanation: Phase activity coefficient of acetone increases and that of methanol decreases due to presence of appreciable water.

8. What is the distillate and bottom in presence of appreciable water?
a) Distillate of methanol and bottoms of acetone
b) Distillate of acetone and bottoms of methanol
c) Distillate of both acetone and methanol
d) Bottoms of both acetone and methanol

Answer: b
Explanation:Due to presence of appreciable water, we get a distillate of acetone and bottoms of methanol.

9. What is the unfortunate point of extractive distillation?
a) Water has low boiling point
b) Water has high boiling point
c) Extractive distillation is costly
d) Extractive distillation is not efficient

Answer: a
Explanation: Water having a low boiling point is an unfortunate aspect of extractive distillation. Aniline is used instead.

10. Which factor does not decide a solvent?
a) Availability
b) Cost
c) Corrosivity
d) Viscosity

Answer: d
Explanation: Viscosity of solvent won’t decide which solvent to be chosen.