Engineering Questions with Answers - Multiple Choice Questions
Separation Processes MCQ’s – Crsytallization Equipmemnts
1 - Question
What is the crystal size range of forced circulation crystallizer?
a) 10-20mesh
b) 20-30mesh
c) 30-60mesh
d) 100-200mesh
View Answer
Answer: c
Explanation: In the forced circulation crystallizer a crystal of size of 30-60mesh are mesh are produced.
Explanation: In the forced circulation crystallizer a crystal of size of 30-60mesh are mesh are produced.
2 - Question
Why the axial pump flow speed is preferred in forced circulation crystallizer?
a) To reduce primary nucleation rate
b) To reduce the crystal size
c) To increase the crystal size
d) To keep the secondary nucleation rate small
View Answer
Answer: d
Explanation: An axial flow pump is preferred, the pump speed should be low in order to reduce the energy input so that the secondary nucleation by contact or attrition remains small.
3 - Question
What is the crystal size range of draft-tube-baffle crystallizer?
a) 1-2 mesh
b) 30-60mesh
c) 8-30mesh
d) 100-200mesh
View Answer
Answer: c
Explanation: The crystal size range of draft-tube-baffle crystallizer is 8-30mesh.
4 - Question
What is the near ambient temperature range for most inorganic solids?
a) 10-20
b) 10-40
c) 40-67
d) 70-80
View Answer
Answer: b
Explanation: The near ambient temperature range for most inorganic solids is 10-40 degrees.
5 - Question
Which type of crystallizers does industry employ?
a) Evaporative
b) Cooling
c) Sublimating
d) Boiling
View Answer
Answer: a
Explanation: Mostly, evaporative crystallizers or a combination of evaporative and cooling crystallizers is used.
6 - Question
What is not an advantage of using mechanical agitation?
a) High purity
b) Uniform crystal size
c) High purity
d) Low rate of primary nucleation
View Answer
Answer: d
Explanation: A high rate of primary nucleation is required so it cannot be an advantage.
7 - Question
What is the result of unagitated batch crystallizers?
a) Undesirably large crystals
b) Impure crystals
c) Entrapment of mother liquor
d) High secondary nucleation rate
View Answer
Answer: d
Explanation: High secondary nucleation rate is the result of high speed of the agitator.
8 - Question
What ensures a reasonable heat transfer rate through a small temperature driving force?
a) High agitation speed
b) High magma velocity
c) High nucleation rate
d) Low nucleation rate
View Answer
Answer: b
Explanation: A high magma velocity ensures a small temperature driving force.
9 - Question
What is the time for a typical cycle, including charging the feed, crystallization, and removal of the magma?
a) 1 hour
b) 2-8hr
c) 7-15hr
d) 5-14hr
View Answer
Answer: b
Explanation: 2-8hr is the time for a typical cycle, including charging the feed, crystallization, and removal of the magma.
10 - Question
What is the specialty of the circulating liquor crystallizer?
a) Supersaturaion is created in separate region
b) Supersaturation is not created
c) Supersaturation is created at every point
d) Crystals are automatically thrown out of crystallizer
View Answer
Answer: a
Explanation: The speciality of circulating liquor crystallizer equipment is that supersaturation is created in a separate region before the liquor flows into the crystal suspension vessel. The “level” of supersaturation drops down as the liquor from the supersaturated zone mixes up with the slurry.
Explanation: The speciality of circulating liquor crystallizer equipment is that supersaturation is created in a separate region before the liquor flows into the crystal suspension vessel. The “level” of supersaturation drops down as the liquor from the supersaturated zone mixes up with the slurry.