Overall tray efficiency of a distillation column is the ratio of the number of

Bubble cap tray is the most commonly used tray in large distillation column, because

A

Of its flexibility and nearly constant efficiency under varying conditions of operation

B

It incurs less pressure drop as compared to any other try designed for the same duty

C

It eliminates the foaming and entrain-ment tendency during operation

D

None of these

An adequate clearance between the tray and the shell wall of a distillation column is provided to

A

Drain the liquid from the tray when the unit is not in operation

B

Allow for thermal expansion and facilitate installation

C

Avoid back-trapping

D

None of these

Pressure drop per tray in the atmospheric distillation column is about __________ psi.

A

0.01 - 0.5

B

0.07 - 0.12

C

0.5 - 1.0

D

1 - 3

An aqueous solution of methanol is to be distilled in a tray column. High pressure steam is available as a source of heat. For a given reflux ratio and overhead composition, two options are being explored; (i) a reboiler is used and (ii) no reboiler is used but steam is fed directly to the bottom of the column. As compared to option (i), in option (ii)

A

Less number of trays are required

B

Composition of the residue remains unchanged

C

More number of trays are required but the residue composition remains unchanged

D

More number of trays are required and the residue composition is more dilute in methanol

Flooding in a vapor-liquid contacting equipment occurs in a tray, when the pressure drop through a tray is __________ the liquid head available in the downcomer.

A

Less than

B

More than

C

Same as

D

Very much less

A rectangular sheet of paper, 10 cm long and 8 cm wide has squares of side 2 cm cut from each of its corner. The sheet is then folded to form a tray of depth 2cm. What is the volume of this tray?

A

32cm3

B

48cm3

C

49cm3

D

54cm3

Overall efficiency of the distillation column is

A

The ratio of number of ideal plates to actual plates

B

The ratio of number of actual plates to ideal plates

C

Same as the Murphree efficiency

D

Always more than the point efficiency

In distillation columns, the number of bubble caps per tray primarily depends upon the

A

Allowable liquid velocity

B

Allowable gas velocity

C

Allowable gas and liquid velocities

D

Feed composition

Packed column distillation is limited to the column __________ metres.

A

[

A. Height

B. Diameter

B

Both A & B

C

Neither A nor B

A distillation column with N plates is being operated under normal conditions. At some point of time, the operation is shifted to total reflux condition (i.e., no product and residue are being withdrawn and feed to the column is stopped). At the new steady state,

A

Composition of vapors and that of liquid do not vary throughout the column

B

Reboiler load and condenser load are minimum

C

The top and bottom compositions are unchanged with and without total reflux

D

The top and bottom compositions correspond to the maximum enrichment available

Overall tray efficiency of a distillation column is the ratio of the number of

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