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

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

A minimum clearance of about __________ mm is maintained between the distillation column wall and the bubble cap.

A

19

B

38

C

76

D

95

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

A

Overall gas transfer units to the number of ideal trays required

B

Ideal trays required to the number of real trays required

C

Real trays required to the number of ideal trays required

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

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

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

The function of manholes provided in the shell of a distillation column is to

A

Keep a check on the liquid gradient over the plate by direct visual observation

B

Give access to the individual trays for cleaning, maintenance and installation

C

Guard against foaming & entrainment by dumping antifoaming agent through it

D

All of the above

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

In a distillation column, minimum clearance to be maintained betweeen the overflow weir and the last row of the bubble caps is __________ cms.

A

2.5

B

7.5

C

15

D

20

A ladder is resting against a vertical wall and its bottom is 2.5 m away from the wall. If it slips 0.8 m down the wall, then its bottom will move away from the wall by 1.4 m. What is the length of the ladder?

A

6.2 m

B

6.5 m

C

6.8 m

D

\7.5 m

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

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