When a multistage tray tower uses a minimum reflux ratio, it implies

In a continuous distillation column, the optimum reflux ratio ranges from __________ times the minimum reflux ratio.

A

1.1 to 1.5

B

1.6 to 2

C

2.2 to 2.6

D

2.7 to 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

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 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

What is the reflux ratio at total reflux?

A

Zero

B

Infinity

C

Unity

D

Data insufficient

In actual operation of a bubble cap distillation tower, the __________ at the bottom of the tower is more than that at the top of the tower.

A

Molal flow rate of vapour

B

Vapour molecular weight

C

Pressure and temperature

D

All of the above

The final stage of a multistage amplifier uses ___________

A

RC coupling

B

Transformer coupling

C

Direct coupling

D

Impedance coupling

In a moderately sized packed absorption tower, channeling (which is most severe with stacked packings) can be minimised by taking the ratio of tower diameter to packing diameter

A

> 4 :1

B

> 8:1

Minimum reflux ratio in a distillation column results in

A

Optimum no. of trays

B

Minimum reboiler size

C

Maximum condenser size

D

Minimum number of trays

When a multistage tray tower uses a minimum reflux ratio, it implies

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