Which of the following is not a valid assumption in continuous binary distillation for calculating the number of equilibrium stages by Mc-Cabe-Thiele's method?

Smoker's equation for the calculation of number of equilibrium stages in a continuous binary distillation column is used, when the

A

Relative volatility is close to one (e.g., separation of close boiling isomers)

B

Feed is not at its bubble point

C

Number of equilibrium stages in only stripping section is to be calculated

D

Number of equilibrium stages required is likely to be very small

Which of the following is not a graphical method (but is an analytical method) for the calculation of theoretical number of stages in case of continuous binary distillation?

A

Sorel-Lewis method

B

McCabe-Thiele's method

C

Ponchon-Savarit method

D

None of these

Fenske-Underwood equation used for calculating the minimum number of theoretical plates in distillation column is valid for

A

Constant molal overflow

B

Total reflux

C

Constant relative volatility

D

All of the above

With increase in the reflux ratio for a fixed production from a continuous binary distillation column, the __________ decreases.

A

Fixed charges initially

B

Running cost of cooling water for condenser

C

Vapour & liquid load both

D

Running cost of steam for reboiler

The assumption made in Elis method in distillation is that enthalpy concentration lines of vapor and liquid are

A

Parallel

B

Straight

C

Both parallel and straight

D

Neither parallel nor straight

Mc Cable Thiele method used for finding theoretical stages in a distillation column assumes that the

A

Sensible heat differences are small, because the temperature changes from tray to tray is small

B

Trouton's rule is applicable

C

Liquid/vapor loading across the column remains constant

D

All of the above

McCabe-Thiele method of binary distillation does not assume that the

A

Sensible heat changes are negligible compared with latent heat changes

B

Molar latent heats of all components are equal

C

Heat of mixing is negligible

D

None of these

Polar organic compounds are normally used as separating agents for the azeotropic and extractive distillation. Which of the following is the most important factor to be considered for the choice of the separating agent for extractive distillation?

A

Cost

B

Availability

C

Toxicity

D

Selectivity

If the amount of the steam used in steam distillation is increased, the temperature of distillation

A

Increases

B

Decreases

C

Remains unchanged

D

Depends on relative volatility

Vacuum maintained in the vacuum distillation tower of the crude distillation plant is about __________ mm Hg (absolute).

A

5-10

B

30-80

C

150-250

D

350-400

Which of the following is not a valid assumption in continuous binary distillation for calculating the number of equilibrium stages by Mc-Cabe-Thiele's method?

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