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

In a distillation operation, what is the effect of the temperature of the reflux stream (given below) on the condenser and reboiler loads? Reflux conditions:
(i) Reflux stream is completely liquid and is at its bubble point.
(ii) Reflux stream is below its bubble point.

A

Condenser and reboiler loads are the same in both the cases

B

Reboiler load is the same in both the cases but condenser load is higher in case (ii)

C

Condenser load is the same in both the cases but reboiler load is higher in case (ii)

D

Both condensor and reboiler loads are higher in case (ii) as compared to case (i)

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

In continuous distillation, the internal reflux ratio (R_i) and the external reflux ratio (R_e) are related as

A

$${{\text{R}}_{\text{i}}} = \frac{{{{\text{R}}_{\text{e}}}}}{{1 - {{\text{R}}_{\text{e}}}}}$$

B

$${{\text{R}}_{\text{i}}} = \frac{{1 - {{\text{R}}_{\text{e}}}}}{{{{\text{R}}_{\text{e}}}}}$$

C

$${{\text{R}}_{\text{i}}} = {{\text{R}}_{\text{e}}}$$

D

$${{\text{R}}_{\text{i}}} = \frac{{{{\text{R}}_{\text{e}}}}}{{1 + {{\text{R}}_{\text{e}}}}}$$

"It is now expected that the variable production cost per unit and the selling price per unit will each increase by 10%, and fixed production cost will rise by 25%. What will be the new break even point?
Selling price - Rs 6 per unit
Variable production cost - Rs 1.20 per unit
Variable selling cost - Rs 0.40 per unit
Fixed production cost - Rs 4 per unit
Fixed selling cost - Rs 0.80 per unit
Budgeted production and sales for the year are 10,000 units."

A

8,788 units

B

11,600 units

C

11,885 units

D

12,397 units

The reflux to a distillation column is 100 moles/hr, when the overhead product rate is 50 moles/hr. The reflux ratio is

A

2

B

0.5

C

50

D

150

In case of a continuous distillation column, increase in reflux ratio may result in the

A

Lower fixed charges for the column

B

Greater cost for the reboiler heat supply

C

Greater cost for the condenser coolant

D

All of the above

Optimum reflux ratio in a continuous distillation column is determined by the

A

Maximum permissible vapour velocity

B

Flooding limit of the column

C

Total cost consideration (fixed cost of the column plus the cooling water & steam cost)

D

None of these

For a fixed number of ideal stages in a distillation column, as the reflux ratio is increased, the difference in composition between the top and bottom product streams

A

Increases

B

Decreases

C

Remains unaffected

D

Passes through a maximum

The fixed cost of a distillation column at minimum reflux ratio is

A

Minimum

B

Infinite

C

Optimum

D

None of these

In case of binary distillation, increasing the reflux ratio above optimum does not result in the increase of

A

Area between operating line and 45° diagonal x-y diagram

B

Condenser and reboiler surfaces

C

Tower cross-section

D

None of these

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

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