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) ____________________?

Related Mcqs:

1. 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 condenser and reboiler loads are higher in case (ii) as compared to case (i)

2. 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

3. 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. Remain unaffected
   D. Passes through a maximum

4. If xD = overhead product molal composition and RD = reflux ratio, then slope and intercept of the operating line for rectifying section are respectively ?

   A. [xD/(RD + 1)], [RD/(RD + 1)]
   B. [RD/(RD + 1)], [xD/(xD + 1)]
   C. [xD/(RD + 1)], [(RD + 1)/RD]
   D. None of these

5. Pick out the correct relationship. (Where, Ri = internal reflux ratio Ro = external reflux ratio.) ?

   A. (1 + Ro) = Ro/Ri
   B. (1 – Ro) = Ro/Ri
   C. (1 + Ri) = Ro/Ri
   D. (1 – Ri) = Ro/Ri

6. If Rm is the minimum reflux ratio, the optimum reflux ratio may be around _________________ Rm ?

   A. 1.2 to 1.5
   B. 2.5 to 3
   C. 3 to 4
   D. 5

7. In continuous distillation, the internal reflux ratio (Ri) and the external reflux ratio (Re) are related as_____________________?

   A. Ri = Re/(1 – Re)
   B. Ri = (1 – Re)/Re
   C. Ri = Re
   D. Ri = Re/(1 + Re)

8. According to the Fenske equation, what will be the minimum number of plates required in a distillation column to separate an equimolar binary mixture of components A and B into an overhead fraction containing 99 mol% A and a bottom fraction containing 98 mol% B ? Assume that relative volatility (αAB = 2) does not change appreciably in the column ?

   A. 5
   B. 9
   C. 12
   D. 28

9. In a distillation column, with increase in the reflux ratio, the heat removed in the cooler ______________________?

   A. Increases
   B. Decreases
   C. Remains unaffected
   D. And the heat required in reboiler decreases

10. What is the reflux ratio at total reflux ?

    A. Zero
    B. Infinity
    C. Unity
    D. Data insufficient