For the same process conditions, the reflux ratio of an unlagged distillation column___________________?

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. 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)

3. 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

4. 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

5. 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

6. What is the reflux ratio at total reflux ?

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

7. A distillation column with N plates is being operated under normal conditions. At some point of time, the operation is shifted to total reflux condition (i.e., no product and residue are being withdrawn and feed to the column is stopped). At the new steady state ?

   A. Composition of vapors and that of liquid do not vary throughout the column
   B. Reboiler load and condenser load are minimum
   C. The top and bottom compositions are unchanged with and without total reflux
   D. The top and bottom compositions correspond to the maximum enrichment available

8. Minimum reflux ratio in a distillation column results in__________________?

   A. Optimum number of trays
   B. Minimum reboiler size
   C. Maximum condenser size
   D. Minimum number of trays

9. The operating cost of a distillation column at minimum reflux ratio is____________________?

   A. Minimum
   B. Maximum
   C. Infinite
   D. Zero

10. At what value of reflux ratio, number of theoretical plates in a distillation column is minimum ?

    A. 0
    B. 1
    C. ∞
    D. < 1