Minimum reflux ratio in a distillation column results in_____________________?

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. 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)

4. 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

5. 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

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

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

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

   A. 0
   B. 1
   C. ∞
   D. < 1

8. As the reflux ratio in a distillation column is increased from the minimum, the______________________?

   A. Slope of the operating line in stripping section decreases
   B. Number of plates decreases very slowly first and then more and more rapidly
   C. Total cost first decreases and then increases
   D. Liquid flow increases while the vapor flow decreases for a system

9. 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 At some point of time, the operation is shifted to total reflux condition (i.e., no product and residue are being withdrawn and feed to the column is stopped).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

10. For a distillation column operating at minimum reflux, the_______________________?

    A. Concentration of liquid and vapour leaving a plate will be same
    B. Reflux ratio will be maximum
    C. Number of plates required will be maximum
    D. None of these