Use of packed towers for distillation is generally limited to the__________________?

Related Mcqs:

1. The reason for preferring packed towers over plate towers in distillation practice is that the packed tower operation gives___________________?

   A. Low pressure drop and high hold up
   B. High pressure drop and low hold up
   C. Low pressure drop and low hold up
   D. High pressure drop and high hold up

2. Use of packed towers for distillation is generally limited to the____________________?

   A. Small sizes
   B. Multi-component distillation
   C. High pressure operation
   D. Vacuum distillation

3. Plate towers are preferred to packed towers, when large temperature changes are involved, because of the reason that the____________________?

   A. Packing may be crushed due to thermal expansion/contraction of the components of the
   equipments
   B. Pressure drop in the equipment will be very high
   C. Viscosity variation of the fluids may cause channelling/flooding
   D. None of these

4. Packed column distillation is limited to the column _____________ metres?

   A. Height < 6
   B. Diameter < 0.6
   C. Both A. & B.
   D. Neither A. nor B.

5. The main reason for dividing a tall packed tower into series of small towers is to________________________?

   A. Minimise the overall pressure drop
   B. Avoid flooding
   C. Reduce liquid hold up
   D. Avoid channelling

6. Very tall packed towers are divided into series of beds to___________________?

   A. Reduce the overall pressure drop
   B. Avoid channelling
   C. Reduce liquid hold-up
   D. Avoid flooding

7. At the same gas flow rate, the pressure drop in a packed tower being irrigated with liquid _______________ that in dry packed tower ?

   A. Is greater than
   B. Is lower than
   C. Is same as
   D. Cannot be predicted as data are insufficient

8. 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

9. 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

10. In case of cooling towers, the ratio of the rates of heat and mass transfer is indicated by the ______________ number ?

    A. Lewis
    B. Grashoff
    C. Sherwood
    D. None of these