Channelling in a packed tower results from the_____________________?

Related Mcqs:

1. In a moderately sized packed absorption tower, channelling (which is most severe with stacked packings) can be minimised by taking the ratio of tower diameter to packing diameter ?

   A. > 4 :1
   B. < 8 : 1
   C. > 8:1
   D. < 6:1

2. 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

3. 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

4. In a packed bed absorption column, the channelling will be noted by the ____________________?

   A. Increase in flow rate
   B. Sharp drop in pressure drop
   C. Sharp rise in pressure drop
   D. None of these

5. Pressure drop through plate tower as compared to that through packed tower, for the same duty will be___________________?

   A. Less
   B. More
   C. Equal
   D. Either A. or B.; depends on the packing height

6. A packed tower compared to a plate tower for a particular mass transfer operation__________________?

   A. Incurs smaller pressure drop
   B. Allows installation of cooling coils
   C. Is less costly when built in large sizes/diameters
   D. Is more suitable, if suspended solids are present in fluid streams

7. Operating velocity in a packed tower is usually __________________ the flooding velocity ?

   A. Half
   B. Twice
   C. Equal to
   D. More than

8. 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

9. Diameter of raschig rings used in packed tower in industry is normally around _____________________ inches?

   A. 2
   B. 8
   C. 12
   D. 18

10. In a packed absorption tower, if the equilibrium and operating lines are both straight lines, then the ratio, HETP/HTUOG ______________ the absorption factor?

    A. Increases with increase in
    B. Is one at unity value of
    C. Both A. and B.
    D. Neither A. nor B.