Normally, the ratio of the total riser area to the tower cross sectional area (for bubble cap towers of diameter more than 3 ft) is around_______________?

Related Mcqs:

1. In actual operation of a bubble cap distillation tower, the ______________ at the bottom of the tower is more than that at the top of the tower?

   A. Molal flow rate of vapour
   B. Vapour molecular weight
   C. Pressure and temperature
   D. All A., B. and C.

2. In case of bubble cap distillation column of diameter greater than 1.2 metres, the cap diameter is roughly about _______________ cms?

   A. 10
   B. 20
   C. 30
   D. 35

3. In common bubble cap distillation column design practice, riser area is approximately equal to (where, Aa = Annular passage area, and Sa = Slot area) ?

   A. Aa = Sa
   B. 1.2 Aa = 1.2 Sa
   C. Sa = 1.5 Aa
   D. Aa = 1.5 Sa

4. The difficulty of liquid distribution in packed towers is accentuated, when the ratio of tower diameter to packing diameter is_________________?

   A. < 30
   B. < 7
   C. > 7 20 < 50

5. Bubble cap diameter used for the distillation column having diameter ranging from 1.5 to 4.5 metres is about ______________ mm?

   A. 10
   B. 50
   C. 100
   D. 200

6. For a given design of bubble cap, the number of bubble caps to be used per tray is set by the _________________?

   A. Allowable gas velocity through the slots
   B. Plate spacing
   C. Diameter of the column
   D. All A., B. and C.

7. Maximum allowable vapour velocity in a bubble cap tower is determined by the ____________________?

   A. Entrainment considerations
   B. Vapour density
   C. Diameter of the column
   D. None of these

8. The operating velocity in the absorption tower is usually 40-50% of the flooding velocity. Packed absorption towers are normally designed for a pressure drop of about _________________ mm of water column per metre height of packing?

   A. 1-5
   B. 20-40
   C. 100-150
   D. 1000-1500

9. In packed towers provided with pall rings liquid redistributors are positioned at heights of every 6 metres or 5-10 times the column diameter, whichever is less. Maximum size of the pall rings should not exceed _______________________ of the column diameter?

   A. 1/10-1/15th
   B. 1/5-1/10th
   C. 1/20-1/30th
   D. 1/2 to 1/4th

10. The ratio of down take area to cross-sectional area of the tube, for calandria type evaporator ranges from_________________?

    A. 0.5 to 1
    B. 1 to 1.5
    C. 1.5 to 2
    D. 2 to 2.5