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

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. 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.

3. 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

4. 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_______________?

   A. 0.4-0.6
   B. 0.35-0.75
   C. 0.1-0.2
   D. 0.55-0.85

5. A high vapour velocity is required for high plate efficiency in a sieve plate column. The satisfactory value of operating vapor velocity for design purpose in sieve plate column is about _______________ percent of the flooding velocity?

   A. 45
   B. 60
   C. 80
   D. 95

6. Bubble cap tray is the most commonly used tray in large distillation column, because______________?

   A. Of its flexibility and nearly constant efficiency under varying conditions of operation
   B. It incurs less pressure drop as compared to any other try designed for the same duty
   C. It eliminates the foaming and entrainment tendency during operation
   D. None of these

7. Pick out the wrong statement pertaining to the use of valve tray, seive tray and bubble cap trays in continuous distillation column ?

   A. Bubble cap trays though most expensive are the best in situations, where low vapour rates is to be handled and a positive liquid seal is essential at all flow rates
   B. Murphree efficiency of all the three trays are nearly equal, however the peak efficiency is generally higher for sieve and valve trays than the bubble cap
   C. Maintenance cost for valve and sieve trays are comparatively more than bubble cap tray due to their relatively complicated construction features
   D. Valve trays have the highest turn down ratio (i.e. the ratio of the highest to the lowest vapour flow rates) and thus provide the maximum flexible operating range

8. 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

9. Typical static submergence for bubble cap plate column operating at atmospheric pressure may be around _________________?

   A. 2.5″
   B. 0.5″
   C. 5″
   D. 50% of the plate spacing

10. A minimum clearance of about _______________ mm is maintained between the distillation column wall and the bubble cap?

    A. 19
    B. 38
    C. 67
    D. 95