In a continuous distillation column, the optimum reflux ratio ranges from _______________ times the minimum reflux ratio?

Related Mcqs:

1. Optimum reflux ratio in a continuous distillation column is determined by the__________________?

   A. Maximum permissible vapour velocity
   B. Flooding limit of the column
   C. Total cost consideration (fixed cost of the column plus the cooling water & steam cost)
   D. None of these

2. In case of a continuous distillation column, increase in reflux ratio may result in the______________?

   A. Lower fixed charges for the column
   B. Greater cost for the reboiler heat supply
   C. Greater cost for the condenser coolant
   D. All A., B. and C.

3. With increase in the reflux ratio for a fixed production from a continuous binary distillation column, the ______________________ decreases?

   A. Fixed charges initially
   B. Running cost of cooling water for condenser
   C. Vapour & liquid load both
   D. Running cost of steam for reboiler

4. The slope of operating line in the rectifying section of a distillation column is unity, if the reflux ratio is___________________?

   A. 0
   B. ∞
   C. 1
   D. Minimum

5. Reflux ratio variation in a distillation column is between___________________?

   A. Zero and infinity
   B. Zero and one
   C. Minimum and infinity
   D. None of these

6. Overall distillation column efficiency for most of the refinery columns can be given by (for μ = 0.07 – 1.4 cp and relative volatility < 4) (where ε = overall column efficiency, % μ = molal average viscosity of feed at average column temperature and pressure, cp Δp = pressure drop per tray, psi) ?

   A. η = 17 – 61.1 log μ
   B. η = 24.6 (Δp/μ)
   C. η = 1.66 – 0.25 log μ
   D. η = 0.25 log μ – 1.67

7. In the downcomer of a distillation column, the minimum recommended residence time is about _______________ seconds?

   A. 2.5
   B. 5
   C. 12.5
   D. 17.5

8. 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

9. Hole diameter of the sieve trays in the distillation column ranges from ______________ mm?

   A. 1 to3
   B. 4 to 8
   C. 3 to 12.5
   D. 12.5 to 18.5

10. Smoker’s equation for the calculation of number of equilibrium stages in a continuous binary distillation column is used, when the_________________?

    A. Relative volatility is close to one (e.g., separation of close boiling isomers)
    B. Feed is not at its bubble point
    C. Number of equilibrium stages in only stripping section is to be calculated
    D. Number of equilibrium stages required is likely to be very small