A. 0.6-0.8 times
B. Equal to
C. Twice
D. 2 ft irrespective of (for column > 3 ft diameter)
Related Mcqs:
- In a distillation column, bubble caps are located on trays with a pitch of ______________ times the outside diameter of the caps?
A. 1.3 to 2
B. 1.6 to 2
C. 2.5
D. 1.5 to 3 - 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 - 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 - 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 - For turbulent flow (NRe > 2100) of low viscosity fluid (μ > 20cp) in steel pipes, the optimum inside pipe diameter is given by(where, Q = fluid flow rate, ft3/sec, ρ = fluid density, lb/ft3 μ = fluid viscosity, centipoise Di = optimum inside pipe diameter, inches) ?
A. Di, opt = 3.9 Q0.45 ρ0.13
B. Di, opt = 3.9 Q0.45. μ0.95
C. Di, opt = 4.7 Q0.36. μ3.2ρ0.13
D. Di, opt = 3 Q0.36. μ0.88 - 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 - Pressure drop due to pipe fittings can be estimated by the equation, ΔP/ρ = 4f, (Le/D) (V2/2gc) where, Le = equivalent length of straight pipeline which will incur the same frictional loss as the fitting and D = diameter of the fitting. The value of (Le/D) (dimensionless) for 45° elbow and 180° close return bends would be respectively around______________________?
A. 5 and 10
B. 45 and 75
C. 180 and 300
D. 300 and 500 - In distillation columns, bubble caps are held in place over trays by ________________?
A. Rivets
B. A hold down bar
C. Bolts
D. Both B. and C. - In a distillation column, minimum clearance to be maintained between the overflow weir and the last row of the bubble caps is ______________ cms?
A. 2.5
B. 7.5
C. 15
D. 20 - A pipe is generally made of circular cross-section, because a circular cross-section has the____________________?
A. Higher structural strength
B. Lowest surface area requirement for a given volume
C. Both A. & B.
D. None of these
