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

Related Mcqs:

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
Pick out the wrong statement about the design of sieve plate column and the bubble cap column ?
A. The downcomer design and the residence time in the downcomer is almost same for sieve
plate and bubble cap columns
B. Weir length for a bubble cap plate is the same as that for the sieve plate
C. Weir height for a bubble cap plate column is the same as that for a sieve plate column
D. Weir height in case of a bubble cap plate ranges from 50 to 150 mm and is higher than the
sieve plate
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
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.
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
Pick out the wrong statement pertaining to the design of the distillation column?
A. Generally, a skirt clearance of 0.5″ to 1.5′ is recommended to prevent plugging of the slots by
residue build up
B. The purpose of the slot is to disperse the gas into the liquid in the form of small bubbles
C. If sufficient slot area is not provided, the gas may pass through the skirt clearance
D. None of these
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
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
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
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