A. Sensible heat differences are small, because the temperature changes from tray to tray is small
B. Trouton’s rule is applicable
C. Liquid/vapor loading across the column remains constant
D. All A., B. and C.
Related Mcqs:
- Which of the following is not a graphical method (but is an analytical method) for the calculation of theoretical number of stages in case of continuous binary distillation ?
A. Sorel-Lewis method
B. McCabe-Thiele’s method
C. Ponchon-Savarit method
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 - Height equivalent to a theoretical plate (HETP) is the height of packing that will give the same separation as one theoretical plate in gas-liquid mass transfer operations like distillation, absorption/stripping and humidification/dehumidification. HETP which is experimentally determined, depends upon the_______________?
A. Flow rates of each fluid
B. Type and size of packing
C. Concentration of each fluid
D. All A, B. & C. - Ponchon Savarit method is based on the use of enthalpy concentration diagram, which contains the bubble point curve (saturated liquid curve), dew point curve (saturated vapour curve) and equilibrium tie lines. As compared to McCabe-Thiele’s method, this method_________________?
A. is more accurate in finding the number of equilibrium stages
B. accounts for the enthalpy changes in the process
C. Facilitates direct calculation of heat load on reboiler & condenser from, the diagram used in
this method
D. All A, B. & C. - 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 - 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. - _____________________ tray arrangement is recommended for distillation column having diameter upto 4 ft ?
A. Radial flow
B. Cross flow
C. Split flow
D. Cascade - 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 - 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
