A. In practical operation, distillation towers having diameter 3-6 metres equipped with bubble cap (round) size of 15 cms are used
B. Height of packing in a packed tower is about 3 times the column diameter for raschig rings and about 5 to 10 times the column diameter for saddle packing
C. In a sieve tray, the minimum hole diameter is equal to the tray thickness
D. In a stainless steel sieve tray, the minimum hole diameter is equal to 10 times the plate thickness
Process Equipment and Plant Design
Process Equipment and Plant Design
A. Plate efficiency increases with increase in superficial vapour velocity till entrainment limit
B. Increase in depth of the liquid about the slots increases the plate efficiency, particularly if the liquid depth is < 1"
C. Too small a plate spacing can cause a low efficiency, if the vapour velocity is greater than the allowable value
D. None of these
A. Riveting provides a permanent fastening method
B. The joint made by overlapping of one plate over the other, and then riveting the two plates together with two rows of rivets is called ‘double riveted butt joint’
C. Shank diameter of the rivets should be less than the size of the hole drilled in the plate for riveting
D. The efficiency of a riveted joint is the ratio of the strength of the riveted joint to the strength of the solid plate
A. The tensile strength of a brittle material is less than its compressive strength
B. The compressive strength of a ductile material is less than its tensile strength
C. In a thick cylindrical shell, the hoop stress is maximum at the inner radius
D. The value of crushing load is more than that of buckling load for long columns
A. It is preferred to use a vertical condenser for condensation of vapor from a distillation column without sub-cooling
B. Draining of residual liquid on tray during shut down of distillation column is facilitated by weep holes
C. Random packing a packed tower offers the advantage of lower pressure drop and higher throughput of fluids as compared to regular/stacked packing
D. Risers are generally not connected to the plate in a distillation coloumn by bolts, rivets or welding
A. It is used for high viscosity liquor having large rate of scaling
B. The tube bundle is suspended on bracket
C. There is no central downtake
D. Downtake is formed by the annular space between the bundle and the shell
A. The minimum value of baffle spacing is 50 mm
B. The maximum value of baffle spacing is equal to the I.D. of the shell
C. The maximum unsupported tube span is generally about 75 times tube diameter, but is reduced to about 60 times for aluminium, copper & alloys of these
D. Disk and doughnut baffle is the most commonly used baffle
A. Ratio of liquid depth to tank diameter (i.e. the filling ratio) recommended for most purposes is 1
B. Filling ratio for dispersing gas in a liquid is 2 for sufficiently long contact period
C. Flat bottom and conical bottom vessels have low agitation efficiency for agitation of heavy solids in liquids
D. Dished bottom vessel has very high power consumption
A. When highly corrosive fluids are to be handled, the plate towers prove to be cheaper and easier to construct than packed tower
B. Packed towers are generally preferred over plate towers, if the liquids have a foaming tendency
C. The pressure drop through the packed towers is generally more than the pressure drop through plate towers designed for same duty
D. None of these
A. For all the cylindrical process vessels operating above atmospheric pressure, formed heads are used for closing the vessel
B. Fouling factor of river water is less than that of sea water
C. Risers provided in bubble cap trays in the distillation column facilitate the flow of both liquid and vapor
D. Both B. and C.
