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
Related Mcqs:
- Pick out the correct statement ?
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 - Pick out the correct statement___________________?
A. Centre to centre distance between two consecutives rivets in a row is called the pitch
B. A riveted joint made in overlapping plates is called butt joint
C. Hole size drilled in riveted plates is less than the actual size of the rivet
D. None of these - Pick out the wrong statement?
A. If sufficient residence time (around 8 seconds) is not provided to the downcoming liquid in
the downcomer, it may entrain some vapour
B. The liquid head in the downcomer should not be greater than one half the plate spacing to
avoid flooding
C. The discharge end of the downcomer must project far enough into the tray liquid so that no
gas bubbles can enter the open end and by pass the bubble caps
D. None of these - Pick out the wrong statement pertaining to shell and tube heat exchanger_______________?
A. Clearance between shell & baffles and between tube & baffles should be minimum to avoid
by-passing of the fluid, but it should be enough to permit the removal of tube bundle
B. Baffles are supported independently of the tubes by tie rods and positioned by spacers
C. Tie rods are fixed at one end in the tube sheet by making blind holes and the minimum
number of tie rods is 4 with at least 10 mm diameter
D. Bracket supports are used for horizontal shell, while saddle support is used for vertical shell - Pick out the wrong statement?
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 - Pick out the wrong statement. In an agitated vertical cylindrical reaction vessel, the___________________?
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 - Pick out the wrong statement about the design of a sieve plate column ?
A. An increased weir height improves the tray efficiency at the cost of high plate pressure drop; optimum wear height being 40-90 mm for column pressure above atmospheric and 6-12 mm for vacuum columns
B. For segmental downcomers, the chord length is 60-80% of the column diameter. An initial value of downcomer area of 12% is taken in the design
C. Width of the calming section provided at the inlet and outlet sides of the plate is 75 mm for column diameter below 1.5 metres and 100 mm for larger diameter columns
D. Minimum recommended downcomer residence time for the disengagement of entrained vapour is the same for both foaming and non-foaming liquids, which is about 20 seconds - Pick out the wrong statement pertaining to the comparative evaluation of performance of the packed tower and the plate tower ?
A. Plate tower is preferred, if interstage cooling is required to remove heats of reaction or
solution
B. Plate tower is preferred over packed tower, if the operation involves liquids containing
dispersed solids
C. The total weight of a dry plate tower is usually much more than that of a dry packed tower
designed for the same duty
D. In operations involving large temperature changes. (e.g. distillation), plate towers are
preferred over packed towers as the packing may be crushed due to large temperature changes - Pick out the wrong statement?
A. Safety valves are provided in heat exchangers for removal of non-condensable
B. Liquid metals and Dowtherm are used for very high temperature heating
C. In a shell and tube heat exchanger, high pressure fluid is generally routed through the tube
D. A loop seal or U-seal is provided in a vertical condenser sub-cooler to prevent quick draining
of the condensate - 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
