Liquid redistribution should be done in a packed tower packed with raschig rings

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Question
Liquid redistribution should be done in a packed tower packed with raschig rings every 6 metres or __________ times the column diameter, whichever is lower.
Options
A. 2.5-3.0
B. 5-7.5
C. 10-12.5
D. 15-20

Correct Answer

2.5-3.0

1. In a vertical short tube evaporator (Calendria type), the
Options
A. tube dia of 2.5-7.5 cms, tube length of 75-200 cms and cylinderical drum dia of 1-6 metres are normally used.
B. area of central downtake is equal to 40 to 100% of total cross-sectional area of the surrounding tube.
C. liquor is inside the tube while the steam is outside the tube.
D. all (a), (b) & (c).

2. In a multipass shell and tube heat exchanger, the problem of differential expansion between the shell and tube passes is taken care of by using a
Options
A. U-bend
B. floating head tube sheet
C. either (a) or (b)
D. neither (a) nor (b)

3. Poisson's ratio of a material is the ratio of unit lateral strain to the unit axial elongation within its elastic limit. The value of Poisson's ratio for structural and pressure vessel steel may be taken as
Options
A. 0.01
B. 0.3
C. 0.75
D. 0.95

4. A certain pressure vessel manufacturer avoids doing reinforcements calculations for openings by always providing a reinforcing pad extending upto double the diameter of the opening and of the same material and thickness as that of the shell wall. If area compensation is accepted as a code guideline, his approach leads to safe design
Options
A. only if the opening is on spherical vessel.
B. only if the opening is on a vertical cylinderical vessel.
C. only if the opening is on a horizontal cylinderical vessel.
D. irrespective of the shape of the vessel.

5. In a shell and tube heat exchanger, the shortest centre to centre distance between the adjacent tubes is
Options
A. called tube pitch.
B. called tube clearance.
C. always less than the diameter of the tube.
D. none of these.

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