In packed towers provided with saddle packing, liquid redistributors are positioned at every __________ times column diameter or 6 metres whichever is less.
Options
A. 2-3
B. 5-8
C. 10-15
D. 20-25
Correct Answer
5-8
Process Equipment and Plant Design problems
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1. In a shell and tube heat exchanger, tube side __________ of the mass velocity.
Options
A. heat transfer co-efficient is proportional to 0.8th power
5. Pick out the wrong statement about the design of a sieve plate column.
Options
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.
Correct Answer: 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.
10. Pick out the wrong statement pertaining to 'Horton sphere' used for the storage of liquid ammonia.
Options
A. Diameter of Horton sphere is normally 6 to 25 metres and it is supported by 6 to 12 nos. tubular or rolled section column.
B. Thickness of spherical shell is half that of the cylinderical vessel under same operating pressure condition. Besides, the ratio of surface area to volume is less for sphere than any other shape ; hence insulation required is less.
C. Horton sphere is used for the storage of gases and volatile liquid at a moderate pressure of 1 to 10 kg/cm2 .
D. Horton sphere is used for the storage of liquid at sub-zero temperature at very high pressure upto 200 kg/cm2 .