Process Equipment and Plant Design

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

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

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

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 cylindrical 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

A. Distillation under vacuum is a substitute for steam distillation
B. In differential (simple) distillation, the vapour is removed as soon as it is formed without appreciable condensation
C. In flash (equilibrium) distillation, a definite fraction of liquid is vaporised in such a way that the evolved vapour & residual liquids are in equilibrium with each other
D. Flash distillation, differential distillation & steam distillation are all continuous distillation processes

A. Facilitate draining out liquid from a tray when the unit is not in operation
B. Are normally located near the overflow weir so that any delivery of liquid during operation
follows approximately the same path as the overflow fluid
C. Must be large enough (usually 1/4″ to 5/8″ dia) to prevent plugging but should not deliver
excessive amount of fluid during operation
D. All A., B. and C.

A. 1
B. 2
C. 3.5
D. 5.5

A. 0.15-030
B. 0.5-0.65
C. 0.75-0.85
D. 0.60-0.90

A. 1.5
B. 3
C. 5
D. 9

A. Poisson’s ratio
B. Bulk modulus
C. Modulus of elasticity
D. Shear modulus