Process Equipment and Plant Design MCQs

hold baffle in space.

fix the tubes in position.

account for thermal strain.

none of these.

plain carbon steel and cast iron parts are used.

wall thickness is > 30 mm.

material of construction is high alloy steel.

both(b) & (c).

lower fixed charges for the column.

greater cost for the reboiler heat supply.

greater cost for the condenser coolant.

all (a), (b) and (c).

overall gas transfer units to the number of ideal trays required.

ideal trays required to the number of real trays required.

real trays required to the number of ideal trays required.

none of these.

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.

Murphree efficiency of all the three trays are nearly equal, however the peak efficiency is generally higher for seive and valve trays than the bubble cap.

Maintenance cost for valve and seive trays are comparatively more than bubble cap tray due to their relatively complicated construction features.

Valve trays have the highest turn down ratio (i.e. the ratio of the highest to the lowest vapour flow rates) and thus provides the maximum flexible operating range.

tearing

shearing

tearing of the plate across a row

none of these

6

18

24

34

called tube pitch.

called tube clearance.

more in case of triangular pitch as compared to square pitch of tube layout.

none of these.

inner

outer

approximate

none of these

D/2 or minimum 2″ to 5D.

D/5 or minimum 2″ to 5D.

D/5 or minimum 2″ to D.

none of these.