Process Equipment and Plant Design
Vertical condenser is advantageous to the horizontal condenser from operation point of view, when

Hydrostatic head is required for refluxing the condensate
Both the functions of condensation & sub cooling are carried out in a single unit
Only the function of condensation is to be carried out
Sub cooling of condensate is desired

ANSWER DOWNLOAD EXAMIANS APP

Process Equipment and Plant Design
Liquid gradient over a tray can be minimised by

Decreasing the number of rows of caps through which the liquid flows or by decreasing the velocity of liquid flow past the caps or by reducing the distance along the tray through which the liquid must
Using split flow, radial flow or cascade flow for column diameter large than 4 ft
All of these
Providing a higher skirt clearance or a higher weir

ANSWER DOWNLOAD EXAMIANS APP