Process Equipment and Plant Design
The function of manholes provided in the shell of a distillation column is to

Guard against foaming & entrainment by dumping antifoaming agent through it
Keep a check on the liquid gradient over the plate by direct visual observation
All of these
Give access to the individual trays for cleaning, maintenance and installation

ANSWER DOWNLOAD EXAMIANS APP

Process Equipment and Plant Design
In the design of a shell and tube heat exchanger, the corrosion allowance

Need not be provided for non-pressure parts like tie rods, spacers, baffles, supports etc
For internal cover and tube sheet is provided on both the sides
For carbon steel and cast iron pressure parts is 1.5 mm (except for tubes) and for severe conditions it is 3 mm
All of these

ANSWER DOWNLOAD EXAMIANS APP