Process Equipment and Plant Design
In a rotary drier, the average retention time of solid is(where Z = length of the drier, metres ρ = apparent solid density, kg/m³ L = flow rate of dry solids, kg/see. m² drier cross-section H = hold up of solid.)

L/Z.H.ρ
Z.H/L.ρ
Z.H.ρ/L
H.ρ/L

ANSWER DOWNLOAD EXAMIANS APP

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
Give access to the individual trays for cleaning, maintenance and installation
All of these
Keep a check on the liquid gradient over the plate by direct visual observation

ANSWER DOWNLOAD EXAMIANS APP

Process Equipment and Plant Design
Ponchon Savarit method is based on the use of enthalpy concentration diagram, which contains the bubble point curve (saturated liquid curve), dew point curve (saturated vapour curve) and equilibrium tie lines. As compared to McCabe-Thiele's method, this method

All of these
Is more accurate in finding the number of equilibrium stages
Facilitates direct calculation of heat load on reboiler & condenser from, the diagram used in this method
Accounts for the enthalpy changes in the process

ANSWER DOWNLOAD EXAMIANS APP