PROCESS EQUIPMENT AND PLANT DESIGN 4.1

In a rotary drier, the average retention time of solid is (where Z = length of the drier, metres ρ = apparent solid density, kg/m^3 L = flow rate of dry solids, kg/see*m^2 drier cross-section H = hold up of solid.)

• (Z*H*D)/L

• L/(Z*H*D)

• (H*D)/L

• (Z*H)/(L*D)

Apex angle of conical heads used in the bottom heads of chemical process equipments is usually

• 30°

• 45°

• 60°

• 75°

In shell and tube heat exchangers, straight tie rods are used to

• hold baffle in space

• fix the tubes in position

• account for thermal strain

• none of these.

In common bubble cap distillation column design practice, riser area is approximately equal to (where, Aa = Annular passage area, and Sa = Slot area)

• Aa = Sa

• 1.2Aa = 1.2Sa

• Sa = 1.5Aa

• Aa= 1.5Sa

The dust collection efficiency of electrostatic precipitator increases with increase in

• gas flow rate

• electrode area

• both (a) & (b)

• neither (a) nor (b)

Tube side heat transfer coefficient for turbulent flow of liquid through tubes is proportional to

• G^0.2

• G^0.5

• G^0.8

• G^1.5

Circumferential (hoop) stress in a thin cylindrical vessel under internal pressure is _________ the longitudinal stress.

• half

• equal to

• twice

• eight times

In the agitators, the power required will be changed with the increase of diameter of agitator (D) as

• D^2

• D^5

• D^9

• D

A pressure vessel is said to be made of 'thick' shell, if the ratio of its diameter to wall thickness is

• >10

• <10

• 20

• none of these

The absorption factor is defined as (where, S1 = slope of the equilibrium curve, S2 = slope of the operating line)

• S1/S2

• S1 * S2

• S2 / S1

• 1/S1*S2