S4 Flashcards
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
Heat transfer co-efficient, hG(Kcal/hr.m^2 .°C) and mass velocity of air, G (kg/hr.m^2 ) for air flow parallel to the surface in case of constant drying rate in batch drying is related as hG = 0.0176G^0.8. But when the flow of air perpendicular to the surface is encountered, this equation changes to
hG = 1.004G^0.37
In the agitators, the power required will be changed with the increase of diameter of agitator (D) as
D^5
Apex angle of conical heads used in the bottom heads of chemical process equipments is usually
60°
Pressure drop due to pipe fittings can be estimated by the equation , where, ∆P/ ρ = 4f . Le/D . v^2 / 2gc, where,
Le = equivalent of straight pipeline which will incur the same frictional loss as the fitting and D = diamter of the fitting. The value of Le/D (dimensionless for 45° and below 180° close return bends would be respectively around
45 and 75
A pressure vessel is said to be made of ‘thick’ shell, if the ratio of its diameter to wall thickness is
10
Tube side heat transfer co-efficient for turbulent flow of liquid through tubes is proportional to
G^0.8
Circumferential (hoop) stress in a thin cylindrical vessel under internal pressure is _ the longitudinal stress.
twice
The dust collection efficiency of electrostatic precipitator increases with increase in the
electrode area.
For storing hazardous chemicals in large storage tanks, the minimum safe distance between the two tanks should range between __________ times the tank diameter
1 to 1.5
Which of the following factors determine the amount of entertainment in a distillation column?
All (a), (b) and (c)
The absorption factor is defined as (where, S1 = slope of the equilibrium curve, S2 = slope of the operating line)
S1/S2
In shell and tube heat exchangers, straight tie rods are used to
hold baffle in space.
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*m^2 drier cross-section H = hold up of solid.)
Z.H.ρ / L
In case of design of a shell and tube heat exchanger,
all (a), (b) & (c).
In a cylinderical vessel subjected to internal pressure, the longitudinal stress σL and the circumferential stress, σn are related by
σh = 2 σL
Nominal size of a pipe is an indication of its __________ diameter.
approximate
Excessive liquid gradient on a tray may result in the
all (a), (b) and (c).
The ratio of tube length to shell diameter in case of liquid shell and tube heat exchanger ranges from
4 to 8