Practice Test: Question Set - 44
1. For achieving rapid drying rate in a spray dryer, the diameter of the particles in the feed should be in the range of __________ microns (1 mm = 1000 microns).
- (A) 1-5
- (B) 10-60
- (C) 200-300
- (D) > 500
2. Berl saddle made of carbon cannot be used for
- (A) Alkalis
- (B) SO2
- (C) H2SO4
- (D) Oxidizing
atmosphere
3. Capacity of a rotary dryer depends on its
- (A) rpm
- (B) Inclination with
ground surface
- (C) Both (a) and (b)
- (D) Neither (a) nor (b)
4. The most common packing used in industrial operations is __________ rings.
- (A) Raschig
- (B) Lessing
- (C) Cross-partition
- (D) Single spiral
5. Refractory bricks are usually dried in a __________ dryer.
- (A) Tray
- (B) Tunnel
- (C) Conveyor
- (D) Festoon
6. Occurrence of 'case hardening' during drying of a high moisture solid cake __________ the drying rate.
- (A) Increases
- (B) Decreases
- (C) Does not affect
- (D) Exponentially
increases
7. The binary diffusivity in gases at atmospheric conditions is about
- (A) 10-9 cm/sec
- (B) 10-1 cm2/sec
- (C) 10-3 sec/cm
- (D) 10-4 cm2/sec2
8. For absorbers, high pressure drop results in
- (A) Increased efficiency
- (B) Decreased efficiency
- (C) High operating cost
- (D) Better gas liquid
contact
9. __________ is the temperature at which a gas-vapor mixture becomes saturated, when cooled at constant total pressure out of contact with a liquid.
- (A) Dew point
- (B) Bubble point
- (C) Dry bulb temperature
- (D) Wet bulb temperature
10. ‘L/mG’ is the expression for
- (A) Absorption factor
- (B) Brinkman number
- (C) Slope of operating
line in absorber
- (D) Slope of operating
line in stripper
11. Which of the following is the most commonly used leaching solvent in vegetable oil industry?
- (A) Phenol
- (B) Hexane
- (C) Furfural
- (D) Liquid SO2
12. When a multistage tray tower uses a minimum reflux ratio, it implies
- (A) Infinite
trays and maximum reboiler heat load
- (B) Infinite trays and
minimum reboiler heat load
- (C) Minimum trays and
minimum reboiler heat load
- (D) Minimum trays and
maximum reboiler heat load
13. In distillation column design, the McCabe-Thiele procedure is inadequate and a Ponchan-Savarit procedure is needed, when
- (A) Saturated feed is not
used
- (B) An azeotrope forms
- (C) The latent heat of
vaporization of the more and less volatile components are greatly different
- (D) A total condenser is
used
14. During drying of a solid, the critical moisture content increases with
- (A) Decreased drying rate
- (B) Increased thickness
of the solid
- (C) Increased drying rate
- (D) Both (b) and (c)
15. Stage efficiency in a leaching process depends on the
- (A) Time of contact
between the solid and the solution
- (B) Rate of diffusion of
the solute through the solid and into the liquid
- (C) Both (a) and (b)
- (D) Vapor pressure of
the solution
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