Chemical Engineering Question Paper Mechanical Operations - Set 17 - ObjectiveBooks

Chemical Engineering Question Paper Mechanical Operations - Set 17

Practice Test: Question Set - 17

1. The most efficient equipment for the removal of sub-micronic dust particles from blast furnace gas is the
    (A) Venturi atomiser
    (B) Gravity settling chamber
    (C) Electro-static precipitator
    (D) Cyclone separator

2. Trommels are revolving screens which normally operate in the range of __________ rpm.
    (A) 1 - 2
    (B) 15 - 20
    (C) 40 - 50
    (D) 60 - 75

3. The maximum slope of a belt conveyor can be
    (A) 15°
    (B) 30°
    (C) 45°
    (D) 60°

4. Filter aids like asbestos, kieselguhr, diatomaceous earth etc. are used to increase the porosity of the final filter cake & reducing the cake resistance during filtration. Filter aid is
    (A) Added to the feed slurry
    (B) Pre-coated on the filter medium prior to filtration
    (C) Separated from the cake by dissolving solids or by burning it off
    (D) All 'a', 'b' & 'c'

5. __________ balls capable of grinding the feed in a ball mill gives the maximum efficiency.
    (A) Cast iron
    (B) Minimum size
    (C) Maximum size
    (D) Elliptical

6. Pick out the correct statement.
    (A) Plastic chips are called non-cohesive solids
    (B) Kick's crushing law is, P/m = K . ln (D̅sa/D̅sb)
    (C) Communition is a generic term for size enlargement operation
    (D) Energy required in kwh per ton of product, such that 80% of it passes through a 200 mesh screen, is called 'Work index'

7. A belt conveyor used for the transportation of materials can
    (A) Run upto 1 km
    (B) Travel at a speed upto 300 meters/minute
    (C) Handle materials upto 5000 tons/hr
    (D) All (a), (b) and (c)

8. Ultracentrifuges running at speeds upto 100000 rpm is normally used for the
    (A) Separation of isotopes based on their density or molecular weights difference
    (B) Concentration of rubber latex
    (C) Separation of cream from milk
    (D) Dewaxing of lubricating oil

9. Which of the following is the most suitable for handling fibrous and dense slurries?
    (A) Propeller agitator
    (B) Cone type agitator
    (C) Turbine agitator
    (D) Radial propeller agitator

10. Maximum size reduction in a fluid energy mill is achieved by
    (A) Compression
    (B) Interparticle attrition
    (C) Cutting
    (D) Impact

11. According to Bond crushing law, the work required to form particle of size 'D' from very large feed is (where (S/V)p and (S/V)f are surface to volume ratio of the product and feed respectively).
    (A) (S/V)p
    (B) √(S/V)p
    (C) (S/V)2p
    (D) (S/V)f

12. Which of the following is not a wet classifier?
    (A) Sharpies super-centrifuge
    (B) Hydrocyclones
    (C) Dorr Oliver rake classifier
    (D) None of these

13. Vibrating screens are used for handling large tonnages of materials. The vibrating motion is imparted to the screening surface by means of
    (A) Electromagnets
    (B) Cams or eccentric shafts
    (C) Unbalanced flywheels
    (D) Either (a), (b) or (c)

14. Size reduction of fibrous materials like wood, asbestos, mica etc. is done by a disintegrator exemplified by the
    (A) Blake jaw crusher
    (B) Cage mill
    (C) Stamp mill
    (D) Bradford's breaker

15. Number of particles in a crushed solid sample is given by (where, m = mass of particles in a sample, Vp = volume of one particle, ρ= density of particles)
    (A) m/ρ . Vp
    (B) . ρ/Vp
    (C) m . Vp
    (D) Vp/m . ρ

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