Practice Test: Question Set - 23
1. Friction factor for turbulent flow in a new pipe is given by
- (A) f = 16/NRe
- (B) f = 0.04/(NRe)0.16
- (C) f = 0.22 NRe0.5
- (D) f = 25/NRe
2. The stress developed in a material without any permanent set is called the
- (A) Ultimate stress
- (B) Yield stress
- (C) Elastic limit
- (D) Breaking stress
3. To keep the power input constant for a stirred vessel operating under fully developed turbulent flow conditions (constant power number), if the impeller diameter is increased by 20%, the impeller speed should be decreased by a factor of
- (A) (1.2)3/2
- (B) (1.2)3/5
- (C) (1.2)2/3
- (D) (1.2)5/3
4. Corrosion allowance in the design of pressure vessel/chemical equipment is not necessary, if
- (A) Plain carbon steel and cast iron parts are used
- (B) Wall thickness is > 30 mm
- (C) Material of construction is high alloy steel
- (D) Both (b) & (c)
5. Triangular pitch tube layout as compared to square pitch in a shell and tube heat exchanger
- (A) Permits the use of less tubes in a given shell diameter
- (B) Facilitates comparatively easier external cleaning because of large
clearance
- (C) Permits the use of more tubes in a given shell diameter
- (D) Both (b) and (c)
6. Height of the flights in the rotary drier is in the range of
- (A) 0.08 to 0.12 d
- (B) 0.02 to 0.05 d
- (C) 0.2 to 0.5 d
- (D) 0.5 to 0.6 d
7. Smaller sized packings are generally dumped to the packed columns, and the large ones of size greater than __________ mm are stacked individually, which provides better control over bed porosity and offers lower gas pressure drop.
- (A) 25
- (B) 50
- (C) 75
- (D) 150
8. The function of manholes provided in the shell of a distillation column is to
- (A) Keep a check on the liquid gradient over the plate by direct visual
observation
- (B) Give access to the individual trays for cleaning, maintenance and
installation
- (C) Guard against foaming & entrainment by dumping antifoaming agent
through it
- (D) All (a), (b) and (c)
9. The ends of a cylindrical vessel can be closed by a head, which can be one of the four shapes. For the same thickness, choose the one which can withstand the highest pressure.
- (A) Flat plate
- (B) Hemispherical
- (C) Torispherical
- (D) Ellipsoidal
10. Column support for the roof of cylindrical storage tank must be provided for
- (A) Small diameter tanks
- (B) Large diameter tanks
- (C) Small diameter tall tanks
- (D) All tanks irrespective of their heights and diameters
11. A stuffing box is used for
- (A) Absorbing the contraction/expansion of pipeline
due to temperature changes
- (B) Prevention of fluid leakage around moving parts
- (C) Facilitating smooth opening and closing of a valve
- (D) Reducing the resistance of fluid flow
12. Pick out the wrong statement about the design of sieve plate column and the bubble cap column.
- (A) The downcomer design and the residence time in
the downcomer is almost same for sieve plate and bubble cap columns
- (B) Weir length for a bubble cap plate is the same as that for the sieve
plate
- (C) Weir height for a bubble cap plate column is the
same as that for a sieve plate column
- (D) Weir height in case of a bubble cap plate ranges from 50 to 150 mm
and is higher than the sieve plate
13. The ratio of shear stress to shear strain is called
- (A) Bulk modulus
- (B) Shear modulus
- (C) Modulus of rigidity
- (D) Modulus of elasticity
14. Back-trapping in a distillation column results due to
- (A) Low gas velocity
- (B) High gas velocity
- (C) Excessive liquid gradient over the tray
- (D) Low reflux ratio
15. In case of a shell and tube heat exchanger, the minimum shell thickness for carbon steel (inclusive of corrosion allowance) depends on shell diameter and is in the range of __________ mm.
- (A) 3-5
- (B) 5-11
- (C) 8-15
- (D) 12-18
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