Process Equipment Multiple Choice Questions - Set 23 - ObjectiveBooks

# 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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