chemical engineering MCQs – Page 178

Practise multiple-choice questions from chemical engineering for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

chemical engineering Mcqs
3541. Cylindrical shell thickness of rotary drier is generally _______________ mm?
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A. 15-Dec

B. 6-8

C. 18-22

D. 3-Feb

3542. Hold up of material in a operating rotary drier is in the range of___________________?
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A. 0.25 to 0.50

B. 0.8 to 0.9

C. 0.5 to 0.8

D. 0.05 to 0.15
3543. In a double pipe (concentric) heat exchanger, the hydraulic radius for heat transfer (for a fluid flowing through the annulus) would be_________________?
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A. More than that for fluid flow

B. Less than that for fluid flow

C. Same as that for fluid flow

D. D2 D1 (D1 and D2 are I.D. of inner and outer pipes respectively)

3544. In shell and tube heat exchangers, straight tie rods are used to_________________?
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A. None of these

B. Account for thermal strain

C. Fix the tubes in position

D. Hold baffle in space
3545. Which tube arrangement in a heat exchanger would facilitate highest heat transfer rate ?
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A. Heat transfer rate is independent of tube arrangement

B. Diagonal square pitch

C. Square pitch

D. Triangular pitch
3546. Excessive liquid gradient on a tray may result in the______________________?
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A. All A., B. and C.

B. Maldistribution of gas

C. Back trapping

D. Gas blowing beneath cap skit

3547. Back-trapping in a distillation column results due to_________________?
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A. Low reflux ratio

B. Excessive liquid gradient over the tray

C. Low gas velocity

D. High gas velocity

3548. The difficulty of liquid distribution in packed towers is accentuated, when the ratio of tower diameter to packing diameter is_________________?
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A. > 7 20 < 50

B. < 30

C. < 7
3549. Generally, elliptical dished heads____________________?
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A. ssure vessels operating above a pressure of 1.5 MN/m2

B. ll of the same thickness and diameter

C. Are manufactured on 2:1 ratio of major to minor axis and is recommended to be used for

D. Are approximately as strong as seamless cylindrical shell having the corresponding I.D and

F. All A., B. and C.
3550. Commercial packed scrubbers are normally designed for a pressure drop range of ______________ mm water column per metre of packed height?
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A. 88-105

B. 52-68

C. 8-Apr

D. 17-34
3551. Lap joints are preferred for plates having thickness _______________ mm?
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A. 10-May

B. > 3

C. > 5

D. < 12.5

3552. An increase in the liquid resistance to interphase mass transfer and a resultant reduction in plate efficiency is caused by______________?
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A. All A., B. and C.

B. Decrease in gas solubility for absorbers

C. An increase in liquid viscosity

D. An increase in relative volatility for rectification columns

3553. In case of bubble cap distillation column of diameter greater than 1.2 metres, the cap diameter is roughly about _______________ cms?
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A. 10

B. 20

C. 30

D. 35

3554. The longitudinal stress induced in a thin walled cylindrical vessel under internal pressure is_________________?
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A. pd/2t

B. pd/4t

C. pd/8t

D. pd/t

3555. Filtration rate is affected by the________________?
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A. Pressure drop across the cake & filter medium

B. All A., B. and C.

C. Cake & filter medium resistance

D. Area of filtering surface & the viscosity of filtrate

3556. Nominal size of a pipe is an indication of its _______________ diameter?
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A. None of these

B. Outer

C. Approximate

D. Inner

3557. Hazards associated with the relief valve leakage for extremely hazardous material storage can be taken care of by providing___________________?
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A. Rupture diaphragm

B. Dikes

C. Surge chamber

D. None of these

3558. Tube side pressure drop in a 1-2 heat exchanger (for turbulent flow of fluids through the tubes) is about __________ times, that in a 1-1 heat exchanger having the same size & number of tubes and operated at the same liquid flow rate ?
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A. 8

B. 4

D. 2

3559. For identical operating conditions, the pressure drop over _______________ tray is the highest out of the following?
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A. Valve

B. Bubble cap

C. Counter flow

D. Sieve

3560. Wind load consideration in the design of a support can be neglected, when the vessel is___________________?
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A. None of these

B. Tall but empty

C. Short (< 2 m) and housed indoor

D. Tall (say 30 metres), but is full of liquid